Subd. 1. Inspection requirements.

All boilers and steam generators must be inspected by the Division of Boiler Inspection before they are used and all boilers must be inspected at least once each year thereafter except as provided under subdivision 2. Inspectors may subject all boilers to hydrostatic pressure or hammer test, and shall ascertain by a thorough internal and external examination that they are well made and of good and suitable material; that the openings for the passage of water and steam, respectively, and all pipes and tubes exposed to heat, are of proper dimensions and free from obstructions; that the flues are circular in form; that the arrangements for delivering the feed water are such that the boilers cannot be injured thereby; and that such boilers and their connections may be safely used without danger to life or property. Inspectors shall ascertain that the safety valves are of suitable dimensions, sufficient in number, and properly arranged, and that the safety valves are so adjusted as to allow no greater pressure in the boilers than the amount prescribed by the inspector's certificate; that there is a sufficient number of gauge cocks, properly inserted, to indicate the amount of water, and suitable gauges that will correctly record the pressure; and that the fusible metals are properly inserted where required so as to fuse by the heat of the furnace whenever the water in the boiler falls below its prescribed limit; and that provisions are made for an ample supply of water to feed the boilers at all times; and that means for blowing out are provided, so as to thoroughly remove the mud and sediment from all parts when under pressure.

Subd. 2. Qualifying boiler.

1. (a) "Qualifying boiler" means a boiler of 200,000 pounds per hour or more capacity which has an internal continuous water treatment program approved by the department and which the chief boiler inspector has determined to be in compliance with paragraph (c).
2. (b) A qualifying boiler must be inspected at least once every 24 months internally and externally while not under pressure and at least once every 18 months externally while under pressure. If the inspector considers it necessary to conduct a hydrostatic test to determine the safety of a boiler, the test must be conducted under the direction of the owner, contractor, or user of the equipment under the supervision of an inspector.
3. (c) The owner of a qualifying boiler must keep accurate records showing the date and actual time the boiler is out of service, the reason or reasons therefor, and the chemical physical laboratory analysis of samples of the boiler water taken at regular intervals of not more than 48 hours of operation which adequately show the condition of the water, and any elements or characteristics of the water capable of producing corrosion or other deterioration of the boiler or its parts.
4. (d) If an inspector determines there are substantial deficiencies in equipment or in boiler water treatment operating procedures, inspections of a qualifying boiler may be required once every 12 months until the chief boiler inspector finds that the substantial deficiencies have been corrected.