Section 65(4) in Maharashtra Factories Rules, 1963
(4)Ever pressure plant in service shall be thoroughly examined by a competent person,-(a)externally once in every period of six months;(b)internally, once in every period of twelve months, and(c)hydraulic test once in a period of four years.Explanation. - If however by reason of construction of the pressure vessel or pressure plant a thorough internal examination is not possible, it may be replaced by a hydraulic test, which shall be carried out once in every period of two years:Provided that in the case of pressure vessel or pressure plant with thin walls such as sizing cylinders made of copper or any other non-ferrous metal, periodic hydraulic test may be dispensed with if the requirements laid down in clause (5) are complied with:Provided further that if the Chief Inspector or any Inspector authorised by him certifies that it is impracticable to carry out a thorough external or internal examination of any pressure vessel or pressure plant as required by clauses (a) and (b) and if owing to its constructions and use a hydraulic test as required by this sub-rule cannot be carried out, a thorough external examination shall be carried out at least once in every two years and a thorough systematic non-destructive test like ultrasonic test, for metal thickness or other defects of all parts shall be carried out at least once in every period of four years.
