No person shall install a gas fitting unless every part of it is of good construction and sound material, of adequate strength and size to secure safety and of a type appropriate for the gas with which it is to be used.
Without prejudice to the generality of paragraph (1) above, no person shall install in a building any pipe or pipe fitting for use in the supply of gas which is—
made of lead or lead alloy; or
made of a non-metallic substance unless it is—
a pipe connected to a readily movable gas appliance designed for use without a flue; or
a pipe entering the building and that part of it within the building is placed inside a metallic sheath which is so constructed and installed as to prevent, so far as is reasonably practicable, the escape of gas into the building if the pipe should fail.
No person shall carry out any work in relation to a gas fitting or gas storage vessel otherwise than in accordance with appropriate standards and in such a way as to prevent danger to any person.