Massachusetts

Statewide summary — confirm with your building department before designing

Two values were corrected by this audit against the state own adopted table. Massachusetts assigns ultimate design wind speed and ground snow load municipality by municipality in 780 CMR ch.51 Table R301.2(2). Ultimate design wind speed corrected from 110 to 120 mph: 110 mph is below every Massachusetts municipality. Boston is 120 mph, Worcester 117, Barnstable 130 and Nantucket 137; the Berkshires are about 112 and the south coast and islands run 127 to 137. Ground snow load corrected from 35 to 40 psf: Boston is 40 psf, while Worcester, Lowell and Pittsfield are 50 psf and the Cape and islands are 25 to 30 psf. The published figures are the Boston values and are not conservative for Worcester County, Middlesex County, the Berkshires, the Cape or the islands; look up your municipality in Table R301.2(2). The remaining values are confirmed by the state code and were not changed: frost line depth is 48 inches statewide, seismic design category B holds throughout the state under ASCE 7-16 at Site Class D and Risk Category II, and termite infestation probability is designated moderate to heavy statewide, the band the stored value moderate sits inside. The winter design temperature is ASHRAE data; 780 CMR refers designers to ACCA Manual J rather than fixing a value, so the stored figure is unverified.