Announcement of the Ministry of Construction on Issuing the National Standard of the Code for Construction and Acceptance of Automation Instrumentation Engineering

The Code for Construction and Acceptance of Automation Instrumentation Engineering is now approved as the national standard with serial number of GB 50093 – 2002, which shall be implemented from March 1, 2003. In which, articles and clauses of 1.0.3, 4.1.3, 4.5.6, 5.2.11, 5.5.1(3) (4), 5.5.2, 6.1.7, 6.1.15, 6.1.17, 7.1.3, 7.2.4, 7.6.5, 8.1.1, 8.1.4, 8.1.5, 8.1.6, 8.1.7, 8.1.9, 8.1.10, 8.1.11, 8.2.5, 8.3.1, 9.1.2, 9.1.6 (12), 9.1.7, 9.1.8 (2) (4), 9.1.9, 9.1.11, 9.2.1, 10. 1.2, 11.1.5, 11.1.10 and mandatory ones and they must be implemented rigidly. The original Code for Construction and Acceptance of Industrial Automation Instrumentation GBJ 93 – 86 shall be abolished at same time.

The Research Institute of Standard Quota under the Ministry of Construction shall organize the China Plan Press to publish and issue the Code.

Ministry of Construction of the People’s Republish of China

January 10, 2003

Foreword

In accordance with the requirements of the Notice on Issuing the Plan for Formulation and Revision of the National Standards for Engineering Construction in 1997 issued by the Ministry of Construction (Jian Biao [1997] No. 108), the original Code for Construction and Acceptance of Industrial Automation Instrumentation GBJ 93 – 86 with ex- Ministry of Chemical Industry as editor-in-chief department was revised together with metallurgical and machinery departments and sub units of SINOPEC to become this Code. This Code includes 12 chapters of the General, Terms, Construction Preparation, Installation of Taps, Installation of Instrumentation Apparatus, Installation of Instrument circuits, Installation of Instrumentation Piping, Degreasing, Electric Explosion-proof and Grounding, Protection, Instrumentation Testing and Engineering Acceptance.

The name of the industrial automation instrumentation has been revised to be automation instrumentation in the new code and the applicable scope is expanded. Two chapters of the Terms and the Construction Preparation as well as four sections of the Mechanical Measuring and testing Instrumentation, Other Testing Instrumentation, Control Instrumentation and Comprehensive Control System, the Testing of Comprehensive Control System have been newly added. Some chapters and sections in original code have been adjusted.

During the preparation of this Code, the Revision Group of the Code made wide investigation and summed up the practical experience in the construction of automation instrumentation in China. Meanwhile, references were also made to numbers of documents and engineering data of international and domestic automation instrumentation engineering as well as the revision situations of relevant national standards for instrumentation products, piping construction, electric construction and electric explosion-proof. Comments on the draft of the Code from organizations of engineering construction, engineering design, petrochemical products production, instrumentation apparatus and material manufacture, quality supervision and testing in fields of chemical industry, petrochemical, metallurgy, machinery and power in China were widely solicited. The Revision Group sorted out and discussed the comments and it was finalized after reviewing.

It is hoped that all organizations, during their implementation of the Code, shall sum up experience and collect data, combining with engineering practice. Any necessary revision or supplementation to the Code found shall be posted, together with supporting documents, to: the Secretariat of Chemical Industry Engineering Committee of China Association of Engineering Construction Standardization, No. 16 Building, Zone 4, An Hui Li, Asian Game Village, Beijing (Zip: 100723, Tel: 84885096) for reference in future revision. The Management Center of National Standardization of Construction of Chemical Industry shall be responsible for the explanation of the Code, Tel (fax): 0311 – 5886241, Website: http://www.hgsgbiaozhun.com, E-mail: webmaster@hgsgbiaozhun.com.

Editor– in –Chief department, preparation participated organizations and key persons for preparation of this Code:

Editor – in –Chief Department: Management Center of National Standardization of Construction of Chemical Industry

Preparation participated organizations:

China 4^th Construction Company of Chemical Engineering

10^th Construction Company of SINOPEC

China 22^nd Metallurgical Construction Company

China 9^th Construction Company of Chemical Engineering

Nanyang Explosion-proof Electrical Research Institute

Key persons for preparation:

Zhang Tongxin Mao Zhongde Yan Zuqing Yan Changsheng Gao Qiuke Hou Zhiwen Zhang Gang

Contents

1. General……………………………………………………………………………………8

2. Terms……………………………………………………………………………………8

3. Construction Preparation………………………………………………………………12

3.1 Technical Preparation for Construction…………………………………………………12

3.2 Inspection and Storage of Instrumentation Apparatus and Materials……………………12

4. Installation of Taps………………………………………………………………………13

4.1 General Rules……………………………………………………………………………13

4.2 Temperature Taps…………………………………………………………………………14

4.3 Pressure Taps……………………………………………………………………………14

4.4 Flow Taps…………………………………………………………………………………15

4.5 Material Level Taps………………………………………………………………………16

4.6 Analysis Taps……………………………………………………………………………17

5. Installation of Instrumentation Apparatus………………………………………………17

5.1 General Rules……………………………………………………………………………17

5.2 Instrument panels, Cabinets and Boxes…………………………………………………18

5.3 Temperature Detecting and Measuring Instrumentation………………………………20

5.4 Pressure Detecting and Measuring Instrumentation……………………………………20

5.5 Flow Detecting and Measuring Instrumentation…………………………………………20

5.6 Material level Detecting and Measuring Instrumentation………………………………22

5.7 Mechanical Performance Detecting and Measuring Instrumentation……………………23

5.8 Instruments for Composition Analysis and Physical Performance Detecting and Measuring

……………………………………………………………………………………………24

5.9 Other Detecting and Measuring Instrumentation…………………………………………24

5.10 Actuators…………………………………………………………………………………24

5.11 Control Instrumentation and Comprehensive Control System……………………………25

5.12 Power Supply Equipment for Instrumentation……………………………………………26

6. Installation of Instrument circuit ………………………………………………………27

6.1 General Rules……………………………………………………………………………27

6.2 Fabrication and Installation of Supports………………………………………………29

6.3 Installation of Cable Trays………………………………………………………………29

6.4 Installation of Protective Tubes………………………………………………………30

6.5 Installation of Cables and Wires…………………………………………………………32

6.6 Wiring of Instrument circuits……………………………………………………………33

7. Installation of Instrumentation Piping…………………………………………………34

7.1 General Rules……………………………………………………………………………34

7.2 Piping of Measuring……………………………………………………………………35

7.3 Pneumatic Signal Piping…………………………………………………………………35

7.4 Gas Source Piping………………………………………………………………………36

7.5 Hydraulic Piping………………………………………………………………………37

7.6 Instrumentation Piping in Panels, Cabinets and Boxes………………………………38

7.7 Piping Test………………………………………………………………………………38

8. Degreasing………………………………………………………………………………39

8.1 General Rules……………………………………………………………………………39

8.2 Method of Degreasing…………………………………………………………………40

8.3 Test of Degreasing………………………………………………………………………40

9. Electrical Explosion-proof and Grounding………………………………………………41

9.1 Construction of Instrumentation Units in Explosive and Fire Hazardous Atmosphere

……………………………………………………………………………………………41

9.2 Grounding…………………………………………………………………………………43

10. Protection…………………………………………………………………………………44

10.1 Isolation and Purging……………………………………………………………………44

10.2 Anti Corrosion and Heat Isolation………………………………………………………45

10.3 Heat Tracing……………………………………………………………………………46

11. Instrumentation Test……………………………………………………………………47

11.1 General Rules……………………………………………………………………………47

11.2 Calibration and Test of Single Instrument………………………………………………48

11.3 Test of Instrumentation Power Supply Equipment………………………………………50

11.4 Test of Comprehensive Control System…………………………………………………50

11.5 Loop Test and System Test………………………………………………………………51

12. Engineering Acceptance…………………………………………………………………52

12.1 Conditions for Handing Over and Acceptance…………………………………………52

12.2 Handing Over and Acceptance…………………………………………………………53

Appendix A Minimum Length of Straight Pipe Sector Required by Throttle Units………………54

Description of Wording in this Code………………………………………………………………56

Explanation for articles……………………………………………………………………………57

1. General

1.0.1 To raise the level of construction and management of automation instrumentation (hereinafter referred to as instrumentation) engineering and to guarantee the engineering quality, this Code is worked out.

1.0.2 This Code applies to the construction and acceptance of industrial and civil instrumentation engineering.

This Code does not apply to the installation of instrumentation in places of manufacturing, storage or using explosive substances as well as the instrumentation of transportation tools, in mining or for metrological use.

1.0.3 The construction of instrumentation engineering shall meet what specified by design documents and in this Code as well as meeting requirements in the product installation instructions. Any modification to the design shall be confirmed by original designer.

1.0.4 The instrumentation and taps directly installed in equipment or piping shall be constructed in accordance what specified by design documents for the division of disciplines.

1.0.5 The equipment and materials used for the instrumentation engineering shall meet relevant mandatory national standards in force.

1.0.6 The welding in instrumentation engineering shall meet relevant stipulations in national standard in force the Code for Construction and Acceptance of Welding Engineering of Site Equipment and Industrial Piping GB 50236 – 98.

1.0.7 The construction of instrumentation engineering shall, apart from compliance with this Code, also meet what specified in relevant mandatory national standards in force.

2. Terms

2.0.1 Automation instrumentation

It is a general term of instrumentation units and instrumentation systems which are used to measure and to control the variables to be measured or to be controlled.

2.0.2 Measurement

A group of operations with purpose to determine the values.

2.0.3 Control

Purposed activities on system or in system to obtain specified target.

2.0.4 Site

The place where the project is constructed.

2.0.5 Local instrument

The instrumentation installed in site out of the control room. In general, they are near the objects to be measured or to be controlled.

2.0.6 Detecting and measuring instrument

The instrumentation used to determine the value of quantity or the characteristics or state of the quantity of variables to be measured.

2.0.7 Transducer

The unit receives the signal of input variables and converts them to output variables of same nature or other nature in accordance with certain law.

2.0.8 Converter

The unit receives signals of one type and converts them to signals of other nature in accordance with certain law.

2.0.9 Transmitter

The transducer transmitting standard signals.

2.0.10 Display instrument

The instrument displaying values of quantity measured.

2.0.11 Control instrument

The instrument to control the variables to be controlled.

2.0.12 Actuator

It is the unit in the control system, which directly changes the variables to be controlled via the action of its mechanism.

2.0.13 Sensor

It is primary elements in measurement chain. They convert the input variables to be signals suitable for measurement.

2.0.14 Tap

They are elements of the special pipefitting, out leading ports and connection valves provided for the objective to install or connect detecting and measuring elements.

2.0.15 Measuring point

Specific positions to detect or measure variables to be measured, i.e., the site installation positions of detecting and measuring elements and taps.

2.0.16 Temperature measuring point

The point to detect and measure temperature.

2.0.17 Pressure measuring point

The point to detect and measure pressure.

2.0.18 System

The integration of specific functions consisting of several mutually related and mutually acted elements.

2.0.19 Control system

The system to obtain anticipated status via precision guide or via operation of several variables. The control system of instrumentation consists of hardware of instrumentation apparatus, instrumentation piping, instrument power and auxiliary facilities as well as related software.

2.0.20 Comprehensive control system

It is the instrumentation control system with comprehensive control functions and using digital technology, computer technology and net communication technology.

2.0.21 Piping

It is an assembly of pipes, pipefitting, flanges, fasteners, gaskets, valves and other components and supports to delivery, distribute, mix, separate, drain, measure, control or block fluid.

2.0.22 Instrumentation piping

It is general term of instrumentation measuring piping, pneumatic and liquid-moved signal piping, air piping and hydraulic piping.

2.0.23 Measuring piping

The piping transmitting medium measured from measuring point to instrument.

2.0.24 Signal piping

The piping transmitting pneumatic or liquid-moved control signals.

2.0.25 Air piping

The piping supplying air to pneumatic instruments.

2.0.26 Instrument circuit

It is general term of instrumentation wires, cables, compensation wires, optical cables and cable trays and protective tubes.

2.0.27 Cable tray

Channel shape products to install and protect cables and wires, including channel body, cover and components.

2.0.28 Protective tube

The tubes and connection pieces to install and protect cables and wires.

2.0.29 Loop

The combination of one or more related instruments and functions in control system.

2.0.30 Heat tracing

The measures to provide heating source near to equipment and piping to trace heating so as to maintain specified temperature of the production units, instrumentation equipment and materials in piping.

2.0.31 Degreasing

The operation to remove organics of oil and dirty from the surface of object.

2.0.32 Inspection

The activity of measurement, testing, examination of substance of products or process and make comparison of the results with the specified requirements to determine the qualification of each characteristics.

2.0.33 Testing

It is to verify the rated values (or limit values) or characteristics, criteria, quality of substance of products or process.

2.0.34 Verification

It is the activity of the legal measuring departments or legal authorized organization to determine, via testing and providing proofing, that the error of display value of the measuring apparatus meets specified requirements.

