Prescription for fire/life safety design in hospitals, health care facilities
Hospital and health care facility projects are especially important due to their sensitive nature. Fire and life safety are key in hospital design.
Michael Chow, PE, CxA, LEED AP BD+C, Member/Owner, Metro CD Engineering LLC, Powell, Ohio
George Isherwood, PE, Vice President, Peter Basso Associates, Troy, Mich.
Michael Lentz, Associate, RMF Engineering, Baltimore
CSE: How might the complexity and scale of fire/life safety systems in hospitals and health care facilities vary from other types of structures?
Lentz: Due to the fact that most health care facilities cannot be evacuated and have to be designed to defend a fire, in-place smoke control systems can become very complex. Smoke zones need to be designed so that when a zone is alarmed, that specific zone can be kept at a negative pressure to the adjacent smoke zones in order to contain all of the smoke in the zone under alarm. We have found that the best way to accomplish this is under the smoke control sequence of operation, we convert the air-handling unit (AHU) that serves the smoke zone under alarm to 100% outside air. We are using the return fan now as a smoke exhaust fan. A modulating smoke control damper is installed on the supply air duct serving the zone, and it modulates to maintain the zone at a negative pressure. The supply air smoke control damper is controlled by a differential pressure sensor located at the doorways between the zone under alarm and all adjacent smoke zones.
CSE: What are some important factors to consider when designing a fire and life safety system in hospitals and health care facilities? What things often get overlooked?
Lentz: Smoke control systems are often overlooked, which can require a hospital to shut down critical AHUs during a fire/smoke alarm. Atrium evacuation systems and stair pressurization systems are also often overlooked, which can be very difficult to install and engineer after construction or even during the design process without a lot of redesign. When designing smoke control systems or atrium smoke evacuation systems within the building’s normal HVAC system, what is generally overlooked is the fact that the components of the HVAC system now have to be UL listed for that use and now have activation or communication with the fire alarm system.