Going Larger
Revisiting the topic of hospital smoke compartments
BY RON COTÉ
SIXTEEN MONTHS AGO, I addressed the failed attempt by the Technical Committee on Health Care Occupancies to revise NFPA 101®, Life Safety Code®, to increase the allowable smoke compartment size in hospitals [“Input Wanted,” January/February 2015]. The proposal called for increasing the size from 22,500 square feet (2,100 square meters) to 40,000 square feet (3,720 square meters), but it failed because it did nothing to limit the number of patients at risk of fire in any smoke compartment.
The committee revisited the subject for the first draft phase of the revision process that will produce the 2018 edition of the code. It addressed the shortfalls identified when the NFPA membership rejected the change, refined the concept, and codified the draft requirements, so as to achieve the consensus necessary to move the change along to public comment and the second draft phase.
The committee leveraged the fact that the premise on which the increase in smoke compartment size for new construction had been promoted remained viable. New hospitals in the United States are designed to the specifications of the Facilities Guidelines Institute (FGI), which allot a greater amount of floor space to individual patients. The FGI guidelines help ensure that a new smoke compartment of 40,000 square feet has an occupant load similar to that traditionally associated with a 22,500-square-foot smoke compartment, so that additional patients are not placed at risk of fire within the smoke compartment.
Even so, the committee could not practicably mandate compliance with the new design guidelines, whether retroactively for existing hospital smoke compartments, in states that are not using the latest edition of the guidelines, or in countries where the guidelines are not referenced at all. As a result, it wrote a requirement that each patient sleeping room be configured for only one patient if the smoke compartment size is to be increased. Configuration is achieved by design, rather than by administrative decision, adding enforceability to the one-patient-per-sleeping-room requirement.
The code changes proposed by First Revision 3507 on 18.3.7.1 will limit smoke compartment size in new health care occupancies to an area not exceeding one of the following, provided the travel distance from any point to reach a door in the required smoke barrier does not exceed 200 feet (61 meters): 22,500 square feet in nursing homes and limited care facilities; 22,500 square feet in hospital smoke compartments where any patient sleeping room is configured for two or more patients; 40,000 square feet in hospital smoke compartments where all patient sleeping rooms are configured for only one patient; 40,000 square feet in hospital smoke compartments that contain no patient sleeping rooms.
Similarly, First Revision 3508 on 19.3.7.1 will offer the same conditional increases in smoke compartment size in existing hospitals, provided the building is sprinklered; that the sprinklers are quick-response or residential sprinklers throughout smoke compartments containing patient sleeping rooms; and that the 200-foot travel distance criterion is met. All of these are features currently mandated for new health care occupancies.
The 200-foot travel distance limitation to reach a door to a smoke barrier is key to preventing smoke compartment size from becoming excessive in new and existing hospitals. To meet the travel limitation, a smoke compartment that approaches 40,000 square feet will typically need access to more than one adjacent smoke compartment. A smoke compartment of typical proportions situated at an end of a rectangular-shaped building, so as to have access to only one adjacent smoke compartment along its narrow dimension, might approach 30,000 square feet (2,790 square meters) before exceeding the 200-foot limitation. In other words, the maximum 40,000-square-foot compartment size may not be realized due to the travel limitation.
RON COTÉ, P.E., is lead engineer, life safety, at NFPA.