# Air tightness test and stoves



## BMD (22 Oct 2011)

Hi,

Does anyone know the correct procedure for carrying out an air-tightness test in a house that has stoves installed? It is clear that chimney's should be blocked in the case of open fires however what is recommended for stoves?

In the case of stoves with external air supplies, should the air inlet pipe into the stove be sealed or left open?

In the case where chimney's are blocked, I assume this should be done from below as opposed to at the top of the chimney?

Finally, should kitchen extract vents be sealed or left open?


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## onq (23 Oct 2011)

This post from 2008 on AAM seems very relevant to the discussion.
The following thoughts spring to mind when you consider the intent of sealing.

- What relevance would the results of an air-tightness test have, if you taped up your vents before the test?
- Unless they are going to be blocked when you use the house you will get a distorted picture of the efficiency of the house.
- If you have uncontrolled admission of air without a heat exchange  operation you will affect both your BER rating and air-tightness.

I am not an expert on this BMD, and I have read some discussions on the subject when seemed to be by knowledgeable people but made no sense to me.
Other people have posted comments recently on this and perhaps Low CO2 Design might comment as I understand he has some expertise with Passive Haus design.
My view - and I accept others may have a different view, - is that if  you want to seal your house to improve thermal efficiency you need an  MVHR system and no vents.


ONQ.

[broken link removed]

All advice on AAM is remote from the situation and cannot be relied upon                                                 as a defence or support -     in     and    of        itself  -         should       legal            action        be           taken.
Competent legal and building professionals should be asked to advise in                                                 Real Life with rights to        inspect     and       issue         reports    on     the            matter     at  hand.


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## lowCO2design (23 Oct 2011)

BMD said:


> Hi,
> 
> Does anyone know the correct procedure for carrying out an air-tightness test in a house that has stoves installed?


sealed temporarily 


BMD said:


> In the case where chimney's are blocked, I assume this should be done from below as opposed to at the top of the chimney?


either-or, it depends on future plans...


BMD said:


> Finally, should kitchen extract vents be sealed or left open?


sealed temporarily 

I notice this is not the only forum you have posted the same question on! but regardless why are you not asking your air-tightness tester?


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## lowCO2design (23 Oct 2011)

onq said:


> My view - and I accept others may have a different view, - is that if  you want to seal your house to improve thermal efficiency you need an  MVHR system and no vents.


yep thats the passive house idea, MVHR or the highway.. preferfectly acceptable option if its a new build or a 'deep retro-fit'. there are studies as far back as the 80's, reckon its the best balance, for conserving energy..

Recently I've been considering DCMEV for retro-fitting.. its something seamus (Viking.H) and J. Little have written about. i like the idea of maybe preheating the air through a conservatory or some variation.  there does seem to be some merit to it given how difficult it can be to retro-fit air-tightness and the main question many people ask 'why do i need wall vents when my house is full of drafts?'


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## onq (23 Oct 2011)

Hi LCO2D,

Thanks for commenting on this

What is DCMEV?

ONQ.

[broken link removed]

All advice on AAM is remote from the situation and cannot be relied upon                                                  as a defence or support  -     in     and    of        itself  -         should       legal             action        be           taken.
Competent legal and building professionals should be asked to advise in                                                  Real Life with rights to         inspect     and       issue         reports    on     the             matter     at  hand.


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## onq (23 Oct 2011)

lowCO2design said:


> sealed temporarily
> either-or, it depends on future plans...
> 
> sealed temporarily
> ...




Intending no disrespect, this sounds like a fudge to me.
How is the air-tightness test relevant to the normal use of the building?


ONQ.

[broken link removed]

All advice on AAM is remote from the situation and cannot be relied upon                                                  as a defence or support  -     in     and    of        itself  -         should       legal             action        be           taken.
Competent legal and building professionals should be asked to advise in                                                  Real Life with rights to         inspect     and       issue         reports    on     the             matter     at  hand.


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## lowCO2design (23 Oct 2011)

onq said:


> Intending no disrespect, this sounds like a fudge to me.
> How is the air-tightness test relevant to the normal use of the building?
> 
> 
> ...


can you elaborate I'm not sure what you mean? 'relevant to the normal use of the building'. I was under the impression Air-testing/tightness is a requirement..


