(1)The requirements of sub-section (4) of Section 37 shall not apply to the following processes carried on in any factory :(a)The operation of repairing a water sealed gas-holder by the electric welding process, subject to the conditions that:(i)The gas-holder shall contain only the following gases, separately or mixed at a pressure greater than atmospheric pressure, namely, town gas coke, oven gas, producer gas, blast furnace gas, or gases other than air, used in their manufacture :Provided that this exemption shall not apply to any gas-holder containing acetylene or mixture of gases to which acetylene has been added intentionally.(ii)Welding shall only be done by the electric welding process and shall be carried out by experienced operatives under the constant supervision of a competent person.(b)The operations of cutting or welding steel or wrought iron gas mains and service pipes by the application of heat, subject to the conditions that:(i)The main or service pipes shall be situated in the open air, and it shall contain only the following gases, separately or mixed at a pressure, namely, gas coke, oven gas, or producer gas, blast furnace gas, or gases other than air, used in their manufacture.(ii)The main or service pipes shall not contain acetylene or any gas or mixture of gases to which acetylene has been added intentionally.(iii)The operation shall be carried out by an experienced person or persons and at least two persons (including those carrying out the operations) experienced in work on gas mains and over 18 years of age shall be present during the operation.(iv)The site of the operation shall be free from any inflammable or explosive gas vapour.(v)Where acetylene gas is used as a source of heat in connection within operated it shall be compressed and contained in a porous substance in a cylinder.(vi)Prior to the application of any flame to the gas, main or service pipes shall be pierced or drilled and the escaping gas ignited.(c)The operation of repairing an oil tank by the electric welding process subject to the following conditions :(i)The only oil contained in the tank shall have a flash point of not less than 150°F. (close test) and a certificate to this effect shall be obtained from a competent analyst.(ii)The analyst's certificate shall be kept available for inspection by an Inspector.(iii)The welding operation shall be carried out only on the exterior surface of the tank at a place (a) which is free from oil or oil leakage in inflammable quantities and (b) which is not less than one foot below the nearest part of the surface of the oil within the tank.(iv)Welding shall be done only by the electric welding and shall be carried out by experienced operatives under the constant supervision of a competent person.
