Green Building Forum - Air Tightness - Door Blower Test Experiences Tue, 19 Dec 2023 05:31:33 +0000 http://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 Air Tightness - Door Blower Test Experiences http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208379#Comment_208379 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208379#Comment_208379 Wed, 03 Sep 2014 13:40:00 +0100 Greenfish
Just had our door blower test run, not got results yet, but was underwhelmed by the experience. Pretty sure we are well within Part L requirements, but was hoping to get below 1 (units confused!) and have a chance to feel and listen for any tiny leaks. In the end the guy was happy things were "good enough", well of course they were, and the fan was on and off in minutes. More worrying he did not seal the MVHR input/output grilles, wish I had done it before hand. He said switching it off was enough, but I am convinced it seals just because the fan isn't running. Also the seal of the fan into the door didn't look that great, I could see daylight around the cracks (no tape).

So I will get a number, but not a true measure of what we have achieved, and no indication of the weak points. Was I hoping for too much?]]> Air Tightness - Door Blower Test Experiences http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208381#Comment_208381 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208381#Comment_208381 Wed, 03 Sep 2014 13:51:21 +0100 tony
I have two done and both times I was moderately happy as they did offer advice and even helped to trace leeks.

The first guy had loads of trouble as he wasn't expecting a masonry house to so air tight and had to reduce his blower fan aperture several times and slow it down a lot too.

I forgot to seal up the cooker hood duct the first time and found a couple of unsealed service penetrations by listening for the sound of wind whistling through the gaps, noted and sealed later on.

They both drew graphs at various pressures and sent a report

Second guy's result was less than one 0.98

I asked about their worse results and both told me that had been to new houses where their fan could not raise the pressure to 50Pa plenty of poor results.

One problem is that a pass is hopelessly leaky and so their standards are low and OK is not OK]]> Air Tightness - Door Blower Test Experiences http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208382#Comment_208382 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208382#Comment_208382 Wed, 03 Sep 2014 14:00:41 +0100 snyggapa http://www.etophouse.com/ , I found him very good and spent time with me skipping around the house feeling for draughts , checking what he had found in other houses as "problem areas" and generally helpful rather than in a hurry. He did my sap calcs too which was an interactive process rather than just a dump n run.

We ended up with a score of about 3, most of which was leaking out of the quirky, wonky, sash windows ..]]> Air Tightness - Door Blower Test Experiences http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208446#Comment_208446 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208446#Comment_208446 Thu, 04 Sep 2014 10:00:02 +0100 borpin Air Tightness - Door Blower Test Experiences http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208447#Comment_208447 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208447#Comment_208447 Thu, 04 Sep 2014 10:10:38 +0100 Triassic
Rather than a quick and dirty job done to a price, maybe you should ring round and see how much a day would cost, might be cheaper than you think.]]> Air Tightness - Door Blower Test Experiences http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208451#Comment_208451 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208451#Comment_208451 Thu, 04 Sep 2014 10:33:22 +0100 Ed Davies
Testing on the final structure is, IMHO, flawed anyway. E.g., you might have areas which are only sealed by the plasterboard with dreadful thermal bypass behind which is, at the end of the process, undetectable and would be very expensive to fix even if it was detectable but would have been trivial to find and sort out if the basic shell of the house had been tested earlier.]]> Air Tightness - Door Blower Test Experiences http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208458#Comment_208458 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208458#Comment_208458 Thu, 04 Sep 2014 11:10:13 +0100 neilu He will have been using a software package that controls the fan and runs the test.
The test does only take 5 minutes and the software gives the result immediately.
So the only reason I can think of as to why he couldn't give you the result was if he hadn't calculated the envelope area, which he should do before doing the test.

Did you go to one of the big companies to do the test or a smaller company?
I know that some companies have people in the office that calculate the envelope areas from drawings rather than it being done by the tester themselves.]]> Air Tightness - Door Blower Test Experiences http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208460#Comment_208460 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208460#Comment_208460 Thu, 04 Sep 2014 11:14:31 +0100 dickster
I sealed all openings beforehand. Architect arrived to witness his first test on site.

Fan in doorway, computerised read out. Didn't work at first, more fiddling and result just over one. Considering there was nowhere for the air to go, I was disappointed, then I noticed that the seal around the door had blown apart. Bloke basically said, well you've passed by a mile so it doesn't matter. I was too slow and didn't voice my objections, bloke went off, architect (and builder, who phoned up for result whilst on holiday) all very pleased.

