Inner Rooms - Glazed partitions

[AndyLeather]

Hi all, I have come across a building (presently un-occupied) that has multiple glazed partitions on a floor, (upper 50% glass non FRG, 50% plasterboard/fibre) it is presently formatted with multiple sections/rooms, most areas presenting the format of at least "inner, inner" rooms (there is 1 section that requires access for escape through 3 areas/rooms) the area has obviously been previously used as multiple offices.
Is any one aware/have examples of this scenario being acceptable beyond the published guidance ("no person should have to pass through more than 1 access room while making their escape"), the client argues that all areas can be seen from any of the rooms so therefore the rooms do not present an issue?
I can see his point however the guidance is quite clear.

[Phoenix]

Inner inner rooms used to be absolutely taboo. But with risk assessment things have slackened off a bit - I'm not saying safety has, I'm saying rules have.  Inner inner rooms are still reasonably uncommon now but not unheard of, but there always has to be justification for accepting them.  You'll have to consider things like travel distances, the presence or otherwise of smoke detection, the direction people face when they're in their offices, the anticipated early fire growth rates in the items on the escape route, ceiling height, the possibility of all the occupants putting posters up round their windows to give them some privacy and anything else that seems relevant on inspection. 

Inner inner inner rooms is pushing it a step further.  If the rooms are any larger than tiny you should start to have problems with travel distance. 

Any layout can be acceptable if the level of safety presented by the compensatory fire safety features is at least as safe as a code compliant layout.  Even better if there is some level of resilience to the safety features that mean we can have faith in the safety features being preserved in the future (e.g. good management, fire safety policy, staff training, fire safety awareness).

Stu

[AndyLeather]

Thanks Stu, I have had a chat with my contact in the local FRS enforcement team about their view also & it is difficult to justify an inner inner room against such clear guidance (although the guidance states "should not" not "must not"), TD's are not really an issue & would be within 18m from any point to the single floor exit (to a protected stair) the exit door can be clearly seen from any point on the floor if sat at a desk or stood within an area.
Worst area involves moving through an additional 3 rooms to get to the exit point (total 4 rooms).

[Midland Retty]

Remember that guides are just that - guidance, they are not law.

They are benchmarks or lines in the sand which would be referred to in a court of law but similarly we can't always accord to a guide book and the spirit of the legislation is to allow deviations from benchmarks where deviations can be justified!

Would an enforcer have a gripe against an inner-inner room scenario? Afterall they can't  simply say "No you cant have that cos the guide book don't allow it guv'nor and I aint gonna say its ok incase someone dies"

There has to be good reason for them to contest something, just as there has to be good reason for you to justify something. So long as you can do so is there an issue?

From what you say, and please take this with a pinch of salt, as I've not seen the premises, you may well be able to justify the situation based on good vision and the fact you can hit guideline travel distance.

Have you also considered the old trick of taking the doors off the inner inner room and classing it as part of the inner room?.

Things to consider

1) Can occupants of inner room see all parts of all access rooms?

2) Would occupants of the inner inner rooms be able to hear the fire alarms?

3) Is travel distance an issue as Stu pointed out above particularly with the 3 access room layout?

[Phoenix]

Andy,

When the guidance says that something "should" be done it has a particular meaning.  It has a different meaning to the "should" in, for example, "you should brush your hair before you go out."  In that case, if you do not brush your hair before you go out in public then it doesn't really matter and brushing your hair is seen as an optional choice.

This is not the case with "should" in fire safety guidance.  When the guides say that something "should" be done they mean that it "must" be done OR, if desired, some other equally safe course of action "must" be taken.  That is, something must be done to address the problem and, in most cases, it should be what the guidance states but, in a few cases, it may be something else.

If we applied the guidance meaning of should to the hair brushing case then we could either brush our hair, as advised, or we might choose to put a hat on - but we would have to do something to protect the public from the sight of our unbrushed hair.

So there you go, you can have inner inners but they must be safe.

Reading your second post it sounds like your FRS enforcer is saying, "it says in the book you can't have them and that's that."  That is not the case.  Also you do not have to "justify an inner inner room against such clear guidance," you have to justify it against the problem.  What's the problem? It is that people in the inner inner rooms might not be able to pass a fire on their escape route before it becomes too large to make it difficult or impossible for them to do so.  So that's what you have to make a judgement on.  To be fair, you do have to err on the side of safety and you do have to satisfy yourself absolutely that the situation that you accept is safe.  Remember that fire safety is about layers of safety, nothing should ever be "only just safe".  And don't forget people in wheelchairs or with mobility problems.

Finally, this inner inner inner room you mention is probably an inner room too far.  With travel across four rooms necessary, to be within the acceptable t.d. you can only have a travel distance of about 4.5m in each room, which means that the rooms must be tiny.  It sounds too cluttered and fiddly.  I'd struggle to justify that.  It would be like escaping from inside a Russian doll.

TMM also makes some good points, above.  Incidentally, low numbers also help to justify...

Stu



 

[kurnal]

Excellent Summary thanks Phoenix.

Particularly enjoyed the concept of the russian doll.

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