Hong Kong Regulations

FACTORIES AND INDUSTRIAL UNDERTAKINGS (WORK IN COMPRESSED AIR) REGULATIONS - SCHEDULE 1

PURITY OF COMPRESSED AIR

[regulation 7(1)]

A sample of air taken from a working chamber, man-lock, medical lock or
decant lock shall not contain impurities in excess of the limits given in the
Table.

Table (See Note below) Carbon monoxide 10 parts per million Carbon dioxide 500
parts per million Oil 1 mg/m3 Water The air shall be as dry as possible and
shall not give rise to condensation of moisture at the maximum filling
pressure and a minimal service temperature of 5℃. At ambient temperature
below 5℃
Celsius there is a risk of freezing inside the chamber or lock, and particular
attention shall be given to the air under these circumstances. The air shall
be dried chemically under extremely cold conditions. Odour and cleanliness The
air shall be free from all odour and contamination by dust, dirt and metallic
particles, and shall not contain any other toxic ingredient. (See Note below.)
Note: Odour and cleanliness of compressed air are difficult to check
accurately without special equipment. A rough check may be made by opening the
cylinder valve and smelling the escaping air, and by noting any discolouration
or wetness when the air is passed through tissue or filter paper.