Exterior Doors/Windows and Fire Safety

[solange]

Hi

I have been looking on this forum, which is way over my head by the way, for details on exterior doors and windows as regards fire safety but have not managed to find anything.  I was hoping that someone may be able to help.

Our neighbour is building a side extension onto his house that when finished will sit 0.9 meters away from the side of our house (the side of our house is all brick and has no doors or windows).

He has got planning for a side door and upstairs window but seems to be building 2 side doors within less than 1 meter of each other (??) and an upstairs window.

Looking at building regs I came across something that said exterior doors when in close proximity to a boundary should be self closing and the number of openings restricted.  

However it is that vague and does not detail how close 'close' is or the basis on which it would restrict openings.

Obviously I am really concerned about this as I do not relish the thought of having a potential fire hazard that close to my house.

Apologies if this has been asked a 1000 times before -also please accept my apologies and ignore if totally irrelevant to this forum!

Thanks

Solange

[saddlers]

Hi,
There are several factors that need to be considered. There is a section in the Building Regulations which deals with "unprotected areas" and fire spread across the boundary. On dwellinghouses, there is a limit on the amount of openings that may be in an elevation facing the boundary. Where less than 1m this is generally limited to small openings less than 1m² that have to be suitably spaced. Any areas larger than this would need to have 30 minutes fire resistance. This would apply to large windows and door openings (the windows would have to be direct glazed).

The fact that your property does not have openings is irrelevant, because the Building Regulations assume a building with similar openings is on the opposite side of the boundary.

This however is only applicable on projects that would require Building Regulations approval. If the extension does not require Building Regulations approval due to its size or type, then the above controls would not be applicable, and there would be no restrictions.


It would be advisable for you to contact your local building control section and seek advice.

Thanks
Colin G.

[solange]

Hi Colin,

Thank you for your reply!

Just to put you completely in the picture we are currently having a 'battle' with the local council about the planning approval for an extension to our neighbour’s house. There are many things which don't add up and to put in bluntly the council have lied on many issues.

We approached the local building control department with a little bit of scepticism as both this department and the planning come under the same management.

To be fair they did send somebody out to review and have also issued us with a report.
I do however have concerns about the content of the report.
Below is the extract relating to the issue if you or anybody else could give comment I would like to know if what they are saying is correct;

“You have suggested that a breach of regulations has occurred as the extension has been built within 1m of the boundary and contains openings in excess of 1m2. Structural openings totalling 3.8m2 have been formed at present on the ground floor by two door openings and an area of glazed wall, with the proposal for a further landing window approx 1m2 to the first floor.

The building control officer has measured the distance between properties to both the front and back of the extension and discovered the width at the front to be 990mm and the rear to be 945mm from the boundary wall. The extension is 2860mm wide both front and back which would indicate that the properties are built at a slight angle.

If there was a distance of 1000mm from the neighbouring property then a total of 5.6m² of unprotected openings would be permissible.

The building control officer has used his expertise and professional judgement to  assess the risk that the work could pose and any mitigating circumstances that exist. The boundary wall to No 4 is solid brick with no openings, so the risk of fire spread is highly unlikely.

If the extension was a further 11mm away from the boundary at the front and 46mm away at the rear, then the proposed openings would not be excessive.

If we interpolate between the two values then we can determine that for every 1mm up to 1000mm an area of 4.6mm² is allowable.  If we multiply 4.6 x 945 given the worst instance a total of 4.35m² of unprotected areas would be reasonable.

Therefore, if the window at first floor level does not exceed 0.8m² then the unprotected areas are not deemed excessive, and a variation of the provisions would be acceptable.

My building control officer is of the opinion that at this stage, a breach of Building Regulations has not occurred, however, there is room for further compromise if agreement can be reached between the relevant parties.  As a gesture of goodwill the building control officer will approach the adjoining owner and request that he consider either the removal of one of the doors completely or the replacement of both of the doors with 1/2 hour fire resisting alternatives.  I would stress however, that these suggestions are purely to increase your peace of mind and cannot be enforced under the regulations.”


Thank you (or anybody) in advance.

Solange

[wee brian]

Its a bit long winded. But treating the distance as 1000mm would be fine.

The figures set out in the Approved Document are a metrification of an old imperial system. For simplicity they rounded one yard  up to one metre. Obviousely many exisitng houses have been built one yard from the boundary so extensions end up being slightly less than a metre or you have to have a silly little step.

I understand your frustrations with the Planning Dept but Building Regs wont help you.

[solange]

Thankyou wee brian for your reply.

I understand what you are saying about the distance from the boundary however in this case, the side wall of our house marks the boundary.  Therefore although our property is detached, on one side of our house we have a 1m gap between the external wall and the boundary fence with a further 1m gap from the boundary fence to our neighbours external wall.  However on the opposite side - the side where we have the issue, there is simply a 1m gap between our external wall and our neighbours new extension.

Does this make any difference?

Also, sorry but a few more questions!

We cannot make sense of their calculations but before we go back and query them, can anyone shed any light as to whether their calculations are correct and how they have derived their figures?

Does the fact that there are no openings on our wall have an impact? Does the roof and boards not come into play?

Have they not contradicted themselves?
"with the proposal for a further landing window approx 1m2 to the first floor."

"Therefore, if the window at first floor level does not exceed 0.8m² then the unprotected areas are not deemed excessive, and a variation of the provisions would be acceptable."

Thank you in advance for your help as we are extremely concerned by all of this.

