Construction and acceptance of auto.instrumentation explanation-Instrumentation-Info Online-SinoEquipment

1.0.1 This chapter describes the purpose of the establishment of this code. The providing of this article is according to standard compiling stipulations. The requirement of on construction technology in part of articles in this code refers to content of construction management.

1.0.2 Applicable and inapplicable scopes for this code are regulated. On the basis of the original code, this code has induced and summarized the experience of construction and acceptance of the industrial and civil automation instrument and has made unified regulations for commonly applicable parts. Proper attentions have been given to features and customs of the concerning trades.

1.0.3 The basis of the construction should be approved design document and the construction drawings being jointly examined. The project construction is only the realization of design intentions and the construction units should have no right to modify the design drawings by themselves.

Because of the special problems occurred in process design, operation and site conditions and the appearance of new products of instrumentation apparatus and materials, it is possible that the requirement of design document is not perfectly according to stipulations of this code. In this case, after confirmed by design unit, the construction unit shall proceed construction according to the design document.

1.0.4 For installation of instrument and tap on equipment and pipelines, definite regulations shall be made for professional division by design document, thus, the division and cooperation between different professions may be easier disposed.

1.0.6 The tap, instrument pipeline in instrument projects as well as instrument directly connected to equipment or pipeline shall contact the medium directly. The requirement on them shall be same as that on the equipment or the pipeline. So, regulations for them concerning welding procedure were not separately made in this code. The welding procedure shall conform to stipulations as regulated in the actual national standard《Code for construction and acceptance of welding project for site equipment and industrial pipeline》GB 50236 – 98.

2. Terms

Part of terms in this chapter were applied referring to the terms used in the actual national standard concerned in order to make them agreeable with each other as far as possible. For terms and definitions not listed in this chapter, concerning national standards such as 《Basic Terms of Instruments and Meters》GB/T 13983 – 1992 and《Terms and Definitions for Measurement and Control of Industrial Procedures》GB/T 17212 – 1998 (idt IEC 902:1987) may be referred to.

2.0.1 Automation instrument is normally abbreviated as instrument, for example, instrument engineering and instrument profession, etc. Also, instrument often means instrumentation apparatus and devices applied separately in detecting and control.

2.0.3 In addition to control function itself, control may include supervision and safety protection.

2.0.5 When local instrument is installed on local instrument panel, it shall be defined as local panel instrument.

2.0.6 Instrumentation may have functions such as sensing, measuring, transmitting, signal conversion and display, etc. The instrument used in measuring is also named as measuring instrument. The instrument used in determining the existence of quantity (not necessary to provide value of quantity) is also named as detector.

2.0.10 Pointer, figure, character, symbol or graphics may be used as different mode of display of the display instrument, sometimes, it is also named as indicating instrument.

2.0.11 Control instrument may have functions of signal conversion, calculation, record, display, operation, control, actuating, supervision and protection, etc. Controller is sometimes also named as modulator.

2.0.12 Control valve, actuating mechanism and solenoid valve, etc. are different kind of actuators. Sometimes control valve, a kind of automatically operated valve controlling medium flow, is also named as modulating valve. It differs from ordinary valves such as manual valve or self-functioned check valve, etc.

2.0.15 Sometimes, testing point is also named as sampling point. It is marked in equipment drawing, piping drawing or layout with notes of size, orientation or coordinate.

2.0.19 Among instrument control systems are detecting system, control and modulating system, alarm system, interlock system and comprehensive control system, etc.

2.2.20 Comprehensive control system is a general term. It includes computer control system, distributed control system, (DCS), programmable logic controller (PLC), field control system (FCS) and computer integrated manufacture system, etc.

2.2.21 Sometimes piping may be named as tubing. Pipe and tube mean piping.

2.0.23 The sealing piping such as capillary, which is integrally made as a part of product and directly connects with instrument is not to be named as measuring piping.

2.0.24 Sometimes, signal piping is also named as control piping.

2.0.26 Instrument circuit may be named separately as instrument electrical circuit, signal circuit, control circuit and communication circuit, etc.

Instrument piping and instrument circuit may be jointly named as instrument pipeline.

2.0.27 The minitype wire casing for wiring in instrument panel, cabinet or box is named as trunking.

2.0.28 Protective tube is also named as conduct.

2.0.30 Steam tracing piping, hot water tracing piping or electrical tracing piping, plate or wire may be used for heat tracing. Heat tracing piping is normally abbreviated as tracing piping.

Mode of heat tracing includes light tracing and heavy tracing.

2.0.33 ~ 2.0.36 Proceeding of testing and adjusting jointly is also named as debugging and proceeding of testing and calibrating jointly is also named as true up. To unify and define terms and make them agreeable with term definitions in concerning international and national standards, the term definitions for “testing”, “verification”, “calibration” and “adjusting” is given in this code. The terms of “debugging” and “true up” in the original code were not adopted in this code and, in normal cases, they may be substituted by a general term “testing”.

2.0.37 ~ 2.0.42 The terms concerning electrical explosion protection in these articles are referred to articles concerned in the national standard《Electrician Terms Electrical Equipment Applied in Explosive Environment》GB/T 2900.35 – 1988.

2.0.37 Explosion-proof electrical equipment is also named as electrical equipment applied in explosive environment. The national standard《Electrical Equipment Applied in Explosive Gas Containing Environment》GB 3836.1 – 2000 has defined electrical equipment as “whole or part of all equipment which utilizes electrical energy”. So, the instrumentation apparatus, which uses electrical power as well as instrument box, cabinet and junction box should be included, but, to make it clear in this code, the term “Explosion-proof instrument and electrical equipment” is still applied. The Explosion-proof electrical equipment applied in explosive gas containing environment is divided into different explosion-proof types and different categories.

2.0.38 The explosive environment includes explosive gas containing environment and explosive powder containing environment.

2.0.39 The hazardous area is also named as dangerous site. This article provides a definition for dangerous area of explosive environment. According to the national standard《Code for Design of Electric Power Facility in Explosion and Fire hazard exposed environment》, the dangerous area in explosive gas containing environment is divided into zone 0, zone 1 and zone 2 in accordance with the frequency and lasting period of the occurrence of the explosive gas mixture; the dangerous area in explosive powder containing environment is divided into zone 10 and zone 11 in accordance with the frequency and lasting period of the occurrence of the explosive powder mixture; the dangerous area in fire hazard exposed environment is divided into zone 21, zone 22 and zone 23 in accordance with the possibility and result of the occurrence of the fire emergency as well as extent of the danger and the state of material.