Hey ho, I wonder what the real result would have been?]]> Air Tightness - Door Blower Test Experiences http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208462#Comment_208462 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208462#Comment_208462 Thu, 04 Sep 2014 11:23:26 +0100 Ed Davies Posted By: dickster… then I noticed that the seal around the door had blown apart …Yes, I've wondered about that - the test does test the temporary seal made by the blower door but doesn't test the actual seal made by the real door. Not ideal.]]> Air Tightness - Door Blower Test Experiences http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208473#Comment_208473 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208473#Comment_208473 Thu, 04 Sep 2014 13:22:51 +0100 Chris P Bacon Posted By: Ed Davies
Posted By: dickster… then I noticed that the seal around the door had blown apart …
Yes, I've wondered about that - the test does test the temporary seal made by the blower door but doesn't test the actual seal made by the real door. Not ideal.Unless you go for dodgy cheap doors you shouldn't have a problem Ed. Our front door and utility room door are almost identical save for a small glazed panel in the front door. I made sure to check the seals on the utility room door with a smoke pen when the house was both pressurised and depressurised and didn't find a hint of a leak.

I'd echo your sentiments about testing the house before the plasterboard is in place so that if there is a problem it can be found and fixed. It did cause us some problems however as the software got upset due to the change in internal volume due to the airtightness layer getting sucked in/blown out. It was also quite scary to witness the pressure put on the foil and the taped joints, it was tight as a drum at 50Pa, but thankfully all held together, the tester told me he had left another house in tatters when testing in similar circumstances for a "professional" builder.]]> Air Tightness - Door Blower Test Experiences http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208479#Comment_208479 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208479#Comment_208479 Thu, 04 Sep 2014 13:38:21 +0100 Shevek Posted By: Ed DaviesMaybe it's best to separate out the diagnosis bit and the testing bit. Make up your own crude fan arrangement to allow finding problems while you're building.
Would a petrol powered garden blower be powerful enough?

Is this too powerful?
http://www.ebay.co.uk/itm/Stoney-Racing-16-120W-Electric-Radiator-Fan-Universal-12v-Slimline-/181428101106

Fan speed: 2100-2390rpm
NTP airflow rating*: 1575cfm
Maximum airflow rating*: 2650cfm
Outer dimensions: 437mm x 405mm x 66mm]]> Air Tightness - Door Blower Test Experiences http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208480#Comment_208480 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208480#Comment_208480 Thu, 04 Sep 2014 13:44:07 +0100 Chris P Bacon http://www.greenbuildingforum.co.uk/forum114/comments.php?DiscussionID=7396&page=1]]> Air Tightness - Door Blower Test Experiences http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208486#Comment_208486 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208486#Comment_208486 Thu, 04 Sep 2014 14:15:20 +0100 Greenfish Posted By: Ed DaviesMaybe it's best to separate out the diagnosis bit and the testing bit. Make up your own crude fan arrangement to allow finding problems while you're building.
Can you hire the fan kit (without the operator) from anywhere?]]> Air Tightness - Door Blower Test Experiences http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208491#Comment_208491 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208491#Comment_208491 Thu, 04 Sep 2014 15:26:06 +0100 Ed Davies
Posted By: Chris P BaconIt was also quite scary to witness the pressure put on the foil and the taped joints, it was tight as a drum at 50Pa, but thankfully all held together, the tester told me he had left another house in tatters when testing in similar circumstances for a "professional" builder.
That's also scary in a different way - windy weather can produce a lot more than 50 Pa. I wonder how many installations pass the pressure test then are reduced to tatters (unseen behind the plasterboard) by the next winter storm.

E.g., 20 m/s (only a Beaufort scale “fresh gale”) would produce a dynamic pressure of ½ρv² = 0.5 * 1.3 * 20 * 20 = 260 Pa and that's just the steady pressure without the effects of momentum and gusts.]]> Air Tightness - Door Blower Test Experiences http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208537#Comment_208537 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208537#Comment_208537 Fri, 05 Sep 2014 11:00:27 +0100 neilu Work out your envelope area see ATTMA guide below:

http://www.bindt.org/downloads/ATTMA%20TSL1%20Issue%201.pdf

Lets say its 400m2.
If the air tightness is 3.00 m3/h.m2 at 50 pascals then the fan would run at a flow rate of 1200 m3/h (cubic metre per hour) at 50 pascals.
An online conversion says that 1200m3/h equals 706 cfm (cubic foot per minute) so well within the range of the radiator fan.

