【 Weak current College 】 on simple automatic sprinkler system nozzle selection of

Summary: simple automatic sprinkler system (hereinafter referred to as "simple spray system") has attracted the attention of the fire community, the relevant standards or specifications are in preparation. Just simple spray system on nozzle selection, offer some insights for system design-time reference.
Key words: simple and fast low pressure spraying system; sprinkler; nozzle selection

1 Introduction
Simple spray system also known as "domestic spraying system" or "topical spray systems", mainly on some existing buildings, the old brick buildings as well as in the building of small and medium-sized entertainment, small shops and other places, there is a fire resistance rating of low, flammable materials, fire-fighting facilities are weak, personnel are crowded, evacuation difficulties in specific situations. This type of architecture in typical fire case and in particular, the consequences are extremely serious. Take appropriate technical measures to simplify the spray system, on the implementation of such buildings is very necessary that truly reflects the "as main, againstdisappears medicine" and "protection of personal safety" approach and spirit.
2 problem
Simple spray system should be used and what kind of nozzle to satisfy the system requirements? from the simple analysis of the characteristics of the spray system. Simple spray system is compared with the conventional sprinkler system is proposed to simplify the system, easy to install. But to simplify the system is not a simple choice of the parts of the system, but rather to take more advanced and reliable technology. Of these, the most critical nozzle should be part of. Analysis of the characteristics of this type of system, is bound to the nozzle made a number of special requirements.
(1) for quick response. As a result of the simplification of the system with the ultimate in system alert feature, water capacity declined. Therefore, a simple spray system is set up for the initial fire, this requires a sprayers response speed
Degrees to accelerate, must be able to make a rapid response in the early days of fire, use quick response sprinklers.
(2) large flow. Due to the system of water supply capacity has declined, simple spray system working pressure is lower, in order to meet the required water spraying extinguishing the strength requirements, nozzle should have the larger flow coefficient.
(3) low pressure water characteristics. Ibid., nozzle should have good characteristics of low pressure water distribution, meet the requirements of the sprinkler head protection areas.
3 head of design
According to the above requirements, in nozzle design aspects taken some measures:
(1) the introduction of fast response sensor glass ball nozzle, RTI ≤ 50;
(2) selection of large-diameter nozzle framework, K = 115;
(3) on the splash plate is optimized low voltage design, meet the performance requirements of water distribution.
As a result of the 3 speed response Thermo glass balls, the intensity of the heat-sensitive element has declined, the average working load nozzles are limited. It is therefore recommended that a simple spray system for maximum working pressure ¡ü1 0.6MPa.
4 fire test
Fire extinguishing performance is an important technique for sprinkler. Reference to the relevant foreign test method standards, on the following test for fire sprinkler.
4.1 test space (see Figure 1)
Laboratory size: long 7m× wide 3.2m× high 3m, open a door, high 2m× wide 1.2m, two Windows, high 1.2m× wide 1.0m, one of the Windows and a door in the same wide 3.2m wall, another window on the opposite wall.
4.2 nozzle arrangement (see Figure 1)
Laboratory Center layout of two action temperature 68 ° c in a quick response, low-pressure sprinkler nozzle spacing as 3.1m.
4.3 temperature measurement point settings (see Figure 1)
Thermocouple layout in two lines in the head to the ground, a vertical line from the ceiling 76mm, one from the ground surface temperature thermocouple 200mm, plus a bezel above, avoid direct is water wet.

Figure 1 laboratory layout
4.4 fire model
Wood Crib: material adopts Cedar or pine density equivalent. Wood crib composition by 32 root Batten, divided into eight layers, each layer four uniform, each layer Batten 354FireScienceandTechnology, July2004, Vol23, No.4 mutually perpendicular cross fixed with nails. Batten size: 38mm×38mm×300mm, average moisture content of 6% to 14%. Wood crib placed in a steel bracket, bracket size: long 250mm× wide 250mm× high 150mm, placement is shown in Figure 1. Flash used pans: diameter 158mm, high 100mm, place the bracket.
Flammable furniture model: sofa model 2 pieces, polyurethane foams (density 20kg? m3, sofa long 800mm× wide 100mm× high 750mm; plywood sheets: long thick 2440mm× wide 1200mm×. 5mm Flammable furniture model of placement is shown in Figure 1. Ignite paper ball: 4K newspaper 10 CDs, pinch into ball.
4.5 test procedure
Will ignite pans in poured into mat water inject ignite 30mm high, 50mL gasoline. Ignite ignition pans, burning wood crib, records the temperature point temperature, 40s After ignition ignition paper ball. Doors and Windows open during the test period, nozzle inlet pressure is kept in continuous spray 30min 0.025MPa,.
4.6 test results
When you close to the sofa model 131s nozzle movement, another nozzle no action; 350s wood crib mattresses are off when; 515s é off when sofa model; when sofa model 734s ê off; plywood is not ignite damage; ceiling temperature point maximum temperature of 130 ° c, the ground temperature measuring point maximum temperature is 22 ° c; stop shuihouwu reburning phenomenon; measurement of wood crib 8.4% loss rate.
5 practical application
Shanghai is China's earliest to implement simple spray system of cities, Shanghai Municipal Government will this work as a municipal government-run practical one of the 12 projects, so far the city installed simple spray system for household up to 63916 families. 15 July 2003, Shanghai Hongkou district one household residents together with the fire occurred in the kitchen, being simple spray system, not causing fires extinguished, protecting the security of people's lives and property. The same year, the workshop Huai Hai road, Luwan district community of a temporary structure in the second floor of the building broke, was a simple spray aisles in the fight against the system.
6 closing
To sum up, Shanghai jindun fire safety equipment co., Ltd., development of rapid response to voltage sprinkler is a suitable summary of special nozzle spray system, it is one of the fast response, high flow coefficient and low-voltage characteristics of water distribution, meet the requirements of simple spray system. It should be noted. This article proposes a fast response to voltage sprinkler, does not mean that the system of minimum working pressure for 0.025MPa, just from the other side stressed the nozzle itself at low pressure condition of a property.