Can I have a fire corridor inside my building?

[Guest Tom]

Hi,

 

Just wondered if anyone can help. I am having some difficulty with negotiating rights over a secondary means of escape of my bar/restaurant so am looking into alternatives. Have had a fire safety officer down to take a look who was helpful but that was a little while back and the situation has changed since then.

 

I'm struggling to find any definitive information as to whether putting in a 'fire corridor' would allow me to utilise the space at the back of my unit, therefore keeping the escape route down to 18 metres travel distance (the beginning of the corridor)? Or is the distance to a protected fire corridor irrelevant as it is still within the building and there is some distance to travel inside the corridor? I have had conflicting information from different sources.

 

I know they have to be 45 degrees apart but am I right in thinking this being protected might solve this problem if it is protected with the right materials? Any help on the matter would be great. Please see pic below, any questions please ask! The unit is 33 metres long so need two means of escape so that my capacity is large enough to make it viable.

[AnthonyB]

It would reduce the initial dead end from the rear to acceptable limits and as it is separated from the other exit by fire resisting construction doesn't need to meet the 45 degree rule and can be counted as separate.

Is the kitchen a 30 minute enclosure or open plan?

[Mike North]

it is possible, however you may then fall foul of the 1.8m rule for distance between for your final exits and need FD30 doors.

[Guest Tom]

Thanks Anthony, it would be enclosed but with a serving hatch, does a 30 minute enclosure refer to the burn time?

[Guest Tom]

Ah thanks for your help Mike, I will look into the FD30 doors. 

[Tom Sutton]

What rule is that Mike could you quote the guidance.

[Mike North]

[Tom Sutton]

Thanks Mike.

[Mike North]

The fire corridor would have to be less than 12m to avoid the need for an additional FD at the midpoint.

You would be constrained by the width of the new corridor as to the occupancy capacity (discounting exits BR 2019 2.21 – 2.23)

Can you not utilise the exit by the men’s toilet?

It could be argued that the design is purely to try and circumvent the building regs.

[AnthonyB]

Which is very common and accepted by AI's and BCO's, I've seen some rather long stretched out protected stair lobbies in flats & offices to justify single directions of escape over what would be excessive TD's and avoid the need for corridor smoke control in flats

[Mike North]

Off topic

But isn’t that where Grenfell went wrong?  There were no major issues with the building, just a catalogue of deficiencies that combined to create a major disaster.

[Tom Sutton]

I have been studying this clause and I have always applied it to external escape routes and this one is a internal escape route how is this.

[Mike North]

Tom,  basically its to stop you putting the final exit from one compartment next to a final exit to another compartment, they must separated by fire resisting construction 1.8m

[Tom Sutton]

The way I interpret it is, if an external MoE has to pass any final exit doors or windows in an external wall, within 1.8m distance or 1100 mm height, they require to be fire resistant.

[Lyledunn]

On 28/09/2021 at 13:29, Mike North said:

The fire corridor would have to be less than 12m to avoid the need for an additional FD at the midpoint.

You would be constrained by the width of the new corridor as to the occupancy capacity (discounting exits BR 2019 2.21 – 2.23)

Can you not utilise the exit by the men’s toilet?

It could be argued that the design is purely to try and circumvent the building regs.

Why would you need to divide the corridor? Division only required where alternative escape routes could be compromised. Note swing of doors should be in direction of travel, unless less than 60 occupancy. Even then, effort should be made to avoid such a situation. You might get a better outcome through BS9999 which if properly employed can allow some valuable trade-offs. Your travel distance is from the furthest point, even should it be a store or loo.