BBRS Official Interpretation No. 2026-08
Date: July 28th, 2026
Subject: 780 CMR R310 – Bulkheads and Emergency Escape Rescue Openings
An Emergency Escape and Rescue Opening (EERO) has been required in nearly all basements and basement bedrooms since promulgation of the 7th Edition of 780 CMR in 2008. An EERO is required in basements that do not contain habitable space. A single interior stairway connecting the dwelling to the basement does not satisfy this requirement by right.
The BBRS recently received a Request for Interpretation (RFI) regarding whether a bulkhead is permitted as a component of a basement EERO. This topic has given rise to uncertainty caused by changes to the 2021 IRC's use of the term "bulkhead." That uncertainty has created a perceived conflict with 780 CMR R310.1, which requires that an EERO "open directly into a public way, or to a yard or court…that opens to a public way." Specifically, questions have arisen as to whether a bulkhead located between the EERO door or window, and the public way, yard, or court complies with the requirement that the EERO "open directly."
This BBRS response reaffirms the 2013 interpretation that a bulkhead enclosure may be installed over a basement EERO area well, provided it is "releasable or removable from the inside without the use of a key or tool or force greater than that required for the normal operation of the Escape and Rescue Opening," as required by Section R310.4.4 and any other applicable provisions of 780 CMR.
Question (2026): Can a metal or plastic bulkhead stair cover with side-hinged doors serve as the required EERO for an unfinished basement exceeding 200 square feet when an interior stair to the first floor is also provided?
Answer: Yes.
Question (2013): A basement has a stairway that serves the living space and a second stairway that leads directly to a garage which has an exterior door that opens to a yard. Does this meet the requirements of R310?
Answer: Yes.
Question (2013): A basement has a stairway that serves the living space and a second stairway that leads directly to a mudroom which is separated from the main living space by a door. This mudroom also has an exterior door or a means of egress door which opens to a yard. Does this meet the requirements of R310?
Answer: Yes.
Question (2013): A basement has a stairway that serves the living space and a second stairway that leads directly to a hallway which is separated from the main living space by a door. This hallway also has an exterior door or a means of egress door which opens to a yard. Does this meet the requirements of R310?
Answer: Yes.
Question (2013): A basement has a stairway that serves the living space and a second egress path that does not lead through the living space. This second egress path leads to an exterior door which opens to a yard. Does this meet the requirements of R310?
Answer: Yes.