Drainsafe® Definition

Limb Entrapment/ Mechanical Inflation

One of the five types of Suction Entrapment. Limb Entrapment is defined as entrapment caused by a limb becoming lodged in an unprotected suction outlet port or unprotected pipe.

Mechanical Inflation could be one of the effects of a limb entrapment.


The most common cause for this type entrapment is an unprotected Suction Outlet.

Note: Any unprotected opening has the potential for Limb Entrapment.

What separates Mechanical Inflation from limb entrapment is the nature of the force holding the limb to the suction outlet. When a limb becomes entrapped the limb could engorge due to higher pressure inside of the limb then externally, causing the affected limb to swell. With the system vacuum released, mechanical inflation can keep the affected area held firm therefore causing entrapment.


The key to suction safety is Layers of Protection. Should one layer fail, there is a additional layer of protection in place to assist in the avoidance of injury and preservation of life.

1. Education - Knowing about this hazard and educating our families is the first step to preventing an incident.

2. Sound Hydraulics - Multiple Suction outlet configurations, if constructed properly is a safety measure in of itself. If incorrectly installed or used with small diameter plumbing, hydraulic issues could create additional hazards for entrapment.

3. Anti-Entrapment Suction Outlet Cover - Use ASME/ANSI A112.19.8b 2008 Certified suction outlet cover on all suction outlets.

4. "Plan B" - Should the Anti-Entrapment Suction Outlet Cover fail (Vandalism, Removal, Improper installation) a Plan B should be in place. These are products which activate when a Body Entrapment type situation occurs. These products include Gravity Feed, Vent to Atmosphere, Safety Vacuum Limiting System, or A112.19.17 VGB Compliant Safety Vacuum Release System.

"Limb Entrapment" - http://www.drainsafe.com/limbentrapment.html

"Retrofit Existing Facilities" - http://www.drainsafe.com/retrofit.html

"CPSC Layers of Protection" - http://www.cpsc.gov/cpscpub/pubs/5101.pdf

"Guidelines for Entrapment Hazards" - http://www.cpsc.gov/CPSCPUB/PUBS/363.pdf

New Water Solutions, Inc., Drainsafe®, drainsafe.com nor I, Ron Schroader recommend the use of one product or device over another. Products must be implemented as per system/job specific application. It is the obligation of the installer to understand the intended use and application prior to installation of any product or device. All products must be installed as per manufacturers instructions and be job site specific to meet the criteria of each individual application.