In this article, Adexon Fire and Smoke Curtains explores the drawbacks and safety concerns of the BS 8524 hot motor test for fire curtains
It’s 400°C, and your fire curtain motor is still working. Is this amazing, or is it dangerous?
“BS 8524 is such a comprehensive standard and has all these extra tests…” One is the BS 8524 hot motor test.
BS 8524-1 requires fire curtains to conduct a hot motor test, where the motor must operate 12 times over 30 minutes with the furnace temperature at 400°C ± 20°C.
Is the BS 8524 hot motor test a positive thing?
Adexon Fire and Smoke aren’t the first fire curtain manufacturers to raise this point. In January 2016, Conor Logan, technical manager of Colt UK, wrote of his concerns.
Hot water burns us at around 70°C. It scalds us at 100°C.
The emergency services would not open a fire curtain with the temperature at even half of 400°C as it would exceed the limits to which firefighters are trained, as mentioned in “Characterizing a Firefighter’s Immediate Thermal Environment in Live-Fire Training Scenarios”, which states, “severe training conditions generally [exposed firefighters to] temperatures between 150°C and 200°C”.
A fire curtain should not be operable in temperatures of 400°C for safety reasons
A fire curtain should never be operable if there are temperatures of 400°C on one side, as this would pose a severe-to-fatal risk to the operator and could allow the fire to pass beyond the designated compartmentation barrier and thus endanger the whole building.
It could be argued that the hot motor test is for applications where the motor is high above the operator, for example, in a ceiling void. In this situation, if there were a fire in the void and not lower down, and if you wanted to operate the fire curtain, you have a rare combination where a hot motor use may be applicable.
But what is the incidence rate of this combination, and who is going to stop the curtain from opening above the safe temperature limit so as to prevent the fire from spreading? If it is 400°C up where the motor is, and 20°C down where the operator is, it stands to reason there is a temperature gradient in-between.
How can we regulate the safe conditions for opening a fire curtain?
What is the safe amount to open the curtain to? Who is going to know this, let alone do it when escaping from a fire?
To justify this test being of potential value, data is required to show how often this combination occurs, and a control measure is required, including easy-to-use instructions by the user in a fire situation, so they don’t open the fire curtain too far and endanger the building further.
A failsafe backup to stop the fire spreading is also required in the event of user error. Otherwise, this is a dangerous capability, and the motors should be designed so they do not work at elevated temperatures, the exact opposite of what the British Standard calls for.
The capability to operate the motor at 400°C in the vast majority of circumstances is dangerous.
Commercial interest should have no influence on safety standards
Even if the BS 8524 hot motor test were a good thing and if it could have benefits somewhere, the expansion of the bottom bar at 400°C is untested, and it is very questionable whether the motor would be capable of moving the curtain if the bottom bar had expanded and jammed in the guides.
The above is an extract from the Adexon white paper, A technical comparison of BS EN 16034 and BS 85243.
If I can make a flying carpet, British Standards for carpets should not say all manufacturers have to make carpets that can fly. It has no benefit for the consumer. In fact, they end up paying for something superfluous at best.
Who is checking that British Standards are written for the benefit of fire safety and the consumer first and foremost?
The post What are the dangers associated with the BS 8524 hot motor test? appeared first on Planning, Building & Construction Today.