2.0.35 Calibration

A group of operations, under specified conditions, to determine the relationship between the display values of measuring instruments and apparatus or measuring system, the values represented by actual measurement tools or standard substances and the reference standard values.

2.0.36 Adjustment

The operations to make the measurement tools and apparatus reach normal performance and the error meet specified value to be at the state for application.

2.0.37 Explosion-protected electrical apparatus

The electrical apparatus, which may not ignite surrounding explosive atmosphere under, specified condition.

2.0.38 Explosive atmosphere

The environment where, at atmosphere condition, gases, steam, thin fog, dust or fiber combustible substances are mixed with air and, after ignition, the burning shall be spread to all mixtures not yet burnt.

2.0.39 Hazardous area

The area where the explosive atmosphere appears greatly or it is anticipated to appear greatly, therefore special measures shall be taken to the structure, installation and application of electrical apparatus.

2.0.40 Intrinsically-safe circuit

The circuit in which, at specified test condition, the spark and heat effect produced in normal work or in specified status of trouble shall not ignite explosive gases or steam.

2.0.41 Intrinsically-safe apparatus

The electrical apparatus of which all circuits are intrinsically-safe ones.

2.0.42 Associated apparatus

The electrical apparatus of which the circuits or part of circuits of the apparatus are not all intrinsically-safe ones, but may affect the safety performance of intrinsically-safe circuits.

3. Construction Preparation

3.1 Technical Preparation for Construction

3.1.1 The construction of instrumentation engineering shall be organized in accordance with construction organization design and construction scheme. Construction technical scheme shall be prepared for complicated and key installations and tests.

3.1.2 Prior to the construction of instrumentation engineering, the Owner or the supervision organization shall organize the joint review of the construction drawings and the contractor shall take part in the joint review.

3.1.3 Prior to the instrumentation engineering, technical details shall be told to the construction personnel.

3.2 Inspection and Storage of Instrumentation Apparatus and Materials

3.2.1 On the delivery of instrumentation apparatus and materials to the site, inspection and verification shall be made to them.

3.2.2 The unpacking inspection and visual inspection to instrumentation apparatus and materials shall be made in accordance with following requirements:

1. Packing and sealing are in good order;

2. Type, specification and quantity are in conformity with the packing list and design documents without any shortage or damage;

3. Nameplate, marks, accessories and spare parts are complete;

4. Technical documents and quality certificate of the product are complete;

5. Other items specified by relevant provisions of this Code regarding the visual inspection.

3.2.3 The unpacking inspection of instrument panels, cabinets and boxes shall also meet following requirements:

1. The surface shall be flat and the painting of the inside and outside surfaces shall be in good order;

2. The profile size and sizes for installation holes, the model, specification of all instrumentation in panels, cabinets and boxes and of all power supply equipment and all other parts shall be in conformity with design documents.

3.2.4 For the performance test of instrumentation apparatus, what specified in Chapter 10 of this Code shall apply.

3.2.5 After inspection and acceptance, the instrumentation apparatus and materials shall be stored in different areas according to their required storage conditions. Key instrumentation materials shall be stored in categories according to their quality, model and specification.

3.2.6 The term for storage of instrumentation apparatus and materials before the construction shall not exceed one year. In case they are stored more than this period, it shall meet what specially specified for the storage of instrumentation apparatus and materials.

3.2.7 Protection shall be provided to instrumentation apparatus and materials already installed during the construction.

4. Installation of Taps

4.1 General Rules

4.1.1 The structural sizes, quality and installation positions of taps shall meet design documents.

4.1.2 Taps in apparatus shall be installed at the time when the apparatus is manufactured while taps in piping shall be installed at the time when the piping is prefabricated and installed.

4.1.3 The opening-making and welding for installation taps in apparatus and piping shall be done before the work of the anti corrosion, lining and pressure test of the apparatus and piping.

4.1.4 Mechanical way shall be used to make openings in apparatus and piping of high pressure, alloy steel and non-ferrous metal.

4.1.5 The taps installed in concrete blocks and concrete articles shall be embedded at the time of laying blocks or concrete casting. In case it is impossible to do in this way, openings for installation shall be reserved.

4.1.6 For installation of taps, opening making and welding should not be done to welds or its near side.

4.1.7 The connection of the tap valves and apparatus or piping should not use clamp sleeve type connectors.

4.1.8 On completion of the installation of taps, they shall be pressure tested together with the apparatus and piping.

4.2 Temperature Taps

4.2.1 The installation of temperature taps in piping shall meet following stipulations:

1. In case they are installed in the way perpendicular to the piping, the axis of the tap shall be perpendicular to the piping axis;

2. In case they are installed at the turning places of the piping, they should be installed in the direction against the material flow in the piping and the axis of the tap shall be coincided to the piping axis;

3. In case they are installed in an angle to the piping, they should be installed in the direction against the material flow in the piping and the axis of the tap shall be crossed to the piping axis;

4.2.2 In case the design documents specify that the tap shall be installed in the enlarged piping, the installation of reducers shall meet design documents.

4.3 Pressure Taps

4.3.1 The installation positions of pressure taps shall be selected at the places of stable flow of fluid to be measured.

4.3.2 In case pressure taps and temperature taps are installed in same piping sector, the pressure taps shall be installed at upstream of the temperature taps.

4.3.3 The ends of the pressure taps shall not projected from the inside walls of the apparatus or piping.

4.3.4 The installation of pressure taps to measure muddy materials with dust, solid particles or settlements in vertical or inclined apparatus or piping, the taps shall be installed upward in inclination however in horizontal piping, they should be installed in an acute angle with the flow direction of material.

4.3.5 The installation of taps of local pressure gauges to detect and measure the pressure of liquids, steam or condensable gases of which temperature is higher than 60℃ shall have cup shape or U shape condensate trap.

4.3.6 When pressure taps are installed in horizontal piping or inclined piping, the position of pressure measuring point shall meet following stipulation:

1. If it is to measure gas pressure, it shall be at the upper part of the piping;

2. If it is to measure liquid pressure, it shall be at the lower part of the piping, in the range of 45°with the horizontal centerline of the piping;

3. If it is to measure steam pressure, it shall be at the upper part of the piping and the lower part is in the range of 45°with the horizontal centerline of the piping;

4.3.7 When pressure taps are installed in concrete blocks, fire resistance fibers shall be closely filled to nearby places of the pressure tap pipe, followed by sealing with refractory mud.

4.4 Flow Taps

4.4.1 The minimum strength of the straight pipe sectors upstream and downstream of the flow taps shall meet design documents and also meet relevant requirements in product technical documents.

4.4.2 The minimum strength of the straight pipe sectors upstream and downstream of orifice, nozzle and Venturi tube shall meet what specified in Appendix A of this Code if it is not specified in design documents.

4.4.3 Within the specified range for the minimum length of the straight pipe sector, other taps or testing elements shall not be installed. The inside of the straight pipe sector shall be clean and without any concave or convex material.

4.4.4 In case thermometer is installed at upstream of the throttle pieces, the space between the throttle piece and the thermometer shall meet what specified in Appendix A.

4.4.5 In case thermometer is installed at downstream of the throttle pieces, the space between the throttle piece and the thermometer shall not be less than 5 times of ID of the piping.

4.4.6 In case the throttle devices are installed in horizontal or inclined piping, the direction of pressure measuring port shall meet following stipulations:

1. If it is to measure gas pressure, it shall be at the upper part of the piping;

2. If it is to measure liquid pressure, it shall be at the lower part of the piping and in the range of 0~45°with the horizontal centerline of the piping;

3. If it is to measure steam pressure, it shall be at the upper part and in the range of 0~45°with the horizontal centerline of the piping;

4.4.7 For orifice or nozzle, in case separate drilling is made to make hole for pressure measuring point, it shall meet following stipulations:

1. The distance between the axes of pressure measuring hole at up stream and down stream and the sides of the up stream and down stream of orifice and nozzle shall be 1/2 of diameter of pressure measuring hole.

2. The diameter of pressure measuring hole should be 4 ~ 10mm. The diameters of the pressure measuring holes at up stream and down stream shall be same.

3. The axis of pressure measuring hole shall be perpendicular to the axis of piping.

4.4.8 In case flange is used for orifice for pressure measuring, it shall meet following stipulations:

1. For the distance between the axis of pressure measuring holes at up stream and down stream and the ends of the up stream and down stream, when β > 0.6 and D < 150mm, it shall be 25.4 ±0.5mm; when β ≤0.6 orβ > 0.6 but 150mm ≤ D ≤ 1000mm, it shall be 25.4 ±1mm;

2. The diameter of pressure measuring hole should be 6 ~ 12mm and diameters of pressure measuring holes at up stream and down stream shall be same.

3. The axis of pressure measuring hole shall be perpendicular to the piping axis.

4.4.9 In case D or D/2 is used to pressure measuring for orifice, it shall meet following stipulation:

1. The distance between the axis of pressure measuring holes at up stream and the end of up stream of orifice shall be equal to D±0.1D while for the distance between the axis of pressure measuring holes at down stream and the end of up stream of orifice, when β ≤0.6 , it shall be equal to 0.5 D±0.02D; when β >0.6 , it shall be equal to 0.5 D±0.01D;

2. The axis of pressure measuring hole shall be perpendicular to the piping axis;

3. Diameters of pressure measuring holes at up stream and down stream shall be same

4.4.10 When uniform pressure cup is used to measure pressure, the pressure measuring holes shall be uniformly arranged at same section and the number of pressure measuring holes at up stream and down stream shall be same.

4.4.11 The axis of the taps of flow testing elements of Pitot tube, Pitot tube of Venturi type and tubes of uniform flow shall be perpendicular to the piping axis.

4.5 Material level Taps

4.5.1 The installation positions of material level taps shall be selected at the places where the change of material level is sensitive and the material will not impact the test elements.

4.5.2 When guide tube or other guide device is used for the inner float barrel level meter or float ball level meter, the guide tube or the guide device shall be installed vertically to secure the smooth flow inside the guide tube.

4.5.3 The installation of dual-chamber balanced vessels shall meet following stipulations:

1. The manufacture size shall be checked before the installation and inspection shall be made for the tightness of inside piping;

2. Installation shall be made vertically. The centerline shall be coincided to the normal liquid level;

4.5.4 Single chamber balanced vessels should be installed vertically and the installation elevation shall meet design documents.

4.5.5 Measures for heat expansion of the vessels measured shall be taken to the installation and fixing of the compensation-balanced vessels.

4.5.6 The installation of the flange short pipe of float ball type level meter shall secure the free movement of the float ball in full scale range.

4.5.7 The measuring barrel of the electric connection point water level meter shall be installed vertically. The center axis of electric pole of the barrel at zero water level shall be at same height of the zero water level line of the vessel measured in normal working condition.

4.5.8 The installation positions of the static pressure taps shall be away from inlets and outlets of the liquid.

4.6 Analysis Taps

4.6.1 The installation positions of the analysis taps shall be selected at places where pressure is stable and it is sensitive to reflect real change of composition and representative analysis samples may be obtained. The nearby places of the sampling points shall not have steam line flow, eddy, air inclusion, dead angle, material blocking or chemical reaction by non production process.

4.6.2. When analysis taps are installed in horizontal or inclined piping, the installation positions shall meet what specified in 4.3.6 of this Code.

4.6.3 In case the gases to be analyzed containing solids or liquid impurities, the angle of elevation between the axis of the tap and the level line shall be > 15°.

5. Installation of Instrumentation Apparatus

5.1 General Rules

5.1.1 The installation of local instrumentation shall meet design documents. In case it is not specified in the design documents, it shall meet following requirements:

1. At places of sufficient sun light and easy operation and maintenance;

2. The space between the centerline of the instrument and the operational ground should be > 1.2 ~ 1.5m;

3. The display instruments shall be installed at places of easy observation of display values.

4. The instruments shall not be installed at places where there is vibration, damp, mechanical damage, interference of strong electric field, high temperature, vigorous change of temperature and corrosive gases.

5. The detecting and measuring elements shall be installed at places where real input variables can be shown.

5.1.2 The instrumentation installed in piping and equipment shall be installed at positions specified by design documents.

5.1.3 Before installation, the position number, model, specification, material and accessories shall be checked against the design data. Technical documents, non-installation accessories and spare parts attached to the packing shall be stored properly.

5.1.4 Instrumentation shall not be knocked or vibrated during the installation. After installation the instrumentation shall be firm, straight and level. The connection and fixing places of the instrumentation and the equipment, piping and structures shall be forced uniformly without any abnormal external force.

5.1.5 For instrumentation specified by design documents for degreasing shall not be installed until they are degreased and qualified.

5.1.6 Instrumentation directly installed in piping should be installed after purging of piping and before pressure test. In case it is necessary to be installed together with piping, they shall be removed before piping purging.

5.1.7 On completion of the installation of instrumentation directly installed in equipment and piping, they shall be pressure tested together the equipment and piping.

