Minimum dimensions of fire exits

[Guest LaurPar]

Good afternoon,

I have an enquiry about a mesh fire exit door on a roof, the measurements are 1,500mm high x 500mm wide. I wondered what is the smallest width and height a door can be?

Kind regards

Lauren

[Sally H]

Hello Lauren

For fire exits, the width is the most important factor, and this is determined by the number of people who are likely to be using a particular exit. Current Building Regulations (Fire Safety, Approved Document B, 2010) specify a minimum width of 750mm for a final exit door, to accommodate a maximum of 60 people. As a matter of interest, the minimum standard dimensions for a fire escape roof window (as opposed to a door) are 660mm by 1180mm. Height wise, your door is OK; but it is too narrow for its purpose.

[Tom Sutton]

If it is subject to the building regulations then Approved Document B Vol 2 Building other than dwelling houses then check out page 37. It states for 60 or less persons, 750 mm width, normal door height, with some provisos. However in an existing premises risk assessment applies and it depends on the number of persons, the speed of exit required, the agility of those involved and a full assessment of the risk. For instance if it is for a couple of service engineers working in a plant room it could be acceptable but for an office full of office workers not acceptable. It is up to the responsible Person.

[Guest DianeLan]

Please can you tell me what the minimum amount of space is required to access a fire exit?

E.g. How much space should be kept between two desks if access to the fire escape is between the two desks?

[Tom Sutton]

The minimum width would be the width of the fire exit but the more space the better, because of bunching up, which happens when numbers of people attempt to pass through the door at once.

[Guest JohnDen]

Hi All,

Please could you confirm the minimum width of access required for a small comms room with 2 cabinets approximately 11 meters square? The room is only likely to have 2 people in at any time. Is this still 750 mm?

kind regards,

John

[Tom Sutton]

Assuming the room is not a bypass room where people enter the room and leave by another exit as part of the means of escape form fire, a standard 750 mm width door is more than adequate.

Check out approved document B (Fire Safety) Vol2, page 36 at http://www.planningportal.gov.uk/uploads/br/BR_PDF_AD_B2_2013.pdf

[Guest Jon r]

 

 

What is the minimum height required for glazed hardwood fire doors entrance.  We are in a building working on a new gym the height of the installed door is 1900 mm high we think it should be 2040 can you please shed some light on this?

many thanks jon r

[Tom Sutton]

The standard height of doors in the UK is 1981mm, except the most commonly used doors in Scotland and Europe is 2040mm. However the height is not a major concern the width is more important in fire safety and the major problem with the height is reducing standard fire doors to fit small frames. This is because you are limited how much you can remove from the top and bottom of fire doors and each one is different you need to read the manufacturer's documentation to find out.

[Guest Lucia]

Hi, 

I live in the block of 140 apartments with 3 double door fire exists. However one of them can’t be opened as double door  as is broken. Manager of the building told me that this doesn’t need to be fixed . 

[AnthonyB]

Check the fire risk assessment. Is this an exit at ground level to open air? Depending upon the location and distribution of the exits and any stairs and if the premises are stay put then there is a slight possibility the exit is for accommodation  only and not required for escape - but I would want to see how they came to this decision.

[Guest CeePee]

Hi,

We have an office building which has a fire exit out onto a shared access driveway which one our neighbours parks on - sometimes parking over the width of the door (not sufficiently close to prevent the door from opening fully, but certainly in front of) - is there a minimum distance from the fire exit to any further obstruction?

[Guest Gary]

We have a fire exit leading from the first floor that is measured at 650mm. This is for staff only and likely to be a maximum of 20 people at any one point? I understand the minimum of a fire exit is 750mm should this be raised as a concern? 

 

Gary

[AnthonyB]

If it's an existing older building there is unlikely to be any realistic solution and your competent fire risk assessor should take an holistic approach based on numbers and type of occupants, other provisions such as early detection & protection of escape routes allowing more time for people to filter through and exit, risks present, etc.

Small numbers of people familiar with the premises can usually be accommodated in narrower exits, in the worst cases numbers can need to be fixed at 5 but you may well be OK, but it will limit numbers to some extent. Do a fire drill when the floor is full and see how long it takes to exit - if still in the 2.5-3 minute window you should be fine.

[Lyledunn]

Setting woke aside, my observation is that exit width and travel distance will need to be reviewed given the epidemic of obesity that has afflicted society. As I understand it the original unit of exit width was determined by the number of gendarmes who could pass through a width of 550mm in one minute. That was just post WW2 when slim bodies prevailed. I know some people who would get stuck in a width of 550 even if they turned sideways! 
Along with several others, I recently got stuck on stairs behind two slow moving, obese individuals who between them blocked a 1100mm stair in a golf club. There was a fire in another part of the club although no real danger to anyone. Nonetheless, it was a lesson in just how vulnerable a timely evacuation can be to such matters.