Wrote in message:
On Saturday, 7 October 2017 15:46:18 UTC+1, Pet @ www.gymratz.co.uk ;¬) wrote:
The inspection chamber "top" is a double lipped frame packed with grease
into which the single lip of the heavy chamber lid nestles and is then
fixed down by 3 (originally 4 but one is sheared off) large brass screws.
Having such a lovely beast in the hall between bedrooms I'd prefer to
replace it with something more "modern" that doesn't rely on loads of
grease to make a gas/excrement/fluid seal but still needs to be
mechanically locked in place should the outlet become blocked and sh1t
backs up flooding the hall.

I think newer ones have rubber seals and you can get double lid ones intended for basements with back pressure eg

http://www.manholecovers.co.uk/catal...airtight-seals

Owain


"All units are airtight and virtually watertight."

That's OK then.....
--
Jim K


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