3. Construction preparation

The work of construction preparation includes content of construction technical preparation, training, labor mobilization, construction machines and tools organization, temporary facility preparation, goods purchase, transportation, acceptance and preservation of equipment and material, etc. This code only provides regulations for construction technical preparation and testing and preservation of equipment and material.

3.1 Technical preparation for construction

3.1.1 The organization design for construction and compiling and practice of construction scheme plays an important role to control of rate of project progress, quality, safety and cost. Normally, content of instrument engineering is included in the organization design for construction. Construction scheme may be compiled for instrument engineering and the construction scheme for instrument engineering may include following content:

1 Project survey and engineering feature;

2 Scheduled plan for project;

3 Plan for labor organization;

4 Plan for construction machines and tools organization;

5 Plan for temporary facility organization;

6 Technical measures for construction and technical scheme catalogue to be compiled;

7 Quality plan and safety measures for construction;

8 A catalogue for standards, codes and specifications that shall be executed in construction.

3.1.2 The design transmitting and jointly examine for design shall be held jointly by the owner, design unit, supervision unit and construction unit. The technical personnel of construction unit shall get familiar with drawings beforehand. The design quality is the very premise to ensure the project quality and proceeding of joint examine for construction drawing design is in favor of enhancing quality of construction preparation, discover and solving problems beforehand and decreasing the loss caused by rework and design modification.

Joint design examine shall include following content:

1 Examination the integrality of design files and depth of design;

2 Inspection of consistency of control flowchart, system drawing, circuit map, layout plan, equipment schedule and installation drawing concerning design for item number, type, spec, material and location of the corresponding instrument;

3 Inspection of consistency of between system skeleton drawing and wiring diagram;

4 Inspection of conformance of conditions of foundations for panel and cabinet, embedded parts and pre-arranged holes as advanced by instrument profession and their corresponding positions, size and quantity in civil design drawing;

5 Inspection of conformance of the corresponding item number of instrumentation apparatus and tap in equipment drawing and in piping drawing concerning their type, spec, material and locations;

6 Inspection of reasonableness of installation position of instrumentation apparatus, instrument piping and instrument cable tray and space layout of the concerning professional facilities;

7 Inspection of consistency, as required in concerning design, between instrument control systems and between different electrical professions on power supply, grounding, interlock and signal as well as the correctness of connection;

8 Inspection of quantity of instrument material;

9 Inspection for possibly missed items in design.

3.1.3 The design transmitting includes specific content and arrangement of project construction tasks as well as requirements on concerning construction process, method, quality, safety, operation procedure and record tabulations. When it is required by project, technical training shall be proceeded.

3.2 Inspection and storage of instrumentation apparatus and material

3.2.1 The inspection and verification of equipment and material before construction is within the scope of construction preparation work and it differs from commodity inspection proceeded against the goods provided by the supplier. The commodity inspection for equipment and material shall be proceeded according to special standard and contract or agreement concerned. All inspection and verification for equipment and material shall be carried out before construction and the regulations concerned is described in detail in ISO 9000 series standards for quality confirmation system. The owner, supervision unit and construction unit shall reach an agreement on procedure and responsibility division for the inspection and verification.

3.2.2 ~ 3.2.4 For manufacture quality of equipment and material indicated on the appearance, structure size and performance, etc., requirement given in design document and technical files of product shall be met and this influences quality of project directly. The product which does not conform to national specifications and standards, or design document and technical files of product and the product for which project quality after installation can not be ensured are not permissible to be applied.

3.2.5 Improper preservation may lead to damage or shortage of equipment and material.

3.2.6 Outdated preservation may cause performance change, invalidation or exceeding of quality guarantee period for certain instrumentation apparatus, material or certain element of them.

3.2.7 During the whole period of construction, the installed instrumentation apparatus and material at site shall be properly protected and any damage, getting dirty or lose of them shall be prevented via civilized construction and effective measures.

4. Installation of tap

4.1 General regulations

4.1.2 For installation position and installation requirement of tap on equipment and pipeline, conditions shall be advanced by instrument engineering profession design and regulations shall be given by design document of equipment and piping engineering profession. The installation construction of tap shall be carried out by equipment and piping profession and cooperated by instrument profession. This arrangement conforms to the requirement on procedure control for equipment and piping construction and is in favor of insurance of project installation quality.

4.1.3 When anti-corrosion and backing construction for equipment and pipeline are finished, starting holes and welding tap on the equipment and pipeline shall inevitably damage anti-corrosion and backing layer. In case starting holes or welding work are proceeded after pressure test, iron dust and welding slag shall inevitably splash and drop into the equipment and pipeline and the weld seam may be not qualified.

4.1.4 The provision of this regulation is to avoid the material from being changed and to ensure alloy steel and non ferrous metal pipeline and equipment not to be damaged as well as quality of started holes.

4.1.6 According to stipulations as regulated in the actual national standard《Code for Construction and Acceptance of Industrial Metal Piping Project》GB 50235 – 97, it is not advisable to start holes on pipeline weld seam or on its fringe.

4.1.7 The place where sampling valve is connected to equipment or pipeline is a key location. Not to apply cutting sleeve type connector here is favorable for insurance of connecting quality, also for maintenance and repairing.

4.2 Temperature tap

4.2.1 It should be ensured that temperature measuring element shall be able to be inserted to the center area of stuff flow filament in order to measure the real temperature of the stuff.

4.2.2 When diameter of pipeline can not meet the requirement for temperature testing depth of thermometer, it shall be regulated in design document for installation of expanding tube.

4.3 Pressure tap

4.3.1 ~ 4.3.3 When pulsating occurs with tested stuff flow filament, unstable and inaccurate testing pressure may be resulted and instrument is easy to be damaged at same time.

4.3.4 Impurities like dust, etc. shall be prevented from entering testing tube or instrument, to plug piping or instrument and influence normal operation of instrument.

