Additional Entrapment Prevention Options
In addition to having a drain cover or another anti-entrapment device that complies with ASME/ASNI A112.19.8-2007, pools and spas operating off of a single main drain, other than an unblockable drain, must also add one or more of the following options:
- Safety vacuum release system (SVRS)—A safety vacuum release system ceases operation of the pump, reverses the circulation flow or otherwise provides a vacuum release at a suction outlet when a blockage is detected.
- Suction-limiting vent system—A suction-limiting vent system with a tamper-resistant atmospheric opening, also called an atmospheric vent, is a pipe teed to the suction side of the circulation system on one end and open to the atmosphere on the opposite end. When a blockage occurs at the main drain, air is introduced into the suction line causing the pump to lose prime and relieving the suction forces at the main drain.
- Gravity drainage system—A gravity drainage system uses a collector tank and has a separate water storage vessel from which the pool circulation pump draws water. Water moves from the pool to the collector tank depending on atmospheric pressure, gravity and the displacement of water by bathers, which removes the need for direct suction at the pool. This type of system is also referred to as a reservoir, surge tank or surge pit.
- Automatic pump shut-off system—An automatic pump shut-off system is a device that would sense a drain blockage and automatically shut off the pump system.
- Drain disablement—This is the only option that eliminates rather than mitigates the hazard. To satisfy the definition of drain disablement, the drain/outlet would need to be physically removed from the system by filling the sump with concrete, cutting and capping the piping in the equipment room or re-plumbing the section line to create a return line and reverse flow.
- Other systems—Any other system that is determined by the Commission to be equally effective as, or better than, the safety systems listed here.
