ultra slimline (slimlite) sealed IG units

[admin]

I've recently been hearing about a new genus of ultra-thin double glazed insulated glass units that have recently come onto the market, directed at renovation / conservation purchasers. And it is said that they can be installed with traditional putty. Obviously I assumed that these were the welded-edge vacuum Nippon/Pilkington "Spacia" units (now called EnergiKare LEGACY).

But oh, no. And oh dear. Apparently they're just conventional IG units! But with slimmer, lesser, everything. In my experience the reduced edge seal thicknesses I've read about so far will lead to early failure and breakdown (misting and fogging). In addition, installing them with traditional putty, in a solid-bedded configuration, will accelerate the failure.

IG units need a ventilated / drained configuration to survive - the fail very fast when solid-bedded.

Traditional putty contains organic oils (linseed, rape etc) that react adversely with all edge sealants (polysulphide, butyl, silicone) which is another nail in the coffin.

Would anyone with information on the suppliers of these new "slim line" units please let me have their contact details. Ultimately we might have to do a little "whistle-blowing" in the time-honoured manner and for all the right reasons.

[Fishrod]

Oh dear, Oh dear, Oh dear.

This has to be a very late April fools joke. No one can be taken in by this surely.

Let's look at the technical bit - (this could be a long one).

The edge of a double glazed unit of conventional manufacture is between 11-12mm. This requires to be buried in the rebate to prevent UV getting at it and causing premature failure.

Then as has been said you need a minimum of 5mm all round to allow the unit to breathe. Are you still with us? To my reckoning that gives 17mm. 7mm upstand rebate for conventional sealed units! Just do the maths it some how does not add up.

The next bit about glazing in putty that has to be about the biggest 'no no' there is. The reason is that the oils from the putty attacks the edge sealant very quickly and results in only months to unit failure.
Even what was termed as non-setting compound in the 70's is not good practice now for the same reasons.

So as you can see to use this type of unit and glaze in this manner, only give only a very short life before replacement is required - even if the unit meets other requirements.

I urge anyone consider using these units to think again and take in the pure facts. Just remember any guarantee is only as good as the company!

[glazedexpression]

FENSA's stance on the subject....

"A number of FENSA companies have been purchasing slim-line sealed units (4mm cavity) from Slimlite Double Glazing of Edinburgh. These units have a U Value of 1.9 therefore with most applications the whole window U Value, which needs to be a minimum of 2, is not achieved, i.e. the installation will fail based on thermal performance.

Please bear in mind that there are two ways to achieve thermal performance:

A. A whole window U Value of 2 w/m2/oK or better.
B. A window energy rating of E or a centre pane value of 1.2 w/m2/oK.

It could be that if narrow sealed units are placed in a Redwood timber frame the whole window U Value of 2 may be achieved but we will look for the installer to have a whole window U Value calculation undertaken to prove to us that the installation conforms to Document ‘L’.

We should be aware that many installations have failed on this account and we have asked for matters to be put right, so please note this situation and only use these sealed units in an appropriate way which may mean that you require to get approval from a Local Authority if the job is in a Conservation Area, it cannot be approved through FENSA."

[goodwood]

It's almost surreal... After thirty years of proving that draining and venting is the ONLY sure way of preventing premature sealed unit failure, we seem to be faced with a resurgence of the very cause of the problem - solid-bedding in oil-based putty. (And/Or NO drain and vent plus insufficient sealant and edgecover, all of which will almost GUARANTEE early failure.

It isn't cofined to one company in Edinburgh. I have a flyer from Holdens Superseal in Birmingham offering 7mm edge cover with a variety of glass and gas options using 4mm SuperSpacer (few of which meet the current Building Regs, let alone the forthcoming amended regs) and suggesting that they should be PUTTIED into georgian windows for an authentic appearance. They do cover themselves in their guarantee by stipulating approved standards of installation. So no guarantee there, then. Their Technical Manager told me that he was deeply unhappy about offering less than 11mm edge-seal but that he "wasn't the boss'.

Once the complaints flood in, (as they surely will) this will just be another damaging issue for the Double Glazing Industry in general.

[admin]

Ouch! I've just had a look at the website of one of the firms offering these ridiculous specs. They actually show the undersized IG units used in traditional "Georgian" glazing bars (astragals) !!

http://www.slimliteglass.co.uk/timber-windows.html

I've been through entire court cases that have focused on this boo-boo.