4.3.5 The direct influence from temperature of hot stuff on measuring element shall be prevented.

4.3.6 For gaseous stuff, it shall be arranged that the small amount of condensed liquid shall be able to flow back to the pipeline easily and not to flow into testing tube or instrument to cause measurement errors.

For liquid stuff, it shall be arranged that the small amount of gas separated out from the liquid shall be able to flow back to the pipeline easily and not to flow into testing tube or instrument to cause unstable measurement; at same time, the solid impurities on bottom of pipeline shall also be prevented from entering testing tube or instrument.

For steam stuff, stable condensate shall be kept within testing tube; at same time, the solid impurities on bottom of pipeline shall also be prevented from entering testing tube or instrument.

4.4 Flow tap

4.4.2 ~ 4.4.5 For flow measurement, the stable stuff flow filament shall be kept without being interrupted by resistance parts. The requirement for inner wall and straight pipe section before and after the throttling element as well as the distance between the thermometer before and after the throttling element and the throttling element are quoted from the actual national standard《Throttling Device for Flow Measurement – Measurement for Flow of Fluid Full of Round Pipe with Orifice, Nozzle and Venturi Tube》GB/T 2624 – 1993.

“D” means inner diameter of piping. The mean value of the inner diameter within scope of a length of 0.5D on upper reach direction from the upstream pressure sampling point shall be taken as value D during calculation of diameter ratio of the throttling element.

4.4.6 When fluid is steam, in fact, liquid material is filled in the testing tube. In order to ensure the level in condenser to keep highly stable, surplus condensate should be able to flow back to pipeline, so, it is reasonable to arrange the pressure sampling point on the upper part of pipeline.

4.4.7 ~ 4.4.9 The three modes of pressure sampling, angle joint sampling, flange sampling, D and D/2 sampling, as well as their regulations are quoted from the actual national standard《Throttling Device for Flow Measurement – Measurement for Flow of Fluid Full of Round Pipe with Orifice, Nozzle and Venturi Tube》GB/T 2624 – 1993.

4.4.10 When measuring flow in pipelines with large diameter, especially for liquid flow, the distribution of pressure around the inner wall of the pipeline may be uneven. So, in order to ensure the accuracy of the measurement, it is necessary to take the mean pressure along same section of the pipeline.

4.4.11 The theory of measurement for these flow measuring elements are all in a way of utilizing the difference between dynamic pressure and static pressure cause by flow of fluid in the testing tube to measure the flow of the fluid in the pipeline. To get the accurate dynamic pressure and static pressure, the measuring element must be installed perpendicular to the flow filament, i.e. the element should be perpendicular to the axis of the pipeline and should pass through its center, therefore, firstly, the installation quality of tap must be guaranteed.

4.5 Material level tap

4.5.1 Protective devices may be established for certain taps that are easily impacted by material.

4.5.2 Vertical installation of guiding tube or guiding device can ensure that no friction shall occur between buoy or ball float and guiding tube or guiding device when the buoy or ball float is moving upward or downward and they may move freely inside the guiding tube or guiding device.

4.5.3 The double chamber balanced container measures the liquid level in theory of pressure difference method and its manufacture size must match with pressure difference instrument. The tightness between the two chambers must be guaranteed, otherwise, it should be impossible to form pressure difference.

4.5.4 When level of easily vaporized liquid in tight container is to be measured by pressure difference method, to avoid the condensate of the tested liquid being accumulated in the testing tube on negative pressure side of the instrument and to cause measurement error, the tested liquid shall be filled into the single chamber balanced container beforehand, and then, the pre-added liquid column shall be compensated by adjusting the removal mechanism in the pressure difference instrument, thus, the measurement in the future shall not be influenced by condensate of the tested liquid. So, the installation elevation of the single chamber balanced container shall enable the pressure caused by column of pre-added tested liquid in the container to conform to the measuring range of the pressure difference instrument as regulated in the design document. Meanwhile, for easier liquid filling and a proper appearance, the single chamber balanced container is advisable to be installed vertically.

4.5.5 Normally, compensation type balanced container is applied to measure the liquid level in equipment of high pressure and high temperature. Heat expansion should occur during operation of high temperature equipment and the compensation type balanced container is rather heavy and it should not be supported by sampling pipe but should be supported by separated supports. Here, it must be taken into consideration that the balanced container should not be damaged when equipment expands.

4.6 Analysis tap

4.6.3 Provision of this regulation is to prevent water content and solid impurities inclusion mixed in sample of fume, etc.

5 Installation of instrumentation apparatus

5.1 General regulations

Requirements on installation of all instrument, instrument panel and box and instrument power supply equipment are given in this chapter. Because there are a lot of species of new instrument and special instrument and they are experiencing a quick development, this code only makes regulations for installation of typical instrumentation apparatus. The installation for instrumentation apparatus not listed in this code may refer to regulations in technical document of manufacturer and the installation regulations of similar instrument given in this chapter. For special installation requirement for instrument applied in explosion or fire hazardous environment, please refer to chapter 9.

5.1.1 Normally the installation position of instrument is indicated by layout plan in instrument engineering design and corresponding regulations are also available for installation position of instrument or tap of instrument in project design of piping and equipment profession and in concerning drawings from manufacturer, but, the specific installation orientation and coordinate of certain instrument need to be determined at site during construction.

5.1.2 Normally, the position of instrument or tap on equipment and pipeline is indicated in the manufacture and installation drawing and piping isometric drawing, with definite profession division margin. The drawings shall be jointly examined by instrument profession and other professions and these professions shall cooperate with each other during construction.

5.1.4 No matter for instrument profession or other professions, instrumentation apparatus shall be emphatically protected and any strong shock or forced assembly of instrument during transportation and installation that may lead to damage or degradation of performance to the instrument shall be prevented.

5.1.6 To avoid damage of instrument element during purging of pipeline, in case there is no available bypass, the instrument may be dismantled temporarily and it may be substituted with a short pipe with same size as the instrument and after purging of pipeline, the instrument may be reinstalled.

