Door Widths (Where to measure)

[Guest Tom]

Hi, 

Premises is a nightclub (Basement) - Occupants - 350

Two exits both lobbied stairwells to the ground floor exits on to the street. The two lobbied doors are narrower than the final exits doors. 

Question - When measuring door widths am I correct in thinking that I should be measuring the two inner doors that a more narrow, or the wider final exits?

Exit widths do not add up. they only accommodate 290 persons. (discounting the main wider entrance). 

Question - When conducting my report can I keep the occupancy and implement controls that will ensure that both exits are available at all times, or are door width capacities the bottom line? 

Appreciate any response, 

Regards

Tom 

 

[Tom Sutton]

From the Home Office guidance Small and medium placesof assembly are the following statements.

The effective usable width of an escape route is the narrowest point, normally a door or other restriction such as narrowing of a corridor due to fixtures and fittings. The capacity of an escape route is measured by the number of persons per minute that can pass through it so, to establish the capacity of the route, it is first necessary to measure the width of the route at the narrowest point. The effective width of a doorway is the clear unobstructed width through the doorway when the door is open at right angles to the frame. The effective width at any other point is the narrowest clear unobstructed width through which people can pass.

When calculating the overall available escape route capacity for premises that have more than one way out, you should normally assume that the widest is not available because it has been compromised by fire. If doors or other exits leading to escape routes are too close to one another you should consider whether the fire could affect both at the same time. If that is the case, it may be necessary to discount them both from your calculation.

[Guest Tom]

Thank you for the reply. Much appreciated.