【 Weak current College 】 high-rise building underground garage exhaust smoke with system design---Power By 【 China power house network 】

1 Overview
　　
Currently there are large and tall buildings, underground car park in order to meet its own users parking needs. There is a flat area of 1 million square meters, the floor up to 4 layers, parking lot, so hop in the design of the exhaust and smoke exhaust system is very important. This article in conjunction with the author, describes the combined exhaust smoke exhaust system of a design method and design process to analyse the problems encountered by the proposed solution.
　　
2 high-rise building underground garage ventilation rate calculation
　　
(1) exhaust volume:
　　
Specification: "underground garage should generally be set mechanical exhaust system, the exhaust volume should be diluted exhaust gas volume calculation. If there is no calculation information, refer to the ventilation exhaust volume estimation, generally not less than 6 times/, the air is not less than 5 times/time. "Above should be directed at the private garage, a high-rise building of underground garage due to core tube, post network, service, ancillary room layout, its utilization is below the private parking garage, simple form ACH volume calculation of ventilation, ventilation rate high, according to the actual number, calculate its parking ventilation rate.
　　
Underground garage ventilation design by fully into account, the required ventilation rate according to the literature [1] recommended formula. Overall ventilation required ventilation rates are:
　　
L0=LM（m3/h）
　　
L=Q/C-CO（m3/h）
　　
Type: L0-garage exhaust volume (m3/h);
　　
L-garage unit floor area exhaust volume (m3/h);
　　
M-car inventory area (m2);
　　
Q-unit floor area automobile CO emissions (mg/h · m2);
　　
C-next car park CO allows concentration, C = 100mg/m3;
　　
CO-CO concentrations in outdoor air, CO = 3.0mg/m3;
　　
Units in the floor area of Automobile CO emissions (mg/h · m2):
　　
Q=ABCD/E
　　
Type: A-garage parking in the surface area per unit;
　　
B-car access frequency (hourly access number and design capacity), desirable 50 ~ 100%;
　　
C-every car in the garage in the engine running time from 3min;
　　
D-automobile CO emissions per unit of time, the g/s. Homemade Santa automobile CO emissions 0.577g/s, imported Ford Motor CO emissions 0.319g/s;
　　
E----CO emissions account for a percentage of total emissions, take 0.89.
　　
Example: a 2000m2 underground parking, storey 3.6m (beam Board converted after clearance height bottom 3.5m), parking capacity 45 vehicles (by imports, domestic cars: 50 meters), the calculation of the overall ventilation rates (to and from the frequency of 0.85%).
　　
By using the above formulas, calculated:
　　
Unit floor area automobile CO emissions: Q = 1574 (mg/h · m2);
　　
Emissions per unit of surface area: L = 16.2 (mg/h · m2);
　　
L0 = 32400 ventilation rate (m3/h);
　　
ACH A ≈ 4.8.
　　
(2) the air in the underground garage
　　
To prevent emissions from overflow, underground parking garage must maintain negative pressure. Therefore, the air should be less than exhaust volume, generally take 70% ~ 85%, the rest by the exhaust volume into supplementary driveway.
　　
3 How to solve the exhaust and smoke production inconsistencies
　　
Underground garage with exhaust smoke exhaust system design process you first need to solve is the exhaust volume and exhaust volume inconsistencies, common methods:
　　
A. selection of two or two above fan parallel operation, usually only running a typhoon machine for ventilation. Fire, start another Typhoon machine running, the second Typhoon machine of air, wind pressure meet exhaust requirements. In this way, the fan number, installation and subsequent management action is difficult.
　　
B. choose two-speed fan, usually the exhaust to run at low speed, high speed operation when the fire, this way to solve the above mentioned a problem, but exist in meeting their exhaust volume normally exhaust volume on the high side.
　　
C. reasonable division smoke partition size, the maximum amount of exhaust smoke partition and the usual exhaust volume agreed or somewhat smaller, so that a strong fan (air press exhaust volume selection) to meet the usual exhaust and smoke in case of fire, which solves these problems in a, b.
　　
So how is the c in the underground garage combined exhaust smoke exhaust system design process and exhaust of inconsistent better.
　　
4 exhaust smoke with system design issues
　　
The following highlights the adoption of the above 3 c style design problems.
　　
A division of, smoke partition:
　　
(1) in the doctrine, to smoke partition area divided only limit restrictions that "not more than 500m2". On the lower minimum smoke partition area last clear limits, then smoke partition size can be scaled without limits? "under the regulations on exhaust fan in 8.4.2.1 air volumeRequirement: "take a smoke partition exhaust, air flow should not be less than 60m3/h · m2 calculation (single Typhoon machine minimum air flow should not be less than 7200m3/h)," thus projected a single smoke partition size should be no less than to satisfy requirements 120m2, so you can have a lower bound of the 120m2, reference.
　　
(2) combined with the system maximum preventing smoke partition size to determine:
　　
Due to the amount of usable system smoke and exhaust volume basically the same, so under the regulations of law No. 8.4.2.2, maximum preventing smoke partition size = exhaust volume 120 (m3/h · m2) (and its area is greater than 120m2), according to this value into smoke partition.
　　
Example: a large underground parking one fire partition (an exhaust smoke exhaust system), garage height 3.2m (after deduction of the plate), exhaust volume by 5 times/hour.
　　
Calculated echausting 31744m3/h, smoke partition area S = 31744/120 = > 120m2 265m2. Under column layout, beam system layout, divided into: EP. 265m2, exhaust fan required air quantity = 30720m3/h < exhaust volume.
　　
B. exhaust (exhaust) air outlet size layout:
　　
Outlet size specifications, except those that meet the usual exhaust smoke, while meeting the requirements of each smoke partition layout based on its size 1 ~ 2 Tuyere, uses the louver and equipped electric sealed valves, fire valves gravity (action temperature 280 ° c).
　　
C. exhaust (exhaust) fan selection:
　　
Use fire exhaust fan, fan press exhaust volume selection, set the duct fan outlet check valve, gravity fire damper (action temperature 280 ° c).
　　
D. make-up air system:
　　
Using the usual air supply systems wind, air flow should meet the requirements of the regulations.
　　
E. fire occurs, Plenum continue to operate, closed, non-fire smoke zone valves, set on fire smoke flue gas, air in the system to continue the wind flow from non-fire district to fire district flows.
　　
When smoke spread to the adjacent smoke, smoke, fume outlet opened in flue gas temperature of more than 280 ° c gravity fire dampers close, stop the smoke zone smoke.
　　
5 conclusions
　　
In a large underground garage with 3-way design in c exhaust emission is combined with the system, through the outlet of the exhaust gas fire close to meet needs, simplify operations, control systems, while reducing fire fan motor power, in areas where conditions permit, the use of the system should be a better choice.