5.1.8 The oil, water, dust and impurities shall be prevented from entering the box.

5.1.9 Measurement of insulation resistance shall conform to requirement of manufacturer’s specification. The light current equipment and electronic element cannot stand the voltage imposed by insulation testing apparatus. So, corresponding safety measures shall be taken during insulation testing, such as separating light and strong current circuit, pulling out plug in unit and making short circuit for part of circuit and after insulation testing, restoration shall be made.

5.1.0 Item number of instrument shall be determined by project design. In case the manufacturer did not mark the instrument item number on the nameplate, it shall be labeled before installation.

5.2 Instrument panel, cabinet and box

5.2.1 The position of instrument panel and cabinet shall be determined by design drawings. The position of local instrument box shall depend on the installation position of local instrument and normally this shall be determined specifically according to the feature of the local instrument and conditions of space and environment around such as nearby equipment and pipeline.

5.2.2 ~ 5.2.4 Making regulations for requirement of installation of foundation section steel is to ensure the installation of the panel and cabinet being firm and with proper appearance. The joint examine of design and construction shall be proceeded under cooperation of civil structure profession. The specific construction method shall e coordinated with different ground design schemes. The distance between upper surface of the section steel and ground is normally 0 ~ 20 mm and this may be determined at site, no specific regulations have been made in this code.

5.2.7 Moving or changing of panels and cabinets is possible during modification of plant, so, they should not be fixed in the way of welding.

5.2.8, 5.2.9 The regulations concerning installation quality of instrument panel and cabinet have been kept. These regulations are in consistency with this code and the actual national standard《Code for Construction and Acceptance for Engineering Panel and Cabinet Installation in Electrical Plant and for Secondary Circuit Tie Line》GB 50171 – 92 and《Code for Qualification of Quality Inspection for Automation Instrument Installation Project》GBJ –131 – 90. To guarantee installation quality of instrument panel and cabinet, firstly, manufacture quality of the instrument panel and cabinet shall be ensured, meanwhile, deformation during installation shall be prevented from being occurred. The instrument panel and cabinet in row means a series of panel and cabinet with same spec and made by same manufacturer.

5.2.10 The installation requirements for instrument box and board are mainly firm and with proper appearance. Their bottom elevation and mode of support and fixing shall be determined according to site situation.

5.2.11 When welding (especially gas welding) is proceeded on panel and cabinet, deformation and painting damage may be resulted, meanwhile, instrumentation apparatus and circuit may also be damaged. In case it is necessary to process on panel, cabinet or box due to reasons of modification, etc., the processing may be proceeded manually or with light machinery.

5.3 Temperature testing instrument

5.3.2 The protective casing pipe for temperature testing element may be worn and damaged by scouring of dust powder, so, protective measures such as installing of angle iron shall be taken to protect the casing pipe from direct scouring of dust powder.

5.3.3 In high temperature locations, vertical installation of temperature measuring element shall be preferentially taken into consideration. Bending of temperature measuring element is easily to occur when longer temperature measuring element is installed horizontally or temperature measuring element is installed in high temperature zone, so, bending prevention measures like supporting and fixing should be taken.

5.3.5 Pressure type thermometer measures temperature on the basis of heat expansion of medium filled in thermometer bulb of temperature testing element. In case the thermometer bulb is not fully submerged into the medium to be tested, measurement error may occur due to decreasing of heated area. The medium in the capillary shall also influence the pressure in the testing system due to heat expansion and cold shrinking, so a constant temperature must be kept for it. Meanwhile, the capillary is easily damaged by foreign mechanical strength, so the minimum bending radius and protective measures have been regulated.

5.4 Pressure testing instrument

5.4.1 Strong vibration may affect normal testing functions of pressure testing instrument and cause damage and failure to it, so vibration decreasing measures should be taken or the instrument should be moved to a ulterior place.

5.4.2 When low pressure is been measured, the pressure of liquid column in measuring tube caused by altitude difference between pressure sampling point and pressure gauge or transmitter may affect the measured value and this should be taken into consideration.

5.4.3 The scope of high pressure may be determined according to stipulations in actual national standards concerning supervision of pressure vessel and pressure piping. The structure and fabrication and fixing method of the protective cover may be determined by design unit and the owner.

5.5 Flow testing instrument

5.5.1 The regulation in the original code concerning installation of flange which clamps tightly the throttling element has been modified to installation of throttling element and the modification shall be based on the actual national standard 《Throttling Device for Flow Measurement – Measurement for Flow of Fluid Full of Round Pipe with Orifice, Nozzle and Venturi Tube》GB/T 2624 – 1993.

5.5.2 The mode of installation of differential pressure gauge or differential pressure transmitter shall be regulated definitely by design.

5.5.3 ~ 5.5.10 The length of straight pipe section on upper reach of rotor meter has no obvious effect on measurement. The length of straight pipe section on upper and lower reach of different flow meters shall be explained in product technical files and regulated by design document and construction shall be made according to design document. The regulations on installation position and flow direction of fluid is to meet the requirement on instrument application and to ensure measurement accuracy. Normally, the requirements on length of straight pipe section on upper and lower reach of flow meters are as follows:

---- rotor meter, not lower than 0 ~ 5 times pipe diameter on upper reach and no requirement on lower reach;

---- target type flowmeter, not lower than 5 times pipe diameter on upper reach and not lower than 3 times pipe diameter on lower reach;

---- turbo flowmeter, not lower than 5 ~ 20 times pipe diameter on upper reach and not lower than 3 ~ 10 times pipe diameter on lower reach;

---- vortex flowmeter, not lower than 10 ~ 40 times pipe diameter on upper reach and not lower than 5 times pipe diameter on lower reach;

---- electromagnetic flowmeter, not lower than 5 ~ 10 times pipe diameter on upper reach and not lower than 0 ~ 5 times pipe diameter on lower reach;

---- ultrasonic flowmeter, not lower than 10 ~ 50 times pipe diameter on upper reach and not lower than 5 times pipe diameter on lower reach;

---- volumetric flowmeter, no requirement;

---- orifice, not lower than 5 ~ 80 times pipe diameter on upper reach and not lower than 2 ~ 8 times pipe diameter on lower reach;

---- nozzle, not lower than 5 ~ 80 times pipe diameter on upper reach and not lower than 4 times pipe diameter on lower reach;

---- venturi tube, bending tube, wedge shaped tube, not lower than 5 ~ 30 times pipe diameter on upper reach and not lower than 4 times pipe diameter on lower reach;

---- even speed tube, not lower than 3 ~ 25 times pipe diameter on upper reach and not lower than 2 ~ 4 times pipe diameter on lower reach;

For detailed requirement on straight pipe section on upper and lower reach of orifice, nozzle and venturi tube, please refer to Annex A of this code.

