Hong Kong Regulations

FACTORIES AND INDUSTRIAL UNDERTAKINGS (WORK IN COMPRESSED AIR) REGULATIONS - REGULATION 8

Man-locks

PART III

MAN-LOCKS AND WORKING CHAMBERS

(1) Every man-lock shall be of adequate internal dimensions and capacity for
the purposes for which it is used.

(2) Every man-lock shall-

   (a)  have efficient means of verbal communication between the lock 
        attendant and any person in the man-lock or working chamber, and
        between persons in the man-lock and the working chamber;

   (b)  have means enabling any person in the man-lock to convey visible
        signals to the lock attendant outside;

   (c)  have an independent supply of fresh air which can be used for
        ventilation and for compression in case of a fire in the
        working chamber;

   (d)  be protected from the weather and the sun;

   (e)  have adequate lighting.

(3) Every man-lock shall be provided with suitable equipment including-

   (a)  pressure gauges which will readily indicate-

        (i)    to the lock attendant the pressure in the man-lock and in each
               working chamber to which the man-lock affords direct or
               indirect access; and

        (ii)   to persons in the man-lock the pressure in the man-lock;

   (b)  valves or taps controlling the flow of air into and from the man-lock
        such as will enable careful compression and accurate decompression to
        be carried out according to the procedures prescribed in the Second
        and Third Schedules respectively; and

   (c)  a clock or clocks so positioned that the lock attendant and any person
        in the man-lock can readily ascertain the time.

(4) All furniture and equipment in a man-lock shall be of incombustible or
fire proofed material.

(5) Every man-lock and its equipment shall be maintained in a reasonably clean
state.

(6) Where heating is provided for the purposes of paragraph (9)(d), the
heating system shall be controlled thermostatically or manually.

(7) The wirings of the lighting and heating systems of a man-lock shall be of
mineral insulated copper cable, complying with the British Standard 6207 or
equivalent standard, and the systems shall be such that there is no fire
hazard.

(8) A notice which can be easily read, indicating-

   (a)  the precautions to be taken by persons during their compression or
        decompression and after decompression; and

   (b)  the maximum number of persons who may normally be accommodated in the
        man-lock, shall be affixed in each man-lock and such notice shall-

        (i)    be approved by the Commissioner; and

        (ii)   be in English and Chinese.

(9) When the pressure in a man-lock exceeds 14 pounds per square inch-

   (a)  the man-lock shall have not less than 45 cubic feet of space per
        person and a sitting space of not less than 2 feet in width (with back
        support) per person;

   (b)  the man-lock shall be ventilated to ensure that the carbon dioxide
        partial pressure does not exceed 1 per cent of 1 atmosphere when a
        sample is measured at atmospheric pressure;

   (c)  if the man-lock is used for timed decompression exceeding 30 minutes,
        a chemical closet shall be provided and shall be regularly serviced;

   (d)  when the man-lock is used for decompression, the temperature in the
        man-lock shall not be allowed to fall below 10oC nor to rise above 27o
        C, for more than 5 consecutive minutes;

   (e)  there shall be a pressure recording gauge, which shall be accurate to
        within half a pound per square inch, and the recording on the man-lock
        decompression chart shall be as approved by the Commissioner; and

   (f)  if a circular recording chart is used it shall rotate at a speed of
        not less than once in 4 hours.

(10) When the pressure in a man-lock exceeds 14 pounds per square inch, the
arrangements controlling the flow of air shall be such that any person inside
the man-lock is able to control the inflow of air but unable to reduce the
pressure except under the control of the lock attendant or through a special
valve to be operated only in an emergency.

(11) The special valve provided under paragraph (10) shall normally be kept so
sealed or protected as to discourage its operation in circumstances other than
emergencies and a notice explaining the use of the special valve in English
and Chinese shall be affixed near the special valve. (L.N. 161 of 1978)