Posted By Bob Matthews AIIRSM Dear All, I am having a dispute with our maintenance team. We are building a new room 30' x 30' to house 12 staff working with chemicals (some carcinogenic and some potentially explosive) on the shopfloor. The building has apparently passed building regs. My point is that although one entry/exit door only is required, this would put the staff in danger if this door was blocked by a fire. I suggested to them on the risk assessment that an alternative way out must be made. I am unable to find anything written down about alternative exits, what is your thinking on this and is there anything written down I can shove under their nose to convince them? Many Thanks Bob

Posted By Bob Pedley Bob, Have a look at HSG 168 Fire Safety in Construction Work, on page 17 there is a table for travel distances showing the recommended reductions from 18 metres for low risk down to 12 metres for high risk in enclosed structures with one direction of travel, ie a dead end condition. I agree with your concerns, best practice is always for an alternative means of escape where possible. Given the nature of you operation, conducting a risk risk assessment should give you some ammunition. Bob

Posted By Ken Taylor From the information you supply, there appears to be good reason to believe that the Building Regulations may not have been satisfied. Approved Document B1 would require 25m max travel distance for escape in one direction only to a storey exit for industrial premises of 'normal fire risk' and should the premises meet the definition of 'place of special fire risk', 9m max travel distance would be required within the room area. Where internal partitions and other fittings have not yet been installed direct distance is taken as 2/3 of the travel distance.

Posted By Nigel Singleton BSc I believe you will find the concrete evidence you are looking for in Chapter 14 section 14.21 of the Fire Precautions Act 1971 'There may also be circumstances where the risk of rapid fire spread is so great that, irrespective of the size of room or the number of persons accomodated, a minimum of two exits are essential e.g. factory premises where processes involve spraying with highly flammable liquid'. Although you do not mention flammable liquids, I think that explosive chemicals would fit the bill just the same. Hope this helps

Posted By Robert K Lewis I am a little puzzled by the term potentially explosive. Any manipulation of explosive materials should be done in specifically designed enclosures with the appropriate bursting discs, negative pressure space etc. This appears to accept that risks will be posed, in the event of a significant failure, to all persons in the building. What is the Risk Assessment for the use? Are the quantities used really sufficient to create the conflagration you envisage. Even in my student days potentially explosive processes were carried out in specific areas- try the distillation of Glacial acetic acid and 100% Hydrogen peroxide - you get peracetic acid which like Hydrogen peroxide is explosively unstable. We never carried this out in an occupied building, a blockhouse was used - with two exits!! Go back to the start - is this a process that can be safely carried out in an occupied building, it is not just a question of how many escape routes. Bob