Hong Kong Regulations

GAS SAFETY (GAS SUPPLY) REGULATIONS - REGULATION 21

General safety requirements for pressure- regulating installations

(1) Subject to subregulation (2), no person shall install a
pressure-regulating installation in a gas supply system unless-

   (a)  the installation is so designed that the malfunction of any part
        thereof, where there is no other malfunction at the same time of any
        other part thereof, does not cause an unsafe situation to arise in
        respect of the pressure of the gas supplied downstream of that
        installation;

   (b)  any pressure-regulators or auxiliary systems used in connection with
        the installation are protected from any dust or debris carried by the
        gas supplied through the installation;

   (c)  where the difference in pressure between the gas supplied to the
        installation and the gas supplied by the installation is such that the
        temperature of the gas may fall below 0 degree centigrade, the
        installation is protected against damage which may be caused by the
        formation of ice inside or outside the installation;

   (d)  the volumetric capacity of the installation is such that it can take
        at the lowest pressure at which gas will be supplied to it, and
        transmit, at the highest pressure at which it will supply gas, the
        volume of gas required for the gas supply system of which it is a
        part; and

   (e)  where a by-pass is fitted to the installation, devices are also fitted
        to the installation to ensure that if there is a mal-operation of any
        valve fitted to that by-pass, an unsafe situation does not arise in
        respect of the pressure of the gas supplied downstream installation.

(2) Subregulation (1) shall not apply to a pressure-regulating installation
which will not be supplied with gas at a pressure other than low pressure.
(Enacted 1990)