If you are trying to find leaks then you want to be running the fans as fast as possible.
When I'm finding leaks in buildings I take all the rings out of the fan and run it at top speed which gives a flow rate of about 7500m3/h. 2650cfm equates to 4500m3/h so not as powerful but still reasonable.
If you think that your house is very airtight then 4500m3/h should be good enough to find the leaks.

There are companies that hire out the equipment (I'm not sure if I'm allowed to mention them on here). I'm not sure if they will hire out to anybody not qualified plus I've no idea of the cost.]]> Air Tightness - Door Blower Test Experiences http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208811#Comment_208811 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208811#Comment_208811 Tue, 09 Sep 2014 16:55:38 +0100 Greenfish
Other than self satsfaction, is there any thing to gain from another test? Would a DIY test be able to locate leaks in such an air tight build? Depressure at max fan speed and feeling for leaks wth a hand? Worth hiring someone specfically to run the fan while we look for leaks rather than just generate a number for building control? Should I wait a year and test then showing how the building is settling in too?

If it had been below 1 then the beers would be on me!]]> Air Tightness - Door Blower Test Experiences http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208812#Comment_208812 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208812#Comment_208812 Tue, 09 Sep 2014 17:10:55 +0100 Triassic Posted By: Greenfishachieved just over 1, not bad given the MVHR was not sealed and there were obvious leaks around the fan itself I'd say the beers are on you..]]> Air Tightness - Door Blower Test Experiences http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208817#Comment_208817 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208817#Comment_208817 Tue, 09 Sep 2014 17:47:56 +0100 djh Posted By: GreenfishI have been told that we achieved just over 1, not bad given the MVHR was not sealed and there were obvious leaks around the fan itself, paper report to follow. Tester thinks it is an amazing result, but I feel quite disappointed. The build is better than that, but I don't know by how much, nor do I know if there are any leaks we could fix.
I'm trying to organize my first test. Who did your test, so I can avoid them? (whisper if you don't want to publically shame). I think it is key to check up front that they know how to do a PH test rather than a building regs one. Can you get him to come back?

Other than self satsfaction, is there any thing to gain from another test? Would a DIY test be able to locate leaks in such an air tight build? Depressure at max fan speed and feeling for leaks wth a hand? Worth hiring someone specfically to run the fan while we look for leaks rather than just generate a number for building control? Should I wait a year and test then showing how the building is settling in too?

I think it's definitely worthwhile to have access to a fan for leak location. Crank it up to max and use a smoke pencil or cigarette or back of the hand etc etc. I figured it was cheap and easy enough to build a simple system to help with leak location. Cetainly cheaper than paying for somebody to come in with their own kit, although you should get the benefit of their experience if you do the latter. The ability to repeat tests later is also something I like the idea of my own lash-up for.]]> Air Tightness - Door Blower Test Experiences http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208823#Comment_208823 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208823#Comment_208823 Tue, 09 Sep 2014 18:21:39 +0100 fostertom
Wind pressures - think of a yacht - enormous pressure to create force to drive it through water and waves at speed - look at the engineering to withstand that pressure and force, which sometimes still breaks - look at the quality of the 'membrane' - any sticky tape there? - know that your house will suffer all those forces over a long lifetime, over very large 'sail area'. A sail generally only experiences forces in one direction; a house's membrane experiences frequent fatiguing pressure reversals, with a yank every time.

I don't rate anything less that glued and screwed OSB, for air barrier. And why not - cheap, ordinary builders merchant materials, ordinary chippy skills, easy and foolproof (though "fools are so damn ingenious" - Mark Twain), robust, repairable, durable.]]> Air Tightness - Door Blower Test Experiences http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208834#Comment_208834 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208834#Comment_208834 Tue, 09 Sep 2014 18:39:20 +0100 Chris P Bacon Posted By: fostertomA sail generally only experiences forces in one direction; a house's membrane experiences frequent fatiguing pressure reversals, with a yank every time.
Unless I misunderstand then there won't be "a yank" on the membrane unless there is a void on one side. A membrane sandwiched between solid layers of construction just won't experience anything like the same forces as a sail in the wind.]]> Air Tightness - Door Blower Test Experiences http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208850#Comment_208850 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208850#Comment_208850 Tue, 09 Sep 2014 20:00:43 +0100 fostertom Air Tightness - Door Blower Test Experiences http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208919#Comment_208919 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208919#Comment_208919 Wed, 10 Sep 2014 20:04:39 +0100 Greenfish Posted By: djhI'm trying to organize my first test. Who did your test, so I can avoid them? (whisper if you don't want to publically shame).Used a local guy, you should be OK if not in my part of the world. To be fair he was nice enough, just didn't get (no matter what I said) that I was interested in more than passing. In 7 years of testing he said I was one of the few even interested in the test process. Mostly he was just worn down by the abusive atttude of most builders and architects he encountered daily. Great shame, and my mistake for not putting my test requrements e.g. seeking leaks even if they are small, and nialing as small a value as possible, on paper as contractual.

