Continued... POOL & SPA NEWS NOVEMBER 20, 1996

"We need to approach this as a technical problem and identify effective solutions that can be realistically implemented in the field. And to do that, we've got to be working off the same page."

As Rowley noted in his briefing at the CPSC round table, suction entrapment refers to four separate types of accidents: hair entrapment, limb entrapment, body entrapment and disembowelment. All such accidents occur when a bather becomes entrapped on a drain by excessive suction power.

In the vast majority of cases, the culprit drain is plumbed to a pump in such a way that it serves as the single suction point for that pump. And in most cases, except those of hair entrapment, the drain is also unprotected by a grate or anti-vortex cover. The combination of these two conditions creates a dangerous situation.


 Hair entrapment accidents occur when a bather dips below the water's surface and his or her hair is sucked into the drain grate or anti-vortex plate.

These accidents are by far the most common form, and the CPSC has investigated 49 such cases since 1978, including 13 deaths. All incidents occurred in spas, both commercial and residential, with many happening in older spas that do not meet current standards. Most of the victims were young girls with long hair.


 Body entrapment typically occurs when part of a bather's torso or buttocks completely covers an unprotected drain in either a pool or spa. (See Figure 1.)


 Limb entrapment is considered very similar to body entrapment. The term refers to accidents in which a bather's arm or leg is sucked into an unprotected suction pipe in the main drain of a wading pool, spa or swimming pool. Limb-entrapment accidents usually occur in vessels with plumbing greater than 2 inches in diameter. (See Figure 2.) Since 1980, the CPSC has investigated nine incidents involving either body or limb entrapment, including six deaths. All but one of the incidents involved a dislodged drain cover.


 Disembowelment accidents occur in wading pools where small children, typically 3 to 6 years old, sit on an unprotected drain. Injury occurs when their lower intestines are sucked out of their body through their anus. Unlike the other types of accidents in which the primary risk is drowning, most victims of these incidents don't die. Rather, they are permanently injured. (See Figure 3.)

The CPSC has investigated 10 such incidents since 1980, nine of which occurred in commercial wading pools.


Each suction-entrapment accident is investigated in terms of its physical description, which includes anecdotal information about the circumstances surrounding the event such as how it was that the victim came into contact with the drain.

Accidents are also examined technically, with investigators looking into issues such as pipe and pump size, and reconstructing the event from an engineering perspective.

Once all the data is examined and a cause identified, recommendations for the prevention of similar accidents are often established and disseminated to the public.

According to Rowley, CPSC investigations coupled with data gathered during the Swimquip study form the basis of some safety recommendations that apply to wading pools, spas and swimming pools nearly across the board.

These measures can be divided into three categories design solutions, protective measures and warnings.

Of these, Rowley notes, the design solution is by far the most reliable way to prevent suction-entrapment accidents.

"These are technical things that we can do to eliminate risk altogether,' he explains. "Obviously, that's what you want to try to achieve before you do anything else."

Noting that the vast majority of all suction-entrapment cases involve a single-suction plumbing arrangement, says Rowley, the primary design solution is to require dual suction outlets for each and every pump installed on a wading pool, spa or swimming pool.


The idea of requiring dual suction points for commercial pools and spas is nothing new. Again, ANSI/NSPI standards already include such language, as do many building codes in counties and cities across the country.

Still, Rowley and others tackling the problem want to improve on the dual-drain standard, and the new language drafted for inclusion in the ANSI/NSPI standard tightens the definition of a safe plumbing installation.

One of the most significant additions to the existing standard is a requirement that, in the event that one drain is completely blocked, the other should have a maximum flow rate of 6 feet per second a rate that would not generate deadly suction.

Another key improvement is a mandatory minimum distance of 3 feet between drains, a measure designed to avoid the possibility that one bather could possibly block two drains at the same time.

"This is the best way to prevent these accidents," says Rowley. "And as far as new construction goes, it's a very simple issue: No one should ever plumb a wading pool, a spa or a swimming pool with a single suction point. When you're installing a pool, for example, it's very easy and inexpensive to install a second main drain."

When looking at retrofits, says Rowley, implementation can be a bit more complicated. To enforce a dual suction-point mandate would require relatively expensive construction work on large numbers of existing wading pools, spas and swimming pools.

Taking a stand

For the record. it is P SN's position that the recommendations discussed in this article and published by the CPSC. NSF) and other organizations charged protecting me public health and safety should be implemented on a national basis.
Included in such recommendations s a requirement for the immediate retrofitting of all public and semi-public wading pools and spas that are currently installed with single suctions drains..
We also support requirements for spa-side cut-off switches and for mandatory inspections of drain covers and grates.
We believe that it is incumbent upon owners and operators of commercial facilities to ensure the safety of those using their pools and spas. Among some of the retrofits required to create a safe bathing environment may be costly. such expense is minor compared with the human suffering caused by suction-entrapment accidents.

The Editors


POOL & SPA NEWS NOVEMBER 20, 1996, Archive page 3




New Water Solutions, Inc., Drainsafe 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.
We do however recommend the use of products certified via (NRTL) Nationally Recognized Testing Laboratories as per ASME/ANSI A112.19.17 & ASME/ANSI A112.19.8 2007 Standards.
 All products must be installed as per manufacturers instructions and be job site specific to meet the criteria of each individual application.

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