【 Weak current College 】 non-conventional conditions high tower building design-fire water supply--Power By 【 China power house network 】

Description: non-conventional conditions high tower building of the fire water system design
Keywords: high tower building, fire water, non-conventional

1 project overview
The golden pagoda engineering is the art of Kunming Jin Bao cemetery is part of the project is located at the foot of the Kunming Dianchi Lake, adjacent to the mountain, is the highest point of the entire zone. The building's first floor area, the top level area 1317m2 335m2, building height 50.38m, total 11 layer for frame structure system, fire danger rating as a class level. The building is mainly used for storing the dead ashes, activities, held for religious activities, etc. Building decoration, furnishings, a variety of neon art lighting requirements, personnel density, fire risk, accident consequences wide, indoor fire water systems must be safe, effective and reliable. Under the high civil building design fire protection standard (hereinafter referred to as the "regulations"), and with the local fire department in charge of coordination, identifying the set of architectural indoor hydrant fire water system and fire sprinkler system. Since building functional requirements and the surrounding environment conditions, water tank, the pump room is installed (from the building exceeds 150m), pool cannot be used as a sink for fire water, especially the works do not have outdoor municipal water supply conditions, the need to set outdoor fire pipe network. Considering the area fire engine to arrive within the 10min, outdoor fire network uses low-voltage network.

2 water

The fire protection water supply water to the groundwater, deep-well pump to reinforced concrete cistern (outdoor ground settings), using terrain elevation difference, meet fire pump from irrigation water requirements. In view of the ground-water, water changes and the possibility of deep-well pump failures, in the design of the tank capacity, regardless of the duration of the fire water tank in supplementary water more appropriate. Because the building no municipal water supply pipe network outdoors, can not provide outdoor fire water consumption, water and fire water effective capacity on fire last time indoors, the total amount of external fire water.

Interior and exterior fire water-how to determine first of all must be addressed. Due to the construction of functional type and fire-fighting water consumption standards in the regulations of § 7.2.2 not included in the article, through its use of functional characteristics, fire hazard, floors, outdoor environmental conditions, and so on, finally determine the fire hydrant, fire water consumption: indoor to outdoor 30L/s, s for 20L/, automatic sprinkler fire-fighting water consumption for 26L/s; duration: fire hydrant system for 3h, automatic sprinkler systems to 1h. Thus a pool fire water effective volume is handy for maintenance 633.6m3, independent work, when you are emptying, pool set in two cells. Due to the pool for living, fire water tank, by setting the siphon break tubes ensure fire water not being used and to meet regulatory requirements.

3 outdoor fire water system

The construction of an outdoor fire water system consists of a water source, water supply facilities, water supply, fire hydrant.

3.1 network and water supply equipment

Under the doctrine of "requirements, outdoor water distribution along the ring road around building fire engines, the resistance of the section 7.3.6 article pointed out:" in the context of municipal fire hydrant can be counted in the number of outdoor hydrant ", so the design time understood as outdoor fire water system can reference the municipal water distribution system is set. According to local fire departments in charge of the building exterior fire water supply network using low voltage network, life, fire. Pipeline fire function mainly in ensuring the water requirements of fire, and fire the water pressure from fire trucks to take water from the fire hydrant, pipeline pressure to achieve the most unfavourable point hydrant 0.10MPa hydraulic press at freedom.

Outdoor fire water system uses pump inverter running, through pressure sensor signal control pump unit of speed and the number of pump operation. Facilities include three main pump (preparation of a second), a voltage pump and a pressure tank. As the device starts to run, the two main pump and the pump to the pipeline regulator and pressure tank filled with water, when regulators cans pressure reaches the upper limit, the device stops running. When the system flow is very small (like small leakage) or zero flow, the device switches to the pressure tank water supply, maintain the pipeline pressure, pressure tank pressure drops to lowest values, the voltage pump starts to pressure water supply pipe network. As the water from the fire hydrant, further reducing the system pressure, when the pressure tank pressure drop to the master pump to start the set value, a number of main pump start, frequency adjusting speed, increase traffic with fire after a certain point, in order to achieve the second main pump inverter running, and two main pump automatically switches to power-frequency.

3.2 hydrant

Reasonably determined hydrant is sure that the outdoor fire water system features an important aspect of the control specification is found, the doctrine of law provisions and provisions indicate less consistent. In accordance with the regulations of section 7.3.6, hydrant sales hydrant water consumption. Whereas the provisions stated in the description, number of outdoor hydrant should ensure supply outdoor and indoor two-part of the firefighting water consumption needs. The design for this, consider the following: in the event of fire, the fire system pump room fails cannot supply Interior fire water, indoor hydrant water added to the water shortage, hydrant's sales guarantee supply Interior and exterior parts to consider more appropriate fire-fighting water consumption. The Interior and exterior parts for fire-fighting water 50L/s total, because each hydrant is responsible for water consumption is 10 ~ 15L/s, it uses 4 outdoor aboveground fire hydrant.