I think it is key to check up front that they know how to do a PH test rather than a building regs one. Can you get him to come back?
Yes, simply telling them my design aims for air tightness was not enough. Find someone intereted in their job rather than jaded. Sure he would come back if I paid him, but I doubt he has accuracy in his skill set.

Have found a place where I can hire a fan for leak testing, but not the manometers, software etc. and didn't get the price. However they advsed that seeking leaks in such an air tight build would be rather futile. Anyone agree?]]> Air Tightness - Door Blower Test Experiences http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208921#Comment_208921 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208921#Comment_208921 Wed, 10 Sep 2014 20:37:49 +0100 Ed Davies Air Tightness - Door Blower Test Experiences http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208923#Comment_208923 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208923#Comment_208923 Wed, 10 Sep 2014 20:59:09 +0100 Chris P Bacon
Maybe just take a worst case scenario of a cold and windy day and figure out what the potential difference will be.

That would be an interesting exercise.]]> Air Tightness - Door Blower Test Experiences http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208924#Comment_208924 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208924#Comment_208924 Wed, 10 Sep 2014 20:59:42 +0100 djh
I posted the bits that I've bought at the bottom of this page:
http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=7396&page=5

It's a very useful thread. For finding leaks, I don't think you need any software, or even a manometer, or an adjustable power supply. Just a fan and something to power it and a smoke pencil or something to find the leaks. Actually, if you have MVHR then you can use it to depressurise the house. I think the details are in that other thread.

I don't see why it's futile to look for leaks. I think it just speaks to a difference between their knowledge and expectations and yours.]]> Air Tightness - Door Blower Test Experiences http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208935#Comment_208935 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208935#Comment_208935 Wed, 10 Sep 2014 22:32:25 +0100 SteamyTea Posted By: Chris P BaconSounds like a job for ST!Greenfish is local too, and the weather data is easy to get hold off (and I can take down my new weather station and bring that along).

I think we had a thread on here about DIY testing and our old mate J S Harris told us how to make a manometer and control a fan.]]> Air Tightness - Door Blower Test Experiences http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208939#Comment_208939 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208939#Comment_208939 Thu, 11 Sep 2014 05:33:58 +0100 Chris P Bacon
Based on historical weather data how many litres of heated air will be lost from the house on a particularly cold and windy day?

How many kWhrs that represents calculated for both 1ACH and 0.5ACH so Greenfish (and others) can figure out how much effort it is worth going to to achieve the absolute best result possible.

A ballpark figure is all that is required. Is the difference going to cost an extra 10p a day or £2 a day?

So given a heating season of around 120 days what is the total cost impact of better airtightness likely to be each year?]]> Air Tightness - Door Blower Test Experiences http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208941#Comment_208941 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208941#Comment_208941 Thu, 11 Sep 2014 08:08:43 +0100 SteamyTea Posted By: Chris P BaconI was thinking more along the lines of a theoretical calculation ST.
Like I did here with windspeed.
http://www.greenbuildingforum.co.uk/forum114/comments.php?DiscussionID=11624&page=1]]> Air Tightness - Door Blower Test Experiences http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208944#Comment_208944 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208944#Comment_208944 Thu, 11 Sep 2014 08:44:03 +0100 Chris P Bacon
https://www.cmhc-schl.gc.ca/en/inpr/bude/himu/coedar/upload/Air-Pressure-and-the-Building-Envelope.pdf]]> Air Tightness - Door Blower Test Experiences http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208967#Comment_208967 http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12521&Focus=208967#Comment_208967 Thu, 11 Sep 2014 18:00:47 +0100 djh Posted By: Chris P BaconHow many kWhrs that represents calculated for both 1ACH and 0.5ACH so Greenfish (and others) can figure out how much effort it is worth going to to achieve the absolute best result possible.
Sadly perhaps, the reason quoted for such a tight airtightness level in PH isn't to do with the energy or cash saved directly. The point as I understand it is to avoid drafts and to maintain internal surface temperature everywhere. That in turn allows you to reduce the internal air temperature by a degree or two whilst maintaining the same level of comfort, and that is what saves the energy and cash.]]>