5.1.8 The leading opening of the wiring box of the instrumentation shall not be upward. If it is inevitable, sealing measures shall be provided. In construction, the wiring box and the leading opening shall be sealed timely.

5.1.9 When measuring insulation resistance of the instrumentation and the power supply of instrumentation apparatus, measures shall be taken to avoid any damage to weak electricity equipment and electronic elements.

5.1.10 The product nameplate of instrumentation apparatus and the marks of the position number of instrumentation shall be complete, firm and clear.

5.2 Instrument panels, Cabinets and Boxes

5.2.1 The installation positions and plan layout of instrument panels, cabinets and operation soles shall meet design documents. The positions of local instrument boxes, insulation boxes and protection boxes shall be selected at places where there is sufficient light, good ventilation and for easy operation and maintenance.

5.2.2 The fabrication size of the bottom seat of sectional steel of instrument panels, cabinets and operation soles shall match instrument panels, cabinets and operation soles and the allowable error for linearity shall be 1mm/m. In case the length of the bottom seat of sectional steel is > 5m, the allowable error in full length shall be 5mm.

5.2.3 For installation of instrument panels, cabinets and operation soles, the upper surfaces shall be level and the allowable error for the h, orizontality shall be 1mm/m. In case the length of the bottom seat of sectional steel is > 5m, the allowable error in full length shall be 5mm.

5.2.4 The bottom seat of sectional steel of instrument panels, cabinets and operation soles shall be installed and aligned before the completion of the construction of the ground and their surfaces should be over the ground. The bottom seat of sectional steel shall be anti- corrosion treated.

5.2.5 In case the instrument panels, cabinets and operation soles are installed in places of vibration, anti vibration measures shall be taken in accordance with design documents.

5.2.6 In case the instrument panels, cabinets and operation soles are installed in places where there is more dust, moisture or corrosive gases or in explosive and fire hazardous atmosphere, they shall be selected in accordance with design documents and sealing measures shall be provide.

5.2.7 The connection between the instrument panels, cabinets and operation soles, and between different elements of apparatus in the instrument panels, cabinets and operation soles shall be firm and the fastening pieces for installation shall be rust proof material. Welding shall not be used for installation and fixing.

5.2.8 The installation of separate instrument panels, cabinets and operation soles shall meet following stipulations:

1. Fixing is firm;

2. Allowable error for verticality is 1.5mm/m;

3. Allowable error for horizontality is 1mm/m.

5.2.9 For the installation of instrument panels, cabinets and operation soles in rows, apart from compliance with what specified in 5.2.8 of this Code, it shall also meet following stipulations:

1. The allowable error for the height of tops of adjoining two instrument panels, cabinets and operation soles of same series and specification shall be 2mm;

2. The allowable error for the height of tops of adjoining two instrument panels, cabinets and operation soles of same series and specification shall be 5mm in case the connection places are more than 2;

3. The allowable error for the degree of plane of the front of adjoining two instrument panels, cabinets and operation soles shall be 1mm;

4. The allowable error for the degree of plane of the front of adjoining two instrument panels, cabinets and operation soles shall be 5mm in case the connection places are more than 2;

5. The clearance between the joint of the adjoining two instrument panels, cabinets and operation soles shall not be > 2mm.

5.2.10 The installation of instrument boxes, insulation boxes and protection boxes shall meet following stipulations:

1. Fixing is firm;

2. Allowable error for verticality is 3 mm while the height of the box is > 1.2, the allowable error for verticality shall be 4 mm;

3. Allowable error for horizontality is 3mm

4. The installation in rows shall be beautiful and in order.

5.2.11 The instrument boxes, insulation boxes and protection boxes shall, during installation and handling, be prevented from any deformation or damage of painting. Gas welding is strictly prohibited in installation and processing.

5.2.12 The installation of local wiring boxes shall meet following stipulations:

1. Ambient temperature should not be > 45℃;

2. The distances to different detecting and measuring points shall be appropriate. The height from the center of the box and the operational ground should be 1.2 ~ 1.5m;

3. It shall not affect operation, traffic and equipment maintenance;

4. Wiring boxes shall be sealed and serial numbers shall be marked. Line numbers shall be marked in the wiring boxes.

5.3 Temperature Detecting and Measuring Instrumentation

5.3.1 The temperature measuring elements of the contact type temperature detecting and measuring instruments (mercury thermometer, dual-metal thermometer, pressure type thermometer, heat resistance, heat coupler and son on) shall be installed at the places where the temperature of the objectives measured can be reflected accurately.

5.3.2 Protection measures shall be provided for the installation of temperature measuring elements in dusty places to avoid wears.

5.3.3 In case the temperature measuring elements are installed in places where the elements are easy to be impacted by the materials measured, and the depth for insertion in horizontal installation is > 1m or the temperature measured is > 700℃, measures for preventing bending shall be taken.

5.3.4 The temperature sensing face of the surface thermometer shall closely contact with the surface of the objective measured and it shall be fixed firmly.

5.3.5 The temperature drum of pressure type thermometer must be dipped in the objective measured completely. Protection measures shall be provided for the installation of the capillaries and the bending radius shall not be < 50mm. Heat isolation measures shall be taken in case the surrounding temperature changes greatly.

5.4 Pressure Detecting and Measuring Instrumentation

5.4.1 The local pressure gauges shall not be fixed to the equipment or piping which has vigorous vibration.

5.4.2 The installation height of pressure gauges or transmitters measuring low pressure shall be same as the height of the pressure measuring point.

5.4.3 In case the pressure gauges measuring high pressure are installed near the working posts, they should be 1.8 above the ground or protection covers shall be provided to the front of the instruments.

5.5 Flow Detecting and Measuring Instrumentation

5.5.1 The installation of throttle pieces shall meet following stipulations:

1. Visual inspection shall be made before installation. The inlet of the orifice and the outlet of the nozzle shall have no spur, round angle or notable damage at their sides and manufacture sizes shall be measured and verified in accordance with design data and manufacture standard.

2. The cleaning before installation shall not damage the throttle pieces.

3. The throttle pieces shall not be installed until the piping is purged and flushed.

4. The installation direction of the throttle pieces must make the fluid flow from the up stream side to down stream side of the throttle pieces. The acute side of the orifice or the curve side of the nozzle shall be against the flow direction of the liquid measured.

5. For the orifices or nozzles installed in horizontal or inclined piping, if there are drain ports, the positions of the drain port shall be: if the fluid is liquid, they shall be just at the upper side of the piping; if the fluid is gases or steam, it shall be just at lower side of the piping.

6. The side of the ring chamber with “ +” mark shall be at the up stream of the fluid measured. In case arrow is used to indicate the flow direction, the direction of the arrow shall be same as the flow direction of the fluid.

7. The end side of the throttle pieces shall be perpendicular to the piping axis and the allowable error is 1°.

8. The ID of the sealing gasket for installation of throttle pieces shall not be < ID of the piping and after tightening, they shall not projected form the inside wall of piping.

9. The throttle pieces shall be in same axis with the piping or the holding piece. The error of non-in-same -axis, between the axis and the piping axis at up stream and down stream, e_x, shall meet requirements of following formula:

e_x≤ (5.5.1)

In which, D —— ID of piping;

β——The ratio of ID of throttle pieces and the ID of piping at working state.

5.5.2 The connection of the positive and negative chambers of the pressure differential meter or pressure differential transmitter with the piping measured must be correct. The inclination direction and slope of pressure guide tube as well as the installation of isolators, condensers, settlers and gas collectors shall meet design documents.

5.5.3 Rotator flow meters shall be installed in piping which has no vibration and the angle between centerlines and plumb lines shall not be > 2°. The flow direction of the fluid measured must be upward. The length of the straight pipe sector at up stream should not be less than 2 times of piping diameter.

5.5.4 The center of the target of target type flow meter shall be concentric with piping axis. The target face shall against flow direction and perpendicular to the piping axis. The length of the straight pipe sector at up stream and down stream shall meet design documents.

5.5.5 The signal line of eddy flow meters shall use shield wire. The length of the straight pipe sector at up stream and down stream shall meet design documents. The distance between the pre-set amplifier and the transmitter should not be > 3m.

5.5.6 The signal line of eddy flow meters shall use shield wire. The length of the straight pipe sector at up stream and down stream shall meet design documents. In case the amplifier and the flow meter are installed separately, the distance between the two shall not exceed 20m.

5.5.7 The installation of the electromagnetic flow meters shall meet following stipulation:

1. Equal electric potential connection shall be made to the housing of the flow meter, the fluid measured and the connection flange of piping, and it shall also be earthed.

2. In case it is installed in vertical piping, the flow direction of the fluid measured shall be upward while in horizontal piping, two measuring electric poles shall not be at right upper side and right lower side of piping.

3. The length of the straight pipe sector at the up stream of the flow meter and the type of installation of supports shall meet design documents.

5.5.8 The scale dial of the ellipse gear flow meter shall be in vertical plane. In case ellipse gear flow meter and waist gear flow meter are installed in vertical piping, the flow direction of the fluid in piping shall be downward.

5.5.9 The length of the straight pipe sector at the up stream and down stream of ultrasonic flow meter shall meet design documents. For horizontal piping, the position of energy converter shall be within the range of 45°to the horizontal diameter. The inside walls of the piping measured shall not have any scales or coating which may affect the precision of measurement.

5.5.10 The installation of flow meter of uniform flow speed tube shall meet flowing stipulation:

1. The measuring holes of total pressure shall be against the flow direction and allowable error for the angle shall be < 3°;

2. The measuring rod shall pass through and perpendicular to the piping centerline, the error for drifting from the center and the error for not perpendicular to the axis shall not be > 3°for both cases;

3. The length of the straight pipe sector at the up stream and down stream of flow meter shall meet design documents.

5.6 Material level Detecting and Measuring Instrumentation

5.6.1 The installation height of the buoyancy type level meter shall meet design documents.

5.6.2 The installation of float barrel level meter shall make the barrel vertical and at the height of the normal operation level of float barrel or at the height of interfacial level.

5.6.3 The guide tube of steel strip level meter shall be installed vertically and the steel strip shall be at the center of the guide tube and it can move freely.

5.6.4 In case pressure differential meters or pressure differential transmitters are used to measure level, the installation height of the instruments shall not be higher than the lower pressure measuring point.

Note: In case air blow method or the method using transmission pressure of the vaporization of low boiling liquid to measure level, they shall not be restrained by this.

5.6.5 Protection measures shall be provided to the installation of capillary of dual-flange type pressure differential transmitters and the bending radius shall not be < 50mm. Measures for heat isolation shall be provided in case the surrounding temperature changes greatly.

5.6.6 Specific installation scheme shall be worked out for the installation of nuclear radiation type material level meter. The safety protection measures for installation shall meet what specified in national standard for the sanitary protection of radioactive isotope work. Notable warning marks shall be provided in installation site.

5.6.7 The installation of weighing type material level meters shall meet what specified in 5.7.1 of this Code.

5.7 Mechanical Performance Detecting and Measuring Instrumentation

5.7.1 The installation of electronic strain weighing instruments shall meet following stipulations:

1. The installation and load of load transducers shall not be done until the installation of the weighing vessel and all parts and connection pieces are completed.

2. The installation of load transducers shall be vertical to secure that the main axis of the transducer and the loading axis are coincided so as to minimize the inclined load and eccentric load. The forcing of different transducers shall be uniform.

3. Baffle measures shall be provided in accordance with design documents in case there is impact load.

4. The connection of the weighing vessel and the externals shall be flexible connection.

5. The installation of level limiter shall meet design documents.

6. The supporting face and the bottom of the transducers shall be smooth without any rust, damage or impurities.

5.7.2 The installation of force measuring instruments shall make the force measured uniformly acts the forcing face of the transducer.

5.7.3 The installation of instruments measuring mechanical quantity of displacement, vibration and speed shall meet following stipulations:

1. The installation of the measuring search unit shall not be done until the mechanical installation is completed and the mechanical parts measured are at working status. The positioning of the searching unit shall be determined and fixed in accordance with product instructions and the technical documents of the manufacturer of the machinery and equipment.

2. Special coaxial cable shall be used for the connection of the measuring search unit of eddy transducers and the pre-set amplifier. The resistance of the cable shall match the search unit and the amplifier.

3. Protection shall be made during the installation to avoid any damage to the search unit and the cable.

5.7.4 The distance from the installation point of the electronic belt scale to the material dumping point shall meet what specified in product technical documents. The frame of the scale shall be installed at the place where there is stable belt tension and there is no load impact.

5.8 Instruments for Composition Analysis and Physical Performance Detecting and Measuring

5.8.1 The installation of analysis and sampling system shall meet design documents and the complete unit for pre-treatment of sampling shall be available. The pre-treatment unit shall be installed separately and it should be near the transmitter.

5.8.2 The drain pipe of the sample analyzed shall be directly connected to the drain header and the header shall be led to outdoor safe location, where the liquid collecting unit shall have liquid draining device.

5.8.3 The installation place of the moisture-measuring element of the hydrometer shall be away from heat radiation, vigorous vibration, oil and water drops or corresponding protection measures shall be provided.