5.6 Material level testing instrument

5.6.2 The requirement on perpendicularity of buoy is not regulated, but the buoy must be installed vertically without touching the buoy chamber. The installation height of the buoy shall be determined by design document.

5.6.5 Refer to explanations for capillary in article 5.3.5.

5.6.6 Special attention must be paid to installation nuclear radiation type instrument, so it is required to set down installation scheme. The scheme shall include requirement on transportation, installation personnel, special tools and method, as well as corresponding protective measures to be taken.

5.7 Mechanical performance testing instrument

5.7.1 To ensure the load sensor not be damaged due to overload or impact during installation, regulations have been made for installation procedure and requirement. During installation, hoisting jack and temporary packing block may be applied to support the vessel and locate it and the load sensor shall be installed after position of the vessel has been adjusted. Welding of pedestal shall be finished before emplacement of the sensor. To guarantee an exact measurement, no attached force other than weight of the vessel and the material to be weighed shall be existed during weighing. Therefore, method of soft connection such as using flexible jointing element shall be applied to connect foreign pipeline or structure other than object to be weighed to the vessel.

5.7.3 The typical ones in this category of instrument include shaft displacement, vibration and rotating speed supervision systems. The installation and testing of the instrument shall combine with installation and testing of mechanism closely. Certain measuring probes need to be tested for their performance curve to make sure that the measuring scope of the measuring probe is within the straight-line section of the performance curve and this work shall be finished before installation and fixing of the probe.

5.8 Instruments for composition analysis and physical property testing

5.8.1, 5.8.2 This code only gives regulations for sampling pretreatment and sample discharge of normal analytical instrument and the specific installation and requirement of the analytical instrument shall observe explanations of product technical files.

5.8.3 Humidity means content of gaseous steam. The provision of this article is to guarantee normal measuring conditions for humidity measuring element.

5.9 Other testing instrument

Other testing instrument means the instrument not within the scope of normally mentioned testing instrument, which measures temperature, pressure, flow, material level, mechanical performance, composition analysis and physical property.

5.10 Actuator

5.10.1, 5.10.2 The installation position of control valve is normally marked in the construction drawing of piping profession. The construction shall be conducted by piping profession and cooperated by instrument profession..

5.10.6 The provision of this article is to guarantee that when heat displacement occurs with process piping, the control and actuating mechanism shall not be damaged.

5.10.8 To ensure the control system pipeline being full of liquid and the gas in the liquid being able to be discharged from the liquid, the installation position of liquid driven actuator shall be lower than controller.

5.11 Control instrument and comprehensive control system

Normally manufacturers of comprehensive control system provide technical document about installation requirement and construction shall be proceeded according to installation descriptions.

5.11.1 ~ 5.11.3 Element, circuit and equipment in technical field of electronics, communication and computer have been extensively adopted in the comprehensive control system. The provision of these regulations is to guarantee the requirement of the comprehensive control system on preservation and working environment and is in favor of safety and protection of instrument apparatus, also in favor of insurance of installation and testing quality and construction management. When normal air conditioning and firefighting facilities are still not available, temporary facilities may be established.

5.11.4 The static electricity carried by human body or other object may damage certain electronic components touched and this shall be prevented from occurring. Anti-static electricity packing may be applied and operation may be proceeded using protective facilities.

5.12 Power supply equipment for instrument

Power supply equipment for instrument includes power supply system for instrument from electric power supply and the power supply system of instrument apparatus itself, for example, power panel and cabinet, power box, power supply and distribution circuit, as well as corresponding switches, transformers, rectifiers, protection and supervision equipment, some of them shall be installed by electricity profession. In addition to stipulations given in this code, the regulations relative to low voltage electric fittings and storage cell as given in the actual national standard《Code for construction and acceptance for installation project of electric appliance》GB 50254 – 96 shall also be executed for normal electrical installation and testing work.

5.12.2 The type, specification and installation position of power box shall be determined by design document, attention shall still be paid to the special environment conditions of the site during construction.

5.12.6 This article is quoted from the regulations on electric clearance and creepage distance for secondary circuit in the actual national standard《Code for Construction and Acceptance for Engineering Panel and Cabinet Installation in Electrical Plant and for Secondary Circuit Tie Line》GB 50171 – 92, so as to keep them agreeable with each other.

5.12.7 The terminal blocks of heavy and light current shall be established separately, in case the heavy and light current are to share one block, they shall be separated by vacant terminals.

5.1.2.9 The provision of this article is to guarantee personal safety and equipment safety during procedure of installation, testing and operartion.

6 Installation of instrument circuit

6.1 General regulations

6.1.2 Though most of instrument cable and wire are using low working voltage, the testing and control signal in the work are mostly on level of millivolt or milliampere. In order to achieve the minimum electric leakage when signal is passing through the circuit, thus to ensure its accuracy, the requirement on insulation performance of cable and wire is rather strict. Even in rainy and moist area, although the climate executes severe influence on insulation performance of cable and wire, so long as insulating layer is not damaged, the value of insulating resistance between core wires, and between core wire and protective sleeve may be higher than 5MΩnormally. As for special required cable and wire with different requirement on their insulating resistance value, inspection shall be made according to the regulated values given in the manufacturer's specification.

6.1.7, 6.1.8 These regulations are provided to ensure safety of circuit during operation and to avoid circuit damage due to environment influence. In the relative product standard concerning rubber and plastic insulating cable, it is regulated that when long period working temperature of cable exceeds 65℃, heat insulation measures shall be taken.

6.1.9 The regulation on distance between circuit and heat insulated equipment or piping is on purpose for easier maintenance.

6.1.12 The provision of terminal redundancy is in favor of construction and maintenance. The compensation redundancy remained at control joint and settlement joint is on purpose to avoid circuit damage.

