Getting my head around Part B and K for our windows

[MikeSharp01]

We are getting close to getting the windows, our first supplier disappeared under us, perhaps lucky as the new ones seem much better,  however today our supplier has asked us to confirm that the scheduled windows all meet building regs. I had thought that was their job but it appears not. We have three escape windows which may also need to be part K compliant. Here are the three windows, it looks like the opening size is OK for escape but I am concerned about having the height to the opening portion too low, am I going wrong somewhere? (The internal sills take about 40mm of the lower portion measurements.)

 

Window 1

 

Window 2

 

Window 3

 

 

 

[ETC]

You just need to consider guarding the floor and safety glass. Safety glass and a non-lockable re-engagable restrictor stay should be acceptable - but check with your BCO.

 

EEWs  need to be 0.33m2 roughly 0.45m x 0.75m clear opening.

Edited March 16, 2023 by ETC

[MikeSharp01]

50 minutes ago, ETC said:

guarding the floor and safety glass

Not sure what guarding the floor is? Safety glass I think is sorted they all have toughened glass on the inside, although one has laminated inside - the inward opening triangle window, and laminated on the outside and toughend on the outside for the inward opening triangle. 

[ETC]

The safety glass sorts out the problem of someone falling against the window but not falling out if it can be opened.

 

If a window has an opening sash where the bottom of the opening sash is less than 800mm above the floor you need to guard the floor so that someone doesn’t fall out.

 

So - two issues:

 

One: safety glass for all openable and non-openable windows located below 800mm above FFL.

Two: Guarding for openable windows located below 800mm above FFL.

 

Hope this helps.

[Mr Punter]

It is better to show the windows in the context of the elevations so they can work out distance from FFL and what security is appropriate for part q compliance.

[craig]

Those should all be treated as safety glass for protection against falling to EN12600 class 3 or BS6206 class C.

 

Most BCs will want the inner pane to be laminated to withstand 0.74kN others will accept toughened inner and outer pane to be circa 6mm.

 

As the openings are below 1100 from FFL, they will look at fire escape (if required) plus safety to prevent someone from falling via the opened window.

 

Edit: for fire escape, the window when opened must have an obstructed area of 0.33m2

 

 

Edited March 17, 2023 by craig

[craig]

To note, 800 from FFL for glazing is about safety primarily and not about protection from falling, unless above ground floor. Which is where the 1100 comes into play for fire escape. The opening window cannot be above 1100 (might be 1150, need to check). If it is a fire escape window it cannot be below  800 without restriction and if it does, it can’t be a fire escape window and must be higher than 800 without restriction. 

 

Which means it cannot be lockable either but you can get away with using a push button lockable handle.

Edited March 17, 2023 by craig

[ETC]

There isn’t a minimum height requirement for an EEW (in England) otherwise a door at first floor wouldn’t comply. In NI the bottom of the EEW should be between 800mm and 1100mm above FFL (except where it is a roof window and the lowest height is 600mm above FFL).

 

Also guarding a floor inside a dwelling only required 0.36kN/m. 
 

Locks and restrictor stays are acceptable on EEWs.

 

@craig

@MikeSharp01

Edited March 17, 2023 by ETC

[craig]

No minimum height but there is a maximum height (1100). Escape windows cannot have lockable handles unless a push button handle.

 

Doors above ground are fine but they cannot open into fresh air without being guarded for protection from falling (balustrade). If opening out onto a balcony for example, then no fall protection, just glazing protection as the glass is below 800. 
 

Edit: Apologies, should have mentioned that your supplier should be telling you all this @MikeSharp01

 

They are correct in that it’s your / architects / contractors responsibility to ensure regs are met. However, they should be fully aware of the regs and ensuring they comply.

Edited March 17, 2023 by craig

[ETC]

@craig

[MikeSharp01]

This is great stuff. On the safety glass is mainly 4tuf, 4tuf, 6.2lam from inside out but some has the 6.2 on the inside. That was down to the window company - never questioned it. I will dig out some sections. 