5.8.4 The installation positions of the flammable gas detecting and measuring instruments and hazard gases detecting and measuring instruments shall be determined in accordance with the density of the gases measured. In case the density is larger than that of air, the instruments shall be installed at the place 200 ~ 300mm above the ground while the density is smaller than that of air, just above the leaking area.

5.9 Other Detecting and Measuring Instrumentation

5.9.1 The installation of nuclear radiation type densimeter shall meet what specified in 5.6.6 of this Code.

5.9.2 Measures to prevent interference of external magnetic field, mechanical impact and wind shall be provided to the installation positions of the sound transmitter of noise measuring instrumentation.

5.9.3 For the installation of radiation type flame detecting and measuring instrumentation, the small hole in the search unit shall be aligned with the flame to avoid entry of the radiation of hot air and hot material into the search unit.

5.10 Actuators

5.10.1 The installation positions of the control valves shall be at the places where it is easy to observe, operate and maintain.

5.10.2 The actuating mechanism shall be fixed firmly. The operation hand wheel shall be at the place to be easy for operation.

2.10.3 When small diameter control valves with thread connection are installed, dismountable movable connecting piece shall be installed.

5.10.4 The mechanical transfer of the actuating mechanism shall be free without any loose or blocking.

5.10.5 The length of the connecting rod of the actuating mechanism shall be adjustable and it shall secure that the adjusting mechanism may act freely and stably in the range of full open up to full close.

5.10.6 In case the adjusting mechanism may displace in heat along with the process piping, the type of installation of the actuating mechanism shall secure that the relative position of it and its adjusting mechanism shall not be changed.

5.10.7 Sufficient allowance for expansion shall be provided to the signal piping of pneumatic and liquid-moved actuating mechanism, which shall not hinder the action of the actuating mechanism.

5.10.8 The installation position of the liquid-moved actuating mechanism shall be lower than the controller. In case it must be higher than the controller, the maximum difference in height between the two shall not exceed 10m and the gas-collecting place of the piping shall have air vent valve and one-way valve and automatic cut-off valve shall be provided to the place near the controller.

5.10.9 The direction of inlet and outlet of the solenoid valve shall be installed correctly. Before installation, check shall be made in accordance with product instructions to the coils and valve body for insulation resistance.

5.11 Control Instrumentation and Comprehensive Control System

5.11.1 The control, display and record instruments and auxiliary units installed in the control room, as well as the equipment of the comprehensive control system, shall be unpacked indoor. During the unpacking and handling, care shall be taken to avoid any vigorous vibration or the entry of dust and moisture into the equipment.

5.11.2 For the installation of equipment of comprehensive control system, following conditions shall be ready:

1. The installation of foundation base is completed;

2. The construction of interior walls, doors, windows, ceilings and floors are completed;

3. The air conditioning system has been put into operation;

4. The construction of power supply system and indoor lighting is completed and they have been put into operation;

5. The construction of grounding is completed and the grounding resistance meets what specified in the design.

5.11.3 When the equipment of the comprehensive control system are installed and positioned, the power supply, temperature, humidity and cleanness specified by the product shall be secured.

5.11.4 Anti static electricity measures shall be taken during the inspection, installation and testing of the insertion pieces.

5.12 Power Supply Equipment for Instrumentation

5.12.1 Before installation of the power supply equipment, visual inspection as well as the inspection of the technical performance shall be made, which shall meet following stipulations:

1. The contact points of relays, contacts and switches shall be tight and reliable and the movement shall be free without any rust or damage.

2. The fasteners and terminals for fixing and wiring shall be in good order without any dirty or rust;

3. The sealing gaskets, packing covers of the explosion-protected electrical apparatus shall be complete and sealed;

4. The electric insulation performance of output voltage, capacity of fuses of the equipment, shall meet what specified in product instructions.

5. Accessories of the equipment shall be complete.

5.12.2 The specification, type and installation positions of the local instrument power supply boxes shall meet design documents. The equipment should not be installed in the places where there is high temperature, moisture, dust, explosive and fire hazard, corrosion and vibration and places where there is possibility of the interference to nearby instruments. In case it is inevitable, special power supply boxes suitable for the environment shall be used or protection measures shall be provided.

5.12.3 The height from the center of the local instrument power supply boxes to the operation ground should be 1.2 ~ 1.5m. If they are installed in rows, they shall be beautiful and in order.

5.12.4 The installation of power supply equipment shall be firm, neat and beautiful. The equipment position numbers, terminal marks, application marks and operation marks shall be complete without any damage.

5.12.5 When checking, cleaning or installing power supply equipment, no damage shall be made to the insulation, internal wiring or contacts. The adjustable parts sealed in equipment shall not be opened. In case it must be opened for special reason, it must be re-sealed after opening and records shall be made.

5.12.6 The power supply equipment and power distribution lines installed in cabinets and panels, the distances between two conductors with electricity, between the conductor and the rude conductor without electricity, the electric clearance and the creepage distance shall meet following requirements:

1. For lines with rated voltage not > 60V, the electric clearance and the creepage distance shall be 3mm;

2. For lines with rated voltage > 60V, but not >300V, the electric clearance shall be 5mm and the creepage distance shall be 6mm;

3. For lines with rated voltage not > 300V, but not > 500V, the electric clearance shall be 8mm and the creepage distance shall be 10mm;

5.12.7 The terminals of strong electricity and weak electricity shall be arranged separately.

5.12.8 Metal power supply boxes shall have clear grounding marks and the connection of the grounding line shall be firm and reliable.

5.12.9 Before energizing the power supply system, all switches in the system shall be at off position and also check the capacity of fuses. During the installation and testing of instrumentation engineering, all power supply switches and the power on and power off status of instrumentation shall have displays or warning marks.

6. Installation of Instrument circuit

6.1 General Rules

6.1.1 For the installation of instrumentation electrical lines, those not specified by this Code shall meet what specified in national standard in force the Code for Construction and Acceptance of the Cable Lines of Electrical Unit Installation Engineering GB 50168 – 92 and the Code for Construction and Acceptance of Line Distribution Engineering of Electrical Unit Installation Engineering of 1KV and Below GB 50258 – 96.

6.1.2 Before installation of cables and wires, visual inspection and the inspection for conduction through shall be made. A DC 500V mega ohmmeter shall be used to measure insulation resistance and for lines of 100V and below, a DC 250V mega ohmmeter shall be used to measure insulation resistance. The value of resistance shall not be < 25MΩ. In case design document has special specification, the design documents shall apply.

6.1.3 The installation of optical cables shall meet following requirements:

1. Before installation of optical cables, visual inspection and the inspection for optical fiber conduction through shall be made.

2. The bending radius of optical fiber shall be < OD of optical cable by 15 times.

6.1.4 Lines shall be installed in a concentrated way with shortest route. They shall be level in horizontal and straight in vertical as well as they shall be beautiful and neat. They should not be crossed. During the installation of lines, no damage shall be made to the lines.

6.1.5 The lines shall not be installed in places where it is easy to be mechanically damaged and there is emission of corrosive material, it is damp and there is interference of strong magnetic field and strong static electric filed. If it is inevitable, protection measures or shielding shall be provided.

6.1.6 The lines shall not be installed at the places where the operation and the maintenance of equipment and piping will be hindered and the transportation passage, pedestrian and hoisting holes shall be avoided.

6.1.7 In case the surrounding temperature of lines is > 65℃, heat isolation measures shall be provided. In case there is fire source near lines, anti fire measures shall be provided.

6.1.8 Lines should not be installed just above high temperature equipment and piping, neither should just be under equipment and piping which has corrosive liquid.

6.1.9 The distance between lines and the insulation layer of insulated equipment and piping shall be > 200mm. The distance from surfaces of other equipment and piping shall be > 150mm.

6.1.10 When lines are entering rooms from outside, waterproof and sealing measures shall be taken.

6.1.11 When lines are entering outdoor panels, cabinets and boxes, they should enter from the bottom and waterproof and sealing measures shall be taken.

6.1.12 Allowance shall be provided to the terminal connection of lines and also at places where lines are passing through expansion joints and settlement joints of the building.

6.1.13 Cables shall not have any interim joint. If it is inevitable, it shall be connected in junction boxes or in pull line boxes. The connection should be press connection one. If welding is used, non-corrosive flux shall be used. The compensate wire shall be press connected. Coaxial cables and high frequency cables shall use special connectors.

6.1.14 On completion of the installation of lines, line calibration and marking shall be made and insulation resistance of cables and wires shall be measured in accordance with what specified in 6.1.2 of this Code.

6.1.15 When measuring insulation resistance of cables and wires, instrumentation apparatus and parts already connected must be removed.

6.1.16 The connection method and testing requirements for optical cables shall meet what specified in product instructions. The connection of optical cables shall be done in accordance with the process specified by the manufacturer and special equipment shall be used for the melting connection. During the connection, care shall be taken to avoid any breaking or damage to optical fiber. Before and after optical fiber connection, test shall be made to the optical fiber.

6.1.17 Marks shall be provided to the terminal of the line. For buried lines, notable identifications shall be provided.

6.1.18 For installation of lines, installation holes should not be made in concrete beams or columns. For installation in buildings and structures, which have anti corrosion layers, the anti corrosion layers shall not be damaged.

6.2 Fabrication and Installation of Supports

6.2.1 When fabricating supports, material shall be rectified to be flat and straight. The cutting places shall not have any side turning or spur. The supports made shall be firm and flat.

6.2.2 The installation of supports shall meet following stipulations:

1. Welding shall be used for fixing to those metal structures and pre-embedded pieces in concrete structures to which welding is allowable.

2. Expansion bolts should be used for fixing in concrete.

3. U bolts or clamps shall be used for fixing to the piping to which welding of supports is not allowable

4. Welding may be used to metal equipment and piping to which welding of supports is allowable. In case equipment and piping are not same material or strength shall be reinforced, one piece of reinforcement plate of same material as equipment and piping shall be welded in advance, and then the supports shall be welded on to it.

5. Supports shall not directly contact with high temperature or low temperature piping.

6. Supports shall be fixed firmly and they shall be level in horizontal and straight in vertical and they shall also be neat and beautiful. The space between supports in same straight pipe shall be uniform.

7. In case supports are installed in sloped cable trenches or in building structures, the installation slope shall be same as the slope of the cable trenches and building structures. In case supports are installed in arc equipment and structures, the installation arc shall be same as the arc of equipment and structures.

6.2.3 For installation of cable trays and protective tubes, the spaces between metal supports should be 2m. At turning places, termination places and other places necessary, supports shall be provided

6.2.4 The space of supports on which cables are directly installed shall be 0.8m if it is horizontally installed while for vertical installation, 1.0m.

6.3 Installation of Cable Trays

6.3.1 Visual inspection shall be made to cable trays before installation. The inside and outside of cable trays shall be flat and smooth. The inside of the tray shall be finished without any spur and the sizes shall be accurate and the accessories shall be complete.

6.3.2 Welding should not be used for the connection of cable trays. If it must do, welding shall be firm and without any notable welding deformation.

6.3.3 When bolts are used to connect and fix cable trays, smooth half head bolts should be used and nuts shall be at outside of the tray. The fixing shall be firm.

6.3.4 The installation of cable trays shall be level in horizontal and straight in vertical and the arrangement shall be in order. Space shall be provided to the top of the cable trays and the buildings and structures for operation. For vertically arranged cable trays, the arc for turning at turning places shall be same.

6.3.5 The connection of the trays, of trays and instrument cabinets and boxes, of trays and covers as well as of covers shall be aligned and closely. The ends of trays should be sealed.

6.3.6 In case cable trays are installed in process piping rack, it should be at the side or over the piping. It shall not be installed over the high temperature piping in parallel.

6.3.7 Mechanical ways shall be used to make opening for cable trays.

6.3.8 Drain ports shall be provided to cable trays.

6.3.9 In case the vertical sector of the cable trays are > 2m, supports for fixing cables shall be provided to the vertical sector at the lower inside part of the tray. In case the vertical sector is > 4m, supports shall also be provided to the middle part.

6.3.10 In case the linear length of the cable trays are > 50m, hot expansion compensation measures should be provided.

6.4 Installation of Protective Tubes

6.4.1 Protective tubes shall not have any deformation or crack and the inside shall be cleaned to be without any spur. The ends of tubes shall smooth without acute side.

6.4.2 Anti corrosion treatment shall be made to the inside and outside walls of steel tubes. In case they are buried in concrete, the outside of steel tubes shall not be painted.

6.4.3 The fabrication of protective tubes shall meet following stipulations:

1. The angle of protective tubes after bending shall not be < 90°;

2. The bending radius of protective tubes shall not be < minimum allowable bending radius of cables passing the tubes;

3. The bending places of protective tubes shall not have any concave, crack or notable flat bending;

4. The right angle bending of single protective tube shall not be more than two.

6.4.4 In case the linear length of the protective tube is > 30m or the sum of bending angles is over 270°, line pulling boxes shall be provided at the middle.

