For section 3 of the principal Act, the following section shall be substituted, namely:--
"3. Limitation of application - Nothing in this Act shall apply to--
(a) locomotive boilers belonging to or under the control of the railways;
(b) any boiler or boiler component,--
(i) in any vessel propelled wholly or in part by the agency of steam;
(ii) belonging to, or under the control of, the Army, Navy or Air Force; or
(iii) appertaining to a sterilizer disinfector used in hospitals or nursing homes, if the boiler does not exceed one hundred litres in capacity.".