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## lowCO2design (23 Oct 2011)

onq said:


> What is DCMEV?


demand controlled mechanical extract ventilation. ie 1 step on from WC & kitchen extract vents, only incorporating RH and CO2 sensors so the standard wall vents are closed till fresh air is required. 
there is an argument re smaller primary energy demand + lower install/ less disruption/ cost V heat recovery + install/ maintenance/ cost (referring to retro-fit only)


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## onq (23 Oct 2011)

lowCO2design said:


> can you elaborate I'm not sure what you mean? 'relevant to the normal use of the building'. I was under the impression Air-testing/tightness is a requirement..




I mean that blocking the vents gives an artificial result for air tightness.
It s seems like testing a ship for sea-worthiness with all holes plugged, them taking them out before going to sea 


ONQ.

[broken link removed]

All advice on AAM is remote from the situation and cannot be relied upon                                                   as a defence or  support  -     in     and    of        itself  -         should        legal             action        be           taken.
Competent legal and building professionals should be asked to advise in                                                   Real Life with rights  to         inspect     and       issue         reports    on     the              matter     at  hand.


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## onq (23 Oct 2011)

lowCO2design said:


> demand controlled mechanical extract ventilation. ie 1 step on from WC & kitchen extract vents, only incorporating RH and CO2 sensors so the standard wall vents are closed till fresh air is required.
> there is an argument re smaller primary energy demand + lower install/ less disruption/ cost V heat recovery + install/ maintenance/ cost (referring to retro-fit only)



Thanks LCO2D - I've heard of this, just not familiar with the acromym. 

It seems an interesting possibility where you have existing vents in the house.
But this is the nub if the matter - this admits cold damp air into the building in an Irish winter.

You may get a lower Co2 footprint than the pseudo-aircon of an MVHR.
Its trading lower operation costs (not much lower I would have thought) for very cold supply air quality.

It seems it basically lets the air get stale until the sensor goes off then opens a hole in the wall to vent the room direct to air.
What's that supposed to be like on a cold damp October day like today - sudden draughts blowing through the house at random intervals?


ONQ.

[broken link removed]

All advice on AAM is remote from the situation and cannot be relied upon                                                   as a defence or  support  -     in     and    of        itself  -         should        legal             action        be           taken.
Competent legal and building professionals should be asked to advise in                                                   Real Life with rights  to         inspect     and       issue         reports    on     the              matter     at  hand.


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## lowCO2design (23 Oct 2011)

onq said:


> Thanks LCO2D - I've heard of this, just not familiar with the acromym.
> 
> It seems an interesting possibility where you have existing vents in the house.
> But this is the nub if the matter - this admits cold damp air into the building in an Irish winter.
> ...


I'm not saying its prefect, (the term 'drafts' makes me think of to air-leakage not ventilation) yes it does admit cold air but, should in theory allow less than permanent wall vents.


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## lowCO2design (23 Oct 2011)

onq said:


> I mean that blocking the vents gives an artificial result for air tightness.
> It s seems like testing a ship for sea-worthiness with all holes plugged, them taking them out before going to sea
> 
> 
> ONQ.


yes I see where your come from now.
ventilation good/ necessary/ required by Breg's : air-leakage bad/ drafts/ now finally getting tighter in Bregs

air-tightness is about the latter


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## onq (23 Oct 2011)

(nods)

That's the point.
MVHR operates a heat exchange system AND ventilates.

Demand driven ventilation ventilates cold air at odd times.
BTW most permavents admit very little drafts - people tend to block them!


ONQ.

[broken link removed]

All advice on AAM is remote from the situation and cannot be relied upon                                                    as a defence or   support  -     in     and    of        itself  -         should         legal             action        be           taken.
Competent legal and building professionals should be asked to advise in                                                    Real Life with rights   to         inspect     and       issue         reports    on     the               matter     at  hand.


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## BMD (23 Oct 2011)

ONQ,

I completely agree, I don't understand why you would seal vents when they are usually left open in the normal running of the house but that seems to be the procedure.

I can't find any conclusive information on how stoves should be treated with respect to air-tightness testing. From what I can tell, the air inlets should be blocked (which doesn't make sense to me) while the chimney should be unblocked (which does make sense).

If the stove is fitted correctly surely it won't impact on the air tightness of the house and hence nothing should be sealed.

I have MHRV installed and again that test criteria state that these should be sealed???


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## BMD (23 Oct 2011)

Perhaps someone can point me towards and air tightness test protocol that states that the inlet air for stoves must be sealed?

