【 Weak current College 】 sprinkler system parameters of the turbo-charged facilities

Abstract: the fire code for automatic sprinkler system requirements of a supercharged facility parameters there is a certain contradiction, thus causing some designers in the design process from the instance through engineering, this article describes the parameters of a supercharged facilities. A home city 5-storey building, with each layer height 22.50m, construction area of 9000m2, 1 ~ 4 layer for business Hall, level 5 as a warehouse. This article to the home city, for example, through the business office and warehouse are hydraulic calculation on sprinkler system design flow of pressurized equipment and lift should meet most adverse nozzle design spray intensity and pressure of work, not copying the code flow is not greater than 1L/s. The home city of pressurized equipment flow 11m3/h, head to 28mH2O.

Keyword: automatic sprinkler system, turbo-charged facilities, water jet strength, design flow, pressure, most unfavorable nozzle

In fire water supply system, water from the fire, the fire pumps, fire fighting pipe network to the end of the fire-fighting facilities and so on each link for guaranteeing the security and reliability of fire protection systems are essential to any aspect of the problem, will give the people of life and property caused a considerable degree of threat and loss. Boost facilities as an automatic sprinkler system is an important component in the fight against the initial fire play an effective role, how to properly determine its flow rate and pressure, and other parameters also becomes the important work of system design.

1 fire water tank and supercharged facilities

Roof and pressurization of fire water tank is to ensure the early stage of building facilities and fire protection water consumption and corresponding strong water pressure, the architectural design fire protection standard "[1] (hereinafter referred to as" jiangui ") and the senior civil building design fire protection standard" [2] (hereinafter referred to as "the regulations"), respectively, on a different set of fire water tank provides. "Jiangui" establishes the effective volume of the tank, the "doctrine of" in addition to the provisions of the effective volume of water tank, also provides for a booster pump water discharge should not be greater than 1L/s. While the automatic sprinkler system design specifications "[3] (hereinafter referred to as the" Jet-discipline) pointed out that the fire water tank of water should comply with the provisions of the existing relevant national standards, and fire water tank made of water, in principle, namely, the "fire cistern, should satisfy the system is the most disadvantageous point minimum working pressure sprinkler and water jet strength." Obviously, if the fire water tank of water does not meet the most negative point minimum working pressure sprayer and spray intensity, you should set booster facilities.

About spec on fire water tank effective volume requirement of reasonableness, many designers have raised questions, we will not make judgments, only the flow of pressurized equipment and hydraulic parameters to be determined.

2 reasonable to determine the parameters of the turbo-charged facilities

From the above code for automatic sprinkler system requirements of a supercharged facilities can be found, "the regulations" and the "Jet-discipline exists to some extent contradictory. In the current construction drawing design and review process, mostly irrespective of high-rise buildings and multistory building, reference "doctrine", will be the flow of pressurized facilities as 1L/s, so that "one size fits all" approach is not appropriate, it should be according to the project's specific circumstances.

"Jet-discipline in the different risk levels of water jet strength and a nozzle of maximum protection area and parameters to calculate the corresponding water jet strength booster facilities design flow, as shown in table 1, the risk level in the light from the value of 85%. Table 1 in the design flow is corresponds to a water spray intensity and nozzle maximum protection area of the design flow, and do not represent a hazard class when the actual flow of pressurized equipment, actual flow generally less than the design flow. Due to the different nozzle selection, and the actual protection sprinkler area tend to be less than the table given in the protection area, so will the pressure facilities design flow.

The following example of a home city to describe the parameters of a supercharged facilities. The home city 5-storey building, with each layer height 22.50m, construction area of 9000m2, 1 ~ 4 layer for business Hall, level 5 as a warehouse. Water tanks are on the 5th floor roof. 1 ~ 4-layer design for grid ceiling, no ceiling level 5. According to the "Jet-discipline provisions and warehouse storage of goods category, 1 ~ 4 layers for the risk level in II, level 5 to level III-class warehouse dangerous. Business standard upright sprinkler (k = 80), the warehouse district adopts ELO-231 warehouse dedicated sprinkler head (k = 165). Composite beam of set of nozzles as shown in Figure 1. Most adverse effect of nozzle area A to 8.57m2, warehouse design Jet strength min for 20L/D · m2, according to the formula

q=D·A(1)

You can calculate the most adverse nozzle design flow q as 171.4L/min, i.e. 2.86L/s. Then, based on a formula

q=k·P0.5(2)

Find the most adverse nozzle pressure P as 108kPa.

To 2.86L/s flow most adverse nozzle to tank head loss between h-lowest point by tank 130kPa to most negative Z nozzle elevation difference, according to the formula for 1.4m

H=h+P-Z(3)

Calculate the most unfavorable for the required pressure nozzles 224kPa.

On business the most adverse nozzle calculation methods are the same, just the design strength of the jet nozzle type, pipe diameter, resulting in the most adverse nozzle design flow (1.37L/s) and the working pressure (105kPa).

In accordance with the above computed results choose the home city of pressurized equipment, consider some safety margin, turbocharged facilities parameter is: flow 11m3/h; head 28mH2O.

3 conclusion

(1) when a high fire water tank of the set height to meet a sprinkler system in the most adverse of minimum working pressure sprinkler and water jet strength requirements,Can not set booster facilities, so as to avoid investment in waste. Otherwise, to set the pressure to ensure the most adverse normal movements. nozzle

(2) the flow of pressurized equipment and lift and other parameters is not fixed and may vary according to the building type, fire danger rating and the nozzle and pipe layout, etc. vary, be sure to avoid the same careful calculations.