6.1.13 When there are too much intermediate connections in circuit, the reliability of circuit operation may be affected, so, normally there shall be no intermediate connections. But, sometimes, the circuit is too long or it splits in the middle part, the intermediate connections shall be inevitable. In these cases, connectors shall be put into the junction box for easier maintenance. To avoid the circuit being corroded by welding fluid of acidity, etc, non-corrosion welding fluid shall be applied during welding.

6.1.15 Provision of this article is to prevent the instrument and its parts being damaged during measurement of insulting resistance.

6.1.18 In order not to damage strength of concrete component, it is regulated in this article that installation holes are not advisable to be started on concrete beam or pillar, with exception of those for small expansion bolts.

6.2 Fabrication and installation of support

6.2.2 Certain specific method and principle for fixing of support are given in this article in order to ensure installation quality and to facilitate construction. When support is to be installed on equipment or pipeline, it must be taken into consideration that the safety operation shall be ensured and original strength and material performance of the equipment or pipeline shall not be damaged.

6.2.3 When installing cab, le tray and protective tube, the distance between supports mainly depends on the strength of the cable tray and the protective tube themselves. There are a lot of factors in this sphere, such as specification of the cable tray and the protective tube and quantity of cable in the tray, all these must be taken into consideration. It is regulated in this article that the distance between supports of the protective tube is advisable to be 2m and the inter-support distance may be increased or decreased during construction according to the specific situation at site.

6.2.4 To lay the cable directly on the support is seldom proceeded in production plants. The determining of distance between supports for cable is mainly according to the consideration that no obvious bending should occur after cable laying. This article has made reference to regulations concerned in the actual national standard《Code for Construction and Acceptance of Cable Circuit in Installation Project of Electrical Appliance》GB 50168 – 92.

6.3 Installation of cable tray

6.3.2 Cable tray is equipped with galvanized or other anti-corrosion protective layer. Normally, for proper appearance, protection and insurance of installation quality, the cable try is connected with bolts.

6.3.8 To prevent water or other liquid from accumulating in the cable tray, damaging insulating layer of cable or entering instrument panel, water discharge opening shall be started on bottom of the cable tray.

6.4 Installation of protective tube

6.4.3 The provision of this article is to ensure a successful laying of cable or wire into the protective tube without damage of the cable or wire.

6.4.4 Installation of wire-pulling box shall be in favor of wire pulling, maintenance and avoiding the conducting wire being damaged.

6.4.7 Provision of regulations on method and requirement for connection of protective tube is to make the protective tube able to protect cable and decrease interruptions.

6.4.8 In order to prevent water or other liquid from entering internal of testing element, instrument, instrument box, junction box and wire-pulling box, sealing and waterproof measures shall be provided when connecting protective tube. For convenient maintenance and dismantling, it is regulated to apply flexible metal pipe connection for connecting testing element and instrument.

6.4.12 When cable passes through wall, a piece of protective tube or coverage shall be embedded in the wall, so as to protect the cable. For more convenient civil construction, the length of the protective tube or the coverage stretched out of the wall shall not exceed 30mm.

6.4.14 To prevent water or other liquid on the ground from entering the protective tube, when the protective tube is led out from underground, its nozzle shall be higher than ground level. The data in the article has adopted regulations concerned as given in the actual national standard《Code for Construction and Acceptance of wiring engineering of 1kV and below in Installation Project of Electrical Appliance》GB 50258 – 96.

6.5 Laying of cable and wire

6.5.1, 6.5.3 Modifications have been made to stipulations in the original code in reference to the actual national standard《Code for Construction and Acceptance of Cable Circuit in Installation Project of Electrical Appliance》GB 50168 – 92.

6.5.5 Classification and separation are on purpose to decrease interruptions between circuitries with different signals and different voltage levels.

6.5.8 The provision of this article is in favor of safety operation and easy maintenance of cable.

6.5.9 The purpose of preparation of cable head (by sealing end of cable)is mainly to protect the cable from being invaded by hazardous gases like moisture, etc., that may lead to damage of insulation of core wire.

6.5.13 The compensating conductor is different from cable. Its outside insulating layer is much simpler than that of the latter, and is easily impaired by mechanical damage. So, when compensating conductor is placed in protective tube or laid in cable tray, it may be well protected.

6.5.14 The forming of thermo-electrical potential where compensating conductor is connected to electric may lead to measurement error. So it should be prevented.

6.5.15 Wrong connection of positive and negative polarities may lead in additive electric potential to the circuit and may ,therefore, increase measurement error..

6.5.16 Separated arrangement of protective tube may prevent interruption between electric lines and mixing of different circuitries and ensure normal operation of the circuit.

6.6 Wiring of instrument circuit

6.6.2 To prevent metal bandage from touching connection terminal and causing danger therefore, so it is regulated that the bandage shall be made from insulating material.

6.6.3 ~ 6.6.9 These regulations are provided to ensure wiring quality and facilitate installation and maintenance.

The wire number compiled by design document shall be marked as number spare core wire and in case design document did not give number for spare core wire, the work of numbering shall be proceeded at site and the number shall be recorded into construction drawing.

7 Installation of instrument piping

7.1 General regulations

7.1.3 This regulation is made to prevent the piping from being corroded, leaky or damaged.

7.1.4 Proceeding cold bending and finishing the procedure in one time operation shall be in favor of insurance of quality of material and the pipe bend.

7.1.5 This article has referred to the stipulations concerning bend radius of metal pipe in the actual national standard《Code for Construction and Acceptance of Industrial Metal Piping Project》GB 50235 – 97.

7.1.9 Keeping axial consistent is on purpose to prevent additive mechanical stress from occurring, thus to ensure connection quality of piping.

7.1.10 Sleeve chuck connection is both reliable and convenient and should be extensively applied. In case the sleeve chuck is not available or this mode of connection is not permissible, welding connection must be applied.

7.1.11, 7.1.12 This regulation is made to keep piping in a condition of tidy and nice looking, as well as reliable operation, easy maintenance and prevention of possible damage.

7.1.13 This article provide instructive regulations for inter-support distance.

7.1.14 Provision of this article is to prevent carbonium ion from penetrate into stainless steel and, as a result, to change performance of the material of stainless steel.

