Value engineering: fixed lights, regulations

[gravelld]

Just trying to do a bit of "value engineering".

 

Currently my window spec (refurb) is almost all openers.

 

I'm wondering about changing to fixed lights where possible, and reduce the existing wider windows to a 1/3 opener / 2/3 fixed light arrangement. Will hopefully save some money.

 

For those I want to change completely to fixed lights, what regulations cover this? And are there any rules of thumb? Ventilation or means of escape?

 

For example, we have two existing windows in toilets that we never open. But does their location mean they must always be openers for ventilation? What if we have a whole house ventilation system (it's planned to go in at the same time as the windows)?

[Jeremy Harris]

The only rules that apply as far as fixed lights are concerned are the means of escape from fire from habitable rooms that are not directly connected to access to an external door.  In general, any room that doesn't have a door leading directly to a circulation space that has an outside door, plus all upper floor rooms, need an opening window that meets the escape from fire part of the regs (lower edge not more than 1100mm above the floor, IIRC, plus minimum dimensions that are given in the regs).

 

If trickle ventilation is required, then this is fitted to the outer frame usually, so can be fitted to fixed or opening lights I believe.

 

For some reason, there isn't a massive saving in cost for fixed lights over opening ones.  No idea why, but I had both options priced and the saving was pretty small.

[PeterW]

I’ve just done F/T/F on some lounge windows that are 1750x1100 and having the tilt and turn in the middle did save about £90-100 per window and this was 3G uPVC. 

[gravelld]

2 hours ago, JSHarris said:

In general, any room that doesn't have a door leading directly to a circulation space that has an outside door, plus all upper floor rooms, need an opening window that meets the escape from fire part of the regs (lower edge not more than 1100mm above the floor, IIRC, plus minimum dimensions that are given in the regs).

 

For these rooms, so long as one of the windows in the room has an openable part, is that ok?

Edited November 10, 2018 by gravelld

[Jeremy Harris]

1 minute ago, gravelld said:

 

For these rooms, so long as one of the windows in the room has an openable part, is that ok?

 

Yes, only one fire escape window is needed in any room that doesn't connect to a circulation space that has an external door, or is above ground floor level.  One issue is appearance, though.  A fixed light next to an opening light can look a bit odd from outside, but if the window is big enough to be divided into three, then a centre opening light can look OK.  There are three windows in our build that I wish now I'd made fixed, as they are never opened. 

[gravelld]

I think these look ok:

 

https://thebox-haus.weebly.com/posts/archives/11-2017

 

The other issue around ventilation was purge ventilation, but IIRC that's only covered by a window if there's no other mechanical ventilation (in a wetroom), correct?