Article 1.0.1  The Code is prepared to design properly the low expansion air foam extinguishing system (hereinafter referred as foam extinguishing system), minimize fire losses and guarantee the safety of personnel and property.

Article 1.0.2  The design for foam extinguishing system shall comply with the relevant national principles and policies, be safe and reliable, advanced in technology, rational in economy and easy in management. 

Article 1.0.3  The Code is applicable to the design for foam extinguishing system for the process, storage , handling and application of Class A (except liquefied hydrocarbons), B and C liquids.

The Code is not applicable to the design for foam extinguishing system for ships and offshore oil platforms.

Article. 1.0.4  In addition to the specifications of the Code, the design for foam extinguishing system shall conform to the relevant standards and codes in force in the country.

 

Article 2.1.1  For non-aqueous liquids of Class A, B and C, it is recommended that protein foam liquid, fluoro-protein foam liquid or aqueous film-forming foam liquid shall be selected if                  injection foam extinguishing system is used while fluoro-protein foam liquid or aqueous film-forming liquid shall be selected if submerged injection foam extinguishing system is used.

Article 2.1.2  Alcohol-resistant foam liquid shall be used for aqueous liquids of Class A, B and C.

Article 2.1.3  Foam liquids shall be stored at a temperature of 0-40 ⁰C and in a well-ventilated dry room or shed.

Article 2.1.4  The formulation of foam liquid into foam solution shall meet the following requirements:

1.   Fresh water or sea water may be used to formulate protein, fluoro-protein and alcohol-resistant fluoro-protein foam liquid into foam solution;

2.   Fresh water shall be used to formulate gel-type and metallic soap type foam liquid into foam solution.

3.   Water that has an impact on the extinguishing performance of the foam is forbidden to be used to formulate all kinds of foam liquid into foam solution.

4.   It is recommended that the temperature of the water used to formulate foam liquid into foam solution be 4-35 ⁰C.

Article 2.2.1  The system shall be sized according to the compound factors such as the scale of the protected object, fire hazard, general arrangement, difficulty of fire suppression and set up of fire station.

Article 2.2.2  It is recommended that fixed foam extinguishing system be selected for one of the following applications

1.  Independent tank farm of non-aqueous liquids of Class A, B and C with a total storage capacity ≥ 500 m³;

2.  Vertical tank farm of aqueous liquids of Class A, B and C with a total storage capacity ≥ 200 m³;

3.  Tank farm of non-aqueous liquids of Class A, B and C, which is affiliated to enterprises with inadequate mechanical fire fighting facilities. 

Article 2.2.3  It is recommended that semi-fixed foam extinguishing system be used for one of the following applications:

1.   Tank farm of liquids of Class A, B and C affiliated to enterprises with strong mechanical fire fighting facilities;

2.   Applications with potential of fire hazard in petrochemical production area.

Article 2.2.4  It is recommended that portable foam extinguishing system be used for one of the following applications:

1.  Ground vertical tank of non-aqueous liquids of Class A, B and C with a total storage capacity ≤500 m³, single tank capacity ≤200 m³  and the height of tank wall ≤7m;

2.  Ground vertical tank of aqueous liquids of Class A, B and C with a total storage capacity <200 m³, single tank capacity ≤100 m³ and the height of tank wall ≤5m;

3.  Horizontal tanks;

4.  The areas easy to leak in the loading place of Class A, B and C liquids.

 

Article 3.1.1  The design for foam extinguishing system for tank farm and the foam solution quantity shall meet the requirements of the sum of solution consumption necessary for suppressing the fire of single tank with maximum solution consumption and solution consumption necessary for the auxiliary foam nozzles used to suppress the spreading fire of the tank.

Article 3.1.2  The amount necessary to fill up the pipes shall be included in the  total storage quantity of foam liquid for tank farm in addition to the quantity calculated with the specified supply strength, number of nozzles and continuous supply duration.

