Design loadings of first floor low level windows

[Dan F]

All our first floor windows have sills at 450mm meaning they are considered "critical locations" for building regulations.  Also, because these are on the first-floor, they are supposed to confirm to "guarding" requirements too.

 

Our BCO is asking for "The design loadings that conform to BS 6180", but so far I haven't been able to get hold of anything that shows this.  Have others had this requirement, and if so, what type of documentation have you provided in response?

- Loadings.

- BS 6180 approval

- EN 12600 category.  (pendulum test)

- other

 

The windows in question are triple-glazed with all three panes thoughened 4ESG-18-4ESG-18-4ESG.

[ProDave]

We have several "low level" windows, and glazed doors, and all BC were interested in was looking at the markings on the glass units to confirm they were toughened glass.

[nod]

58 minutes ago, ProDave said:

We have several "low level" windows, and glazed doors, and all BC were interested in was looking at the markings on the glass units to confirm they were toughened glass.

 

58 minutes ago, ProDave said:

We have several "low level" windows, and glazed doors, and all BC were interested in was looking at the markings on the glass units to confirm they were toughened glass.

Plus 1

 

BUT There is no consistency between inspectors 

One may ask for loadings 

9 others will probably look at the units 

[Russell griffiths]

Should they not be toughened and laminated, just like a balcony, or balustrade.
if you fall against a full height window that is just toughened as it shatters you fall out side. 
unless it has a rail at mid point. 
sounds b&&&ocks but I could see the reasons behind it.  

[ProDave]

4 minutes ago, Russell griffiths said:

Should they not be toughened and laminated, just like a balcony, or balustrade.
if you fall against a full height window that is just toughened as it shatters you fall out side. 
unless it has a rail at mid point. 
sounds b&&&ocks but I could see the reasons behind it.  

Just checked, my outer panes are "safety toughened" and inner panes are "safety laminated" both with respective EN numbers.

[Nick Laslett]

Two useful docs for BS6180:

 

https://techhub.uk.saint-gobain-building-glass.com/sites/default/files/document-files/Guards %26 Barriers 5A - SGBG Guidance for Low Risk Design - 19-09-2018.pdf

 

https://www.fhbrundle.co.uk/files/pdf/co1/Technical/Glass Loading Data Sheet 7.2.pdf

 

BS EN 12150 kite mark for thermally toughened safety glass

 

The majority of our upstairs windows are 250mm from floor level. They are all 6.8mm laminated and 4mm toughened DGU. 
 

I suspect your units would pass the test, but have not be subjected to them, so there is no certificate. 
 

Edited April 24, 2022 by Nick Laslett

[Mr Punter]

A development opposite us had a lot of frameless glass balustrades to balconies.  One of them shattered and it was clear it was not laminated.  The contractor came back and replaced all of them with laminated / toughened.

[craig]

I'll put my hands up, this is for me. The glass is all marked with the EN norm 1279:5 and EN:12150-2  but the documents which have been supplied haven't been accepted (yet) and I'm not entirely certain why but the BC may be wanting an exact report.

 

22 hours ago, nod said:

BUT There is no consistency between inspectors 

One may ask for loadings 

9 others will probably look at the units

 

Exactly, to be honest, all the BC should need to do is look at the glass, the CE performance declaration if/when supplied and the glass datasheets for the EN norm of 1279-5 and that should be sufficient. Doesn't actually take away from them being robust though and stringent, which is a good thing. A pain in the ass but a good thing.

 

22 hours ago, Nick Laslett said:

They are all 6.8mm laminated and 4mm toughened DGU. 

 

The inner and outer pane should match in thickness (as close as possible) and your 4mm should be 6mm.

 

22 hours ago, Nick Laslett said:

Two useful docs for BS6180:

 

https://www.fhbrundle.co.uk/files/pdf/co1/Technical/Glass Loading Data Sheet 7.2.pdf

 

I disagreed with a structural engineer recently, he was insisting that we should be adhering to table A3 and for some units, it should be 8mm outer, 8mm inner and in some cases 10mm inner/outer. The client has to pay for this at the end of the day and when it was highlighted that he was wrong and using the wrong table. He fully accepted that the correct table is A4. The only thing he disagreed with, was my take on the m² requirements going from 4+4 to 6+6 for example. 

