IGU

thanks paulb & certainly proven to date! "No truer word has e'er been said."

Insulated Glass Units Markings: As previously mentioned the stamp on the glass of our existing double glazing is BS EN 12150-1. Online information states that this consists of: The product number for the type of glass BS EN 12150 = Thermally Toughened Soda Lime Silicate Safety Glass? The impact performance classification e.g. 1, 2 or 3 to BS EN 12600 or A, B or C to BS 6206. Although BS 6206 was withdrawn in 2006 it is still referenced in National Building Standards so is shown below for comparison purposes. The comparisons between the classification systems under BS 6206 and BS EN 12600 are shown below. Both BS 6206 and BS EN 12600 use pendulum impact tests with similar drop heights and grades safety glass under one of three impact performance classifications. BS 6206 grades are ‘A, B or C’ with ‘A’ being the highest performance grade. BS EN 12600 grades are ‘1, 2 or 3’ with ‘1’ being the highest performance grade. So if reading this all correctly our glass is classified Toughened Safety Glass under BS EN 12150 and classified as the Highest Performance Grade under BS EN 12600? One would think all involved e.g. Glass Manufacturer, Glazing Unit Manufacturer, Builder/Distributors, Builder/Contractors and last but not least the Consumer would all want to know how or why such a top rated safety product failed?

Muckle Oxters certainly has a good een yunder hakama It wid maybe tack a Holey-Wood Blockbuster tae pit this topic back on ony original track?

This thread has come along way on this forum but it has indeed deviated well from the original issue posted and the original question asked! So could it be the time as hakama suggests for something along the lines of Monty Python, at least that would provide some kind of comedy approach to something really serious i.e. not the Holy Grail, only our holey window?

Belated thanks for that George! However I just wondered: Fensa: “The first and most well-known Competent Person Scheme for the window and door installation industry in England and Wales.” “Scotland got its own new Building Standards on the 1st March 2003 with the full implementation of Part J. This Building Standard requires an even higher performance level from a window than in England and Wales.” www.windowstoday.co.uk/part_j.htm So is there some Competent Person Scheme for Scotland?

Hi paulb Many thanks for your input! Fensa was briefly discussed a few posts back with suffererof1crankymofo and it was discovered that it only applies to England & Wales. Hobbiniho thought the Scottish equivalent i.e. “the building regs wont have any effect on the warranty of the windows, the building regs are only worried about u value, ventilation requirements, emergency escape requirements and location of safety glass etc” Does anybody know if providing certifications or guarantee’s is the normal by the builders? They were certainly never given or offered by ours! The list I obtained from the websites that you so kindly supplied did indeed have triple glazing that was 4mm x 4mm x 4mm Argon filled/Toughened Glass but neither company ever came back with a price on the ‘Heat Soaked’ version.

Hello Nigel Bridgman-Elliot, I certainly can't comment on glazing units being rated up to 120mph winds but maybe others can? I can tell you that this glazing unit used to 'flex' its inner pane on certain occasions during our local windy weather periods? No water was ever noticed inside our unit but I can certainly see what you mean if it ever did and then froze!

