Anti-Hair Entanglement
Triodyne Safety Alert v. 1 #1 (February 1998)
Ralph L. Barnett

When bathers or swimmers place their heads in the vicinity of active pool drains, their hair may become entangled in the drain cover or grating. For the period 1978 to 1996, the Consumer Product Safety Commission reports 49 entanglement incidents (including 13 deaths) where the victims' heads were held under the water in spas, hot tubs, and whirlpools. This paper outlines several drain cover concepts that may mitigate or eliminate the entanglement danger.

Anti-Hair Entanglement: Cantilevered Grating Elements
Triodyne Safety Alert v. 2 #1 (March 2000)
Peter J. Poczynok, Adam K. Dybek, and Ralph L. Barnett

Hair entrapment is a failure mode shared by swimming pools, wading pools, spas, hot tubs, and whirlpool bathtub appliances. When hair is entrained in the discharge flow through a suction fitting or drain, its withdrawal will generally be resisted by gravity, drag, friction, buoyancy and interface. Large withdrawal forces obviously lead to a horrifying safety problem. In an attempt to manage the magnitude of these forces, the pool industry introduced their first standard relative to hair entrapment on November 3, 1987; ASME/ANSI A112.19.8M - 1987, Suction Fittings for Use in Swimming Pools, Wading Pools, Spas, Hot Tubs, and Whirlpool Bathtub Appliances. The 1987 ANSI standard does not recognize self-locking types of entanglement. Nevertheless, 30 cases were reported to the Consumer Product Safety Commission from January 1990 through May 1996 where hair entanglement occurred because of tangling rather than strong suction forces. An additional four cases of entanglement are reported by the CPSC from April, 1981 through February, 1985. This paper explores the use of cantilevered grating elements in rectangular and circular drains for shedding these self-locking tangles.

A drain cover for swimming pools, spas and hot tubs has been designed which addresses eight hazards associated with conventional drain systems. This new drain cover, illustrated in Fig. 1, eliminates hair entanglement, child evisceration and finger entrapment as well as minimizing body entrapment. Furthermore, its design and construction provide effective countermeasures against vandalism, broken drain covers, missing drain covers and structural deterioration due to environmental antagonists. Additional features unrelated to safety include a universal fastening system which adapts the cover to all circular main drains available in the United States. Also the drain cover is an order of magnitude stronger than its competitors and has a safe flow rate that is 37% greater than its nearest competitor. This paper presents an anatomy of the product’s development.

The current ASME/ANSI standard for pool/spa drain covers is relied upon as an effective guideline for drain system safety by pool industry practitioners, state building code commissions, the Consumer Product Safety Commission, the National Spa and Pool Institute, and a myriad of pool safety sophisticates. In fact, it is a license to kill. To demonstrate its shortcomings in the dawn of its next revision, an ordinary steering wheel is shown to satisfy the current standard while exposing bathers to every known fatal drain cover scenario. The paper raises a new issue: ASME, ANSI and pool professionals may all be in legal jeopardy.