Why isn’t smoke control included within a standard fire test?
Through the course of our work, we often encounter surprise from customers when they learn that the smoke test for a doorset is completely separate to a fire test. We all know that, statistically, smoke kills more people than fire does, so wouldn’t it make sense to test for smoke at the same time as fire? To answer this question, we need to look at how each is measured and the standards to which they are measured.
There are separate standards for smoke and fire
Firstly, it’s important to note that there are separate standards for fire testing and smoke testing. Fire doors must be tested and certified to BS EN 1634-1 (or BS 476-22 in the UK-only market), whereas smoke is a separate standard, BS EN 1634-3 (or BS 476-33 in the UK-only market). The testing for both standards is complex and rigorous, and including both within one set of apparatus, within one test, would be very tricky indeed. The methods and units of measurement for fire and smoke are very different.
Fire testing is measured in minutes
To test for fire resistance, a fire doorset is exposed to a fully developed fire in a test furnace until it fails. We all know that the integrity of the doorset is measured by how many minutes it remains uncompromised by the fire, so an FD60 doorset will remain uncompromised for at least 60 minutes.
Smoke testing is measured in pascals
Smoke leakage testing is used to determine smoke leakage from one side of a door to the other. Smoke is measured in air pressure, in units of pascals. The test is conducted using a specially designed smoke leakage chamber which uses fans to control the pressure exerted and includes a pressure transducer, a flow meter and digital displays to record pressure and leakage rates throughout the test. You can imagine why it might be difficult to make such sophisticated equipment record accurately and consistently in furnace conditions – temperatures reach over 1000ₒc.
Smoke and fire are different beasts
Whilst it is common sense for fire doors to have the ability to restrict the spread of smoke, the testing methods and measurements for each are entirely different and the apparatus to assess both in one test does not exist as yet. Whilst fire is normally accompanied by smoke, and vice versa, the behaviour and dangers of each are quite different, so it makes sense that they are tested entirely separately.