6.4.5 In case the linear length of the protective tube is > 30m or it is installed along furnaces or passing building expansion joints, following heat expansion measure shall be taken:

1. The bending tube shall be naturally compensated in accordance with site condition;

2. One flexible tube shall be added;

3. Appropriate space shall be reserved at connection place of two tubes and they shall be sleeved and fixed in one end.

6.4.6 The both ends of protective tubes shall have line protection rings or shall be horn shape.

6.4.7 The connection of metal protective tubes shall meet following stipulations:

1. In case threads are used for the connection, the length of threads at tube ends shall not be < 1.2 of pipe connector;

2. In burying installation, sleeve welding should be used. The butt of tube shall be at center position of the sleeve. Welding shall be firm and welds shall be tight. Anti corrosion treatment shall be provided.

3. Thread connection or sleeve tight fixing bolt connection shall be used for galvanized tubes and thin wall tubes, however melting welding shall not be used for the connection.

4. Sealing shall be made to both ends of protective tubes which are installed in places where there is possibility of the entry of dust, liquid, steam corrosive or damp gases to the tubes.

6.4.8 Metal flexible pipes shall be used to connect the protective tubes and the detecting and measuring elements or local instruments and S water trap shall be provided. Sealing shall be made to the connection with the junction boxes, local instrument boxes and line pulling boxes and tubes shall be fixed firmly.

6.4.9 For buried protective tubes, shortest route shall be selected for installation. In case they are buried in walls or in concrete, the net distance from the surface shall not be < 15mm.

6.4.10 The protective tubes shall be arranged in order and the fixing shall be firm. In case tube clamps or U bolts are used for fixing, the fixing points shall be uniform.

6.4.11 In case rain or damp gases may dip the protective tubes, drain measures shall be provided to the lowest point.

6.4.12 The length of the protective tubes or protective covers projected from walls shall not be > 30m.

6.4.13 When protective tubes are passing slabs, pre-embedded pieces shall be provided. In case it is necessary to make openings in slabs or in steel platform, it shall meet following requirements:

1. The positions and the sizes of openings shall be appropriate;

2. When making openings, reinforcement steel bars in slabs or the steel beam of the platform shall not be cut.

6.4.14 When leading the buried protective tubes out from the ground, the tube end should be 200mm over the ground; in case it is led from underground to the ground mounted instrument panels, cabinets and boxes, it should be higher than the inside ground of the panels, cabinets and boxes by 50mm.

6.5 Installation of Cables and Wires

6.5.1 The ambient temperature for installation of instrumentation cables shall not be < following values:

1. For plastic insulated cable, 0℃;

2. For rubber insulated cable, -15℃.

6.5.2 The installation of cables shall be arranged reasonably and they shall not be crossed. During the installation, care shall be taken to avoid any friction between cables and between cables and other hard materials and the tension shall be proper.

6.5.3 The bending radius of plastic insulated and rubber insulated multi-core control cables shall not be < 10 times of the OD. The bending radius of power supply cables shall meet what specified in national standard in force the Code for Construction and Acceptance of Cable Lines of Electrical Unit Installation Engineering GB 50168 – 92.

6.5.4 In case instrument cables and power supply cables are installed in a cross way, it shall be a right angle; in case in parallel way, the distance between the two shall meet design documents.

6.5.5 In cable trays, metal isolation plates shall be provided to separate the AC power supply lines and the instrumentation signal lines.

6.5.6 In case cables are installed along supports, they shall be tied and bundled to avoid any loose.

6.5.7 The net distance between the instrument signal lines installed in open and the electrical equipment which has strong magnetic field and strong static electric field should be > 1.50 m; in case they are shield cables or they are installed with metal protective tubes or in covered metal cable trays, it should be > 0.80m.

6.5.8 In case cables are installed in tunnels or trenches, they shall be installed on supports or in trays.

6.5.9 Cable heads shall be made to both ends on completion of installation of the cable.

6.5.10 When making cable heads, insulation tapes shall be dry, clean without folding or winkle and there shall be no gap between layers. When drawing out shield cables, insulation shall not be damaged. Anti damp and anti oil measures shall be provided to places where there is damp or oil.

6.5.11 The cable installation for comprehensive control system and for the digital communication lines shall meet design documents and product technical documents.

6.5.12 Special cables attached to the equipment shall be installed in accordance with product technical documents.

6.5.13 The compensation wire shall have protective tube or shall be installed in cable trays but not directly buried in ground.

6.5.14 In case switch over switches or cold end temperature compensator is not used between the compensation wire and the measuring instrumentation, the compensation wire and the instrumentation shall be connected directly.

6.5.15 When making interim or terminal connection of compensation wires, polarity shall not be wrong connected.

6.5.16 Instrument signal lines, instrument power supply lines, safe interlocking lines, compensation wires and intrinsically-safe instrument lines and other special instrument lines shall have their respective protective tubes.

6.6 Wiring of Instrument circuits

6.6.1 For the cables and wires entering the instrument panels, cabinets and boxes from outside, the line distribution shall not be made until the conduction through test and insulation , resistance test are made and qualified.

6.6.2 Lines in the instrument panels, cabinets and boxes should be installed in line collecting channels. In small junction boxes, it may also be installed in open. In case they are installed in open, cables and wires shall be bundled and tied firmly with insulation material and the space of the tying points should be 100 ~ 200mm.

6.6.3 The wiring of instrumentation shall meet following stipulations:

1. Line calibration shall be made before wiring and marks shall be provided to line terminals;

2. When peeling insulation layer, no damage shall be made to cores;

3. The connection of the cables to terminals shall be firm and uniform and the conduction shall be good;

4. The core ends of several strings of wires should use wiring plate. The connection of wires and wiring plate shall be press connected.

6.6.4 No connects shall be made to lines in instrument panels, cabinets and boxes and no damage shall be made to the insulation layer.

6.6.5 The lines at both ends of terminals of instrument panels, cabinets and boxes shall be numbered in accordance with design drawing. The numbering shall be correct and characters shall be clear and untingable.

6.6.6 The installation of terminal plate shall be firm. In case the terminal plate is at bottom of instrument panels, cabinets and boxes, the height from the foundation face should not be < 250mm; in case the terminal plate is at side or at top, the distance from the sides of the instrument panels, cabinets and boxes shall not be < 100mm. In case several groups of terminal plates are installed in rows, the net space of the distance should not be < 200mm.

6.6.7 Insulation sleeve shall be provided to rubber insulated core wires and shield wires of which the external protective sleeve is removed.

6.6.8 Allowance shall be provided for the connection of lead wires and wiring terminal plates, instrumentation and electrical equipment.

6.6.9 Spare core wires shall be connected to spare terminals or reserved with maximum possible application length and line numbers shall be marked in accordance with design documents.

7. Installation of Instrumentation Piping

7.1 General Rules

7.1.1 The construction of metal piping in instrumentation engineering shall, apart from compliance with this Code, also be in conformity with national standard in force the Code for Construction and Acceptance of Industrial Metal Piping Engineering GB 50235 – 97.

7.1.2 The installation positions of instrumentation piping shall meet measuring requirements and they should not be installed at places where the inspection and maintenance will be hindered and there is mechanical damage, corrosion or vibration.

7.1.3 In case instrumentation piping is buried, it shall not be buried until it is pressure tested and anti corrosion treated and qualified. For the connection of piping directly buried, welding shall be used and protective sleeves shall be provided to places crossing roads and entering into and coming out of the ground.

7.1.4 The bending of metal piping should be done in cold way and it shall be completed at one time.

7.1.5 The bending radius of high-pressure piping should be 5 times larger than the OD of pipe while for other metal piping, 3.5 times. The bending radius of plastic piping should be 4.5 times larger than the OD of pipe.

7.1.6 After bending, pipes shall have no crack or concave.

7.1.7 Before installation of instrumentation piping, inside shall be cleaned. The piping needs degreasing shall not be installed until it is degreased.

7.1.8 Tees shall be used for high pressure piping branches. The material of Tees shall be same as that of piping.

7.1.9 For the connection of piping, the axis shall be same.

7.1.10 For copper pipes or stainless steel pipes with diameter < 13mm, clamp sleeve type connectors shall be used for the connection. Socket type or sleeve pipe type welding may also be used for the connection. When socket type welding is used, the direction of insertion shall be same as the flow direction of the fluid.

7.1.11 In case piping is installed in rows, the arrangement shall be in order and the spaces shall be uniform.

7.1.12 Clamps shall be used to fix the instrumentation piping to the supports. In case there is frequent relative movement between the piping and the supports, wooden blocks or soft cushions shall be provided between the piping and the supports.

7.1.13 The fabrication and installation of instrumentation piping shall meet what specified in 6.2 of this Code and it shall also meet the requirements for the slope of the instrumentation piping. The space of supports shall meet following stipulations:

1. For steel pipes:

Horizontal installation: 1.00 ~ 1.50m;

Vertical installation: 1.50 ~ 2.00m.

2. For copper pipes, aluminum pipes, plastic pipes and pipe cables:

Horizontal installation: 0.50 ~ 0.70m;

Vertical installation: 0.70 ~ 1.00m.

7.1.14 When fixing the stainless steel pipes, they shall not contact carbon steel pipes.

7.2 Piping of Measuring

7.2.1 The measuring piping shall be installed in shortest route subject to meeting measuring requirements.

7.2.2 In case measuring piping is installed in horizontal, there shall be a slope of 1:10 ~1:100 depending on different materials and measuring requirements and the inclination direction shall secure the removal of gases and condensate. In case it is impossible to meet this, air vent device shall be installed at the air-collecting place of the piping while drain device shall be installed at the liquid collecting place of the piping.

7.2.3 When measuring piping is passing through walls or slabs, protective sleeves or protective covers shall be provided. The ends of piping shall not be in the protective sleeves or protective covers. In case piping is passing through the isolation walls of explosive hazardous areas and fire hazardous areas of different classes and poisonous locations, the protective sleeves and protective covers shall be sealed.

7.2.4 In case measuring piping is connected to high temperature piping and equipment, heat expansion compensation measures shall be provided.

7.2.5 The negative pressure tube and the positive pressure tube to measure the pressure differential shall be installed at places where the ambient temperature is same.

7.2.6 In case measuring piping is connected to the glass tube micro pressure meter, flexible pipe shall be used. The connection place of the piping and the flexible pipe shall be higher than the instrumentation connection by 150 ~ 200mm.

7.2.7 The distance between the measuring piping and the equipment, piping and surfaces of buildings should not be < 50mm. The distance from the piping measuring oil and flammable and explosive substances and the surface of the heat should not be < 150mm and it shall not be installed over them in parallel.

7.3 Pneumatic Signal Piping

7.3.1 Pneumatic signal piping shall be bronze pipes, stainless steel pipes, PVC pipes or nylon pipe cables. The installation of piping shall have no interim joints. If it is inevitable, clamp sleeve connectors shall be used. Dismountable movable connecting pieces shall be provided to the terminal of the piping.

7.3.2 Pneumatic signal piping should be installed in rows.

7.3.3 The installation of pipe cables shall meet following stipulations:

1. There shall have not notable deformation or damage in appearance;

2. The ambient temperature for installation of pipe cable shall not be < minimum ambient temperature specified by product technical documents.

3. During installation, mechanical damage or alternative friction to pipe cables shall be avoided.

4. The piping after installation shall have allowance.

7.4 Gas Source Piping

7.4.1 Thread connection shall be made if galvanized steel pipes are used for air source piping. Bends shall be used at turning places and connections shall be sealed. When wrapping seal tapes or applying seal glue, they shall not enter the pipe. If seamless steel pipes are used, welding shall be applied for the connection and the welding slag shall not enter the pipe.

7.4.2 The air source header in the control room shall have a slope not < 1:500 and drain valve shall be installed at liquid collecting place. The port of drainpipe shall be away from the instrumentation, electrical equipment and lines. Operational space shall be provided between the drain valve installed under the filter and the ground.

7.4.3 The pipe distribution of air source system shall be in order and beautiful. Drain valves shall be provided at the end and at the liquid collecting place. The out leading port of the horizontal trunk pipe for the branches shall be at the upper of the trunk pipe.

7.4.4 On completion of the installation of air source system, purging shall be done, which shall meet following stipulations:

1. Before purging, air source inlet in the control room, all head inlets of different sub air sources and filter pressure relieve valves connected to the air source inlets of instrumentation shall be removed and open. Headers shall be firstly purged followed by trunk pipes, branches and piping connected to different instrumentation in sequence.

2. The air for purging shall be qualified clean instrument air.

3. The purging air blown out shall be inspected with a white paint panted wooden target plate. In case within one minute, there isn’t any rust, dust, moisture or other impurities in the target, it is qualified.

7.4.5 On completion of purging of air source system, the inlet valves of the air source in the control room and the local air source header and the inlet and outlet valves of the dryers and air tanks shall have marks of “No closing without permission”.

7.4.6 Before the application of air source unit, air source pressure values shall be set in accordance with design documents.