Article 3.1.3  If fixed foam extinguishing system is used, portable foam extinguishing devices such as foam hook pipe, foam nozzle and foam fire vehicle shall be provided in addition to fixed foam extinguishing devices.

Article 3.1.4  The number of foam nozzles necessary for suppressing the spreading fire of liquids of Class A, B and C shall be determined with the diameter of the tank with maximum consumption of foam solution, the number and continuous supply duration shall not be less than the specifications in Table 3.1.4.

Number of foam nozzles and continuous supply duration             Table 3.1.4

 

Diameter of Tank (m)	Number of PQ8 Nozzles  Provided (piece)	Continuous Supply Duration (min)
<23	1	10
23-33	2	20
>33	3	30

Article 3.2.1  The firing area of injection foam extinguishing system for fixed roof tank shall be calculated with the cross section  area of tank. The supply strength and continuous supply duration of foam solution shall conform to the following specifications:

I.  For non-aqueous liquids of Class A, B and C, the strength and duration shall not be less than those in Table 3.2.1-1.

Class of liquid	Supply Strength (L/min.m2)		Continuous supply duration (min)
	Fixed and semi-fixed type	Portable type
Class A & B	6.0	8.0	40
Class C	6.0	8.0	30

Class of liquid	Supply Strength (L/min.m2)	Continuous supply duration (min)
	Fixed and semi-fixed type
Acetone, butanol	12	30
Methanol,alcohol,butanone, acrylon, ethyl acetate	12	25

Note: For those aqueous liquids not listed in the table, their supply strength  and continuous supply duration of foam solution shall be determined by tests.

Article 3.2.2  The design for foam extinguishing system for outer floating roof tank shall conform to the following specifications:

I.                   The flow of foam solution shall be calculated based on the annular area between tank wall and foam weir plate, the minimum supply strength and the maximum protection perimeter of foam generator and continuous supply duration shall all conform to the specifications of Table 3.2.2;

II.                 The distance from foam weir plate to the tank wall shall be ≥1.0m. If mechanical seal is used, the height of the weir plate shall be ≥0.25m; If soft seal is used, the height of the weir plate shall be ≥0.9m. Water discharge holes shall be provided at the lowest part of the weir plate, the opening area shall be calculated based on the assumption that two 12mm x 8mm rectangular openings are provided for every square meter of annular area.

Foam Generator		Supply Strength	Protection Perimeter	Continuous Duration
Type	Flow of Solution (L/min)	(L/min.m2)	(m)	(min)
PC4	240	12.5	18	30
PC8	480	12.5	36	30

Article 3.2.3  The design for foam extinguishing system for inner floating roof tank shall conform to the following specifications:

I. For shallow-pan type inner floating roof tanks and the inner floating roof tanks with the floating pan made of fusible material, the firing area, supply strength and continuous supply duration shall conform to the specifications in Article 3.2.1 of the Code.  

III.               For single- and double-pan type inner floating roof tanks, the firing area, supply strength and continuous supply duration of foam solution shall conform to the specifications of item 1 of Article 3.2.2 of the Code, the distance from foam weir plate to tank wall shall be ≥0.55m, and the height of the plate shall be ≥0.5m.

Article 3.2.4  The foam generator for injection foam extinguishing system shall be provided according to the following specifications:

I.                    For fixed roof tank, inner floating roof tank of shallow-pan type and with the floating roof made of fusible material, the type and number of foam generator shall be determined by the flow of foam solution calculated, and the number provided shall not be less than those specified in Table 3.2.4.

 

Diameter of Tank (m)	Number of Foam Generator Provided (set)
<10	1
10-20	2
21-25	3
26-35	4

II.                 For outer floating roof tanks and inner floating roof tanks of single and double –disc type, the type and number of foam generator shall be determined according to the specification in Article 3.2.2;

III.              
The inlet pressure of foam generator shall be 0.3—0.6 Mpa, the corresponding flow of foam solution shall be calculated with the following equation:

Where  q—Flow of foam solution (L/s);

       K₁—Flow characteristic coefficient of foam generator;

       p -- Inlet pressure of foam generator (Mpa).