7.2 Measuring tube

7.2.1 In order to ensure measuring accuracy of instrument and decrease delay, the measuring tube shall be laid as short as possible and tidy arrangement shall also be taken into consideration.

7.2.5 The additive error may be formed to positive and negative tube measuring pressure difference due to different environment temperature.

7.2.6 The liquid in instrument may flush into measuring tube when pressure fluctuates and this may be prevented when connection point is higher than instrument connector.

7.2.7 The provision of regulations against these distances is for convenient and safety construction and maintenance.

7.3 pneumatic signal piping

7.3.1 The regulations in this article is to ensure conduit clean, less of leaking point and for easy dismantling and repairing of instrument.

7.3.3 When tube bundle is being laid, its inner and outer layers shall be protected from any damage and the laying shall make it facilitate maintenance.

7.4 Piping for air supply

7.4.1 The provision of this article is to ensure clean of instrument air and normal operation of pneumatic instrument.

7.4.4 Purging and testing of air supply system is to ensure clean of piping of the whole air supply system.

7.4.5 The establishment of symbol is in favor of continuous safety air supply and prevention from misoperation.

7.5 Hydraulic piping

7.5.2 To ensure of height difference may make the liquid flow back to liquid storage tank successfully.

7.5.3 The purpose of this regulation is to avoid occurring of fire hazard.

7.5.9 To apply flexible tube to the connector which subjects to vibration and often changes its position is more reliable than rigid connection.

7.5.13 The establishment of symbol is in favor of continuous safety liquid supply and prevention from misoperation.

7.6 Instrument piping within panel, cabinet or box

7.6.3 Provision of this regulation is based on consideration of convenient maintenance for instrument piping and circuit.

7.6.4 Provision of this article is to ensure connection quality and avoid leakage and instrument damage.

7.7 Test for piping

7.7.2, 7.7.4 The fabrication of the regulation on pressure test for instrument piping has referred to the actual national standard《Code for Construction and Acceptance of Industrial Metal Piping Project》GB 50235 – 97, meanwhile, the characteristic of instrument piping has been taken into consideration.

7.7.6, 7.7.7 For selection of medium of pressure test, not only cost and convenience should be considered, the quality of the pressure test shall also be guaranteed. Meanwhile, the corrosive action from pressure test medium against the equipment and piping in the system shall be prevented.

7.7.8 ~ 7.7.10 This article has referred regulations concerned given in the actual national standard《Code for Construction and Acceptance of Industrial Metal Piping Project》GB 50235 – 97.

8. Degreasing

The content of this chapter has mainly referred to the experience in chemical and oxygen making industries as well as regulations in standards concerned.

8.1 General regulations

8.1.1 Certain stuff (like oxygen, aqua fortis, etc.) is easy to burn or explode when contacting grease. For production safety, all instrument, control valve and pipe fittings that contact these kinds of stuff must be thoroughly cleaned from oily dirt and then, after inspected and qualified, they may be installed and applied.

8.1.3 For selection of degreasing solvent, among factors that should be considered are: the strictness of degreasing requirement, degreasing ability of the degreasing agent, non-corrosive degreasing pieces, the by-product from decreasing should be easily removed from the degreasing pieces, toxicity, inflammability, volatility and cost, etc. of degreasing solvent.

8.1.4 The complicated reaction produced by mixing of degreasing solvent may result in occurring of fire or explosion emergency.

8.1.5 With existence of water, carbon tetrachloride, dichloroethane and trichlorethylene may be decomposed and create hydrochloric acid, which is corrosive.

8.1.10, 8.1.11 This regulation is provided to ensure safety.

8.2 Methods of degreasing

8.2.2 ~ 8.2.4 General methods have been regulated for degreasing of instrument, control valve and pipe fittings that are easily dismantled, not easily dismantled instrument and the inner surface of instrument tubes. The aim of these methods is to clear up oily dirt and ensure quality of degreasing.

8.3 Testing of degreasing

8.3.2 Testing method may be selected at site, based on structure features of degreased object, extent of easiness or difficulty for operation and effect inspection.

9. Electrical explosion-proof and grounding

9.1 Construction for instrument apparatus in explosion and fire hazard exposed environment

9.1.1 The regulations for equipment and circuit installation for instrument apparatus in explosion hazard exposed environment in this code is in consistency with the requirement in electrical construction codes for installation of corresponding explosion-proof electrical equipment and circuit.

9.1.2 Requirement on quality of equipment and material for instrument and electricity applied in explosion-proof project has been emphasized in this article.

9.1.3 Gases in explosion hazard exposed environment may enter instrument box, junction box and internal of instrument and electrical equipment along the space cavity around the not sealed core wire of cable and this may lead to explosion or fire hazard accident.

9.1.4 Safety measurement to avoid misoperation.

9.1.6 During procedure of operation or running, the mutual contact of current conducting part of intrinsic safety and non-intrinsic safety circuit system may lead to energy mixing. To avoid this from occurring, regulations are given in article 1, 4, 5, 6 and 7 in this section.

Guard grating and isolator are equipment relative to safety and they are used to isolate intrinsic safety system from non-intrinsic safety system. So, it is regulated in Article 8 that they should be installed in safety area.

The provision of article 10 in this section is to prevent shortcircuit spark and multi-point grounding.

9.1.7, 9.1.8 The regulations concerning separation sealing are aiming at separation of explosive mixture or flame, so as to prevent them from propagating to other parts or other areas.

9.1.11 Metal product shall not be ignited and burned.

9.2 Grounding

9.2.4 Normally, the earthed pole and earthed network of the protective grounding are designed and constructed by electricity profession and the testing value of grounding resistance shall also be provided by it.

9.2.6, 9.2.7 Because the regulations concerning grounding mode and earth resistance of grounding system from project design unit and manufacturers of computer control system and distributed control system are different, the independent setup of earthed pole and common regulations are also different. So, for grounding system, construction unit shall proceed construction according to design document of project. According to the principle of equal potential connection in electricity profession, instrument and control system, including grounding of comprehensive control system, shall finally be connected to the grounding device of electrical system and this is similar to the grounding requirement of computer system and information apparatus. The regulations given in concerning national standard and international standard may be referred to.

