Did you know that there are over 900,000 elevators in use worldwide? New York City alone is home to over 84,000 elevators. That’s a lot of ups and downs, especially when it comes to safety concerns. Many AHJs across the US base their elevator regulations on ANSI’s ASME A17.1, Safety Code for Elevators and Escalators. Often, sprinkler protection is required in the elevator pit. When a sprinkler is installed, NFPA 72 and ASME A17.1 require elevator hoist-way pits to be protected via “fire detection devices.”
An elevator hoist-way and pit can be considered harsh environments due to their potential for dust, dirt, and humidity. Standard spot-type smoke detectors can become prone to false alarms. It’s also a location that can be difficult for functional testing of devices as required by NFPA 72. In some jurisdictions, sprinklers are not permitted in elevator shafts. When sprinklers are not installed in elevator shafts, NFPA 72 prohibits the installation of smoke detectors.
In sprinklered elevator hoist-ways, heat detection is required to be installed within twenty-four (24) inches of each sprinkler head, and it needs to have a lower temperature rating than the sprinkler system (i.e., 135-degree heat threshold versus 194-degree sprinkler head). This is required for elevator power shunt trip to ensure that power is interrupted to the elevator prior to sprinkler discharge of water.
Smoke Detection in an elevator hoist-way/pit plays a key role in elevator passenger safety. Its purpose is to recall the elevator to ensure safe passenger egress before elevator shutdown. To achieve this, it is important to detect a fire in the elevator hoist-way or pit as soon as possible, before a fire can generate enough heat to trigger sprinkler deluge.
NFPA 72, 2019 edition adds a new requirement, stipulating that initiating devices installed in the elevator hoist-way must be accessible for service, testing, and maintenance from outside the elevator hoist-way. Alternative detection solutions for an elevator hoist-way and pit, which are compliant and easily maintained from outside the hoist-way, are becoming a necessity.
For heat detection, a linear heat detection can be used within the elevator pit to detect a fire. Linear heat detectors are functionally tested by shorting the end-of-line resistor. To ensure compliance with NFPA 72 and ease of testing, the junction box containing the end-of-line resistor should be located outside the elevator pit, preferably in the elevator machine room.
Modular Aspirating Smoke Detectors (MASDs), such as ModuLaser, can be an ideal solution. This is because the MASD is located outside the hoist-way and pit—such as the elevator machine room. The MASD actively samples air from the protected area via a network of CPVC piping. These modular air aspirating detectors can provide a cost-effective means for elevator hoist-way and pit smoke detection.
Key MASD design considerations should include routing the sampling pipe back to the detector location area and adding a test port, so that testing can be completed without entering the shaft. It is also important to ensure the MASD exhaust pipe is routed back to the elevator hoist-way so that sampled air can be returned to the protected area for pressure maintenance. If high humidity is present in the hoist-way, a "P-trap" or condensate drain loop within the pipe network should also be considered before entering the MASD.
Aspirating Detection Solutions | 