Article 3.2.5 The routing of foam solution pipe on the tank shall conform to the following specifications:

I.  For fixed roof tank, inner floating roof tank of shallow-pan type or with the floating pan       made of fusible material, each foam generator shall be routed out of the fire-proof embankment with separate solution pipe.

II.  For outer floating roof tank and inner floating roof tank of single and double –disc type, every two generator shall be routed with one common pipe at the bottom of the vertical pipe of foam solution out of the fire-proof embankment. When three or more generators share one pipe at the bottom end of the vertical pipe of foam solution being routed out of the fire-proof embankment, control valve shall be provided in each vertical pipe of foam solution. The solution flow necessary for each foam solution pipe of fixed foam extinguishing being routed out of the fire-proof embankment shall not be greater than the supply amount of one fire vehicle.

III. The vertical pipe of foam solution connecting foam generators shall be fixed with clips on the tank wall, with a clearance ≦3m. Rust cleaner shall be provided at the bottom end of the vertical pipe of foam solution. The vertical pipe of foam solution shall be connected to the horizontal pipe with metal hose. It is allowed that outer floating roof tank be not provided with metal hose;

IV.               The ladder and platform for outer floating roof tank shall be provided the pipe connection with cover, the connection is routed along the tank wall to 0.7m above the ground or out of the fire-proof embankment, and corresponding connections shall be provided.

Article 3.2.6 The routing of foam solution pipe within the fire –proof embankment shall conform to the following specifications:

I.                    The horizontal pipe of foam solution shall be routed on pipe stand or support, however not fixed with them.

II.  The pipe of foam solution shall be inclined with 30% slope to the fire-proof embankment.

Article 3.2.7  The routing of foam solution pipe out of fire-proof embankment shall conform to the following specifications:

I.                    It is recommended that hydrants be provided in the foam solution pipe, the number shall be determined according to the number of nozzles and the radius of protection  specified in Article 3.1.4 of the Code;

II.                 The foam solution pipe shall be inclined with 2% slope to vent valve, the control valve in the pipe shall be located out of the fire-proof embankment and be provided with clear mark;

III.               High vents shall be provided in foam solution pipe.

Article 3.2.8 The design flow for foam solution pipe shall be ≤3m/s, the hydraulic calculations shall be done based on the national standard in force “Design Code of Auto Spraying fire extinguishing system “.

 

Article 3.3.1 The submerged injection foam extinguishing system shall not be adopted for tanks of aqueous liquids of Class A, B and C, neither should it be used for outer floating and inner floating roof tanks.

Article 3.3.2 For ground fixed roof tanks, when submerged injection foam extinguishing system  and fluoro-protein foam liquid is used, the following specifications shall be satisfied:

I.   The supply strength of foam solution shall ≥6L/min.m², foam expansion of 3 shall be used;

If the storage temperature exceeds 50 ⁰C or the viscosity is greater than 40mm²/s, the supply strength of foam solution shall be determined by tests;

II.                  The continuous supply duration of foam solution shall be 30 min;

III.               The speed of foam entering into oil shall be ≤3m/s;

IV.               The injection nozzle shall be inclined upward with an inclined angle of 45⁰, the length of injection pipe intruding into the tank shall be ≥10 times the diameter of injection pipe. If only one injection nozzle is available, it shall be located at the center of the tank; if more than one nozzle is provided, they shall be located evenly with an approximate equal flow for each injection nozzle;

V.                 Foam injection nozzle shall be installed above the water layer of the tank. The number of injection nozzle provided shall not be less than that specified in Table 3.3.2.