 

I say it's from and to i.e. 0.15m² for 4+4 to 3.2m² - he says that if it's above 0.15m2, it needs to be 6mm glass. Just for a side note at 0.15m² for the glass unit, we're looking at 390mm x 390mm and anything above that needs to be 6mm to act as a barrier. Which is wrong IMHO. I'm not a specialist on the subject, but hopefully, the issue should be resolved fairly soon.

 

22 hours ago, Russell griffiths said:

Should they not be toughened and laminated, just like a balcony, or balustrade.

 

No, toughened both sides is fine for class 2 building occupancy (a house).

Edited April 25, 2022 by craig

[Russell griffiths]

@craig how come they are not classed as a fall arrest system then, I would have thought it was just as easy to fall through a 2m x2m window as it is through a glass balustrade. 

[craig]

1 minute ago, Russell griffiths said:

how come they are not classed as a fall arrest system then

 

Don't know the answer to that I'm afraid but regs are clear that either or is fine.

[Dan F]

The complication seems to be that our BCO wants BS6180 loadings for first-floor low-level windows, in same way they would would require them for a balcony ballustrade, as technically low-level first-floor windows also come are considered "guarding".  The EN12600 pendulum test certifies impacts resistence, but doesn't give any loadings. 

 

I've sent through the EN12600 (class 2) certification regardless though and we'll see what happens.

Edited April 25, 2022 by Dan F

[Nick Laslett]

1 hour ago, craig said:

 

The inner and outer pane should match in thickness (as close as possible) and your 4mm should be 6mm.

 

The frames will only take a 28mm DGU, (Sadly, SWMBO aesthetic requirements trump U-values). A 6mm inner pane would make it 28.8mm in total. 
 

These are Guardian Glass SN 70/30 units, the 6.8mm-16mm-4mm sizing looks like the default according to their website. 
 

https://www.guardianglass.com/gb/en/our-glass/sunguard-superneutral/sn-70-35

 

I see Saint-Gobain Planiterm Comfort Plus DGU has the same specs. 

 

https://www.planitherm.com/media/5598/422757-sgg-planitherm-a4-info-leaflet.pdf

What are the draw backs to not having the panes the same thickness? Is it condensation?

 

Edited April 25, 2022 by Nick Laslett

[craig]

Nothing as far I know, other than the specs dictate inner and outer should be the same size for barrier loading.

[craig]

1 hour ago, Dan F said:

I've sent through the EN12600 (class 2) certification regardless though and we'll see what happens.

 

Fingers crossed, if I need to go back to the glass manufacturer/supplier I will but current info indicates it should be everything that's needed.

[Temp]

5 hours ago, Dan F said:

The complication seems to be that our BCO wants BS6180 loadings for first-floor low-level windows, in same way they would would require them for a balcony ballustrade, as technically low-level first-floor windows also come are considered "guarding".  The EN12600 pendulum test certifies impacts resistence, but doesn't give any loadings. 

 

I've sent through the EN12600 (class 2) certification regardless though and we'll see what happens.

 

As I see it the situation is the same a glass balcony so not surprised.

 

I would ask window suppliers to quote for the windows and point out the first floor windows must be designed to meet BS6180 due to their height above the floor and ground levels. See what they say. 

 

Edit: There will also be rules on which bits can open. Don't think anything below 800mm or is it 850mm can be opening unless there is a restriction?

Edited April 25, 2022 by Temp

[craig]

2 hours ago, Temp said:

I would ask window suppliers to quote for the windows and point out the first floor windows must be designed to meet BS6180 due to their height above the floor and ground levels. See what they say. 

They are, I supplied them 😉

[Dan F]

@craigOur BCO is not insisting on further documentation on this occasion, but he is right that EN12600 is only about "safe breakage" and not "containment" and that documentation should be available to show that design-loadings comply with BS1680, in the same way that this is required for balconies.

 

The complication is that BS1680 is a UK-only standard and the design loadings required are also UK-specific so it's not easy to get this from european manufacturers.  There is generic guidance, which @Nick Laslett linked to, but none of this covers triple-glazed units directly so isn't suitable.

 

The one thing I was able to use to make BCO a bit happier was the AGC Glass Europe online "glass thickness calculator" which uses EN 16612 to calculate loadings/delfection and shows that a 4Tc+4T+4Tc does meet requirements BS1680 point/line/unform loadings for the size of our glass units.  Our glass is Saint Gobain, not AGC, but toughened glass is pretty much the same whoever makes it.