From open office floor layouts to exterior glass curtain walls, visible connectivity between buildings and floor levels remains one of the major features in architectural design desired by our clients. One of the challenges with incorporating such connectivity is reconciling the building and fire codes’ requirement for rated separations. While there are various prescriptive and performance-based options available, a common preference is to use non-rated glazing with automatic sprinkler protection.
There are very limited applications where the code recognizes sprinkler protected glazing as a prescriptive alternative to a rated assembly. One of these applications is an alternative to a 1-hour atrium separation. In other instances, specialized sprinklers are used to protect glazing that has been tested as a 2-hour fire resistance rated wall assembly. With this approach, the glazing is not subject to some of the limitations imposed on typical opening protectives by the building code, such as size.
Under the 8th Edition of the Massachusetts State Building Code (780 CMR), it was unclear if sprinkler protected glazing could be used as a prescriptive alternative to a 2-hour wall. This ambiguity allowed for the design consultant to negotiate the reasonableness of substituting an active fire protection system for a fire-rated passive barrier. Now under the 9th Edition of 780 CMR, the newly added Section 703.4 requires the fire resistance rating of a building element, component or assembly to be established without the use of sprinklers or any other fire suppression system. With this new section, it is clear that the use of sprinkler protected glazing in lieu of a rated wall assembly under the 9th Edition of 780 CMR requires either approval from the building official or a state variance.