 

 

Diameter of Tank  (m)	Number of Injection Nozzle (piece)
<23	1
23-33	2
>33	3

Article 3.3.3  The high back-pressure foam generator for submerged injection foam extinguishing system shall be provided as follows:

I.   The number of generators provided shall be determined according to the foam solution flow calculated in Article 3.2.2;

II.The outlet pressure shall be greater than the sum of pipe resistance and hydraustatic pressure inside the tank;

III.               The inlet pressure shall be 0.6-1.0 Mpa, the corresponding flow of foam solution shall be calculated with the following equation:

Where q—the flow of foam solution (L/min);

      K₂—the flow characteristic coefficient of high back-pressure foam generator;

      p—the inlet pressure of high back-pressure foam generator(Mpa).

Article 3.3.4  The foam pipe of submerged injection foam extinguishing system shall be routed according to the following specifications:

I.    The foam pipe inside the fire-proof embankment shall be routed according to Article 3.2.6 of the Code.

II.                  Vent valves shall be provided in the foam pipe out of the fire-proof embankment, and with 2% slope to vent valves; no hydrants and gas valves shall be provided.

Article 3.3.5  The hydraulic calculations shall conform to the following specifications:

I.  The hydraulic calculations shall be based on the following equation:

H = CQ^1.72                                 (3.3.5)

Where h—Resistance loss of unit length of foam pipe (Pa/10m);

      C—Coefficient of pipe resistance loss

      Q—Foam flow (L/S)

II.                 The coefficient of pipe resistance loss shall be selected from Table 3.3.5-1.

Pipe Diameter (mm)	Coefficient of Pipe Resistance Loss
100	12.920
150	2.140
200	0.555
250	0.210
300	0.111
350	0.070

III.               The valve in foam pipe and equivalent length of some pipe fittings shall be determined according to Table 3.3.5-2.

Nominal diameter  (mm)   category of pipe fitting	150	200	250	300
Gate valve	1.25	1.50	1.75	2.0
900 elbow	4.25	5.00	6.75	8.00
Swing check valve	12.00	15.25	20.50	24.50

Article 3.3.6  For submerged injection foam extinguishing system, the routing of foam solution pipe and hydraulic calculations shall be determined according to Article 3.2.7 & 3.2.8 of the Code.

Article 3.3.7  For submerged injection foam extinguishing system, steel control valve and check valve shall be provided in foam pipe within the fire-proof embankment, and steel control valve be provided out of the embankment.

Article 3.4.1  The foam spraying system is applicable for the protection of Class A, B and C liquids which might leak and with inadequate mechanical fire fighting facilities.

Article 3.4.2  For foam spraying system, if suction type sprinkler is used, protein, fluoro-protein, aqueous film-forming foam or alcohol-resistant foam liquid shall be used while aqueous film-forming foam liquid shall be used if non-suction type sprinkler is adopted.

Article 3.4.3  If protein foam liquid or fluoro-protein foam liquid is used to protect non-aqueous liquids of Class A, B and C, the supply strength shall not be less than 8L/min.m², and the continuous supply duration shall not be shorter than 10 min.

If aqueous film-forming foam liquid is used to protect non-aqueous liquids of Class A, B and C or alcohol-resistant foam liquid is used to protect aqueous liquids of Class A, B and C, the supply strength and continuous supply duration of foam solution shall be determined by tests.

Article 3.4.4  The head-spraying foam sprinkler shall be located 3-10 m above the lowest part of the protected object; if it is beyond this range, it shall be determined by tests.

Article 3.4.5  Automatic fire alarms shall be provided for foam spraying system. They shall be in auto control mode, but also provided with manual control device.

Article 3.5.1  It is recommended that foam pump station  be constructed combining with fire fighting water pump house, with a fire –resistant grade not lower than II. The distance from pump station to the protected object shall not be less than 30m, and it shall not take longer than 5 min. to delivery foam or foam solution to the farthest protected object after the start-up of foam pump .