[wee brian]

Yes it does - The one yard from the boundary rule was based on the fact that you would get at least 2 yards between window openings. This is because flames coming out of windows will be about that long. Its a bit simplistic but actually they are about that long! (all the firefighters will jump in now and talk about 60 foot flames etc etc)

The regs do allow some small openings in walls closer than this but you cant really interpolate down from the 1 Yard.   The permited areas over 1 yard (ie 2 yards between) are based on radiation, not flame contact.

As it is if you dont like what Building control have approved then your only recourse is court or maybe the Local Authority Ombudsman.

[solange]

Wee Brian, you advice is totally invaluable!!!

Can I be as bold to ask one further bit of clarity!!

I have downloaded the monster they call 'Building Regulations Part B'.

In chapter 14.13, if I have read it correctly, states that if a wall is situated within 1000mm of relevant boundary the only unprotected areas are shown in diagram 44.
To my untrained eyes diagram 44 only shows window openings but what is also being built is two door openings and an area of glazed wall!!!!!

It also mentions that the wall should be fire resitance from both both side.

Am I correct in my assumptions?
Is there not a independant 'fire safety' body that could help??

Thank you again!
Getting concerned by the minute!

Solange

[CivvyFSO]

14.19 points you towards Diagram 46.

It almost seems to me like they are saying that they can move it closer than 1m if the area of 5.6m2 is taken down accordingly? Someone trying to baffle you with maths?

In these days of risk assessments some things can be hard to argue, but for what its worth, if someone was altering some standards as part of an assessment of risks, but those risks possibly affected my property I think I would be arguing against it too.

I am in no way an expert with ADB but the 1000mm does not seem like something intended to be flexible.

[Mike Buckley]

One thing I have noticed is that the building control officer is talking about the distance between the two houses. If you at the earlier parts of Section 14 it tells you where the boundaries are. It also brings in the idea of a notional boundary see diagram 42. So if the wall of the new building is on the real boundary of its property the notional boundary would run between that wall and the wall of your property.
If I read the report from the building control officer correctly your the distance between the two walls is 945 mm at the minimum so the notional boundary would be only 472.5 mm away from both properties.
I tend to agree that the 1 meter distance is a cut off point and not to be used to extrapolate the area. It would seem to me that the regulations do state that the largest unprotected area that can be put into the wall is not more than 1 sq m. On a similar basis if the extension was built you would not be allowed to have an unprotected area of more than 1 sq m either.
Another reason I can see for this restiction is that given the constricted space between the buildings a fire would be deflected upwards and affect the roofs of both buildings.

[kurnal]

Solange

Lets just take a step back. If I have understood your posts correctly your building is right  on the edge of your property, it has masonry walls and no openings along the site boundary between your plot and the the one in question. So the building regulations would allow this, as you have no openings, right up to the edge of the plot. For purposes of fire spread between buildings the notional boundary for your house- the first to be built - is your wall.
Your neighbour then has to satisfy space separation requirements from your wall. If less than 1 metre then diagram 44 dictates the maximum unprotected openings. But at 1 metre he could have 5.6 sq m of unprotected openings. I dont think you need worry unduly about the difference between 945mm and 1 metre. Its just about two inches after all.

I dont see many occupiers of terraced or semi detached houses losing sleep about the danger from a fire next door. And they share the same roof.

[solange]

Thank you all for your invaluable advice.

Thank you to Kurnal for at least giving us some peace of mind!!!!

I would add that although safety as been paramount in our minds, we continue to have a ‘battle’ with the technical department of the council and therefore this has now become a matter of principle.

We have been walked over by the council with regard to planning, therefore I don’t want them to palm us off with another unacceptable response.
(Sorry, I’m starting to sound like a right moan!!!!)

From what Kurnal is saying the distance of 945mm should not cause us a safety issue.
However the guidelines in chapter 14, if  my untrained eyes have read correctly, advise that anything less the 1m should have no more than 1 sq m unprotected openings.
For simplicity the council appear to have rounded up the distance to 1m and then said that the acceptable unprotected openings are 5.6 sq m.
They then appear to have pro-rated down the 5.6 sq m to 945mm and then stated that 4.35 sq m is acceptable for unprotected openings;

Can they simply round the distance up to 1m?

Is it standard practise to pro-rate down for a distance less then 1m?
I though it was very black and white, one rule for less then 1m, one rule for 1m+?

[kurnal]

I think your summary of the logic is correct, but its nothing like an exact science.
It is impossible to predict the size and intensity of a fire in your neighbours property with such accuracy that the difference of 55mm in the spacing  can be assessed in any significant, scientific way.

The closer the walls the greater the flue effect of the two parallel faces but in the same way 4.35 is very much smaller than 5.6, and the performance of a flue is very much dependent on the heat source at the base.
I really would not worry from a fire spread point of view. I must say it  looks to me as though the BCO has made an  pragmatic decision based on an educated guess as most of us would in the circumstances.  

It can upset clients sometimes that the first neighbour to act and knock a hole in a wall can usually get away with it but then this prevents the other party from making desired changes to their home. Have seen this type of problem a number of times before- including an extension to an existing house being allowed that wiped thousands off the value of an adjoining confined building plot.

[kurnal]

Just to add a final after thought- any opening can be protected by steel fire shutters or water drenchers, a solution often used in commercial premises such as shopping malls where the extensive shop windows are needed for commercial purposes but the spacing of the buildings does not allow large unprotected areas.

Sometimes the logic does not appear to stack up, for example I was looking at one shop the other day where two buildings were opposite each other at an angle of about 25 degrees, the new shop had one half of its windows protected with automatic shutters  to meet the boundary conditions, the other half were not.

Guess which windows they chose to protect- those furthest from the building opposite!! But they do meet the letter of ADB4.