Mechanical Smoke Extraction

The net is tightening on fire protection measures and especially in relation to the protection of stair cores using smoke control. Recent catastrophes indicate that the existing approach simply does not get the results intended.

We are advocates of pressurisation protection of stair cores for both means of escape & firefighting.  It is the case that that the Pressurisation code (EN12101/6) is well backed up by fire science.

Part of the reason is that the current code is little different fundamentally from the earliest BS pressurisation code in the 1970’s, (BS5588/4: 1978) and the NFPA codes in the USA (NFPA92A).  Any weakness in the logic would have become apparent long ago.

That the system operates in many sub modes is understood by the code developers, and many benign sub modes have been witnessed on previous installations by us.  It does not need any CFD modelling to prove its efficacy.  Systems generally pressurise the stairs to 50Pa with a +/- tolerance of 10%, – it was 30 in earlier codes.

Real time solid state pressure transducers allow the readout of actual core pressure real time, so firefighters know exactly what their degree of protection is at that precise moment. The compartment fire pressure in the current code for means of escape is assumed by the code to be approx just 1Pa, and for firefighting 6Pa.

So the margin of stair protection at 50pa over the 1Pa of the compartment is huge, and likely to be fundamentally effective in an actual incident.

The same logic of pressurisation protection is used in operating theatres, and micro chip manufacturing environments, to keep out contamination as opposed to smoke

0.12 Regulation 16B requires that where building work is carried out which affects fire safety, and where the building affected will be covered by the Regulatory Reform (Fire Safety) Order 2005, the person carrying out the work must provide sufficient information for persons to operate and maintain the building in reasonable safety.

This information will assist the eventual owner/occupier/employer to meet their statutory duties under the Regulatory Reform (Fire Safety) Order.

For larger buildings, a more detailed record of the fire safety strategy and procedures tor operating and maintaining any fire protection measures of the building will be necessary. Appendix G provides advice on the sort of information that should be provided.