According to the specification, GB 15930-2007 Fire Valves for Building Ventilation and Smoke Exhaust System only specifies three types of valves: fire valve (FHF), smoke exhaust fire valve (PFHF) and smoke exhaust valve (PYF). Of course, the definitions and symbol classification marks in this standard are optional provisions, which means that other valve types besides the above three can appear.
As can be seen from the definition, the fire damper (FHF) is always open at 70℃, the smoke exhaust fire damper is always open at 280℃, and the smoke exhaust valve (here equivalent to the smoke exhaust port) is always closed.
Question 1: Is there a 70℃ normally closed fire damper?
There should be DFHF(B70℃), that is, 70℃ normally closed electrically controlled fire damper, which can be opened electrically, reset manually and electrically, and fused and closed at 70℃, and is suitable for gas fire-fighting rooms that do not need ventilation at ordinary times (such as archives with air conditioning).
Question 2: Is there a smoke and fire damper which is normally closed at 280℃?
Personally, I don't think there is a smoke and fire damper which is normally closed at 280℃. As can be seen from the definition, the smoke exhaust fire damper is mainly used for smoke exhaust, and it is fused and closed at 280℃ for fire prevention. Since it needs to be used in smoke exhaust, it is more reliable to make it always open, which can avoid the situation that the valve often closes and fails to open in case of fire.
If it is an air duct that does not exhaust air at ordinary times and only needs to exhaust smoke in case of fire, normally closed smoke exhaust valve/smoke exhaust port+normally open smoke exhaust fire valve at 280℃ can be used. (If the smoke outlet is blown at 280℃, the normally open 280℃CPFHF can be omitted. )
There is an "automatic smoke exhaust fire damper", which is often closed and opened in case of fire, similar to the smoke exhaust valve, but the smoke exhaust valve generally does not have the fire prevention function of fusing at 280℃, and the automatic smoke exhaust fire damper can be fused and closed at 280℃. The valve should be installed on the pipeline of the smoke exhaust system or at the suction inlet of the smoke exhaust fan. Personally, I think the "automatic smoke exhaust fire damper" here can be replaced by a normally closed smoke exhaust valve/vent+a normally open smoke exhaust fire damper at 280℃. In case of fire, you can open the smoke outlet and start the chain fan. If it is installed at the end of the fan suction port and the smoke exhaust pipe, it is necessary to start all the "automatic smoke exhaust fire dampers" in chain in case of fire, and it is also necessary to start the fan in chain, so the control is more complicated. If one of them fails to start halfway, the system will not run normally, and the reliability is not as good as that of 280℃ normally closed smoke exhaust valve/smoke exhaust port+normally open smoke exhaust fire damper.
Question 3: Is there a normally open smoke exhaust valve?
The smoke exhaust valve here is also equivalent to the smoke exhaust port. For the common plate-type smoke vents and multi-leaf smoke vents, they are normally closed in the market, and generally do not need a normally open smoke vent. The smoke outlet of smoke exhaust system can be controlled by "single louver +280℃ electrically controlled smoke exhaust fire damper".
Question 4: What are the applications of 70℃ fire damper?
There are many applications of fire dampers, such as air conditioning return air drying pipes, inlet and outlet of ventilation fans, air inlet of air shafts, pipes passing through partition walls or floors of fire prevention zones/deformation joints/important rooms/computer rooms/rooms with high fire risk, and joints between vertical and horizontal air ducts of each floor. Many occasions need to set fire dampers.
Question 5: How to set fire dampers for air conditioners in rooms without air conditioning, such as fresh air ventilator and ceiling air conditioner?
At this time, there is no need to set fire dampers. Fire dampers are set on the return air pipe and on the return air. Personally, if there is a fire, the air conditioner can be directly turned off by the fire control room, and there is no need to set a fire damper. If there is no control center, a fire damper can be set on the return air pipeline to interlock the air conditioning host. When the return air temperature reaches 70℃, it will fuse and turn off the air conditioning host. It is not feasible to install a fire damper on the air supply pipeline, because the air enters the air conditioner through the return air pipeline first, and it can meet the requirements by installing a fire damper on the return air pipeline.
Question 6: Should the fire damper sent back to the air main pipeline be linked with the air conditioning main engine?
Personally, I think it is necessary to chain the air conditioning host (if it can be realized).
Question 7: Is it necessary to install a fire damper in the fresh air intake duct of air conditioner?
Personally, I think it is generally unnecessary. Especially if fire dampers are installed in both return air and supply air, there is no need to install fire dampers in the fresh air intake. In general, the air inlet is located outdoors, and the horizontal distance from the smoke outlet is greater than 10m or the vertical distance is greater than 3m according to the specification requirements (the smoke outlet is above). Generally, flue gas will not enter the air conditioner from the new air inlet, so it is generally unnecessary to install a fire damper.
Question 8: When the air-conditioning duct is connected to the air shaft, it is not necessary to install a fire damper if it does not pass through the fire partition and the air shaft has only one duct.
When the air duct of the air conditioner is connected to the air shaft, if it does not pass through the fire partition and there are two or more air ducts in the air shaft (that is, the air shaft is shared by multiple systems), a 70℃ normally open fire damper should be installed at the joint between the air duct and the air shaft, and a check valve should be set behind the fire damper. If the air duct passes through the fire zone, a fire damper must be added.
Question 9: Where is the fire damper located?
Personally, I think the fire damper should be set on the same side as the airflow direction, that is, if it is an air supply pipeline, the fire damper should be set on the side that has not penetrated the wall. Fire dampers should be set on both sides of deformation joint. If the side where the fire damper needs to be installed has no space or is inconvenient to install, it can be changed to the other side according to the construction requirements?
Question 10: If the fan outlet is directly louvered outward, is it necessary to install a fire damper on the fan outlet side?
For the fan in the fan room, its outlet is directly louvered to the outside, and there is no need to set a fire damper at the outlet of the fan. If you install a 70℃ normally open fire damper and interlock the fan, of course, but at this time, if the fan room catches fire and burns through the air duct, this valve only works, and the outlet of the fan directly leads to the outside through the louver, and this valve has little effect. If the air duct at the outlet of the fan needs to pass through an important room/fire-prone room/fire zone before being led to the outside, a 70℃ fire damper should also be set at the outlet side of the exhaust fan in the fan room.
Question 1 1: Does the outlet valve need to be interlocked with the fan?
Personally, I think it is safer to interlock the valve with the fan, that is, when there is a fire in the fan room, the fan will be turned off by interlocking the flue gas that has spread to other areas. Air supply fan in the fan room: a 70℃ normally open fire damper is set at the outlet side of the fan against the wall (within 200mm), and the fan is shut down by interlocking. If the fan inlet leads directly to the outdoor louver, there is no need to set a fire damper at the fan inlet. If the air duct at the inlet of the fan needs to pass through an important room/fire-prone room/fire zone before being led to the outside, a 70℃ fire damper should be set at the inlet side of the fan room, and it is best to interlock the fan to close it (see question 10).
Question 12: How to set the fire dampers at the inlet and outlet of the fan when the fan is not in the fan room?
Similar to Question 5, it is considered that it is necessary to set a 70℃ normally open fire damper at the inlet/outlet of the exhaust fan and close the interlocking fan, and it is not necessary to set it at both ends.
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