Any protocols I have read only deal with open fireplaces (and state that the chimney should be blocked)


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## onq (24 Oct 2011)

I'm a bit lost with all this fudging - perhaps LCo2D might oblige 


ONQ.

[broken link removed]

All advice on AAM is remote from the situation and cannot be relied upon                                                     as a defence or    support  -     in     and    of        itself  -         should          legal             action        be           taken.
Competent legal and building professionals should be asked to advise in                                                     Real Life with rights    to         inspect     and       issue         reports    on     the                matter     at  hand.


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## lowCO2design (24 Oct 2011)

lads I fail to see the question here.. 

bmd, you have a stove (the air-supply is 'only' for the stove) and MVHR (both required to be temporarily sealed during testing) because:
the heating source (& imo this includes the required internal air-supply) and the ventilation/recycled heat source, are both outside of the remit of air-tightness testing and managed separately under the regs, so both are discounted from a test designed to assess air-leakage.

I don't have an air-tightness manual, your assessor will. I would recommend this guy (no connection) [broken link removed]

if you look through his references, you will get more info on the subject


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## BMD (24 Oct 2011)

Low C02,

I could argue whether the rationale for the testing design is correct, however I accept your point that the regulations state that air inlet vent should be sealed. A deviation to the test will have to be performed to assess whether the air inlet is well sealed.

Given that the chimney is integral to the building, am I right to assume that it should not be sealed when a stove is fitted? This is what my tester told me but I just want to confirm


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## lowCO2design (24 Oct 2011)

BMD said:


> Low C02,
> 
> I could argue whether the rationale for the testing design is correct, however I accept your point that the regulations state that air inlet vent should be sealed. A deviation to the test will have to be performed to assess whether the air inlet is well sealed.
> 
> Given that the chimney is integral to the building, am I right to assume that it should not be sealed when a stove is fitted? This is what my tester told me but I just want to confirm


stove is sealed to the chimney flue? so I don't see the issue, But finally we have gotten to the bottom of this - if you don't trust your tester, get a second opinion (from another tester, not from me) best of luck with, comeback and tell us how you go


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## BMD (24 Oct 2011)

I'm afraid you are wrong with your conclusion, however thank you for your input. After reading further articles I am satisfied that the recommended procedure is as follows;

In the case of stoves, seal the air inlet but not the chimney.

I don't agree with the science behind this approach but that's for another day.


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## porridge (24 Oct 2011)

*Airtight Stove*

BMD, 

We installed two room sealed stoves in our new build. We deliberately did not seal any part of the systems (air supply, stove or chimney) as we wished to test the installation quality from the supplier.

The results, one of the stoves was correctly installed, there was no passage of air between the house and the stove. (confirmed by smoke test). 

The other stove had been badly installed and was leaking. Supplier came back, and found some of the system had not been installedadequately. 

If we had taped up the stoves for the test, it would still be leaking!


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## lowCO2design (24 Oct 2011)

porridge said:


> BMD,
> 
> We installed two room sealed stoves in our new build. We deliberately did not seal any part of the systems (air supply, stove or chimney) as we wished to test the installation quality from the supplier.
> 
> ...


while this is probably what BMD is asking, and worth while doing. don't you think this assessment should be done separately (as in one after the other) to the air-test for part L/ BER compliance?


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## BMD (24 Oct 2011)

Yes, this was exactly my point.

In summary, in a house with stoves to comply with the air-test for part L/ BER, the external air inlet should be sealed but the chimney should not.

A separate test should then be performed with the external air inlet open to assess the quality of the installation.

low Co2, you seem well versed on this area, would you agree with my summary?


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## lowCO2design (25 Oct 2011)

are you for real, were still on this


BMD said:


> in a house with stoves to comply with the air-test for part L/ BER, the external air inlet should be sealed but the chimney should not.


 if the stove, is sealed to the chinmey flue (which i presume it is) then yes, that's grand
when your guy is doing this he will go around with the smoke contraption and check for leaks anyway. so unless your builder is super-duper you will have a few area's to address. 


BMD said:


> A separate test should then be performed with the external air inlet open to assess the quality of the installation.


 well yes, this is for your piece of mind and to check if the installer did a good job..

best of luck with it


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## onq (25 Oct 2011)

If you find leaks try to do a proper seal with good detailing and materials- don't just point a spray foam cannister at it


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