7.5 Hydraulic Piping

7.5.1 This section applies to the installation of hydraulic control liquid supply system with pressure not > 1.6Mpa.

7.5.2 The installation position of liquid storage tank shall be lower than the return liquid collecting pipe. The minimum difference in height of the return liquid collecting pipe and the return liquid connector in the liquid storage tank should be 0.3 ~ 0.5m.

7.5.3 The oil pressure piping shall not be installed over the high temperature equipment and piping in parallel. And the distance from the insulation layer of the heat surface shall be > 150mm.

7.5.4 The slope of the natural flow of the return liquid collecting pipe of hydraulic pump shall not be < 1:10, otherwise the diameter of the return liquid pipe shall be increased. In case the fall difference of the return liquid is large, to reduce foam, a horizontal sector or U bend shall be installed before liquid collecting tank.

7.5.5 For the connection of branches of return liquid piping with the header, the branches shall be connected in the way that there is an acute angle with the header in the flow direction of medium.

7.5.6 Air vent valves shall be provided to air collecting places of the liquid collecting tank and the hydraulic piping. The upper part of the vent pipe shall be turned down by 180°.

7.5.7 Before installation of the filter of the liquid supply system, check shall be made to the filtration net for the compliance with what specified in product technical documents and it shall also be cleaned. The inlet and outlet direction shall not be wrong installed. A space for operation shall be provided between the drain valve and the ground.

7.5.8 The hydraulic piping connected to the hydraulic controller shall not have any ring bending or turning bending.

7.5.9 For the connection of the hydraulic controller and the liquid supply pipe and the return liquid pipe, pressure resistance flexible pipe shall be used.

7.5.10 Check valve and locking valve in liquid supply system shall be cleaned, inspected and tested before their installation.

7.5.11 The pressure test of the liquid supply system shall meet what specified in 7.7 of this Code.

7.5.12 The liquid supply system shall be cleaned and it shall be examined, adjusted and tested in accordance with what specified in design documents and in product technical documents.

7.5.13 On completion of cleaning of liquid supply system, the liquid supply valve, return liquid valve and the cut-off valve between the actuator and the header of the hydraulic unit shall be marked with “No closing without permission”.

7.6 Instrumentation Piping in Panels, Cabinets and Boxes

7.6.1 The instrumentation piping shall be installed at places where operation and maintenance will not be hindered.

7.6.2 The instrumentation piping shall be installed in rows and it shall be in order and beautiful. The fixing shall be firm.

7.6.3 The instrumentation piping shall be separated from instrument circuits.

7.6.4 When instrumentation piping is connected to instruments, the instruments shall not have any mechanical stress.

7.6.5 When instrumentation piping is induced to be installed in instrument panels, cabinets and boxes in explosive, fire hazard, poisonous and corrosive atmosphere, the induction openings shall be sealed.

7.7 Piping Test

7.7.1 Before test, inspection shall be made to instrumentation piping already installed and there shall be no miss welding, blocking or wrong connection.

7.7.2 Liquid shall be the test medium for pressure test of instrumentation piping. Gases may be used as test medium for instrument air source piping and pneumatic signal piping as well as instrumentation piping with design pressure ≤ 0.6Mpa.

7.7.3 Hydraulic test pressure shall be 1.5 times the design pressure. When design pressure is reached, hold it for 10 minutes and then fall the test pressure to design pressure for holding 10 minutes. If there isn’t pressure drop or any leakage, it is qualified.

7.7.4 Air pressure test pressure shall be 1.15 times design pressure. Pressure shall be raised gradually and slowly. When test pressure is reached, hold it for 10 minutes and then fall the test pressure to design pressure for holding 5 minutes. Check it with foam agent, if there isn’t leakage, it is qualified.

7.7.5 In case process system requires vacuum test or leakage test, the instrumentation piping system in it shall be tested together with the process system.

7.7.6 Clean water shall be used as the medium for hydraulic test. For the test of austenite stainless steel piping, chlorine content in water shall not be > 25mg/L. After test, liquid shall be drained completely. Anti freezing measures shall be taken when the test is made at ambient temperature of 5℃ and below.

7.7.7 Air or nitrogen shall be used as the medium of air pressure test.

7.7.8 The pressure gauges used in pressure test shall be tested and qualified. The precision shall not be lower than 1.5 Class. The value of full scale shall be 1.5 ~ 2.0 times test pressure.

7.7.9 In case leakage happens in pressure test, repair shall not be made until pressure is released and the test shall not be resumed until it is repaired.

7.7.10 After pressure test is qualified, pressure should be released at other end of piping to check for any blocking of the piping. Temporary plugs and blind plates for test use shall be removed.

8. Degreasing

8.1 General Rules

8.1.1 The instrumentation, control valves, tubes and other piping components necessary to be degreased must be degreased in accordance with design documents.

8.1.2 The oil content of organic solvent used for degreasing shall not be > 50mg/L. The solvent with oil content of 50 ~ 500mg/L may be used for coarse degreasing.

8.1.3 If it is not specified in design documents, degreasing solvent may be selected according to following applicable scope:

1. Industrial use carbon tetrachloride is applicable to the degreasing of ferrous metals, copper and non metal pieces;

2. Industrial use dichroloethane is applicable to the degreasing of metal pieces;

3. Industrial use trichroloethylene is applicable to the degreasing of ferrous metals and non ferrous metals;

4. 10% NaOH solution is applicable to the degreasing of aluminum products;

5. 65% concentrated nitric acid is applicable to the degreasing of instrumentation, control valves, tubes and other piping components with concentrated nitric acid as working material.

8.1.4 Degreasing solvents shall not be used in mix and they shall not contact with concentrated sulfuric acid or concentrated alkali.

8.1.5 In case carbon tetrachloride, dichroloethane or trichroloethylene is used for degreasing, pieces to be greased shall be dry without any water content.

8.1.6 The tools, measuring tools and instrumentation contacting degreasing pieces shall not be used until they are degreased and qualified.

8.1.7 The instrumentation, control valves and other piping components degreased and qualified shall be sealed for storage with marks. They are strictly prohibited to be oil contaminated during installation.

8.1.8 The instrumentation and accessories degreased and sealed by manufacturer may not be degreased again in installation. However visual inspection shall be made. In case any oil trace or organic impurity is found, they must be re-degreased.

8.1.9 The instrumentation and instrumentation piping degreased and qualified shall use oil free medium for pressure test and for instrumentation calibration.

8.1.10 Degreasing solvents must be kept properly and the wastes after degreasing must be handled properly.

8.1.11 Degreasing shall be done at outdoor ventilated places or indoor places with ventilation facilities. During the work, safety measures of putting on protective wares shall be taken.

8.2 Method of Degreasing

8.2.1 The parts of piping, which have notable rust, shall be firstly de-rusted and then degreased.

8.2.2 For degreasing instrumentation, control valves and other piping components which are easy to be dismantled, the parts, accessories and packing to be degreased shall be dismantled and dipped in degreasing solvent and the dipping time shall be 1 ~ 2 hours.

8.2.3 For degreasing instrumentation, which are not easy to be dismantled, the way of filling degreasing solvent may be used and the time for dipping after filling shall not be < 2 hours.

8.2.4 The degreasing of tubes may use the method of dipping in degreasing channels and the dipping time shall be 1 ~ 1.5 hours.

8.2.5 In case cleaning and washing is used for degreasing, cloth or silk which is not easy to fall fiber shall be used. Cotton yarn shall not be used. It is strictly prohibited that fiber is attached to the degreased pieces after degreasing.

8.2.6 In case NaOH solution is used for degreasing, the solution shall be heated to 60 ~ 90℃ to dip degreasing pieces for 30 minutes. Flush the degreasing pieces with water and then put the degreasing pieces in 15% HNO₃ for neutralization and then wash them with clean water and dry them in air.

8.2.7 The degreased instrumentation, control valves and other piping components shall be dried in natural ventilation or dried with clean, oil free dry air or nitrogen.

8.3 Test of Degreasing

8.3.1 The instrumentation, control valves and other piping components after degreasing must be inspected and qualified.

8.3.2 Any of following cases shall be deemed as qualified:

1. White filter paper shall not have any oil trace when it is used to clean the degreased pieces.

2. When violet lamp is used to light the degreased surfaces, there shall have no violet blue fluorescent light.

3. Use steam to blow and wash degreased pieces and put several pure camphor pills with grain of <1mm in steam condensate, the camphor shall rotate continuously in condensate surface.

4. When concentrated nitric acid is used for degreasing, the total quantity of organics in acid analyzed shall not exceed 0.03%.

9. Electrical Explosion-proof and Grounding

9.1 Construction of Instrumentation Units in Explosive and Fire Hazardous Atmosphere

9.1.1 The construction of instrumentation units in explosive and fire hazard atmosphere shall, apart from meeting what specified in this Code, also be in conformity with what specified in relevant national standards and specifications.

9.1.2 The specifications and models of the instrumentation, instrument circuits, electrical equipment and materials installed in explosive hazardous atmosphere shall meet design documents. Explosion-proof apparatus shall have nameplate and explosion-proof marks. In the nameplate the serial number of the explosion-proof certificate issued by state authorized department shall be noted.

9.1.3 When introducing the cable of explosion-protected instrumentation and electrical equipment, explosion-protected seal rings shall be used to against it or seal packing shall be used for sealing. Surplus holes in housing shall be sealed for explosion-proof. One hole of plastic seal ring shall seal one piece of cable.

9.1.4 Explosion protected instrumentation and electrical equipment, excluding intrinsically-safe ones, shall have marks of “No open it unless power is cut off”.

9.1.5 The ventilation tubes of the explosion-protected instrumentation boxes with positive pressure for ventilation must be through and no cut-off valve shall be installed. The installation shall secure that the pressure specified by design documents in the box shall be maintained. In case low pressure interlocking or alarming is provided, the action shall be accurate and reliable.

9.1.6 The installation and line installation for intrinsically-safe instrumentation shall, apart from meeting what specified in 9.1.2, 9.1.7 and 9.1.8 of this Code, also be in conformity with following stipulations:

1. Intrinsically-safe circuits and non-intrinsically safe circuits shall not share one cable or one protective tube.

2. In case cables of non-shield cores or non-shield wires are used, two or more intrinsically-safe circuits shall not share one cable or one protective tube.

3. Intrinsically-safe circuits and their accessories shall have blue marks.

4. In case the intrinsically-safe circuits and non- intrinsically safe circuits are installed in same cable tray or cable trench, they shall be separated in arrangement by earthed metal isolation plate or insulation plate of sufficient pressure resistance strength and the space shall be > 50mm. They shall be firmly fixed separately.

5. In case intrinsically-safe circuits and non-intrinsically safe circuits share on wiring box, earthed metal plates shall be used to separate terminals of intrinsically-safe circuits and non-intrinsically safe circuits.

6. The space between terminals of the intrinsically-safe circuits and terminals of associated circuits or other circuits in instrument panels, cabinets and boxes shall not be < 50mm; when the space can not meet this requirement, insulation plate higher than the terminal shall be used for isolation.

7. For installation and line distribution of intrinsically-safe circuits in instrument panels, cabinets and boxes, they shall be separated from non- intrinsically safe circuits and covered cable trays shall be used or tied and bundled for fixing. For line distribution, the distance from the wiring terminal to fixing point of bundles shall be as short as possible.

8. The installation positions of the associated equipment of safety screens, isolators of the intrinsically-safe circuits shall be at one side of safe area or in another protected area for explosion-protected apparatus which is suitable to the atmosphere. The associated apparatus shall be reliably earthed.

9. In case shield cables or wires are used, the shield layer shall not be connected to the grounding terminals of the safe screen.

10. The grounding line and shield grounding line of the intrinsically-safe circuits shall have insulation layer.

11. Intrinsically-safe circuits shall not be inducted by strong electromagnetic field or strong static electric field of other circuits. The length and installation of circuit shall meet design documents.

12. Intrinsically safe instrumentation and intrinsically-safe associated apparatus shall have product explosion-proof certificate issued by state authorized organization and the substitution of model and specification must be confirmed by original designer,

9.1.7 In case the cable trays or cable trenches are crossing isolation walls of explosive hazard areas of different classes, packed sealing must be done at the places of isolation walls.

9.1.8 The protective tubes of cables and wires installed in explosive hazard areas shall meet following stipulations:

1. Pillar pipe round threads shall be used for the connection between protective tubes, between protective tubes and wiring boxes and line pull boxes. The effective matched part of threads shall not be less than 5 threads. Conductive anti-rust grease shall be applied to threads. Locking nuts shall be used to lock threads. Good electric continuity shall be maintained to the connection places.

2. When protective tubes are passing through the isolation walls of explosive hazardous areas of different classes, explosion-protected fire retardant article and sealing components must be used to the interfacial places and packed sealing shall be well done.

