Section 56A(5) in The West Bengal Factories Rules, 1958
(5)In the case of gasholder in use for more that 10 years, the internal condition of the sheeting shall, within year of the coming into force of this rule and thereafter at least once in a every period of four years, be examined by a competent person by means of electronic or other accurate devices.Provided that if the Chief Inspector is satisfied that such electronic or other accurate devices are not available he may permit the cutting of samples from the crown and the sides of the holder at places to be indicated by the competent person.Provided further that if the above examination raises a doubt, an internal visual examination shall be made.
