Section 408.4047. Exempt boilers.

These rules do not apply to any of the following:

(a)     A boiler under federal control.

(b)       A swimming pool heater, open car wash heater, and similar types of equipment which do not have intervening valves on the return or discharge piping, which do not have a reduction in pipe size in the return or discharge piping, and which do not generate more than normal circulating pump pressure.

(c)     A miniature steam or marine engine used for a hobby.

(d)     A boiler used in the power plant of a self-propelled vehicle designed primarily for transportation of persons or property on a highway, except for a vehicle used exclusively on stationary rails or tracks.

(e)     A boiler used on a mint farm for mint processing purposes.

(f)    A nonvaporizing, organic fluid boiler if the boiler meets all of the following criteria:

(i)     The system is vented and does not have valves or restrictions in the pipe between the boiler and the vent.

(ii)     The vent pipe is sized so that the thermal expansion of the fluid will not result in an increase in pressure on the system, which is verifiable with engineering data.

(iii)      The owner or user provides the boiler division of the department with calculations performed by an engineer, which verify that pressure due to thermal expansion cannot exist in the boiler as installed.

(g)     A low-pressure steam boiler that has a volume of less than 5 cubic feet and that does not have piped feed connections.

History: 1979 AC; 1998-2000 AACS; 2006 AACS; 2009 AACS; 2013 AACS.