Free internet download - Approved Document B2 table 2.3:

Up to 60 persons 750mm

Up to 110 persons 850mm

If your occupancy can be up to 70 then it would be 850mm for able bodied

D4 Width is measured according to the following. a. For a door (or doorway), the clear width when the door is open (Diagram D1). b. For an escape route, either of the following. i. When the route is defined by walls: the width at 1500mm above finished floor level. ii. Elsewhere: the minimum width of passage available between any fixed obstructions. c. For a stair, the clear width between the walls or balustrades. On escape routes and stairs, handrails and strings intruding into the width by a maximum of 100mm on each side may be ignored. Rails used for guiding a stair-lift may be ignored, but it should be possible to park the lift’s chair or carriage in a position that does not obstruct the stair or landing.

Originally Posted by: Roundtuit

Free internet download - Approved Document B2 table 2.3:

Up to 60 persons 750mm

Up to 110 persons 850mm

If your occupancy can be up to 70 then it would be 850mm for able bodied

D4 Width is measured according to the following. a. For a door (or doorway), the clear width when the door is open (Diagram D1). b. For an escape route, either of the following. i. When the route is defined by walls: the width at 1500mm above finished floor level. ii. Elsewhere: the minimum width of passage available between any fixed obstructions. c. For a stair, the clear width between the walls or balustrades. On escape routes and stairs, handrails and strings intruding into the width by a maximum of 100mm on each side may be ignored. Rails used for guiding a stair-lift may be ignored, but it should be possible to park the lift’s chair or carriage in a position that does not obstruct the stair or landing.

Thanks for the reply Roundtuit. I'm a little confused now; can I assume the 850mm distance is the distance in-front of the fire exit door that must be clear? Does that apply even if all 70 plus people are unlikely to use the same fire exit door (given the size of the building and production is spread throughout)? Not sure I understand the "Elsewhere: the minimum width of passage available between any fixed obstructions"; please can you elaborate further? I assume if someone were to walk around the back of the machine where we have a wall adjacent, according to the above, there'd have to be a space of 1500mm from the wall to the beginning of the machine; is that the case? I don't think the space behind the machine is technically to be used for escape, it is there I believe primarily to access and service the machine, so if thats the case, even if the aforementioned 1500mm was correct, would it be discounted in this instance? Thanks for your help.

PS - Please could you provide the page number? I've looked within the Approved document and can't find the table you are referring to. However, I can see that HM fire safety RA for factories and warehouses provides slightly different amounts and sizes (page 70); please can you explain why? Just trying to understand the differing info. Thanks.

Approved Document B Volume 2 "Buildings other than dwellings"

Page numbered as 19 (but in a pdf reader shows as 29 of 204)

Edited by user 11 September 2020 11:23:54(UTC)  | Reason: hyperlink stretched the post

Thanks again Roundtuit. I also wanted to ask, in terms of travel distance, in our case we have to have no more than 45m between fire exits (as we have more than one escape route and are a low to normal fire-risk) but, I wasn't sure if you can count a fire exit door whereby you have to go from one room to another. Basically, I'm trying to take some measurements from our shopfloor area at its furthest point (to see if we take a fire exit out, to accommodate a new machine being put in) to see if we break that 45m; in some cases we do. However, there are other fire exit doors close by, but to get to them, you have to go through other internal fire doors. Would they then be considered acceptable to fall within the 45m or does the rules change if you have to go through adjacent rooms to get to said fire exit doors? Sorry if this is confusing; I looked through the fire safety RA for factories and warehouses but couldn't seem to find a specific answer to that query. Thanks.

Bump again. Please can someone answer my query? Thanks.

I think the reason the guidance doesn't answer your question is that "travel distance" just literally means how far you have to travel, with no caveats such as whether you go through an internal door.  In other words I think you may be over-thinking it.

Some of the diagrams in the guidance you refer to illustrate escape routes that pass through doors, so clearly it is recognised that this can happen.

There is also a section in the guidance on "inner rooms" which does specifically talk about "the travel distance from any point in an inner room to the exit from the access room".

Hi Svick

Perhaps the first time you overthought it was when you mentioned 1500mm. That's a height not a width.

So, you define your level of risk, which in turn prescribes minimum single direction or multidirection travel distances, in your case presumably 25m and 45m (Table 2.1 item 6).

Then you work out how many people need to use the route and exit (Table 2.3) - in your case 850mm width for both route and exit (subject to certain variations set out in Table 2.3 and Appendix D.

If you have internal walls and doors to pass then this may impact your angles when it comes to defining whether you have single direction rather than multidirection routes (effectively applying the principle shown in Diagram 2.2, but with the addition of barriers along the route).

All assumes you are in England!

P