3. When protective tubes are connected with instrumentation, detecting and measuring elements, electrical equipment, wiring boxes, line pull boxes, or when they are entering into the instrument panels, cabinets and boxes, explosion-protected sealing pipe fittings shall be provided and packed sealing shall be well done. The distance from the sealing pipefittings and the instrument boxes and line pull boxes shall not exceed 0.45m. Flexible tubes may be used for the connection of the sealing pipefittings and the instrumentation, detecting and measuring elements and electrical equipment.

4. All protective tubes must be sealed.

9.1.9 The wiring of lines in explosive hazardous areas must be done in explosion-protected wiring boxes specified by design documents and the wiring shall be firm and reliable with good contact. Devices for preventing from loose or removal shall be provided.

9.1.10 The instrumentation and electrical equipment used in fire hazardous atmosphere shall meet design documents.

9.1.11 The boxes or panels installed with instruments or electrical equipment in fire hazardous atmosphere shall be metal products.

9.2 Grounding

9.2.1 For the metal parts which do not have electricity in normal condition of the housing of electric instrumentation, the instrument panels, cabinets boxes and cable trays, protective tubes, supports and seats, if there is possibility of having electricity due to damage of the insulation, they shall be earthed for protection. The local instruments and switches with voltage not higher than 36V may not be earthed if the design documents do not have special requirements for it.

9.2.2 Metal housing of small LV appliances of buttons, signal lamps and relays installed in metal panels or plates in non explosion hazardous atmosphere may not be earthed in case they have well contacted with earthed metal panels and plates.

9.2.3 The grounding system for instrumentation protection shall be connected to the protective grounding network of the LV electrical equipment of electrical engineering and the connection shall be firm and reliable. The grounding shall not be in series.

9.2.4 The grounding resistance values of the protective grounding shall meet design documents.

9.2.5 The cable trays and cable protective tubes installed in buildings may be earthed repeatedly.

9.2.6 Working grounding shall be done for instrumentation and control system. Working grounding includes signal loop grounding and shield grounding as well as grounding of intrinsically-safe circuits specially required. The type of connection of grounding system and the grounding resistance values shall meet design documents.

9.2.7 The grounding of the instrumentation and signal loop of control system and the grounding of shield shall share one grounding unit.

9.2.8 Only one signal loop of different instrumentation loops shall be earthed unless isolators are used to isolate DC signal loops of two grounding places.

9.2.9 The grounding place of signal loop shall be at display instrumentation side. In case the thermo coupler of grounding type and the instrumentation of which the detecting and measuring elements have earthed, it shall not be earthed at display instrumentation side again.

9.2.10 The shield layer of cables and wires of instrumentation shall be earthed at the side of instrumentation panels and cabinets in the control room. The shield layers of same loop shall have reliable electrical continuity and there shall have no float in air or repeated grounding.

9.2.11 In case there is anti interference requirements, the spare core of multi-core cables shall be earthed at one point. The spare core of shield cables and the cable shield layers shall be earthed at same side.

9.2.12 Different grounding of different loops in instrument panels, cabinets and boxes shall be led to grounding collecting rack or grounding terminal plate from respective grounding branches. Grounding trunk shall be led from the grounding collecting rack or grounding terminal plate and then be connected to the grounding general trunk and grounding poles. The non-connection places of grounding branches, collecting racks and terminal plates shall be insulated.

9.2.13 The connection line of grounding system shall use cope core insulated cables or wires fastened with galvanized bolts. The grounding collecting racks in instrument panels, cabinets and boxes shall use copper material fixed with insulated supports. Welding shall be used for the connection of grounding general trunk and the grounding conductor.

9.2.14 The intrinsically-safe circuits shall not be earthed otherwise design documents specify it specially. In case diode safe screen is used, the grounding shall be connected to the common side of AC power supply.

9.2.15 The color of grounding lines shall meet design documents and green and yellow marks shall be provided.

9.2.16 The anti static electricity grounding shall meet design documents, which may be done at same time of the anti static electricity engineering of the equipment, piping and electrical

10. Protection

10.1 Isolation and Purging

10.1.1 In case membrane is used for isolation, the installation position of isolators of membrane type should be close to the detecting and measuring point.

10.1.2 In case isolation vessels filled with isolation liquid are sued, the isolation vessels shall be installed vertically. The elevations of paired isolation vessels shall be same.

10.1.3 In case isolation tubes filled with isolation liquid are used for isolation, the pipe distribution of measuring pipe and the isolation pipe shall be proper so as to facilitate liquid filling and reliable storage.

10.1.4 The selection of isolation liquid shall meet following requirements:

1. No chemical reaction with materials measured;

2. No mixing or solving with materials measured;

3. The density difference with materials measured shall be as great as possible and the layer division shall be notable;

4. Volatilization and evaporation at working environment temperature shall be less without sticking or condensing.

5. No corrosion to instrumentation or measuring piping

10.1.5 In case purging method is used for isolation, the inlet of the purging medium shall be near the detecting and measuring point. The purging and purging liquid medium shall meet following requirements:

1. No chemical reaction with materials measured;

2. It is clean and will not contaminate materials measured;

3. Purging medium is non corrosive and there shall have no change in phase after throttle and pressure release;

4. The pressure of purging liquid shall be higher than the pressure of materials measured so as to secure the stability and continuity of flush flow.

10.2 Anti Corrosion and Heat Isolation

10.2.1 The structures and parts of carbon steel instrumentation piping, supports, instrumentation apparatus seats, cable trays, protective tubes and fixing clamps which need anti corrosion shall be applied with anti rust paint and finishing paint in case their outer walls have no anti corrosion layer.

10.2.2 The application of paint shall meet following stipulations:

1. Rust, welding slag, spurs and dirt shall be removed from surfaces before application of paint;

2. The ambient temperature for paint application should be 5 ~ 40℃;

3. For multi-layer application, the paint shall not be applied until the paint film of previous layer is dry;

4. The application shall be uniform and without any miss application;

5. The color of finishing paint shall meet design documents.

10.2.3 The paint application of welding parts of instrumentation piping shall be done after the pressure test of the piping system.

10.2.4 The heat isolation engineering of instrumentation can be constructed along with the heat isolation engineering of equipment and piping and shall meet what specified in design documents and national standard in force the Code for Construction and Acceptance of Heat Isolation Engineering of Industrial Equipment and Piping GBJ 126.

10.2.5 The construction of heat isolation engineering of instrumentation shall not be done until the pressure test of measuring piping and heat tracing piping is qualified and the anti corrosion works is completed.

10.3 Heat Tracing

10.3.1 In case the tracing method is heavy heat tracing, the traced pipeline shall directly contact with instrumentation and instrumentation measuring piping. In case the tracing method is light heat tracing, the traced pipeline shall not directly contact with instrumentation and instrumentation measuring piping, for which one layer of asbestos board may be used for the isolation. Carbon tracing piping shall not directly contact with stainless steel piping.

10.3.2 When the tracing piping is crossing the accessories of the traced level meters, instrumentation piping valves and isolators, removable joints shall be provided.

10.3.3 In case steam tracing is used, following stipulation shall be observed:

1. The steam for steam tracing piping shall be supplied separately; the heat tracing systems shall not be connected in series;

2. Draining device shall be provided to liquid collecting place of the tracing piping;

3. Welding should be used for the connection of the tracing piping and the fixing shall not be too tight, which shall provide free expansion. The steam inlet place shall be at the top of steam pipe.

10.3.4 In case hot water is used for heat tracing, following stipulations shall be observed:

1. The hot water for hot water tracing piping shall be supplied separately; the heat tracing systems shall not be connected in series;

2. Vent device shall be provided to air collecting place of the tracing piping;

3. Welding should be used for the connection of the tracing piping and the fixing shall not be too tight, which shall provide free expansion. The water inlet place shall be at the bottom of hot water pipe.

10.3.5 In case electric heat tracing is used, following stipulations shall be observed:

1. Visual inspection and insulation testing shall be made to electric heating lines before installation and the insulation electric resistance value shall not be < 1MΩ;

2. The installation of electric heating lines shall be uniform and the fixing shall be firm;

3. The installation of electric heating lines shall not damage the insulation layer;

4. The electric heating pipes and plates in instrumentation boxes shall be installed at the bottom or rear wall of the instrumentation boxes.

11. Instrumentation Test

11.1 General Rules

11.1.1 Inspection, calibration and test shall be made to instrumentation before installation and application to confirm the compliance with technical performance specified by design documents and product technical documents.

11.1.2 The calibration and test of instrumentation before installation shall be done indoor. The test room shall meet following conditions:

1. The room shall be clean and quiet with sufficient sun light without any vibration or any electric magnetic field interference to instrumentation and lines;

2. The room temperature shall be maintained at 10 ~ 35℃;

3. The water supply and drain facilities are available.

11.1.3 The voltage of power supply for instrumentation test shall be stable. The voltage fluctuation of AC power supply and DC power supply of over 60V shall not exceed ±10% while for DC below 60V, not exceeding ±5%.

11.1.4 The air for instrumentation test shall be clean and dry with dew point lower than minimum ambient temperature by 10℃ and more.. The pressure of air source shall be stable.

11.1.5 Loop test shall be made to instrumentation engineering before putting the system into operation.

11.1.6 The power supply and air source for loop test of instrumentation test should be supplied by formal power supply and air supply.

11.1.7 The standard instruments and apparatus used for calibration and test of instrumentation shall have valid measurement verification certificate and the absolute value of basic error should not be more than the absolute value of basic error of instrumentation calibrated by 1/3.

11.1.8 The conditions, items and methods for the calibration of instrumentation shall meet what specified in design documents and product technical documents and special tools and test apparatus provided by manufacturer shall be used.

11.1.9 For instrumentation of which the condition for calibration is not available in construction site, the effectiveness of verification certificate shall be verified.

11.1.10 The calibration and test of instrumentation for which design documents specify oil prohibition and degreasing must be done in accordance with what specified.

11.1.11 The calibration points of single instrument shall be selected uniformly within full-scale range of the instrument and in general it shall not be less than 5 points. For loop test, the calibration point shall not be less than 3.

11.2 Calibration and Test of Single Instrument

11.2.1 The calibration and test of pointer type display instrumentation shall meet following requirements:

1. The panel shall be clean and the scales and characters shall be clear;

2. The movement of the pointer in full scale range shall be stable and free and the error of values displayed and the error of return travel shall meet what specified for the precision of the instrument;

3. The displacement of the pointer after light knocking and in inclination at specified working condition shall meet what specified for the precision of the instrument;

11.2.2 The displayed values of digital display instrumentation shall be clear and stable and the error of values displayed shall meet what specified for the precision of the instrument.

11.2.3 The calibration and test of pointer type record instrumentation shall meet following requirements:

1. The error of values displayed and the error of return travel of the pointer in full scale range shall meet what specified for the precision of the instrument;

2. The underlining and printing of record mechanism shall be clear and the movement of printing paper shall be normal;

3. The numbers or color printed in record paper shall be same as that shown in switchover switches and wiring terminals.

11.2.4 The precision of accumulation and calculation instrumentation shall meet performance requirements specified in product technical documents.

11.2.5 Test and calibration of input and output performance shall be made to transmitters and converters and the precision shall meet performance requirements specified by product technical documents. The range and type of input and output signals shall be in conformity with what specified in the nameplate and design documents and shall match display instrumentation.

11.2.6 The calibration and test point of temperature detecting and measuring instrumentation shall not be less than 2 points. The error of values displayed of direct display thermometer shall meet what specified for the precision of the instrument. Detecting and measuring of elements of thermo coupler and heat resistance may be done at ambient temperature. Heat electric performance test may not be done.

11.2.7 The calibration and test of pressure and pressure differential transmitters shall, apart from the compliance with 10.2. 5 of this Code, also be zero adjusted, scale range adjusted and zero drift adjusted in accordance with what specified by design documents and application requirements.

11.2.8 For flow detecting and measuring instrumentation, manufacturer’s product certificate and valid verification certificate shall be verified.

11.2.9 Dry calibration or wet calibration may be used for float barrel level meter. The determination of the mass of the weight for dry calibration as well as the conversion of the test medium density for wet calibration shall meet requirements for product application status.

11.2.10 Local calibration may be done with direct analog material level to storage tank level meters and inclined face level meters when their installations are completed.

11.2.11 Local calibration with uniform loading standard weights may be done to weighing instruments and their transmitters on completion of their installation.

11.2.12 Special test equipment shall be used for the calibration and test of instrumentation, which measures mechanical quantity of displacement and vibration and so on.

11.2.13 The calibration of the part of display instrumentation of analysis instrumentation shall be made in accordance with requirements for the display instrumentation specified in this section. The test and calibration of detecting and measuring, transmission and conversion performance, including the requirements for test samples, shall meet what specified by design documents and product technical documents.

11.2.14 Test and calibration shall be made to different units separately for unit combination instrumentation and assembling type instrumentation. The requirements for performance and precision shall meet product technical documents.

11.2.15 The calibration of the part of display instrumentation of control instrumentation shall be made in accordance with requirements for the display instrumentation specified in this section. The error of control point, ratio, the integration and differential function, signal treatment and different control and operation performance shall be examined, tested calibrated and adjusted in accordance with what specified by design documents and product technical documents. Pre-setting of parameters shall be made for related grouping module configuration and adjustment.

