MGL c.146 + 522 CMR (Board of Boiler Rules, within DFS); heating-boiler rules 522 CMR 4.00 (Mass. Register #1539, Jan 17, 2025) adopt 2021 ASME Section IV. Enforced by Department of Fire Services Boiler & Pressure Vessel program (district engineering inspectors) and authorized in-service/insurance inspectors; Board of Boiler Rules (within DFS) writes 522 CMR. Reported, in verification; the state record was last reviewed 2026-11-12.
Heating boilers over 3 hp: external inspection yearly; internal yearly (steam) or every 3 years (hot water) where manholes/handholes exist; certificate posted near the boiler and pulled if unsafe. Exempt: private residences, units of 3 hp or less, low-pressure units under 4 sq ft grate, federal and agricultural boilers (522 CMR 4.05).
Source: primary document
Statewide layer. County and city amendments sit on top; confirm the local office for the address.
522 CMR 4.00 (Mass. Register #1539, Jan 17, 2025; read Oct 27, 2026): heating boilers inspected externally yearly; internal inspection yearly (steam) or every three years (hot water). Board of Boiler Rules Oct 1, 2026 agenda lists a '522 CMR revision process' item; no proposed text, hearing or date published
There is no federal boiler certificate; the state program below is the whole obligation, with the ASME Boiler and Pressure Vessel Code and the National Board Inspection Code as the referenced standards.
These apply when the building has the equipment or fits the type named. The frequency is the standard one; your local official can set a stricter one, so confirm it for the address.
MGL c.146 + 522 CMR (Board of Boiler Rules, within DFS); heating-boiler rules 522 CMR 4.00 (Mass. Register #1539, Jan 17, 2025) adopt 2021 ASME Section IV. Heating boilers over 3 hp: external inspection yearly; internal yearly (steam) or every 3 years (hot water) where manholes/handholes exist; certificate posted near the boiler and pulled if unsafe. Exempt: private residences, units of 3 hp or less, low-pressure units under 4 sq ft grate, federal and agricultural boilers (522 CMR 4.05).
Department of Fire Services Boiler & Pressure Vessel program (district engineering inspectors) and authorized in-service/insurance inspectors; Board of Boiler Rules (within DFS) writes 522 CMR.
Rulemaking pending. 522 CMR 4.00 (Mass. Register #1539, Jan 17, 2025; read Oct 27, 2026): heating boilers inspected externally yearly; internal inspection yearly (steam) or every three years (hot water). Board of Boiler Rules Oct 1, 2026 agenda lists a '522 CMR revision process' item; no proposed text, hearing or date published
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