9.2.8 When multi-points of signal circuit are grounded, errors may occur during signal transmitting due to different earth potential. But, there exist certain systems of “floating working earth” with their signal circuit not grounded.

9.2.11 Because the situation of instrument damaged by lighting did occur, all spare core wire of cable to be grounded at same point may make them not to play the role of antenna and thus the possibility of interruption and being stroke by lightning shall be decreased.

9.2.12 Because of the existence of grounding resistance, different grounding potential may be produced on the grounding bus line in different grounding systems and, therefore, electric potential difference between grounding wires shall be formed. A current signal produced by the electric potential difference passes through the grounding wire shall create interruption in the system. To avoid this interruption, it is regulated that all groundingbranches, all busbars and all grounded terminal strips shall be isolated from each other.

9.2.14 Please refer to explanations in article 9.2.6 and 9.2.7 of this section. Normally intrinsic safety circuit itself shall not be grounded and diode guard grating is a kind of grounding type of guard grating.

10. Protection

10.1 Isolation and purging

10.1.2 The inconsistent elevation of isolators installed in pairs may result in measurement error.

10.1.4 Because seal liquid directly contacts the stuff to be measured, so proper seal liquid must be selected according to physical and chemical properties of the stuff to be measured.

10.2 Corrosion protection and heat insulation

10.2.1 The regulations in this article includes rework for corrosion protection task for the material of the original anti corrosive coating which has lost its anti corrosive coating due to reasons like processing or welding in construction.

10.2.3 Welding position is one of most possible leakage positions. So, it is regulated in this article that before pressure test, the welding position should not be painted, so that the possible leakage at welding position can be found.

10.3 heat tracing

10.3.1 Application of heavy or light heat tracing shall be determined by design document. Wrongly usage of light tracing in stead of heavy tracing may cause some stuff with lower boiling point to evaporate due to overheating of measuring tube and this may lead to measurement error consequently.

10.3.2 Application of union joint shall facilitate dismantling of traced instrument and appendixes such as valves and isolators, etc. in instrument piping.

10.3.3.1, 10.3.4.1 Separately arranged steam supply and water supply are to ensure reliable supply of heat source.

11. Instrument testing

11.1 General regulations

11.1.1 Inspection, calibration and testing of instrument before installation and application are aiming at discovery of quality problems of instrument product and damage and defect occurred during transportation and preservation of the instrument product.

11.1.2 Testing for heavy actuator may be proceeded at site like indoor warehouse, etc. Normally, establishment of testing laboratory may be based on available site equipment and conditions, permanent building facilities may be utilized. Basic conditions of the testing laboratory are regulated in this article. For requirement of testing environment of comprehensive control system, please refer to Article 11.4.2 of this code.

11.1.5 Loop test is an overall testing against instrument performance and correctness of instrument piping connection. Its target is to proceed overall inspection against design quality, equipment and material quality and installation quality of instrument and control system and confirm the quality of instrument engineering to conform to operation requirement.

11.1.7 Regulations in the original code are preserved in this article and the requirement against the basic error of standard apparatus and instrument is pretty high. Because the instrument applied in present projects is with rather high accuracy, so, for the standard apparatus and instrument to be selected for testing, their accuracy shall be higher than calibrated instrument for at least 1 grade.

11.1.9 Control room and testing laboratory are also included in construction site.

11.2 Calibration and testing of single set of instrument

General regulations on calibration and testing of single set of typical instrument are given in this book. Performance and quality of single set of instrument depends on manufacture quality. According to usual practice and actual conditions of engineering project in many years, for items for which calibration and testing conditions are not available at site, verification may be proceeded on product certificate, test report and inspection testimony provided by the manufacturer.

11.2.6 The thermoelectricity performance of thermocouple and thermo-resistance are ensured mainly by their consisting material and the normal or damage state of them may be tested by ordinary electrical measuring instrument under atmospheric temperature.

11.3 Testing of power supply unit of instrument

The content in this section means testing for independent power supply of instrument. For power supply unit on panel or in cabinet, measuring and adjusting its output voltage shall be enough.

11.4 Testing of comprehensive control system

General requirement against testing for comprehensive control system is advanced in this section according to practical experience summarized in construction of distributed control system and different computer control system for many years and normal construction procedures. Because product of comprehensive control system is of multi species, different system structure and different project scales, the compiling of technical scheme and arrangement of inspection and testing work shall be based on requirement of design document and technical files of product during construction.

11.5 Loop test and system test

11.5.1, 11.5.2 Instrument system may consist of simple loops and complicated loops. In design document, each loop and instrumentation apparatus in the loop shall be marked with item number consists of code name, symbol and serial number and a loop map for each loop shall be available. Considering site features of the engineering project, a scheme for instrument loop test and system test may be reasonably arranged according to the loop map and the inspection and control of the test progress and test quality may be proceeded according to the test record.

12. Acceptance

12.1 Conditions for hand over and acceptance

12.1.1 Because the load of instrument and load of production plant are different concepts, so the exposition of uncharged test run and on load test run are not adopted in this code and they are described separately as loop test and system test of instrument engineering and startup running of instrument engineering.

12.1.2 After installation of instrument system, loop test and system test may be conducted according to requirement of design document. After system inspection, if connection of circuit and piping are without any problem, quality conforms to the requirement of the code, no problem has been found with working performance, function and action procedure of each instrument and loop in the system, this shows that the instrument system may be put into startup running or proceed running test in cooperation with plant engineering.

12.1.3 After startup running of instrument, the instrumentation apparatus and instrument system has already played the role as they should against the object to be tested or controlled. The normal running for 48 hours means instrument engineering itself.

12.2 Hand over and acceptance

12.2.2 The form of delivery document and record tabulation may be determined according to concerning regulations of each industry and requirement of contract.

, le tray and protective tube, the distance between supports mainly depends on the strength of the cable tray and the protective tube themselves. There are a lot of factors in this sphere, such as specification of the cable tray and the protective tube and quantity of cable in the tray, all these must be taken into consideration. It is regulated in this article that the distance between supports of the protective tube is advisable to be 2m and the inter-support distance may be increased or decreased during construction according to the specific situation at site.