Beyond the sound bites surrounding entrapment protection lie equally important questions regarding how the technology works, its strengths and limitations, and what issues remain to be solved.
- Entrapment Diagram
A closer look at what happens during an entrapment incident.
- Product Placement
The SVRS devices and automatic pump shut-offs on the market vary in their placement within the circulation system.
- On-site Solution
Suction-limiting vents provide an alternate vacuum-breaking system.
Generally speaking, an entrapment occurs when a person comes in contact with an improperly protected suction outlet, and a part of their body, jewelry, clothing or hair is entrapped, entangled or held down by the force created by the pump. There are currently five recognized types of suction entrapment:
How this happens: A part of the body, generally the torso, backside or other expansive area, completely covers the outlet, causing a vacuum to form and the skin to adhere to the drain.
Number of incidents: Between 1999 and 2009, there were 33 recorded body entrapments, comprising 35 percent of the total occurrences.
The challenge: Single-drain pools and spas can pose a danger that many swimmers, especially children, are not aware exists.
How to prevent it: The only way to completely eliminate the hazard is to disable the drain or build a drainless system. However, the risk can be greatly reduced by installing VGBA-approved outlet covers, multiple-drain systems, secondary devices or gravity-feed systems.
How this happens: A broken or missing drain cover causes the outlet to be exposed, and a bather’s limb becomes entrapped in the pipe.
Number of incidents: Between 1999 and 2009, there were 32 recorded limb entrapments, comprising 34 percent of the total occurrences.
The challenge: Children, or even adults, may insert an arm into an exposed drain.
How to prevent it: Install VGBA-certified drain covers and make sure they remain secure. Even more effective: Build a pool with no submerged suction outlets of any kind.
How this happens: Hair entrapment is not caused by the formation of a vacuum, but rather is the result of hair getting stuck in the drain and wrapping around components.
Number of incidents: Between 1999 and 2009, there were 13 recorded hair entrapments, comprising 14 percent of the total occurrences.
The challenge: Strands of hair are tiny, allowing them easy access through the grate.
How to prevent it: After drainless systems, the most effective preventive measure is the use of certified outlet covers with a flow rating higher than the maximum pump flow.
How this happens: When the backside completely covers the drain, and there is no system in place to prevent a vacuum, the force can cause a tear in the tissue and the intestines begin exiting the body.
Number of incidents: Between 1999 and 2009, there were two recorded eviscerations, comprising 2 percent of the total entrapments.
The challenge: Eviscerations happen very rapidly, making them more difficult to curtail once the process has begun.
How to prevent it: Install a drainless system or VGBA-certified drain covers. Multiple outlets and gravity-feed systems are believed to mitigate the problem; however, this has not been proven.
How this happens: An object, such as a chain or bathing-suit strap, catches on a drain, wraps around a component or otherwise becomes lodged.
Number of incidents: Between 1999 and 2009, there were 13 recorded mechanical entrapments, comprising 14 percent of the total occurrences.
The challenge: Like hair entrapment, this is not caused by suction, but involves a mechanical attachment, which must be broken for the person to become freed.
How to prevent it: Install drainless systems or VGBA-certified outlet covers.
Please note: One entrapment incident between 1999 and 2009 was unexplained and, therefore, was not recorded as falling into any of the five categories.