Fire safety and fire resistance

Why physics and law belong in one topic

Most misunderstandings about fire safety come from knowing only one side.

Someone who only looks at the material concludes that “steel is non-combustible, so there is nothing to do” — while the thin-walled section is far more sensitive than it looks, because of how fast it heats up.

Someone who only looks at the paperwork concludes that “there is a certificate, so it is fine” — while the fire resistance rating applies not to a board or a product but to the whole structure.

How to read it

Concepts first

What REI means, and what it has — and does not have — to do with the reaction to fire class of materials. These two concepts are mixed up most often.

Then the physics

The section factor, the speed of heating, and what follows for the choice of protection: why intumescent coating is not a viable route, and why fire protective boards only make sense as part of a system.

Finally the law

The logic of the fire regulation, the risk class, the concept of lightweight technology, and the place of the fire safety technical guidelines — applying the latter is voluntary, but doing so gives the presumption of compliance.

What this topic does not give

The fire safety concept for a specific project. The fire resistance requirement depends on the use, the number of storeys, the risk class and the size of the fire compartment, and working it out is the fire safety engineer’s task.

The point

With this technology fire safety is not a detail but the point where the quality of the design shows most. Not because the structure is poor, but because this part has to be taken seriously.