Schedule XXI

COMPRESSION OF OXYGEN AND HYDROGEN PRODUCED BY ELECTROLYSIS OF WATER:

1.Location of electrolyser plant.—The room in which the electrolyser plant is installed shall be

separate from the plant for storing and compressing the oxygen and hydrogen and also the electric generator

room.

2.Testing of purity.—(1) The purity of oxygen and hydrogen shall be tested by competent person

at least once in every shift at the following posts—

(a) in the electrolysis room;

(b) at the gas-holder inlet; and

(c) at the suction and of the compressor.

(2) The purity figures shall be entered in a register and signed by the persons carrying out such

tests:

Provided that if the electrolyser plant is fitted with an automatic recorder of purity of oxygen and

hydrogen with alarm lights, it shall be sufficient to the purity of gases if tested at the suction and of the

compressor only.

3. Restrictions as to the compression.—The oxygen and hydrogen gases shall not be compressed if

their purity as determined under Paragraph 2 above falls below 98 per cent at any time.

4. Limit switch for gasholder.—The bell of any gasholder shall not be permitted to go within the

30 centimeters of its lowest position when empty and a limit switch shall be fitted in the gasholder in such a

manner as to switch off the compressor motor when the limit is reached.

5. Provision of negative pressure switch.—In addition to the limit switch in the gasholder, a

sensitive negative pressure switch shall be provided in or adjacent to the suction main for hydrogen close to

the gasholder and between the gasholder and the hydrogen compressor to switch off the compressor meter

in the event of the gasholder being emptied to the extent as to cause vacuum.

6.Purity of caustic soda.—The water and caustic soda used for making lye shall be chemically pure

within pharmaceutical limits.

7. Precautions against reversal of polarity.—Electrical connections at the electrolysis cells and at

the electric generator terminals shall be constructed as to preclude the possibility or wrong connections

leading to the reversal of polarity and in addition an automatic device shall be provided to cut off power in

the event of reversal of polarity owing to wrong connections either at the switchboard of at the electric

generator terminals.

8. Colouring of gas pipes.—Oxygen and hydrogen gas pipes shall be painted with distinguishing

colours and in the event of leakage at the joints of the hydrogen gas pipe, the pipe after reconnection shall

be purged of all air before drawing in hydrogen gas.

9. Use of flame proof fittings.—All electrical wiring and apparatus in the electrolyser room shall

be of flame proof construction or enclosed in flameproof fittings and no naked light or flame shall be

allowed to be taken either in the electrolyser room or where compression and filling of the gases is carried

on and such warning notices shall be exhibited in prominent places,

10.Prohibition of hot work.—No part of the electrolyser plant and the gasholders and compressor

shall be subjected to welding, brazing, soldering or cutting until steps have been taken to remove any

explosive substance from that part and render the part safe for such operations and after the completion of

such operations no explosive substance shall be allowed to enter that part until the metal has cooled

sufficiently to prevent risk of explosion.

11.Repair etc. to be done under supervision.—No work or operation, repair or maintenance shall

be undertaken except under the direct supervision of a person who, by his training, experience and

knowledge of the necessary precautions against risk of explosion is competent to supervise such work. No

electric generator after erection or repairs shall be switched on to the electrolysers unless the same is

certified by the competent persons under whose direct supervision erection or repairs are carried on to be in

a safe condition and the terminals have been checked for the polarity as required by Paragraph 7,

12.Checking of plant.—Every part of the electrolyser plant and the gasholders and compressor

shall have a regular Schedule of overhaul and checking and every defect noticed shall be rectified forthwith.