Existing windows guarding requirements

[WC_B]

I am fitting out an old boarding school to convert to temporary accommodation. It is a combination of 3 Georgian buildings, one is Listed.
I understand that the sill must be 800mm above floor level or guarding is required, but there is some leniency for existing buildings.

There are 3 windows conditions, I'm wondering if anyone has experience of addressing:

1. Rear windows Existing Georgian sash windows. Top of sill varies 700-750mm. Windows open from bottom.
Is additional guarding required or is 700-750 deemed acceptable for existing building?
Can restrictors be used instead of guarding?

2. Front windows Existing 80s/90s pvc windows. Top of sill varies 700-750mm. Windows open from top, well above 800mm.
The lower level glazing would not meet todays loading requirement for guarding, but is it acceptable as an existing condition?
And again, is 700-750 deemed acceptable for existing building?

3. Rear windows exceptions There are a couple rear sash windows with top of sills circa 500mm - I assume they need addressed.
Is adding restrictors acceptable or a new guarding inevitable here?

I am going to contact the council building control officer but thought I'd ask here as I'll probably get a quicker response!

Cheers

Edited Monday at 10:26 by WC_B
typos

[kandgmitchell]

You are carrying out a "material change of use" as per Regulation 5 of the Building Regulations, you appear to come within circumstance a) , i.e the building is used as a dwelling where previousy it was not.

 

Regulation 6 sets out the various technical requirements of the Building Regulations that apply to the various types of change of use. Those technical requirements for circumstance a) do not include Part K - Protection from falling. Thus in your situation the minimum guarding heights etc do not apply, the building is as existing. 

 

That is not to say that if you feel some of these cill heights are too low that you should not deal with them but just that you will not be obliged to deal with them.