Guide
Mezzanine fire protection: where the budget actually goes
Updated
Two mezzanines of identical size and loading can differ enormously in price, and the difference is almost always fire.
Two separate questions
- Protecting the structure
- Whether the steel columns and beams and the underside of the deck have to achieve a period of fire resistance. This is delivered by boarding, sprayed protection or intumescent coating, and it is a substantial package of work over a large floor area.
- Getting people out
- Means of escape from the new floor: how far anyone has to travel to a staircase, how many staircases there are, whether routes need protecting, and the alarm, detection, signage and emergency lighting that go with them.
Why the answer is building-specific
Whether a raised floor level can be treated lightly or has to be fully protected depends on its size relative to the space it sits in, what it is used for, how many people are on it, and the fire strategy of the building as a whole. Approved Document B is the guidance (gov.uk, Approved Document B), and building control or a fire engineer applies it to your building. Be sceptical of any supplier who gives you a firm answer on fire protection before anyone has looked at the building. Verify it, in writing, with the people who will sign it off.
What the fire package can include
- Fire resistant protection to columns, beams and the deck soffit.
- Additional or repositioned staircases to satisfy travel distances.
- Protected escape routes, fire doors and compartment lines.
- Alarm and detection extension to cover the new floor.
- Emergency lighting and escape signage.
- Sprinkler alteration or extension in a sprinklered building, which is specialist work.
- Smoke control or ventilation implications where the deck interrupts an existing strategy.
How to keep control of it
- Get the fire strategy agreed before the steel is designed, not after. Late fire requirements mean redesign, and redesign after fabrication is the expensive kind.
- Ask every installer to state whether fire protection is included, excluded or provisional, and to price it as a separate line.
- Ask who is talking to building control, and when.
- If the answer is that fire protection will be confirmed later, treat the quote as incomplete and compare accordingly.
- Update the building's fire risk assessment once the floor is in, as the Regulatory Reform (Fire Safety) Order 2005 requires (legislation.gov.uk).
Sprinklered buildings deserve early attention: adding a deck under existing sprinkler heads usually means altering the system, and that is a specialist package priced by a sprinkler contractor, not by the mezzanine supplier.