Article 3.5.2  It is recommended that foam pump be started by self dumping, no less than two suction lines shall be provided for each group of foam pumps, when one line fails, the other one can handle all the water consumption.

Article 3.5.3  It is recommended that hydrants be provided in foam solution pipe in and out of the foam pump station; and foam nozzles be provided in foam pump station.

Article 3.5.4  Standby pump shall be provided for foam pump , its capacity shall not be less than the maximum capacity of one pump. No standby pump shall be provided if one of the followings is met:

I.       The total storage capacity of non-aqueous liquids of Class A, B and C is less than 2500m³ and the capacity of single tank is less than 500m³.

II.     The total storage capacity of aqueous liquids of Class A, B and C is less than 1000m³ and the capacity of single tank is less than 100m³.

Article 3.5.5  Backup power shall be provided for foam pump station, combustion engine can be used as power source if it is difficult to supply by double power supplies or double circuits.

For foam pump station without standby pump, no backup power is necessary.

Article 3.5.6  Water level indicator shall be provided for the water pond in the pump station. The pump station shall be provided with communication devices which can communicate directly with the fire station or fire security department of the unit.

 

Article 4.1.1  The system assemblies such as foam pump, foam proportioner, foam solution pressure vessel, foam generator, valves and piping, shall be the acceptable products inspected and tested by the fire product quality monitoring and testing center of national grade.

Article 4.1.2  The painting of major system assemblies shall conform to the following specifications:

I.                     Foam solution pipe, foam pipe, foam liquid tank, foam proportioner and foam generator shall be painted red;

II.                 Foam pump and feedwater pipe shall be painted green.

Note: If there are many kinds of pipe and their paintings are in contradiction to those of process pipes, corresponding color belts or color rings can be applied.  

Article 4.2.1  It is recommended that centrifugal pump with smooth performance curve be selected for foam pump. If  ring pump type proportioner is used, the design flow of pump shall be 1.1 times that of calculated flow.

Article 4.2.2 Vacuum pressure gauges or vacuum meters shall be provided in the feed line of foam pump.

Pressure gauge, check valve or return line with control valve shall be provided in the discharge line of foam pump. 

Article 4.2.3  If ring pump type proportioner is used, the following specifications shall be satisfied:

I.                    It is recommended that discharge back pressure be zero or negative, when the suction pressure is 0.7—0.9Mpa, its discharge back pressure may be 0.02—0.03Mpa;

II.                 The suction shall not be 1m higher than the lowest level of foam liquid in the tank.

III.               If the discharge back pressure is greater than zero, precautions against the `back feeding of water into foam liquid tank shall be taken in the suction pipe;

IV.               It is recommended that no less than one back up proportioner be provided for foam proportioner.

Article 4.2.4  If pressure type foam proportioner is used, the following specifications shall be satisfied:

I.          The inlet pressure shall be 0.6—1.0 Mpa;

II.                 The pressure loss shall be calculated as 0.1 Mpa.

Article 4.2.5  If pressure balanced type proportioner is used, the following specifications shall be satisfied:

I.       The water inlet pressure shall be 0.5—1.0 Mpa;

II.       The inlet pressure of foam liquid shall be greater than that of water, however the pressure difference shall not be greater than 0.2 Mpa;

Article 4.2.6  When foam eductor is used, it shall be connected in series with fire hose, and the outlet pressure shall meet the requirements of the inlet pressure of foam devices.

Article 4.3.1  Constant pressure vessels shall be selected when ring pump or pressure-balanced-foam proportioning process is adopted; Pressure vessel shall be selected when pressure type foam proportioning process is adopted.

Article 4.3.2  It is recommended that the vessel be fabricated by corrosion resistant materials; When steel vessel is used, the inner wall shall be treated with anti-corrosion measures .

