Starting from the standard, GB15930-2007 «Fire dampers for building ventilation and smoke-control systems» defines only three valves: fire damper (FHF), smoke-fire damper (PFHF) and smoke damper (PYF). The definitions, symbols and marking in this standard are non-mandatory, so valve types other than these three are allowed.
Fire damper (fire damper)
Fitted on the supply and return ducts of ventilation and air-conditioning systems. Normally open; when the duct smoke temperature reaches 70°C it closes and, within a set time, meets the leakage and fire-integrity requirements to stop smoke and fire spread. It is usually made of body, blades, actuator and thermal sensor.
Smoke-fire damper (fire damper in smoke-venting system)
Fitted on the ducts of a mechanical smoke exhaust system. Normally open; when the exhaust duct smoke temperature reaches 280°C it closes and, within a set time, meets the leakage and fire-integrity requirements. Made of body, blades, actuator and thermal sensor.
Smoke damper (smoke damper)
Fitted at the end of each branch (smoke inlet) of a mechanical smoke exhaust system. Normally closed and leak-tight; on fire or when exhaust is needed it opens manually or electrically to exhaust smoke. A valve with a decorative mouth is called a smoke outlet. Made of body, blades and actuator.
Question 1: can a smoke damper be normally open?
Here the smoke damper is effectively a smoke outlet. Common plate and multi-leaf outlets are normally closed and rarely need a normally-open one. For a combined exhaust/smoke system, use a «single louvre + 280°C motorised smoke-fire damper».
Question 2: is there a 70°C normally-closed fire damper?
Yes, DFHF (B70°C): a 70°C normally-closed motorised fire damper. Normally closed, opens electrically, resets manually or electrically, fuses shut at 70°C. Used in gas-fire rooms that need no normal exhaust (e.g. an air-conditioned archive).
Question 3: on which side is the fire damper set?
It should be on the same side as the airflow direction — on a supply duct, before the wall. Set one on both sides of an expansion joint. If the required side has no space, it may move to the other side per the construction needs.
Question 4: where is the 70°C fire damper used?
It is used in many places: main supply/return ducts, fan inlets/outlets, shaft inlets, where ducts cross fire compartments, expansion joints, important rooms, plant rooms and rooms of high fire risk, and at each floor connection of vertical and horizontal ducts.