Passive Fire Building Elements and Flood Damage

The effect of inundation on passive fire elements, particularly fire doors, is much harder to detect and demonstrate, than the potential for damage or deterioration of things like fire pumps, smoke detectors and electrical controls.

There are a number of different manufacturers of fire doors and a number of different ways by which the door achieves its required Fire Resistance Level (FRL).  Typically, the vast majority of door panels comprise of:

  • wooden peripheral frame comprising two vertical stiles, two horizontal rails
  • fire resistant core of either vermiculite, calcium silicate, cellulose fibre or mineral fibre; and
  • facing panels on either side of the door leaf of plywood, mdf or metal sheet.

Whilst there are rigorous test criteria with which fire doors must be shown to comply to validate their approvals, including tests for misuse, slamming, body impact and of course fire resistance, none of the criteria (or tests) relate to water resistance. 

It is therefore the case that fire doors typically only have the level of water resistance anticipated for an ‘ordinary’ door, in order to meet common law/trade practices requirements to be fit for purpose and of merchantable quality for a door (not a fire door).

Indeed, since, by definition the vast majority of fire doors are internal doors (since they separate adjacent fire compartments) it is not necessarily safe to assume that they have any significant level of weather resistance, let alone resistance to immersion in water.

The layers of fire resistant compound packed in the cores of fire doors, along with the joins in the critical wooden framing, required to hold those cores in place can and will be damaged by water immersion.  In some cases, the core may be considered to be like a ‘WeetBix’ that will essentially disintegrate and fall to the bottom of the door after becoming waterlogged.  Even if it is only the wood that swells and deforms and the door’s tolerances change, or that its internal structure is contaminated with the unknown contents of the floodwater, it can no longer be relied upon to function as required in a fire.

Of course, that is the critical point: it is only when the door is actually subjected to a fire that we will know whether it still works, and it is then too late to find out.  Once a door has been even partially submerged, we know it has been subjected to a condition for which it was not designed and we know what the adverse effects of that immersion could be.  Such doors would require destruction to validate any internal damage and so must be replaced.

As an industry, we carry out routine service for clients who are obliged to have that work done by s54 of the Queensland Building Fire Service Regulation 2008. S54 also obliges them within 30 days to take appropriate corrective action when the record of maintenance indicates that it is required.  We, in turn are bound to carry out our work (within the bounds of what the client engages us to do) in accordance with the relevant maintenance standard, the Queensland Development Code MP6.1 and our QBCC licence.

The Queensland Fire and Emergency Services Act 1990, also requires (at 104D) the occupant to “maintain at all times every prescribed fire safety installation to a standard of safety and reliability in the event of fire.”  Naturally, the doors in question constitute prescribed fire safety installation/s and our advice to the occupant/occupant’s representative will be that flood-subjected doors need to be replaced to fulfil that obligation.

A little over fourteen years ago, the space shuttle Columbia disintegrated spectacularly over Texas, because of the failure of its heat resisting shield.  It failed because it was subjected to a condition for which it was not designed, namely the impact of foam insulation shed from the external tank during launch.  Experts in the field were concerned the impact could have compromised the heat shield.  Prior to the disaster the NASA managers limited the investigation into what the consequences of the impact might have been, because there was no way for the crew to fix it anyway.  Perhaps they and their families would have liked to know, all the same.  Maybe they could have thought of something.

With regard to flooded doors, they too have been subjected to a condition outside those for which they were designed – namely submersion, not just in water but in a noxious soup of contaminants ranging from suspended solids, to solvents to sewerage.  Experts must question their ability to now do the job for which they were designed and installed – to contain a fire.  Unlike Challenger, however, the fix is simple, obvious and relatively inexpensive.  Countenancing metaphorically ‘landing the shuttle’ anyway defies good sense, logic and the law.

Article supplied by National Fire Industry Association (NFIA).

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