I thought the following from an Australian website quite interesting: Causes of exploding glass: Incorrect Installation: While glass is being moved and installed, it is easy for the glaziers to nick or chip the edges of the glass with various tools. These small nicks or chips may not result in immediate breakage. However, over time, as the glass expands and contracts, stress concentrations can develop around the nick, leading to breakage. In the case of tempered glass, the entire unit usually breaks. Binding in the frame: Glass expands and contracts with changes in temperature, so almost all modern glass is set on resilient blocks at the bottom and with space for expansion at the sides and top. If no space is provided at the perimeter of the unit, the glass will bind against the frame, causing internal stresses to develop in the glass which can exceed the strength of glass, resulting in breakage. Manufacturing faults: Nickel sulphide inclusions can be present in the glass. The most common cause of these inclusions is the use of stainless-steel machinery in the glassmaking and handling process. Small shavings of stainless steel containing nickel change structure over time and grow, creating internal stresses in the glass. This type of breakage is almost always found in tempered glass. What is nickel sulphide? Sodium sulphate is added during float glass manufacture to promote bubble removal from the molten glass during the melting process. When combined with nickel contamination, sodium sulphate forms nickel sulphide (NiS). Nickel contamination can be caused by: an impurity in the raw materials; contamination during the storage and handling of raw materials; or contamination from the float line equipment, e.g. firebricks and burners. Improving performance: Heat Soaking Toughened Glass Heat soaking is a test process that attempts to eliminate nickel sulphide inclusions, which can cause spontaneous fragmentation in toughened (tempered) glass. What effect does nickel sulphide have on glass? During the manufacture of float (annealed) glass, the raw glass materials are heated to around 1100°C and the nickel sulphide consequently reduces in size. When the glass is slowly cooled during the annealing process, the nickel sulphide expands back to its original size. This expansion does not interfere with the properties of the glass. However, an issue arises if the glass is toughened. Glass is heated to around 600°C during toughening, and the nickel sulphide consequently decreases in volume. To create toughened safety glass, stress and tension is induced in the hot glass by rapidly cooling it. Unlike the slow cooling of annealed glass, this rapid cooling arrests the transformation of the nickel sulphide. The nickel sulphide will expand to its original size over time. If this expansion occurs in the area of the toughened glass that is under tension, it will cause the glass to fragment. The presence of nickel sulphide is quite rare: Approximately one ‘stone’ of nickel sulphide is present per 8 tonnes of raw glass (although it can come in batches). The incidence of nickel sulphide varies from manufacturer to manufacturer with estimates ranging from one stone per 8 tonnes of glass to one stone per 13 tonnes of glass and some suppliers having a more frequent incidence than this. Nickel sulphide can cause glass to fragment at any time in the product’s life – from a few moments after thermal treatment to years after glazing installation. Nickel sulphide can also affect some types of heat strengthened glass. Essentially, heat soaking artificially ages the glass and although not 100% effective, will significantly minimise the risk of glass exploding at a later stage. This process is an ‘extra’ and can be completed by a glass manufacturer upon request. Due to this extra processing, Heat Soaked panels are significantly more expensive.

Hello again paulb, The broken glazing is almost 3yrs old, we in fact paid the majority of that renovation billing in September 2016. It is suspected that the glazing unit was 6mm x 4mm Toughened Safety Glass but our paperwork does not tell us any detail, the supplier/contractor/builder has shown no interest, the supplier/distributor says its too old to be found in his paperwork and the manufacturer won't deal directly with the public only with whoever in the trade purchased & ordered it. I know you only gave the links to those companies as examples and fully understand that you are not saying to use them, so please don't pick me up wrongly I am indeed truly very grateful for the information you have supplied. This incident is not covered by our insurance but by changing the wording to accident, accepting the blame and altering the series of events a claim could well be approved if one had chose to follow that pathway. I agree it may well happen again but if I go down the road of replacing like for like i.e. if I could definitely prove its exact construction, I'd constantly live in fear that its just about to happen. So what's left e.g. make the replacement 6mm x 6mm Heat Soaked Toughened Safety Glass and possibly live in a slightly better atmosphere thinking that as we've improved on the glazing units version it really shouldn't happen again? If it happens again after all that, I think we would have to be having some kind of major problem i.e. especially if nobody else is experiencing this type of issue.

