186

Lett hand
screw
threads for
certain
valves.
Prohibition
of grease
oil, ete.
Periodical
examination
and test.

Identifying
colours.

Ch. 30. No. 3.) Gas Cylinders (Use, Conveyance and Storage).

metal cap or cover shall be so made that it is nowhere in actual contact
with any part of the valve or valve body. Every valve cap or cover
shall be provided with a vent of such size as to prevent any gas pressure
inside the cap or cover.

8. The valves of cylinders containing carbon monoxide, coal gas,
hydrogen, methane, propane or butane shall be provided with left-handed
screw threads for the pipe or other connection.

9, Grease oil and similar lubricant shall not be used in any cylinder or
on any valves or other fittings of any cylinder.

10, At least once in every two years each cylinder shall be subjected
by the person who fills it with compressed gas to the hydraulic test
specified in the Schedule to these Regulations. Prior to any such test
the cylinder shall be thoroughly cleaned and examined externally and,
so far as practicable, internally for surface defects, corrosion and foreign
matter. Where internal rust or foreign matter is observed the cylinder,
prior to the hydraulic test, shall be heated to a temperature not exceeding
300° C. and again cleaned and examined. After each hydraulic test and
before being filled with compressed gas the cylinder shall be thoroughly
cleaned and dried internally, and shall be stamped on the shoulder below
the neck or on a brass tag securely fastened to the neck with marks and
figures indicating the person and the date of the test as specified in clause 3
of the said Schedule. Any cylinder which fails to pass the test shall
not be filled with any compressed gas to which the Ordinance applies.
Provided that in the case of cylinders used solely for liquid carbon dioxide
the hydraulic test aforesaid may be carried out once in every five years
instead of every two years if the cylinder is fitted with a safety disc set
to burst at a pressure not more than 25 per cent. higher than the maximum
working pressure of the cylinder and the cylinder is thoroughly cleaned
and examined as aforesaid at least once in every two years.

11. (1) Cylinders containing gases shall be painted with the following
identification colours :-

Air Grey.

Argon Blue.

Carbon Dioxide Green.

Sulphur Dioxide Yellow.

Carbon Monoxide Red with yellow band.

Coal Gi Red.

Hydrogen Red.

Methane Red.

Prop: Red.

Butane Red.

Neon Medium brown with black band.
Nitrogen Dark grey with black band.
Oxygen Black.

(2) The identifying colour or colours, as the case may be, shall be
painted in the form of a band round the neck of the cylinder close to the