To prepare a journal article I'll need the names of companies who offer and/or advocate these ludicrous ideas.

[admin]

Here are some screen shots from the 2008 Grand Designs programme featuring these "new" 10mm IG units (must be 3-4-3 ?) featuring a "Krypton/Xenon mix" in the void. The edge seal (from the company's website, not the programme), is hot-melt buytl.

The Grand Designs episode in which these marvels are given such huge approbation may be viewed on YouTube - http://www.youtube.com/watch?v=qGzNkDGFOGQ

Once you've ignored washing up liquid adverts, don't wade through all the sycophantic twaddle - go straight to 00:31 (31 minutes in). The damage is done in the next 90 seconds. This was 2008. Surely the units must have misted up by now - a candidate for one of the specialist DG unit de-misting companies perhaps

[goodwood]

The reference to a nipple is interesting, Philip. Holdens tell me that they stack a batch of DGUs to be gas-filled in a room which is then filled with the gas in question, and the gas replaces the air by displacement. I am unsure about the final sealing details, but I was assured that this method gives a more certain and complete filling. I might ask for a site tour to find out just what is going on.

I was also told that if, for instance, a cylinder of argon costs $30 (sorry, I can't find the pound sign on this German keyboard) a cylinder of krypton costs $300 and a cylinder of Xenon $3000. I wonder how much xenon there is in this krypton/xenon mix?

[admin]

Does the # key get you the £ sterling sign?

I find it difficult to buy the "gas-filled room" story. I acted in a Trading Standards prosecution many years ago where that was the defence - essentially that the IG units were assembled from scratch on a table in an argon-filled room. My questions about the operative's breathing apparatus went unanswered. Surely they were losing several guys a day

The perp eventually pleaded guilty to consumer-law charges and paid a big fine, rather than risk being found guilty by a jury of something even more serious and being handed a prison sentence.

Back to the matter at hand, I'm intrigued that someone would mix Xenon and Krypton. The more I think about it, the stranger that seems. It must need some very special equipment to do it accurately. But why would anyone do it at all?

[stephen]

I can't see any sense, reason or likelyhood of creating a "gas chamber" style room either. A room large enough to accomodate large unit movements in and out, with the air-tightness required, evacuation of gas afterwards for health and safety, the labour and cycle times, the sheer waste of gas etc etc ..... How would they close/plug the units when filled optimally would be my first question?

Maybe something has been lost in translation??? There are IGU line inline gas chambers, which is certainly possible on modern high end lines in high investment factories. Units stay on the line, and pass through a gas chamber individually, being then pressed and sealed immeadiately. This is the only real system that has no need for plugs or other usually visual forms of cavity penetration. Maybe someone has has misunderstood "gas chamber", and came up with a 'room' theory when they told you? Looking at the photos on the website, I see what looks like two IGU lines. One is a standard press Willian (yellow+grey), and the other blue coloured machine that looks like a line and has an offline argon filling station right behind it.(silver cannister, red pipes for probe and sniffers). It could be an online gas chamber somewhere there, with a manual fill beside it. Can't really tell. Maybe they have more equipment not shown.

It's a wacky first idea anyway.


The other real questions relating to this thread as well as gas mixture evidence :-

Are cut-down super spacer products like these gas filled in any meaningful way or reliable way?
Do they retain gas with sealant depths well below manufacturer's guidelines, and without primary seals?

[goodwood]

All good questions, some of which had already crossed my mind. The 'room' was given to me by Holdens Technical Manager himself. I had no reason to doubt him at the time, but I did later start to wonder how they seal the units afterwards.

I learned long ago that the hi-tech sits bizarrely alongside the very low-tech in this business. Many years ago (decades, more like) I bought DGUs from a company equipped with several Lisec lines (?). One day one of their big DGUs just delivered had a bad case of Brewster's fringes. The rep dashed over and fixed it by banging a nail through the seal and blowing hard into what I thought was a High-tech unit made under controlled atmosphere conditions. It was only when I visited the works on a rainy day, and found all the doors wide open along with open drums of dessicant scattered about, that I realised they didn't really understand what they were doing, notwithstanding the half a million pounds or more of investment.