50-74-215. Interior and exterior examination of boiler. (1) The inspector must be satisfied by a thorough interior and exterior examination that the:

(a) boilers are well-made and of good and suitable material;

(b) openings for the passage of water and steam, respectively, and all pipes and tubes exposed to heat are of the proper dimensions and free from obstructions;

(c) flues are circular in shape;

(d) fire line of the furnace is at least 2 inches below prescribed minimum waterline of the boilers;

(e) arrangements for delivering the feed water are such that the boilers cannot be injured by the feed water; and

(f) boilers and the steam connections may be safely employed without danger to life.

(2) A boiler or steam pipe or any of the connections to a boiler or steam pipe that are made in whole or in part of bad material or are unsafe from any cause may not be approved. Nothing in this section may be construed to prevent the use of any boiler or steam generator, that is not constructed of riveted iron or steel plates, when the inspector has satisfactory evidence that the boiler or steam generator is equal in strength to and as safe from explosion as boilers of the best quality, constructed of iron or steel plates.