Article 4.3.3  It is recommended that constant pressure vessels be of horizontal type or vertical cylindrical type, level gauge,  rust cleaning hole, feeding hole, manhole, sampling hole, breather, or vent pipe with control valve shall be provided.

Safety valve, rust cleaning hole, feeding hole, manhole, or sampling hole shall be provided on pressure vessel.

Article 4.4.1  It is recommended that injection foam generator be located evenly around the vessels.

Article 4.4.2  The high back pressure foam generator shall be located out of the fire-proof embankment, sampling hole shall be provided in the outlet pipe.

Article 4.5..1  It is recommended that motor-driven valve, pneumatic valve or hydraulic valve be used if the diameter of foam pump discharge pipe is greater 300 mm.

Valves shall be provided with clear opening/closing sign.

Article 4.5.2  Steel pipe shall be used for foam and foam solution pipe.

The outer wall of the pipe shall be treated with anti-corrosion measures and asbestos rubber gaskets shall be used at the flange connections.

Description	Description used before	Explanation
Low expansion air foam		Foam with expansion less than 20 when foam solution is sucked up by air.
Class A liquid	Inflammable liquid	Liquid with a flash point <280C.
Class B liquid	Inflammable  (flammable ) liquid	Liquid with a flash point ≥280C  to   600C.
Injection foam extinguishing system		Extinguishing system with foam being injected into the vessel from above the liquid level.
Submerged Injection foam  extinguishing system		Extinguishing system with foam being injected into the  vessel from below the liquid level.
Foam solution		Water solution formulated with foam liquid and water with certain proportion.
Fixed foam extinguishing system		Extinguishing system consisting of fixed foam pump, foam proportioner, foam generator and piping.
Semi-fixed foam extinguishing system		Extinguishing system consisting of fixed foam generator, foam vehicle or mechanical pump and connected with fire hose; or consisting of fixed foam pump, corresponding pipes and portable foam generator and connected with fire hose.
Portable foam extinguishing system		Extinguishing system consisting of fire vehicle or mechanical fire pump, foam proportioner, portable foam generator and connected with fire hose.
Fixed roof vessel		Vertical cylindrical vessel with a fixed roof.
Outer floating roof vessel		The roof of the vessel is floating above the level and floats up and down with the level.
Inner floating roof vessel		Fixed roof vessel, there is a inner roof floating up and down with the level.
Dual-pan type inner floating roof		The floating roof is of floating  bin type, the floating bin is separated by several division plates.
Single-pan type inner floating roof		Part of the floating roof is of floating bin type.
Shallow-pan type inner floating roof		The floating roof is of pan shape without bin.
Foam spraying system		Fixed extinguishing system using nozzles to spray foam
High back pressure foam generator	Submerged injection foam generator	Foam solution can suck up air through this device and generate low expansion foam, certain pressure exists at the outlet.

 

 

I.  It is required in this provision to define the wordings used to express the degrees of strictness. In implementation, deal with each case in accordance with the following statements of wordings:

(1). Wordings used to express requirements that must be very strictly followed without any deviation therefrom.

Wording in positive form to be used is "shall", and the equivalent expressions are "it is necessary (required to)…", " only … is permitted…".

Wording in negative form to be used is "shall not", and the equivalent expressions are " it is not allowed (permitted, acceptable or permissible)…".

(2). Wordings used to express something shall be done in this way under normal conditions.

Wording in positive form to be used is "shall".

Wording in negative form to be used is "shall not" or "is required to be not …", "it is not allowed (permitted, acceptable, permissible)…".

(3). Wordings used to expression the action steps are allowed with possibilities for selection or when the conditions are permissible it should be done first:

Wording in positive form to be used is "should" or "may", and the equivalent expression is "it is recommended that…".

Wording in negative form to be used is "should not", and the equivalent expression is "it is not recommended …".

II.  Wording of “shall be executed according to …….” or “Shall comply with the provisions of…….” is used when other relevant codes and standards shall be followed.