Sprinkler systems part2

Distributor Johnson Control Indonesia – The working principle of the theory of fire sprinkler utilizes compartment (SFPE Handbook of Fire Protection Engineering, 3rd Edition, 2002). Fire on the floor will make the room air entrainment of smoke and float to the top, called plume. When the plume strikes the ceiling, then a hot air flow radially at or near the ceiling. The hot air flow is called the ceiling jet and occurs at a maximum thickness of 30 cm from the ceiling.

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When the jet ceiling sprinkler heads then there is the convective heat transfer from the ceiling jet to heat the sensor element sprinkler (fusible link or glass bulb) which causes the temperature to rise from the previous same as the temperature of the room. This heat sensor element has a nominal working temperature varying from 57 ° C s / d 343 ° C, can be selected for each depending on the design of a fire hazard occupancy.

Sprinkler heads will operate when the temperature of the heat sensor element has climbed to a nominal working temperature. For residential apartments, commonly used nominal temperature of 57 ° C or 68 ° C. The operating principle is exactly the same sprinkler operating principle of a thermal detector such as that used in the detection and alarm system. Therefore, when the building was protected by a sprinkler then no longer need to be equipped with a heat detector and only need to be equipped with smoke detectors.

If the fire continues, then in the room / compartment will form two layers, namely, (a) the smoke layer above, and (b) non-relative layer underneath. The temperature and the thickness of the smoke will rise and continue to grow as long as there is a fire. While the temperature of the smoke-free layer beneath it is relatively the same as the temperature of the room.

At the time of sprinkler operation, the temperature of the room (not the temperature of the flame) is relatively unchanged or increase is not great, unless there is a failure of the sprinkler system so the fire is not extinguished and the smoke layer will continue to fall to the floor. It can be predicted by the simulation program fires in compartments (CFast and ASSET Program).

Although the percentage is very small sprinkler failure than success, sprinkler can fail mainly due to the following reasons, first, the design error, Haras sprinkler systems designed in accordance with the level of risk of fire building. For example, a building with residential apartments above and paserba on the podium, has a different hazard, so the design was different densities.

Second, installation errors, execution in the field kuang, for example, the position of the sprinkler head on the ceiling and obstacles (column and beam structure) does not meet the installation requirements thus greatly reducing the performance of the sprinkler. Third, the absence of a program of inspection, testing and periodic maintenance of appropriate standards (NFPA 25), resulting in the system does not operate when required if there is a fire.

And fourth, the characteristics of the building as an open architecture so that the floor is open to the outside air, and compartments that do not have a fire resistance (from combustible material wood and others). These characteristics affect the performance of the sprinkler system.

Sprinklers is a system used to extinguish a fire at a building. Sprinkler will automatically turn on when a fire occurs.

Things that should be considered in the planning system of fire sprinkler:

• The system type and function of a fire hazard
• Calculation of hydraulic every type of dwelling (fire hazard light Q = 225 l / min, p = 2.2 kg / cm2; the fire hazard was Q = 375 – 1100 l / min, p = 1.0 – 1.7 kg / cm2; severe fire hazard Q = 2300-4550 l / min, p = 1.8 – 7.3 kg / cm2).
• The density of the emission and the maximum work estimated
• The water supply system
• Placement and location of sprinkler heads
• type sprinkler head (57 0C-orange, 68 0C-red, 79 0C-yellow, 93 0C-green, 141 0C-blue, 182 0C violet, 203/260 0C-black).

While the maximum number of sprinkler heads which can be mounted on a control valve for a fire hazard light system (considering our topic is the analysis of the hotel) was 500 pieces of the sprinkler head. Supplies alarms for the sprinkler system should consist of a control valve alarm (the alarm control valve) or a flow detection device (flow switch) are justified with the necessary equipment to provide a warning signal.

SPRINKLER CLASSIFICATION
sprinkler system consists of three classifications in accordance with the classification of residential fire hazard, namely:
1. The system is light a fire hazard
Density planned emission 2:25 mm / min, with an estimated maximum work area: 84 m2, while the lighter types of residential fires, among others such as office buildings, housing, education, hospitality, hospitals and others.

2. Systems fire hazard being
Density jets planned 5 mm / min, with an estimated maximum work area: 72-360 m2, while including the types of residential fires are: light industry such as: dairies, electronics, canning, textile, cigarettes , keremik, metal processing, auto repair shops and others.

3. System of severe fire danger
for the industrial process emission density of the planned 7.5 – 12.5 mm / min, with an estimated maximum work area is 260 m2, while the danger in high-density warehouses planned accumulation of 7.5 – 30 mm / min. Work area maximum estimated 260-300 m2 with a density of jets planned for hazards on building hoarding high depending on the nature of the danger of the goods stored, as for the kind of residential fires are the heavy industries such as: chemical plants, lighters, explosives, rubber foam, oil refineries, and others.

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