Voids on escape routes

[Guest Paul Walker]

Can anyone please explain where the 4.5m distance for means of escape past a void originates (with a reference if possible).

 

Thanks

[Tom Sutton]

What guidance are you quoting and most fire safety guidance originates from the post war studies with a bit of tweaking through the years.  

[Guest Paul Walker]

The guidance is contained in Approved Document B and BS9999; Diagram 14 and Figure 4 respectively.

[Tom Sutton]

I do not believe you will get an answer to this one, as I said most fire safety guidance originates from the post war studies with a bit of tweaking through the years. You will never know who tweaked it and for what reasons.  I think you will find many similar situations in fire safety and I think you will find a rational scientific reason for any of them.