【 Weak current College 】 duplex garage closed aqueous film forming foam spray system design---Power By 【 China power house network 】

Summary: from the design perspective details closed aqueous film forming foam spray system composition and working principle and computing, explains the advantages and disadvantages of the system, called for the timely formulation of the corresponding specification.

Keywords: duplex garage; automatic foam spray;

Chinese book classification number: TU998.1 document identification code: C article number: 1000-4602 (2000) 04-0037-02 multiple use of elevated storage garage, simple structure, small size, low investment, at the same time changes according to the venue size, arrangement, and is widely used in hotels, institutions, and other vehicles denser residential district. In Wolong Pavilion design underground compound garages and found that the traditional sprinkler systems is not a good fit for firefighting tasks, in a safe and reliable, economical and technically advanced principles, while drawing on the experience of developed countries, using aqueous film forming foam spray system, i.e. in a traditional automatic sprinkler system configuration for foam mixture consisting of devices that can spray and spray foam, fixed fire-extinguishing system. Under the protection of the object can be divided into open-systems and closed circuit system, this article focuses on closed aqueous film forming foam spray system. 1 system design of theoretical basis of the garage, garage, parking design fire protection standard (hereinafter referred to as the "garage code) GB 50067 — 1997 No. 7.2.3.2 stipulates: mechanical garages, double garage and nozzle, except in the roof or floor press parking above the layout, you should press parking pallet location hierarchy layout and should set the nozzle plate above the collector, that is both the head and the side nozzles to fire. However, in practical engineering design and construction, layout side above the print head nozzles and set hot plate very difficult and is not optimal. The garage specification section 7.3.1 and the sprinkler system design specifications "(hereinafter referred to as the" spray standard ") GBJ 84-85 (feed reader), 3.1.10 stipulates that automatic sprinkler system able to control the fire, but is not suitable for rapid fire fighting, and after the spray foam extinguishing water cooling is needed to continue; prevent recurrence of premises or parts of the use of automatic sprinkler-system of foam extinguishing, and may use the water film and other fire extinguishing efficiency higher fire extinguishing agent. 2 system composition and working principle of the system from the traditional design of wet sprinkler systems and extensive proportioner, foam liquid storage tanks.
When a fire occurs, the temperature, located on the reserve of the closed-head cracked water flow indicator movements, regional and fire control centre alarm display fire zone; wet alarm valve changes in water pressure, hydraulic alarm actions and automatic alarm, the pressure switch actions start the pump and at the same time open the foam liquid storage tank inlet of solenoid valve. When the water flow through the foam liquid storage tanks, some water will flow into the foam liquid storage tanks for the storage of foam liquid in extrusion of capsules, and through extensive proportioner proportionally (3% or 6%) the formation of foam mixed liquid sent to put out the fire double garage on the ground floor. Parking of a car and use ordinary gasoline for use 3%, the use of lead and parked unleaded petrol car with 6%. 3 design and calculation of the system by pressing the relevant specification ① conduct traditional wet sprinkler system design and layout of the nozzle.
② Select foam fire extinguishing agent. Design selection more mature aqueous film forming foam fire extinguishing agent is the United States 3 m special developed fluoride foam AFFF (Aqueous Film Forming Foam). This kind of light-water-foam fire extinguishing agent is divided into AFFF and light alcohol type AFFF/ATC, the fire-fighting mechanism is: light-water-foam fire extinguishing agents and water (freshwater and seawater can) in mixed to form homogeneous and stable foam layer to isolate the air in the foamy water lowers the temperature of the oil, while in the foam layer following may form a layer of sealing and rapid diffusion of water into a layer of thin films, this water can be layered films quickly burning oil surface diffusion and seals (Seal) isolated from the air, so you can prevent heat oil resulting from flammable gas (Vapor). In addition to the light-water-alcohol-water-type characteristic, when extinguishing water soluble or polarity of fuel to the fire to the fuel surface forming a layer of condensation polymerization layer (Cohesive Polymeric Layer), this can prevent the thin layer of aqueous film forming foam and film is polar solvent, to give full play to the fire-fighting capabilities. In addition this aggregation layer also has a regeneration function, even if the aggregation layer because of fracture is stirred after automatic forming another new aggregation layer.
United States 3 m recommended storage of vehicles equipped with lead-free petrol fuel, you can use 6% AFFF/ATC as closed aqueous film forming foam spray the foam fire extinguishing system.
③ Select foam liquid storage tanks and large scale blender. Our formulation of the principle of "norms" are: a the development of a mature. At present not yet launched aqueous film forming foam liquid spray test, specification nor to the water film-forming foam liquid protect non-water soluble liquid supply strength. Design reference to the United States National Fire Protection Association NFPA11 — 83 States: use aqueous film forming foam liquid, its minimum foam liquid supply strength 4.1 L/(min.m2). Whereas the existing provisions of the spray specification: the risk level in the most negative point protection area of 200 m2, sprinkling strength 6.0 L/(min.m2). Therefore, system design parameters for: foam liquid supply strength 6.0 L/(min.m2), protection of an area of 200 m2, continuous spray foam time ≮ 10 min. Foam extinguishing agent for ATC, proportional 3M.AFFF/6%.
Amount of foam mixed = 200 × 6.0 × 10 = 12 000 L
Foam concentrate capacity = 12, 000 × 6% = 720 L
Double garage with double-column-rack, taking into account the portion of the fire when spraying foam be rack pallet isolation block of loss, the actual design of foam concentrate storage doubled, i.e. v total= 720 × 2 = 1 440 L. Selection of Xi'an sentry fire-fighting equipment manufacture factory production of foam liquid pressure 1.5 m3 tank, large-scale model ZPHY proportioner — 100/50. ① 4 strengths and weaknesses of the system without changing the traditional wet sprinkler systems structure adds on buildings with flammable and combustible liquids when extinguishing fire place with the reliability of the fire.
② can effectively fight fire. The initial fire: nozzle spray water cooling control failure, fire, fire extinction phase: spray foam, to reduce burning body surface temperature, cut off from the oxygen in the air to prevent heating oil producing flammable gas; end: maintaining the traditional sprinkler system features, continue to spray water cooling to prevent renewed until the fire is completely out.
③ closed aqueous film forming foam spray system for automatic sprinkler systems in buildings in compound garages or large garage with less investment, fire extinguishing efficiency. For independent construction of compound garages, parking, recommended the use of high-expansion foam fire extinguishing system.
④　3M. AFFF foam of ATC/is extremely stable fluoride, preferably up to 20 years, odour, non-toxic, non-corrosive fire-fighting equipment, and do not pollute the environment. The current dependence on imports, more expensive. 5 conclusion closed aqueous film forming foam spray system has a safe and reliable, economical and practical, fire extinguishing efficiency, suitable for extinguishing the flowing a, b, c liquid fire, underground parking, fuel boiler house fire and flammable liquids and solids storage warehouse fire. But the foam also rely on imports (cost), and domestic has not yet developed specific design, construction, acceptance, to the difficulties of design and construction. Hope that the sector to formulate some product standards and specifications for the design and construction, fire-fighting technology in China's more practical and efficient. Zheng He (Shenzhen Yue-Peng architectural design co., Ltd., Guangdong Shenzhen 518027)
Yang sword (Tianjin City, Tianjin 300040 gonganxiaofangju)
Qi civilization (Shenzhen Longgang Shenzhen Guangdong dexing real estate development company, 518001)