I was commissioned to prepare a Fire Safety Strategy report and assist in discussions with the local the Building Control authority to gain approval for the proposed renovation scheme involving the continued use of the prestigious buildings for commercial/institutional purposes. Secondary uses of my report are a) to provide data useful for a Fire Risk Assessment which is needed according to the Regulatory Reform (Fire Safety) Order 2005 when the works are completed and b) provide documentation on the building for future reference.
The Listed 17th century main building is set in a site of outstanding natural beauty next to the River Thames. The building has a nominal gross internal floor area of 3,500 m2. Both buildings are 3 storeys high excluding the basement.
Upgrading fire resistance of timber floor using expanded steel mesh and rock wool slab placed above lath and plaster ceiling to minimise charring of joists when ceiling collapses in fire.
My work involved the following: preparing a skeleton report to show the client the scope of the fire safety aspects to be covered, reviewing the current drawings, agreeing with the client the occupancy numbers in different parts of the building, making several site inspections, meeting the building control officer and answering questions raised, advising on the possibility of alternative escape via the flat roof enabling floor space below to be more effectively and flexibly used, identifying the need for an evacuation lift, giving advice on upgrading horizontal and vertical compartmentation, upgrading the fire resistance of historic doors (based on the authors publication on upgrading historic buildings – see Publications on his website), decidingfire resistance ratings of fire doors and where automatic door hold-open devices could be used to advantage, formalising and unambiguously defining protected fire escape routes accepting that the building was un-sprinklered and that fire service attendance times could be variable, rationalising travel distances, preparing formal fire strategy drawings with the help of the client’s CAD draughtsman, advising on what areas need be covered by a BS 5839-1 automatic fire detection and alarm system and marking location and type of detectors on the fire strategy drawings, recommending a proprietary voice alarm system, deciding where refuges could be located for disabled people, preparing a first draft of a fire safety management manual, raising questions on fire-fighting that the local fire service could guide on. My work had to bear in mind English Heritage Grade 1 Listing constraints which prevented altering room sizes and shapes and made difficult the inclusion of fire protecting lobbies.
Enhanced fire detection and alarm was proposed for some inner rooms where travel distances exceeded the ADB guidance. The strategy drew on the advice in ADB, BS 9999 and BS9991, and I made some calculations of smoke fill time at the request of building control to assess the effect of large storey heights using numerical models in BS 7974. Project ongoing.
Client: Firm of Chartered Building Surveyors acting as project manager.