4 indoor fire water system

4.1 pump adapter

Pump adapter is a fallback when the system is not enough water, fire or the fire pump maintenance, power failures, failure, need to use fire engine by pump adapter send water to indoor network. For a pump adapter of the load flow for 10 ~ 15L/s, for indoor hydrant system uses two sets of ground-Pump adapter, for automatic sprinkler systems also uses two sets of aboveground fire pump adapter.

4.2 roof fire water tank

The building uses temporary high-pressure fire water supply system, the need to set the roof fire water tank for fire fighting water consumption at the beginning of the fire.

① scenario analysis

The building has an attic roof water tank is placed. Since the classical architecture of more structural limits, water tanks when the geometric form of the arrangement of the existence of such characteristics: big water tank plane size is small height dimensions, and height dimensions larger then the plane of the small size. Try out the water tank size found that water tank height H is too large or too small water tank volume V will not be able to meet the requirements, in addition to water level control on water height is required. This requires clear, is not a loft itself does not meet the requirements for how to optimize and make the water tanks can best adapt to the specific space and to meet the water tank and water level control on its height requirement?

According to the building, structure, we provide professional, through simultaneous tank relationships, found that such a rule: the actual width L water tank, when the value is less than a certain value, L, L tank with V increases; when L is greater than a certain value, V with L increases decrease. For extreme values: L = 7.03m, Vmax = 57.90m3.

As a result of any actual tank integrated small than Vmax, tank length L and the height H, tank, water level control on water height requirements, as well as the tank bottom and floor clearance distance requirements for proper adjustment tank length L and the height H, so that the water tanks set up to adapt the attic space.

② water level control

Roof tank for 26.2m3, (including fire water storage tank for 18.0m3). Water tank upgrade by pump life pump, water pump, a life, with a water tank level relay control by, according to the setting of minimum water level and the highest level of start-up and shutdown. Lowest water level set to consider two aspects: one is the high water level ＞ fire, high 100mm out part of the water capacity ＞ 1min hourly water consumption. This avoids water pump starts to spout out stream this time supply of continuous and prevents water pump starts too frequently. Life forms with siphon outlet, located in the highest Office of the fire water level, and set the siphon break out of the water, both to ensure that the fire with water is not used, so that the entire flow of water storage tanks.

4.3 indoor hydrant fire water system

Fire hydrant system responsible indoor firefighting tasks according to the regulations of law requirements, the indoor hydrant interim fire protection water supply system for high pressure water supply system, the pipeline is stereo ring network layout. Fire vertical tube diameter using DN100, flat ring tube diameter using DN125, hydrants as required to ensure that any part of the same layer has two full water column at the same time meet the fire hydrant. Introducing-pipe two, from the construction of two different directions. System components are shown in Figure 1.



① fire hydrant

System selection SN65 fire hydrant, mm nozzle water gun, diameter 65mm, length 25m of mazhi hose. According to the most disadvantaged fire hydrant water gun minimum flow requirement calculation 5L/s, full water column for the desired 11.4m, for fire protection design pressure 18.5 ¡á 104Pa. A timely start of fire pumps, as well as non-fire professionals promptly remove water gun fire, indoor hydrant box set remote reboot the pump button with self-help-style small fire hydrant SN25.

② pressure equipment

Due to the building structure, roof set height to top fire hydrant water pressure requirements, the system sets the pipeline pump compaction, pipeline pump located in the tank, through remote automatic control of the pressure gauge.

In the analysis as pressurized equipment piping pump control pressure, noting that the doctrine of the provision: section 7.2.2, 7.4.6.2 and 7.4.7.2. Because the building is the largest storey, calculate 5.1m can be seen, as long as they meet the 7.2.2 bar fire hydrant water gun minimum flow requirements, we will be able to meet the 7.4.6.2 in ＞ 10m enrich the water column. Whereas article article 7.4.7.2, architectural geometry at the top three layers of fire hydrants as 9.0m altitude difference, if you press the top fire hydrant hydrostatic pressure reached 0.07MPa consider, beginning at the fire, the fire pump outflow before (including pump failure cannot flow), the building may have three layers of fire hydrant water gun will not reach the minimum flow requirements. So, whether by hydrostatic pressure 0.07MPa as set of standards, as well as booster facilities to hydrostatic pressure value 0.07MPa as booster device control pressure depending on the construction of fire water system security, reliability, have adversely affected. The fire hydrant fire water system booster device control pressure set, calculated according to meet the most adverse fire hydrant for fire protection design pressure: 18.5 ¡á 104pa consideration.

