Page 70 - Safety and health in construction
P. 70
Safety and health in construction
(d) means of enabling the persons in the lock to convey visible or other non-verbal
signals to the lock attendant;
(e) efficient means enabling the lock attendant, from outside the lock, to reduce or cut
off the supply of compressed air to the lock.
10.2.12. Persons in the lock should not be able to reduce the air pressure except:
(a) under the control of the lock attendant;
(b) in an emergency, by special means that should normally be kept sealed or locked.
10.2.13. In every man lock there should be a suitable notice indicating the
precautions to be taken by persons during compression and decompression, and after
decompression.
10.2.14. Every man lock should, while any person is in it or in any working
chamber to which it affords direct or indirect access, be in the charge of an attendant
who should:
(a) control compression and decompression in the lock;
(b) if the pressure exceeds 1 bar, keep a register showing:
(i) the times at which each person enters and leaves the lock;
(ii) the pressures at the times of entering and leaving;
(iii) the times taken to decompress each person.
Air supply
10.2.15. Compressed-air installations should be provided with air-supply plant
capable of supplying any working chamber with sufficient fresh air at the pressure in
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the chamber, and not less than 1.0 m per minute per person in the chamber.
10.2.16. Pollution of the air supplied to the caisson from a compressor or any
other source should be prevented.
10.2.17. All air lines should be in duplicate and be equipped with non-return
valves.
10.2.18. There should be a sufficient reserve of air in compressor installations to
allow a safe margin for breakdowns or repairs.
10.2.19. There should be a stand-by or reserve compressor for emergencies.
10.2.20. Two power units supplied from independent sources should be provided
for each compressor.
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