Protected common staircase

[Hi Tower]

I wondered if someone could enlighten me on the following:

Single common staircase leading from ground floor to 1st and 2nd floor of an apartment block.  Stairway protected on ground floor with lobby to 3 apartments, 2 x lobbies on 1st floor, each leading to 1 x apartment and a single apartment on same floor but with no lobby access, and same configuration on 2nd floor as 1st floor.

I can't understand why:

• some of the 1st and 2nd floor apartments are accessed via lobbies whilst others are not - isn't this against modern building regs
• the apartments that are not accessed by a lobby have no internal lobby either - once the door is opened access is straight into the living accommodation

• the build was completed in 2004 so should meet with current regs
• and why do we continue to find common area AFD being installed within new builds

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[kurnal]

Hitower examples of inconsistencies are rife throughout England. Not seen any similar buildings in Scotland so I dont know if its just an English thing.

Logic does not appear to enter into the minds of most architects or approved inspectors. Neither does Regulation 16B. Many of them approve buildings and never leave their desks. Installing a full part 1 system is so common and is so often accepted as a compensatory feature without any consideration of equivalence. And no written justification.

[CivvyFSO]

Hitower

Could the lobbies have been created purely to meet travel distance requirements within the flats?

It would seem to me that with 3 flats per floor on a single stair the actual stair should be lobbied, and if this is the case then there is no need for an internal lobby to the flats apart from to meet the travel distances quoted for internal layout within the flats.

[kurnal]

It would seem to me that with 3 flats per floor on a single stair the actual stair should be lobbied,

I would agree with that Civvy. But if the single staircase was not lobbied and there were three flats per floor would a fire detection and alarm system in the common areas be a reasonable compensation for this variation from the ADB?

I find this quite often in new builds and it doesnt make much sense to me.

I cant see why at 2 flats per floor and no lobby we adopt a stay put policy and no detection and alarm in the common areas (apart from to operate the AOV) but where there are 3 flats per floor and no lobby we alert everybody and tip everybody out, presumably passing through the smoke in the common areas as they go.

Whilst there is greater probability of a fire occuring as there are more flats, the chance of the staircase being affected by smoke and fire is surely the same?

[Hi Tower]

Kurnal/CivvyFSO

I take your point about travel distance and can see the reasoning behind it.   To press my original point can you explain why in App doc B it states that stairways of aprtment blocks should be protected by way of lobbies when I often find flat doors open directly into the stairway.  I regularly find this on new builds.  Are we saying that the installation of AFD at the time of design (as a so called compensatory measure) permits the ommittance of a fully protected stair?  If I were then to do a FRA and determine the alarm more of a hinderance than of use (due to a confused full evac policy)  would I have to consult with Building Control to determine why the alarm was first installed?  In trying to do so (with BC) in the past I have not been successful in being able to get the necessary details from them (prior or post 16b)

[Midland Retty]

HiTower

Is there just AFD in the communal routes or do the individual apartments have interlinked detectors too?

[Hi Tower]

MR

Interlinked to flats on a timed delay (i.e. if smoke alarm activates with flat resident has a set time to silence it before it goes into full evac mode)

[Stinky]

Kurnal/CivvyFSO

To press my original point can you explain why in App doc B it states that stairways of aprtment blocks should be protected by way of lobbies when I often find flat doors open directly into the stairway.  I regularly find this on new builds.  Are we saying that the installation of AFD at the time of design (as a so called compensatory measure) permits the ommittance of a fully protected stair? 

Flat doors can open into stairs if classed as small single stair buildings.  As long as flats have a protected internal hallway. 

With regards to a risk assessment.  If 3 flats open into the stair at each level instead of 2, the risk is negligable.  Does it really matter that there is one more flat?  No.   But with a FRA you would have to ask the question to see if there are internal protected hallways.  In this case there are not.  But you don't need a protected internal hallway if travel distance within the flat is 9m to the front door. 

We know that the lobbies or internal protected hallways are provided in order to protect the staircase from smoke ingress, so do we think that an alarm system compensates for this?   Possibly. 

But generally afd is not required if built in accordance with building regs.  Many blocks do have them installed, but it is about knowledge.  Architects are not aware, and when risk assessors from AFD companies go in and risk assess, they recommend AFD because they have a hidden agenda.
AFD can be a hinderance, however it can have benefits.  If just a communal system, I feel there is a benefit that it will tell everyone that there is smoke in the stair.  If connected with flats I would like to see heat detectors in the entrance to flats linked to smoke detectors in the communal areas, otherwise there will be too many false alarms.

[kurnal]

Kurnal/CivvyFSO

Are we saying that the installation of AFD at the time of design (as a so called compensatory measure) permits the ommittance of a fully protected stair?  If I were then to do a FRA and determine the alarm more of a hinderance than of use (due to a confused full evac policy)  would I have to consult with Building Control to determine why the alarm was first installed?  In trying to do so (with BC) in the past I have not been successful in being able to get the necessary details from them (prior or post 16b)

I agree with you HT and fight the same corner. I dont think AFD in the stairway is generally a good compensatory measure for a lack of staircase protection. But too many approved inspectors accept it as a matter of course. Not sure about local authorities- dont seem to encounter them any more in this type of property.

And in such cases perhaps removal of a  working system could be a material alteration, but I reckon if it has already fallen into total disrepair through vandalism then unless the completion certificate was issued in the last 12 months you would not be required to inform them.

[mevans421]

My nightmare has recurred.

Just fire risk assessed a brand new purpose built small single stair block of flats - asked to do so by social housing group prior to first occupation.

When I entered the block I noted that 3 flats on ground and 1st floor open directly onto the stairway (no lobbied protection) whilst 2 flats opened directly onto the stairway on the top floor.  An AOV is fiited.  So I noted in my report that the block did not comply with the prescriptive requirements of ADB, Volume 2, diagram 9b in that only two flats were permitted on each floor, and as such an enquiry should be made with the developer/regulator (LABC in this case) for justification of such a variation.  I added that such a variation should be supported (in my opinion) with a fire strategy report having been duly considered by the regulator and fire service, otherwise how could they make an informed decision.

The reply I got back from the regulator was that the absence of lobbied protection to the stairway as required of ADB, dia 9 b did not represent any risk worth mentioning, and that no compensatory measure was required.  No comments had been made by the fire service and therefore he was happy with the condition.

So I am left with a social housing provider scratching their heads in respect to why had I raised the (awkward) question when of course BC would know best!!  and I am now saying that in the absence of receiving a fire strategy report how can I consider the condition acceptable under the FSO.

The client is starting to loose patience.

It seems to me that the regulator can make it up as he goes along without justification.  Has anyone else experienced such a thing. 

Also, what is now stopping the regulator saying that paper walls are ok for a stay put policy to be acceptable - no fire strategy report required!!

[kurnal]

Can I put a query on this issue from a different angle. In the old days of CP3 Chapter 4 part 1 we were always told that apart from protecting the means of escape for flat occupiers, the internal protected lobby also played a role in the protection of the communal areas in support of the stay put strategy, the entrance hallway being of limited size results in the flat entrance door being shielded from the full radiant heat from a fire in a habitable room.
 
But this was never explicitly stated  in CP3 or in BS5588-1 as far as I can see.

It is implied in the footnote to the ADB diagram 9b which allows, in small single staircase buildings with no more than 2 dwellings per storey, the door between the staircase and the lobby to be omitted provided the dwellings have protected entrance halls.

What do you think? Is there any evidence apart from ADB that this internal protected lobby plays a role in the protection of the communal areas in shielding the flat entrance door from fire or is this an old wives tale?