DFE ventilation requirements

[kris]

ment to ask is there any other appliances in the same room?

 

[firemant]

Good point from Kris: re another appliance in same room?

Kirsty, re air changes. No, the fitting of cavity insulation will not affect ventilation. If they fit draught proofing, the fire should be spillage tested afterwards - but it will not affect the fact that the fire does not normally need ventilation, This is a specific issue for very new houses.
Frankly, I would get the fire checked anyway, after insulation:
http://www.manchestereveningnews.co.uk/news/cavity-insulation-firm-up-court-8637491

 

[Last Plumber]

Last plumber- you say spillage test can vary, I know nothing about the spillage test- does the spillage test give you a yes/no or a quantified result? Ie would a spillage test let us know how close it may be to failing the test if conditions vary like you suggest?

The spillage test carried out on the day, will pass or fail and generally give the indication that a chimney / flue is working.
It is carried out with windows and doors closed. The reason for this is so that the appliances flue is tested using what we call adventitious air.

As far as cavity wall insulation is concerned, in some circumstances, filling the cavity with insulation can, ( not always I stress), block ventilation that was designed to ventilate the underfloor area of a property, ( if you have suspended floors). This could ( in some properties), reduce the adventitious air entering that room and in turn effect the flue's operation ( unlikely but not impossible). This is why there is a necessity to have the fire tested after the wall is insulated. Some properties do have solid floors and in those type of properties, cavity wall insulation will have a lot less effect on the adventitious air.

Company's that insulate cavity walls have a responsibility for your safety but in most cases they are not gas safe registered Engineers ( I suspect), therefore they will have a very generalised view of this situation and will not want to get involved with your fire.

If they insulate your wall and your fire spills products of combustion, afterwards, they could be found liable, hence their stance.

Will they not insulate the wall on the understanding that you take responsibility for having the fire tested after they finish?

Show them the manufacturers installation instructions and offer to sign something that takes responsibility away from them.

It should be tested after the wall is insulated anyway in my opinion, it is not impossible for insulation that is pumped into a cavity wall to enter the flue itself. Again, these things are all very unlikely but happen on occasion.

If they do fill the cavity wall, make sure ( please) that you get the test done by a gas safe registered engineer, so you know the fire is safe.

 

[Gasmancoops]

The confusing bit from the manufacturer is that they have quoted BS 5871-3 in their installation instructions which is the British Standard for DFE's. All DFE's need ventilation typically but if the manufacturer is claiming a vent is not required, this takes precedence over the standard providing the appliance PASSES the spillage test.

The regulations dictate that if someone is doing something to house/property that may affect the safe operation of an appliance, then it is their responsibility to ensure the appliance continues to work safety after the work is completed. (REG 8(2) GSIUR states:

(2) No person shall do anything which would affect a gas fitting or any flue or means of ventilation used in connection with the fitting in such a manner that the subsequent use of the fitting might constitute a danger to any person, except that this paragraph does not apply to an alteration to premises.

Therefore the business carrying out the cavity wall insulation has a duty to ensure the fire works safely so they should either carry out the spillage test or arrange for someone to do it.

Hope this helps.

 

[jtsplumbing]

Lots of very good advise given , new styles vents will let in extra air and reduce the chance of draft, vent does not need to be visible so could be located behind something , Doing spillage test is very hit or miss depending on a lot of factors, Test at 9am it could fail do same test at 10am and it could pass, so for your own pice on mind fit a vent !

 

[Whyme]

the 7kw your talking about is to do with gaps in the house ie windows doors floorboards etc, not owt to do with the cavity of your external wall. go with instructions get insulation done then get engineer round to spilllage test. then if you need one you need one.

 

[firemant]

Whyme, you clearly have not read the OP

 

[kris]

A 7kw gap that's a new one to me lol, Whyme think u picked her up wrong mate,

 

[firemant]

The 7Kw allowance is because, until the advent of modern construction methods, it was considered impossible to draughtproof a house to the extent that you can prevent the ingress f enough fresh air to support the complete combustion of 7Kw of gas. Proper DFE's are different in that there is absolutely no control of air passing through the flue, increasing the volume of fresh air required. So Whyme is actually correct, if you analyse what he means.

My point about the OP is that the installers (of the insulation) are refusing to complete the work without a vent.

 

[kris]

I know mate it was a joke,, Jeepers wits happened to the banter