Many thanks for the information paulb! Yes, I also want to know why it broke as well but without utilising some kind of expertise in that type of field it may never be known? Nickel Sulphide Inclusions (NiS) have been suggested but that has never (as yet) been confirmed and structural movement simply isn’t visible. I've waited most of the day for certain information from both these companies (see paulb's links) but sadly still wait, so have decided to post my findings so far: Looking on the links paulb has kindly supplied, I've found prices for our possible replacement by estimating some sizes etc: No 1: 1400mm x 1500mm (Black Spacer/Supplies but doesn’t advertise Heat Soaked so I’ve requested a quote on their 6mm x 6mm version.) 6mm x 4mm Toughened/Argon filled/28mm thickness = £308.70 Inc VAT 6mm x 6mm Toughened/Argon filled/28mm thickness = £409.50 Inc VAT This company doesn’t actually advertise any Island delivery but delivery to any location within UK mainland cost e.g. 3 days at £180, 7-10 days at £60, up to 14 days £30, up to 28 days £15 (all excluding VAT) & up to 45 days FREE. No 2: 1400mm x 1500mm (Black Spacer/Doesn’t advertise Heat Soaked either, so I’ve asked via email if they can supply that? I’ve also asked if they can supply 6mm glazing as I don’t see that on their website?) 4mm x 4mm Toughened/Argon filled/28mm thickness = £238.72 Inc VAT 4mm x 4mm x 4mm Toughened/Argon filled/28mm thickness = £342.11 Inc VAT No Island delivery advertised again but by making the delivery ‘Scottish Highlands between 8am – 6pm it makes the total costs £298.76 Inc VAT for their double glazing & £484.61 for their triple glazing. It is clear that some savings could indeed be made i.e. compared to the local quotes I’ve already been given but how much would surely depend on what is required, chosen or requested and transportation/shipping to its final destination still needs to be factored in. Out of what I see on offer, my replacement preference would be either the 6mm x 6mm toughened double glazing or the 4mm x 4mm x 4mm toughened triple glazing but preferably with Heat Soaked Toughened Safety Glass which I still await possible quotes on.

Hello again Hobbiniho Yes, you are perfectly correct i.e. ours does qualify for the use of toughened glass being less than 800mm from the floor. While you're on, do you think the glazing units in paulb's £309 example is more likely to be laminate and any idea where one can purchase them?

Hi paulb You seem to be one in the know regarding certain glazing prices, can you enlighten us any as to where these examples are available? What type of glass would be in the triple glazed units you've mentioned? I certainly agree that a grand for the glass and fitting is very OTT but it would probably be because of the type of glass used e.g. 6mm x 6mm, Heat Soaked, Thermally Toughened Soda Lime Silicate Safety Glass would surely carry the major part of its total?

Good to hear from you again Suffererof1crankymofo, The estimated cost of +/-£1000 was given because: The original window was suspected to be 6mm glass outside & 4mm inside? A quote which has already been supplied for its replacement is for a 6mm both sides glazing unit and is in excess of £560 including its VAT but this quote has not allowed for any 'Heat Soaked' Toughened Glass nor for the work of removing & replacing those glazing units. The exact size of the 'shattered' glazing unit hasn't actually been established but if the 1400mm x 1500mm roughly taken is any kind of clue, that has in fact already been utilised for another quote and this has been given as £378 including VAT. The only problem is, its currently unknown if that was for 6mm x 4mm/6mm x 6mm glass, Toughened Safety or 'Heat Soaked'. I'm quite sure billing won't be much shy of the estimated +/- £1000 if the quote caters for: 6mm x 6mm Safety Glass Heat Soaked Toughened Removal & replacement As another small point the following link supports a glazing glass guide table: https://www.glasssystems.co.uk/downloads/ltd/DAS%20Glass%20Systems%20Limited%20Sizes.pdf On this guide our window/glazing unit size places it in the green category i.e. must be 6mm Glass but of course its only a guide!

Although that forum's thread had been closed, I decided to try contact with the contributor and see if I could find out a little more, not long afterwards I received the following reply: "The window was by Selectaglaze. I was lucky because I live in a Housing Association property. It had just been refurbished including the windows and I was able to speak to the builder in charge and he sorted it for me, dealing with the company who were still selling him windows for the rest of the street to be refurbished. You may have to threaten court action."

I found the following on another forum that was about rented accommodation, it was dated 2017 but sadly the thread has since been closed: "I had the internal window of a secondary glazed window spontaneously break a few months ago. That too was caused by a nickel sulphide inclusion and it was replaced by the window company as they agreed it was a latent fault. The landlord should be dealing with it with the manufacturer but if they refuse you have to consider how far you want to fight it."