[Default] On Sat, 04 Aug 2012 17:49:36 +0100, a certain chimpanzee,
Roger Mills , randomly hit the keyboard and
wrote:

That is certainly the case for new windows - i.e. for new build or
extensions - but are you sure that it also applies to *replacement*
windows, where you are simply replacing one window with another?

Correct. The Building Regulations would only apply to new openings,
not to the replacement of existing windows (except to determine
whether they comply with the requirements for energy efficiency).
There is guidance in a British Standard that at least one replacement
window on the first floor should be suitable for means of escape, but
I don't know if it is enforcable by Trading Standards.

For the OP, the guidance for the means of escape is that the window
should have a clear unobstructed area of at least 0.33m^2 measured at
right angles to the glass, with a minimum opening width or height of
0.45m, and that the bottom of the opening (not necessarily the window
sill) should be between 900mm - 1100mm above the floor. Consideration
should also be given to where the window is placed in relation to any
fragile or glazed roofs below.

Having said all of that, a decent smoke detection system is a much
better bet.
--
Hugo Nebula
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just how far from the pack have I strayed"?