Protection of external exits

[shaunmckeever]

In a large building 8 floors above ground constructed around 1940/50 with only a type 'm' system and a single internal protetced route and three unproteted external routes, would it be appropriate in  FRA to recommend upgrading of the glazing to protect the external routes?

I am aware of a risk assessment in which this has been done and the fire authority have said they think it would be onerous and advised not to bother.

I'll be interested to hear other opinions.

[Paul]

I know ADB1, section 6.25 is retro but I think the guidance is valid here.  I would suggest that AFd is justified as a compromise.  I am a little surprised that the FSO has said not to bother at all.  Easy for him to say now he's about ot loose responsibility.

Tried to copy and paste this over but seems the new online version doesn't allow this.

Good luck

P

[jokar]

Shaun,  I suppose it depends on whether a fire in any area can affect all 4 escape routes.  Early warning is wonderful but movement times still have to be taken into account.  The idea of FRA is not to downgrade existing fire protection but to enhance and either AFD or upgrading the glazing will achieve this.  The difficulty with glazing is unless there is air con people want openable windows to achieve circulation especially in this weather.  Cost has its own implication of course and the RP will have to defend that in "as low as reasonably practicable".

[shaunmckeever]

Thanks PSmith/Jokar.

The building is 'T' shaped with the protected route at the centre. The external exits are at the far end of each section of the building so a single fire would not cut off more than one exit. The reported cost for upgrading the glazing is approximatley £300000! - Don't ask me who qoted or where they got their figures from.

The cost seems prohibitive to me and I can see why there is some reluctance to upgrade but I feel to do nothing, as suggested by the fire officer, is not appropriate. I'm considering recommending full AFD and not upgrading the glazing.

[Brian Catton]

Shaun,

Unless I have missed it I do not think the use of the building has been mentioned yet.

 As someone said the whole solution depends on whether or not a single fire could affect all the escape routes.
AFD to L2 or perhaps L1 standard (Dependant upon the speed of response and mobility of the occupants) would give an early warning but some separation of the escape routes may also have to be considered.

There are a lot of factors to be considered.

[shaunmckeever]

Hi Brian

The building is a low risk multi-occupied office. It is unlikely that a fire will cut off more than one exit route. I have suggested an L2 system along with some management recommendations.

Thanks

[Graeme]

and it would be slightly less than your gold framed windows with bullet proof glass..

[wee brian]

Assuming a fire took hold. is there anything like a compartment wall that would stop the whole floor, and therefore both stairs.

Whilst offices are fairly low on the list of risk premises it is not unheard of for a whole floor to go up.

If there was a compartment wall in the middle then it may be reasonable to accept that only one of the external stairs would be affected.

[shaunmckeever]

Hi Brian

each section of the 'T' is separated by FR construction. The centre of the 'T' is where the internal protected route is located and the external escape routes are located at the far end of each section of the 'T'. A fire is not likely to affect an entire floor unless fire doors are wedged open - this is where part of my management recommendations came in.

I thought I would raise this issue because I noticed in the draft version of the new guidance for offices that there was no mention of protecting external escape routes but in the final version on page 81 there is a section that refers to it. It seems like it was slipped in at the last minute presumably after some debate.

[wee brian]

Probably overlooked in the first draft.

I think the layout you have is reasonable grounds for omiting protection. Thats assuming you can get from one half of the building to the other without some security problem.

[Firewolf]

I'd be careful here.

The problem is that when the fire alarm goes off staff in the premises will have no way of knowing where the fire is.

As a result staff may choose to use an external staircase which might become affected by fire or smoke (due to the lack of FR glazing)

They could get half way down for example only to find that the escape route has become inpassible because a window has been breached etc.

It is a tough call. Risk assess it. Look at the rooms that adjoin the external staircase. What is the risk? If it is only office space then maybe it ill be ok, if it were kitchens or a boiler room then we begin to increase the risk.

Im assuming that the external staircases are'nt particularly wide and that once you have got onto the external you can not re-enter the building?

[wee brian]

Good point - but I think with an open stair you will probably see the fire from the top.

It could be developing as you escape but we are talking about an office building here.

[jokar]

Hey everyone, we are talking Risk Assessment online and people think it is difficult.  Strange eh!!!!

[shaunmckeever]

I thought about the escape routes becoming impassable so I recommended an L2 system with detectors located near to the external escape routes so that if the routes were likley to be affcted there should be sufficient warning to enable the routes to be used before they become impassable.