(2) Any vessel in use on July 1, 1961, or in use on the effective date of any adoption of different rules, shall be deemed to meet the minimum safety standards so long as the same use continues and no change occurs which would reduce the safety of its operation. Provided that if the Board of Boiler Rules finds that there is a variation from the minimum safety standards which is dangerous to health or safety, it may order that all vessels having a like variation be brought into conformity with the rules created under this section, or adopted after July 1, 1961, without variation.
(3) The Board of Boiler Rules shall adopt minimum safety standards for pressure piping substantially equal to the published codification of standard engineering practices and formulae known as the "Code for Pressure Piping" of the American Society of Mechanical Engineers, numbered B 31.1, B 31.3, B 31.5, B 31.7 and B 31.9 together with the published revisions and interpretations thereof. [1961 c.485 §8; 1969 c.582 §8; 1973 c.830 §3; 1983 c.676 §9a; 1999 c.823 §1]