 

 

 

 

[MikeSharp01]

1 hour ago, ETC said:

There isn’t a minimum height requirement for an EEW (in England) otherwise a door at first floor wouldn’t comply. In NI the bottom of the EEW should be between 800mm and 1100mm above FFL (except where it is a roof window and the lowest height is 600mm above FFL).

So does that mean that if the window is an escape window then the min 800mm does not apply - I just need a restrictor? In which case all my windows are fine as they are all designated escape windows 1 on the ground floor - window 1 in the snug and the others on the first floor in bedrooms!

[ETC]

17 minutes ago, MikeSharp01 said:

So does that mean that if the window is an escape window then the min 800mm does not apply - I just need a restrictor? In which case all my windows are fine as they are all designated escape windows 1 on the ground floor - window 1 in the snug and the others on the first floor in bedrooms!

 

From what I can understand:

 

EEWs.

There does not appear to be a minimum height for the bottom of the opening of an EEW in ADB1.

The maximum height for the bottom of the EEW is 1100mm above FFL.

 

Guarding.

Any window which has an opening sash less than 800mm above FFL needs guarding. Where it is a EEW a non-lockable and re-engageable restrictor stay is acceptable. Picture attached. Just check with your BCO what kind of restrictor stay is acceptable.

 

Safety Glass.

Any window sash (fixed or openable) that is below 800mm above FFL (at any floor level) is deemed to be in a “Critical Location” the glass in these windows needs to be safety glass. See pictures attached.

 

Why do you have an EEW on the ground floor?

 

Your window supplier should be aware of all this.

 

[ETC]

The NI Guidance shows a minimum height of 800mm above FFL for an EEW. Rarely enforced as long as guarding or a restrictor stay is fitted to the EEW.

[craig]

42 minutes ago, ETC said:

@craig

I have to stick my hands up, I’m wrong on that and I’ll check if/when that changed. As in my experience and from what I recall BCs reject key lockable handles in escape windows.

 

You can’t escape if the handle is locked from operating and no key is present.

[ETC]

1 minute ago, craig said:

I have to stick my hands up, I’m wrong on that and I’ll check if/when that changed. As in my experience and from what I recall BCs reject key lockable handles in escape windows.

 

You can’t escape if the handle is locked from operating and no key is present.

I agree - a lockable EEW is a death trap. Unfortunately BC cannot reject an EEW if it has a lock on it. Presumably it’s more important to keep a burglar out than to let someone escape in an emergency. I have had this conversation many times with my colleagues in BC and although we cannot reject a lockable window we sometimes ask the applicant to think seriously about putting a lock on a window. If they want a lock we would suggest one that you can push and turn a handle on the inside.

[craig]

They can and they do, they’ll accept a push button lock but not key lockable.

[ETC]

I wouldn’t like to test the legislation in court. BC would lose.

[craig]

They’re a law unto themselves at times but I agree with them when that call is made, EEWs should not be key lockable.

[craig]

7 hours ago, craig said:

They can and they do, they’ll accept a push button lock but not key lockable.

 

I should emphasis, that it isn’t across the board and depends where you are but ask 10 different BCOs from 10 different areas and you’re likely to get 10 different answers.

 

Not just on this but in general. A prime example is these full height turn and tilt windows (turns first, tilts second).

 

Rejected initially with customer being informed they “must” install a balustrade. A bit of a fight with BC and eventually accepted a simple child restrictor as above diagram.

 

Exactly the same principle, flat out rejected everywhere else. Slightly unique here due to the external venetian blinds required and nowhere to fit a balustrade but still accepted.

 

[MikeSharp01]

I have been struggling with this whole debacle over the last 48 hrs. I have had a response from our BC who just reiterates the Part K stuff really but also does confirm that:

• Providing a restrictor, such as the one illustrated above, and safety glazing is provided he will be happy - in which cases we do not need to move the transoms up.
• The fall protection IS needed, in our case the restrictor and safety glazing, on the GF as the BC cannot be sure how the external landscaping might be finished.
• The glass in the windows must meet the requirements of BS6206 or EN12150 and be marked and certificated as such. (He did not set a kN lower limit - just BS6206)
• Laminated glass is required in all doors and windows on the GF for security purposes. 

So we have crossed off all the issues - talk about stressful!

 

Thanks for all the help.