Protection for recessed light fittings

[Dominic]

Apologies if this is a repeat question. We have a new mental health unit where the electrical contractor has cut bedroom ceilings to install recessed light fittings thus breaking the 30 fire resistance. This is a single storey unit with an open roofspace above. Due to walkways, partial flooring and M&E services etc, there is no room to retrofit plasterboard boxes above the lights. We have researched smoke hoods but none will comply with BS476 part 20. All seem to comply with part 21 and 22 but when you study the graphs all fail on temperature. Anyone any thoughts or am I misreading reading the graphs. TA

[nearlythere]

Do the light units need to be ventilated?
This is a common problem with light installers. I wouldn't use the word electrician because a good one would know not to do it. Mind you he may only have done it because that what was on the plan.

[Tom Sutton]

Try http://www.firehalt.com/lighting%20units.pdf they are tested to a BS EN standard this may make a difference.

[Dominic]

Thanks TW and NT. I have requested a copy of their technical data. We may however have difficulty retro installing through the circular hole in the ceiling.

[Tom Sutton]

We may however have difficulty retro installing through the circular hole in the ceiling.

Check out the Firehalt website they show how it is done.

[Dominic]

Installation seems straight forward however its only compliant with the structural and accoustic elements, not heat insulation. The BS EN reference is for the make-up of the ceiling during the fire testing.
According to the company the cover is no longer being marketed.

[nearlythere]

Is this a central corridor situation with rooms either side?
Is it a sleeping risk?
Are there recessed lighting units throughout?
Are you fire risk assessing or snagging?

[Dominic]

Yes, Yes, Yes and snagging
My point is that some hood manufacturers are implying that their products are heat (part 20) compliant and when you read the test results they are not.

[kurnal]

Hi Dominic
I congratulate you on your diligence. I am interested to know a little more about your concerns because I have recommended this type of product in the past and had not picked up on a problem.

I note that the following company claims  a 60 minute rating for their products but have not looked at their test results cos you have to register and request. May be of interest though.

http://www.astroflame.com/fire-test-request.html

In this case are your concerns in respect of life safety, property protection or code compliance? From your description of the building it does not sound like a life safety issue in this case.

[Tom Sutton]

They appear to be making the same claims as Firehalt and look very similar I think you may be disappointed again Dominic.

[Dominic]

My concerns kurnal are that some of the residents may be sedated at night and that fire may break into the roofspace within 10 minutes. From memory I think the BS states that the temp rise on the unexposed side of these hoods may not rise more than 180 deg C within the rated time. From the test data so far, this temp is reached within 10 min and is around 300 deg C after 30 min with one thermocouple reading reading over 500. By my thinking this hood does not comply with the BS yet they claim it does. 

[kurnal]

Thanks Dominic. I cannot comment further on the test performance without doing some reading up on this. I will try and research it a little more over christmas.

I take it there is no subdivision in the roof space between rooms and escape routes?

[Dominic]

There is protection between the bedrooms and escape routes but there are 4 bedrooms under each of the roofspace voids.
Anyway, I hope everyone has a good Christmas and New Year.
Kurnal, I am sure you can find better things to do over the festive period than to read up on this :-)

[Tom Sutton]

Dominic

I would not even try to argue the technical aspect and it dose highlight the caution required when accepting manufacturers claims but what about the practical side. Assuming the fire starts in the down lighter this will activate the intumescent hood which I accept will reach a temperature of in access of 300 degrees C but where is it going to spread to? I would assume above it is fire resistant insulation, at least 150mm each side is the ceiling joists protected to some degree by the insulation material and the plaster board is practically non combustible so how is the fire going to spread? However if the down lighters are immediately below the walk ways then they could be involved but it wouldn’t be a rapid spread of fire. Installing AFD in the roof space would give early warning for both life and property protection.