4.4 sprinkler system

Automatic sprinkler system in a variety of different features of the building has a very high rate of fire extinguishing. The building uses temporary high voltage wet sprinkler systems, fire danger rating in danger level, design Jet strength to 6L/(m2 · min), the role of area 200m2, system design flow according to the calculations take 26L/s. According to the automatic sprinkler system design specifications "(hereinafter referred to as the" self regulation "), each system control nozzle range not exceeding 800. The building is located two automatic sprinkler system, alarm valve two sets, centrally located in a layer between the respective alarm valve, control of one to six layers (low zone) and seven to ten layers (high) extinguishing nozzle, pipe layout chengzhizhuang, system diagram shown in Figure 2.



① Network hydraulic calculation

To avoid water sprayEffect of inhomogeneity system fire extinguishing performance, according to the article since the rules 7.1.1 article role area sprinkler strength requirements for hydraulic calculation. Most adverse nozzle pressure by 5 ¡á 104Pa consideration, its flow is 0.94L/s.

In the most unfavorable nozzle contains role area, net minimum spray intensity is unfavourable non-most with disadvantaged sprinkler nozzle near connection nozzle, spray intensity calculation in table 1.

Table 1-the most adverse of minimum water spray nozzles strength calculation of the nozzle spacing
Nozzle spacing
(M) diameter
(Mm) frictional resistance losses
(104 Pa) nozzle pressure
(104 Pa) nozzles
(L/s)-Jet strength
L/(m2·s)3.0251.166.161.040.116320.255.250.960.1073.6251.396.391.060.082320.305.300.970.075

Can be seen from table 1: when the nozzle spacing as 3.0m, whether or not and the most adverse nozzle pipe diameter is DN25 or DN32, non-disadvantaged nozzle spray intensity of minimum will not be less than the specified value: 6L/(m2 · min), i.e. 0.1L/(m2 · s) by 20%. When the nozzle spacing to use DN32 3.6m of tube connected with the most adverse nozzle, its minimum requirement-Jet strength of less than 20% of the value, not the self regulatory code requirements.
In the most unfavorable nozzle contains function area (square layout), with the greatest strength of water sprinkler, press the self regulatory law section 7.1.1 does not exceed 20% of the required values, its maximum intensity Jet 0.12L/(m2 · s), the required nozzle pressure and the maximum allowed along side the head loss calculation in table 2.

Table 2-maximum pressure nozzle spray strength requirements
Nozzle spacing
(M) nozzles
(L/s) nozzle pressure
(104 Pa) allows the frictional resistance losses
(104 Pa)3.01.086.611.613.61.5613.808.80
Can be seen from table 2: effects of area to achieve the maximum intensity of water sprinkler is not greater than the self-regulatory code requirements, it shall adjust the diameter to control nozzle and the most adverse nozzle head loss between. When the nozzle spacing as 3.0m, head loss shall control within the 1.61 ¡á 104Pa; when the nozzle spacing as 3.6m, head loss shall control in the 8.80 ¡á 104pa.

② system composition

For ease of monitoring and observation of fire zones, each layer with water dry pipe set flow indicator and with opening and closing signals, signal butterfly valve to fire control rooms.

Located at the end of each layer network test water drop water valve for easy network maintenance time pipeline flush venting. Network requirements set to drop water valve slope, water valve, venting tube after connection pipe layers, emptying into a layer followed to alarm valve Chamber of drains, the caliber is DN40.

In accordance with the requirements of the regulation, since the nozzle nominal action temperature 68 ° c, with ceiling-glass ball closed sprinkler. By radiator set height does not meet the high area of the system requirements for the most unfavorable nozzle pressure, the system pressure equipment pressure, pressure pump head press meet high pressure nozzle most negative: 10 ¡á 104Pa requirements set by the automatic control of electric node pressure gauge pressure pump starts and stops.

5 conclusion

Non-conventional conditions fire environment, are relatively, fire restrictions by many and complex, the fire water design requires special attention.

① reasonable, proper analysis to determine fire water, fire water and set up the appropriate facilities are first of all you must solve the problem, design for the actual situation on the specification and its provisions for an in-depth understanding of the description, analysis, ensure that the system is safe, effective, and reliable.

② from current conditions and actual effect, the fire is still an important means of extinguishing fire. In view of the unusual circumstances of the actual fire fighting, fire hydrant sets out indoor, fire water consumption consider might be more appropriate.

③ for building construction and other factors limit the use of mathematical tools for feasibility analysis and optimization is imperative.