A safety vacuum release system (SVRS) automatically monitors the pump pressure. When outlets are blocked, the suction line is vented, which releases any suction caused by the blockage.
A suction-limiting vent system (SLVS) is a pipe connected between the suction fitting of the pool main drain and the pool pump. If the main drain is blocked, the high suction forces air from the vent pipe into the plumbing lines. This causes the pump to lose prime, releasing the suction.
A gravity drainage system with a collection tank has no direct suction at the pool at all. Instead atmospheric pressure, gravity and water displacement move the water from the pool to the collection tank.
An automatic pump shut-off system disables the pump in the case of suction-causing blockage. When the pump is shut off, the suction is released.
Finally, the drain or outlet can be removed from the system and the sump filled with concrete. In addition, the equipment-room piping is capped and cut or replumbed to create a return line and reverse flow. This is called drain disablement, and it’s the only option that completely eliminates the possibility of entrapment.
The Virginia Graeme Baker Pool and Spa Safety Act was enacted in 2008 to help avoid death and injury by entrapment.