Posted By Keith Ralph
This will obviously depends on what you equipment you wish to take down into the confined area. If you are looking at a person entering the confined space for inspection purposes than the entry should be large enough to allow the worker and their breathing apparatus to pass through the apparture. This then should be in the region of 500mm square.

I hope this helps

Posted By peter gotch
John,

Quote from the relevant ACOP/Guidance.....

The following Standards are relevant:
• BS 8007:1987 Design of concrete structures for retaining aqueous fluids. Code
of practice. Minimum openings specified as 600 mm x 900 mm;
• Silos UK: Draft design code for silos, bins, bunkers and hoppers, published by
BSI in association with the British Materials Handling Board, gives the
minimum as 600 mm x 600 mm;
• BS 5502: Part 50 1993: Code of practice for design, construction and use of
storage tanks and reception pits for livestock slurry gives access hatches etc as
not less than 600 mm x 600 mm;
• BS 8005: Sewerage Part 1 1987 Guide to new sewerage construction gives the
minimum clear opening dimension for manholes for drainage purposes as
600 mm x 600 mm for sewers less than 1 m diameter, except for very
shallow manholes where this dimension may be 550 mm;
• BS ISO 9669:1990 Series 1 freight containers. Interface connections for tank
containers.

These are all minima !!!

Regards, Peter

Posted By Gary Beckley - SHE Management (UK) Ltd
Hello John
Paragraph 93 of the CSRegs ACoP and guidance L101 may help (575mm if rescue facilities are to be considered using SCBA)
Regards
Gary