In simple terms a fire curtain is a fire rated, motorised, roller blind. Fire rated fabric is wound around a cylindrical motor which is placed inside a small galvanised steel housing. Vertical guides provide a seal at the sides when the curtain descends.
The fabric is kept retracted in day-to-day mode, but in the event of a fire it will descend to provide a fire-rated barrier.
Ideal solution to stop fire and hot gases
A fire curtain is used to prevent the spread of fire and hot gases, in order to assist occupant evacuation and aid fire service access. It is an ideal alternative to roller shutters and fire-rated glass: it can be less obtrusive, it is generally lower in cost, and it requires less supporting structure.
Safety is in the correct certification
Specifying fire curtains can be confusing due to the many different standards available. The UK has BS 476 parts 6 and 7, but these only look at how to test a fire curtain. BS 8524 is currently under review and when released it will contain information on fire curtain product requirements.
There are European standards which can be used but none of these are specifically for fire curtains. EN 1634-1: “Fire resistance test for doors, shutters and windows”, and BS EN1363-1: “Fire resistance tests” are commonly used.
PAS 121 is a document that is being quoted by certain manufacturers. It is purely a publicly accessible specification, and since it is neither BS nor EN approved it should therefore not be used.
Fire Resistance Classification
There are 3 types of fire resistance classification:
- Integrity (E) measures the ability of the barrier to prevent cross-over of flames and hot gases. Most curtains are designed and tested on this basis.
- Radiation (EW) measures the ability to maintain cross-over temperature, that is, what reduction of temperature the barrier will provide at a certain distance.
- Insulation (EI) measures the ability to maintain surface temperature. This is similar to EW, but measures the temperature on the surface of the barrier on the opposite side of the fire affected area.
Each curtain is given a classification for the relevant category and time. For example, a curtain certified Class E30 will provide integrity (E) for 30 minutes. Testing fire curtains for EW and EI is more complicated and is a contentious issue at present. We will look at this in our next fire curtain blog.
Conor Logan is a Technical Manager of Colt UK, Smoke and Climate Control Division. Conor designs innovative smoke control and HVAC systems and is also Chairman of the Smoke Control Association.