Green Fire Retardants for Structural Timber
The key to our project is fulfilling the need for 'green' fire retardants to be researched, investigated and eventually tested. Equally as essential is the context in which we are testing these, namely the pre-constructed 'bare' structural frames where so many fires in recent times have occurred (1)(3)(4)(5)(6).

This principle is fundamental to our project as most building codes relating to timber framed fires are concerned with life safety in indoor situations. This usually means that they are orienatated in such a way to be applicable to indoor materials and scenarios, eg. BS476-7 (10) where flamespread is classified for internal linings (i.e. plasterboard etc). By extension this means they are usually classified for light timber structures which have fire resistant cladding materials. Since our reseach is focused on heavy timber frame structures which are in the process of being constructed, we have to look for retardants which can both function in an exterior environment and also meets the specific retardation requirement for this setting.

The type of retardation required for this purpose is one that will increase the char depth of the wood and decrease the char production rate (i.e. lengthen the process).

The reason why we adopted this postion is because after conducting a literature review over five weeks we came to several conclusions.

  • Construction-phase fires are the most prevalent problem facing the timber construction industry at present (1)(3)
  • Once a structure is fully built and protected with fire resistance cladding materials and/or insulation, the severity and probability (overall risk) of a fire decreases (4)
  • If a fire does occur in this type of scenario, rapid collapse is a strong possibility (5)
These issues are explored in greater depth in the section Timber Framed Fires and the Need for Retardants.

After discussions regarding the key parameter in timber-frame building fires (flame spread rate, time to ignition, heat release rate(s)) it was decided that charring rates ultimately controlled the eventual structural failure.

Our solution and future work will be geared around looking for retardants that can prolong the charring process which will protect the timber for longer, which will hopefully prevent total collapse by the time reactionary forces (i.e. fire brigade) can act to extinguish the fire.

Man is the only creature that dares to light a fire and live with it. The reason? Because he alone has learned to put it out ~ Henry Jackson Vandyke Jr