11.2.16 The test of control valves and actuators shall meet following stipulations:

1. Verifying the product certificate and test reports issued by the manufacturer may do the seal test of valve seat and pressure test of valve body. Seal test shall be made to valve seat of emergency cut-off valves and the results shall meet what specified by product technical documents.

2. The leakage test of the membrane head and valve cylinder shall be qualified and the travel test shall be qualified;

3. The emergency cut-off valves and valves of which the time for full scale travel has been specified by the design must be tested for the time for full scale travel;

4. For the test of actuators, they shall be adjusted to working status specified by design documents.

11.2.17 When single instrument is tested and calibrated and qualified, records for test and calibration shall be filled in timely. Qualified marks and position number marks shall be provided to the instrument. Seal and paint seal shall be provided to the places of the instrument necessary for it.

11.3 Test of Instrumentation Power Supply Equipment

11.3.1 The insulation resistance between the part of the power supply equipment which has electricity and the metal housing shall not be < 5MΩ measured with a mega ohm meter. In case it is specially specified by product instructions, what specified shall apply.

11.3.2 The test of rectification and voltage stabilizing performance of power supply shall meet what specified in product technical documents.

11.3.3 Automatic switching over performance test shall be made to UPS and the switching over time and switch over voltage value shall meet what specified in product technical documents.

11.4 Test of Comprehensive Control System

11.4.1 For comprehensive control system, before loop test and system test, test shall be made to the plant itself.

11.4.2 The test of comprehensive control system shall be made at the time when the installation of that system is completed and related facilities of power supply, lighting and air conditioning have been put into operation.

11.4.3 The items of test of hardware of the comprehensive control system include:

1. Measuring of the insulation resistance of panels, cabinets and instrumentation units;

2. Inspection of grounding system and measuring of grounding resistance;

3. Measuring and adjusting of different output voltages of power supply equipment and insertion pieces of power supply;

4. Inspection of power through status of all equipment and all insertion cards in the system;

5. Calibration and test of single unit of separate display, record, control and alarm instrumentation apparatus in the system;

6. Make inspection of the status of the insertion cards, control and communication equipment, operation stations, computers and their external equipment in the plant via the displaying of direct signal and software diagnose program;

7. Calibration and test of input and output insertion cards;

11.4.4 The items of test of software of the comprehensive control system include:

1. Inspection and test of the basic functions of displaying, processing, operation, control alarm, diagnose, communication, redundant, printing and coping of the system,

2. Inspection of control solutions, control and interlocking procedures.

11.4.5 The test of the comprehensive control system shall be made in accordance with what specified in design documents and product technical documents.

11.5 Loop Test and System Test

11.5.1 Loop test shall be done before the putting into operation of the system. Before the test, following conditions shall be ready:

1. The installation of instrumentation apparatus, units and instrument circuits, instrumentation piping in the loop is completed;

2. The test and calibration of single unit of different instruments making up the loop is completed;

3. Inspection of instrument circuit distribution and pipe distribution has been made and it is confirmed that they are complete and correct and accessories are complete;

4. The power, air source and hydraulic source of the loop may supply normally and meet the requirements for operation of instrumentation.

11.5.2 The loop test shall be reasonably arranged in accordance with site conditions and the complicity of the loop as per the position numbers of loops and the type of signals.

11.5.3 The loop test shall be made firstly in the control room to the comprehensive control system within the input and output boundary connected to the local mounted lines, and then make whole loop test after connection with local mounted instrumentation.

11.5.4 The test of detecting and measuring loops shall meet following requirements:

1. At the signal input side of the detecting and measuring loop, standard signals of analog variables to be measured shall be input. The error of values displayed of the part of display instrumentation in the loop shall not exceed the square root of the sum of the square of allowable basic errors of different individual instrument in the loop.

2. For temperature detecting and measuring loop, value of resistance or analog signals of mV values may be input to the loop at the output side of the detecting and measuring elements.

3. The loops for which the signals of analog variables to be measured are not available in site, signals shall be input at the most front side of the possible analog input signal for the loop test.

11.5.5 The test of control loops shall meet following requirements:

1. The action direction of controllers and actuators shall meet the design.

2. Transmit control signals from controllers or operation stations to actuators to check the correct action direction and position of the actuation mechanism of the actuators in full travel. If the actuators have positioners, they shall be inspected and tested at same time.

3. In case there is display of the opening, starting and ending signals in the controller or in the operation station, they shall be inspected and test at same time.

11.5.6 The test of alarm system shall meet following requirements:

1. The instrumentation apparatus with alarm signals in the system, such as different detecting and measuring alarm switches, alarm output components and contacts of instrumentation, shall be set at the setting values specified by the design documents.

2. Analog input signals shall be produced at the signal producing side of the alarm loop to check the correct alarm light, sound and screen display. After setting of alarm points, seal should be made to the apparatus adjusted.

3. The function of sound elimination, reset and record of alarm system shall be correct.

11.5.7 The test of program control system and interlocking system shall meet following requirements:

1. The test of the function of related hardware and software of related units of the program control system and the interlocking system is completed and the related loop test of the system in completed.

2. The setting values for the action of all related instrumentation and components of the system have been be set in accordance with design documents.

3. For systems with more interlocking points and complicated programs may be tested in items and in sections, followed by the test of integration.

4. The check and test of program control system shall be done step by step in accordance with program design and the condition for judgment, the logic relationship, the action time and the output status shall meet design documents.

5. For functional test of the system, instrumentation which have been tested, set and qualified and the alarm output contacts of detecting and measuring alarm switches may be used to directly produce signals of analog conditions.

6. The system test shall be coordinated with related disciplines to jointly confirm correct program running and correct condition and function of interlocking protection. Necessary measures shall be taken to associated apparatus and units during the test for their running status and safe protection.

12. Engineering Acceptance

12.1 Conditions for Handing Over and Acceptance

12.1.1 The installation of taps, instrumentation apparatus and units, instrumentation piping, instrument circuits, power supply, air source supply and liquid supply systems of instrumentation within the design documents shall have been completed in accordance with what specified in design documents and in this Code. When calibration and test of single unit of instrumentation is qualified, loop test and system test of instrumentation engineering can be done.

12.1.2 When the loop test and system test of instrumentation engineering is completed and met what specified in design documents and in this Code, it can be put into operation.

12.1.3 After putting into operation and normal operation of the instrumentation engineering for 48 hours, the condition for handing over and acceptance is ready.

12.2 Handing Over and Acceptance

12.2.1 When the conditions for handing over and acceptance of instrumentation engineering are ready, the formality for handing over and acceptance shall be gone through.

12.2.2 Following documents shall be submitted for the handing over and acceptance:

1. Project as-built drawings;

2. Design alteration documents and material substitution documents;

3. Records of items to be covered;

4. Records of installation and quality inspection;

5. Records of insulation resistance measuring;

6. Records of grounding resistance measuring

7. Records of degreasing and pressure test of instrumentation piping;

8. Product quality certificates of instrumentation apparatus and materials;

9. Records of calibration and test of instrumentation;

10. Records of loop test and system test;

11. List of instrumentation apparatus for handing over

12.2.3 Interim handing over and acceptance formalities may be gone through for those items, which cannot be completed due to objective conditions, and a detailed list of uncompleted items shall be provided. The construction of uncompleted items shall be arranged in accordance with what specified in the contract.

Appendix A Minimum Length of Straight Pipe Sector Required by Throttle Units

Table A.0.1 Minimum Length of Straight Pipe Sector Required by Orifice, Nozzles and Venturi Nozzles (mm)

Ratio of diameter,β≤	Type of flow obstructing piece at upstream side of throttle pieces and minimum length of straight pipe sector							Length of minimum straight pipe sector at down stream of throttle pieces (including all flow obstructing pieces in this table)
Ratio of diameter,β≤	Single bend of 90° or Tee (fluid just flows out from one branch)	Two or more bends of 90°in one plane	Two or more bends of 90°in different planes	Reducing tube (from 2D to D in length of 1.5D to 3D)	Expanded tube (from 0.5D to D in length of 1D to 2D)	Full open ball valve	Full hole ball valve or full open gate valve
0.20	10(6)	14(7)	34(17)	5	16(8)	18(9)	12(6)	4(2)
0.25	10(6)	14(7)	34(17)	5	16(8)	18(9)	12(6)	4(2)
0.30	10(6)	16(8)	34(17)	5	16(8)	18(9)	12(6)	5(2.5)
0.35	12(6)	16(8)	36(18)	5	16(8)	18(9)	12(6)	5(2.5)
0.40	14(7)	18(9)	36(18)	5	16(8)	20(10)	12(6)	6(3)
0.45	14(7)	18(9)	38(19)	5	17(9)	20(10)	12(6)	6(3)
0.50	14(7)	20(10)	40(20)	6(5)	18(9)	22(11)	12(6)	6(3)
0.55	16(8)	22(11)	44(22)	8(5)	20(10)	24(12)	14(7)	6(3)
0.60	18(9)	26(13)	48(24)	9(5)	22(11)	26(13)	14(7)	7(3.5)
0.65	22(11)	32(16)	54(27)	11(6)	25(13)	28(14)	16(8)	7(3.5)
0.70	28(14)	36(18)	62(31)	14(7)	30(15)	32(16)	20(10)	7(3.5)
0.75	36(18)	42(21)	70(35)	22(11)	38(19)	36(18)	24(12)	8(4)
0.80	46(23)	50(25)	80(40)	30(15)	54(27)	44(22)	30(15)	8(4)
For all ratios of diameter,β	Flow obstructing piece							Minimum length straight pipe sector at upstream
For all ratios of diameter,β	For symmetric sudden reducing reducers with diameter ratio > or = 0.5 For thermometer sleeves and insertion holes with diameter < or = 0.03D For thermometer sleeves and insertion holes with diameter of 0.03D ~ 0.13D							30(15) 5(3) 20(10)
Notes: 1. The length of straight pipe sector in this table is shown as the multiple of diameter D 2. Values without ( ) is values of “zero additional indetermination” while values with ( ) is values of “0.5% additional indetermination”.

Table A.0.2 Minimum Length of Straight Pipe Sector Required by Classic Venturi Tubes (mm)

Ratio of diameter,β	Single short radius bend of 90°	Two or more bends of 90°in one plane	Two or more bends of 90°in different planes	Reducing tube from 3D to D in length of 3.5D	Expanded tube from 0.75D to D in length of D	Full open ball valve or gate valve
0.30	0.5	1.5(0.5)	(0.5)	0.5	1.5(0.5)	1.5(0.5)
0.35	0.5	1.5(0.5)	(0.5)	1.5(0.5)	1.5(0.5)	2.5(0.5)
0.40	0.5	1.5(0.5)	(0.5)	2.5(0.5)	1.5(0.5)	2.5(1.5)
0.45	1.0(0.5)	1.5(0.5)	(0.5)	4.5(0.5)	2.5(1.0)	3.5(1.5)
0.50	1.5(0.5)	2.5(1.5)	(8.5)	5.5(0.5)	2.5(1.5)	3.5(1.5)
0.55	2.5(0.5)	2.5(1.5)	(12.5)	6.5(0.5)	3.5(1.5)	4.5(2.5)
0.60	3.0(1.0)	3.5(2.5)	(17.5)	8.5(0.5)	3.5(1.5)	4.5(2.5)
0.65	4.0(1.5)	4.5(2.5)	(23.5)	9.5(1.5)	4.5(2.5)	4.5(2.5)
0.70	4.0(2.0)	4.5(2.5)	(27.5)	10.5(2.5)	5.5(3.5)	5.5(3.5)
0.75	4.5(3.0)	4.5(3.5)	(29.5)	11.5(3.5)	6.5(4.5)	5.5(3.5)
Notes: 1. The length of straight pipe sector in this table is shown as the multiple of diameter D , started from the plane of press port at up stream of classic Ventiri tube; 2. Values without ( ) is values of “zero additional indetermination” while values with ( ) is values of “0.5% additional indetermination”; 3. Length of straight pipe sector at down stream shall be 4 times of the length of throat diameter.

Description of Wording in this Code

1. For the implementation of provisions of this Code, the wording for different degree of strictness is described as follows:

(1) The wording for very strict and for having to do it:

The positive word is “must”, the negative word is “ be prohibited strictly”.

(2) The wording for strict and for doing it in normal conditions:

The positive word is “shall”, the negative word is “ shall not” or “ must not”.

(3) The wording for allowed selection and for doing it in a priority when condition allows:

The positive word is “should”, the negative word is “ should not”.

The wording for choice and you can do it under certain condition is using “may”.

2. The wording in this Code for implementation of designated relevant standards and codes is “shall meet requirements or stipulations of… or meet what specified in…” or “… shall apply”.

Previous: Design code for high voltage
Next: Construction and acceptance of auto.instrumentation explanation

Website Designed by Unimaple

Construction and Acceptance of Automation Instrumentation Engineering-Instrumentation-Info Online-SinoEquipment