It was May 2011, and the pool season was about to begin. Service technicians were scrambling to open customers’ pools while contractors rushed to have final plaster completed in time for summer.

Then, two days before Memorial Day weekend, the Consumer Product Safety Commission announced the largest product recall in the industry’s history — approximately one million suction outlet covers sold by 10 manufacturers — all of which had been installed within the last three years to satisfy a national mandate intended to make pools and spas safer.

Now, they were deemed hazardous, with the government advising that certain commercial vessels be closed immediately until repairs were made.

“I know this is a very difficult message for many communities to hear so close to Memorial Day weekend,” said CPSC Chairman Inez Tenenbaum in announcing the historic recall. “But we cannot risk a child becoming entrapped in a recalled drain cover. ... We know that drain entrapment is a hidden, horrific and preventable hazard.”

The news threw the industry into chaos: Service techs, builders and retailers frantically tried to accommodate the massive recall while manufacturers and distributors cleared the channels of “tainted” product and hurriedly began producing replacement units. For their part, commercial pool and spa owners across the country had to make split-second decisions on whether to shutter their most popular attractions — kiddie pools and shallow-water features — or keep them open and fly in the face of the CPSC’s directive.

Behind the scenes, plenty of finger-pointing took place, with culprits ranging from the testing laboratories where covers were certified, to the standard governing the products’ design, to the CPSC itself, whose officials oversaw the timing of the initial requirements as well as the recall.

Getting beyond the controversy to examine the actual workings of drain covers is no small feat.

Nevertheless, it’s critically important that industry professionals understand what these products do, the standard and testing regulations governing them, and where discrepancies exist.

Not-so-simple science

Although basic in appearance, a properly engineered drain cover is the result of considerable research and design expertise.

Despite the nomenclature, pool and spa drains don’t utilize the same principles as their sink and tub counterparts. Rather than permanently ushering water from the vessels via gravity, they function in a closed, pressurized circulation system in which water is pulled from the vessel by a pump for recirculation. Because of this distinction, many engineers use the more technically accurate term “suction outlet.”

Most outlets consist of a sump — a hole in the pool or spa shell containing the open end of the pipe leading to the pump — which is then capped by the drain cover, or “suction outlet fitting.” This last element has assumed a crucial role in mitigating suction entrapment, the sometimes deadly phenomenon that occurs when an outlet is blocked, water is no longer fed into the pipe, and a powerful vacuum forms, pinning down whatever is causing the blockage. A different type of entrapment results when hair, limbs or objects connected to an individual find their way in the outlet and become stuck.

The cover acts as the first line of defense against entrapment, creating a physical barrier between human and sump and incorporating design characteristics meant to resist the various forms of entrapment. To date, there have been no entrapments occurring on drain covers that meet current standards.

Preventing such incidents is a complex task, as the five types of entrapment are caused by slightly different combinations of proximity, access and suction. (See sidebar.) To accomplish this goal, manufacturers must address several aspects of the product’s design.

A Acceptable flow

It was this issue that led to the CPSC recall. Based on results from several tests, third-party laboratories determine the maximum rate, in gallons per minute, at which water can move through the outlet cover without creating an entrapment hazard. This poses a balancing act: While lower flow rates mean safer drains, higher rates are often needed to provide power for features such as waterfalls and spa jets.

B Hole size/configuration

In concert with appropriate flow rates, properly designed openings help prevent fingers, jewelry, bathing suit strings and even hair from entering and becoming affixed to internal hardware. Some manufacturers include patented design features such as tiny tubes that will help displace suction or larger slots that taper down to a small hole serving as a diffuser of suction. Hole placement also can help prevent body entrapment: Some manufacturers configure them in staggered patterns that may allow a victim to “peel off” by dislodging the vacuum in a single hole. Others position the openings on different planes so it’s unlikely that they can all be covered simultaneously.

C Dome effect

Before entrapment prevention factored into the design of drain covers, most units sat flush against the floor or wall, potentially enabling the larger planes of a human body — back, side or abdomen — to block the entire cover and form a seal. Today, drain covers that are 18-by-23 inches or smaller feature a domed shape or raised design that holds the swimmer away from the pool floor or wall, thus helping to prevent a seal from developing. To reduce tripping or toe-stubbing hazards, these covers sit no more than 2 inches above the pool or spa shell.

D Sump depth specifications

To avoid hair entrapment, flow should be dispersed as evenly as possible over the area of the suction outlet cover, rather than concentrated directly above the pipe. To this end, manufacturers specify a minimum distance between the outlet cover and the pipe’s opening below it, often affecting sump depth or doming height. (Some drain covers meant for spas can function without a sump by incorporating internal flow channels.)

E Materials, hardware

The products must be strong enough to withstand abuse and sun exposure without deforming, cracking or becoming unattached. This is addressed by certain tests for wear, including ultraviolet, mechanical, strength and impact resistance protocols, and minimum criteria for attaching screws.

Regulatory measures

The increasing emphasis placed on suction outlet covers — and the road to this year’s recall — largely began in late 2007 with the passage of the Virginia Graeme Baker Pool and Spa Safety Act.

The federal law’s requirements stated that, within a year, all commercial pools, spas and waterfeatures were to be fitted with certified suction outlet covers. Additionally, only compliant fittings could be entered into commerce after Dec. 19, 2008.

To become certified, a drain cover must undergo third-party testing to determine whether it meets a set of design specifications and performance parameters to ensure entrapment resistance. The certification standard named in the VGB Act — ASME/ANSI A112.19.8-2007 — lies at the heart of the recall. It was replaced last month by ANSI/APSP-16.

The standard came under fire in 2010  amid allegations of misconduct in the testing methods. Broadcast network ABC and the Chicago Tribune publicized the issue, and Senator Dick Durbin (D-Ill.) called for action, prompting the CPSC to launch an investigation. It was then revealed that some product readings were off by as much as 35 percent, with one extreme case seeing a variance of more than 600 percent.

Inconsistencies were found in all three testing labs, but officials with the facilities claimed the standard’s language was too vague. Some accused the International Association of Plumbing and Mechanical Officials (IAPMO) — the lab with the most variances in results — of purposely conducting tests to meet the letter of the standard while violating its spirit, so that the lab could market higher flow ratings. IAPMO denied these accusations and others maintained that, even if the lab had such intentions, such malfeasance wouldn’t have been possible if the standard were more specific. The standard writers concurred and began a rewrite to fill in the gaps.

The rating discrepancies that led to the recall involved two historically controversial areas: the body-block and hair-entrapment tests. 

Body block test

Added in 2007, this test was devised to simulate a body entrapment, thereby gauging a drain cover’s ability to prevent the phenomenon, even when installed in a single-outlet configuration without a backup anti-entrapment device.

The suction outlet cover is mounted onto a backing plate meant to replicate the floor or wall of a pool, and a pump is activated to achieve the maximum flow for which the cover is rated. Key to this process is the “body-blocking element,” a form made of plywood and foam meant to represent the area between the shoulders and hips of a large adult male. The technician uses an air cylinder to thrust the body-blocking element onto the drain with 120 pounds of force, approximating the downward pressure of a 240-lb. man lying, with minimal buoyancy, on the outlet cover in a wading pool. This sizable pressure compacts the foam on the blocking element, forcing it to conform to the drain cover, even if the unit is domed the full 2 inches.

The technician then reverses the air cylinder to pull the blocking element from the drain, measuring the amount of force required to do so. For the suction outlet cover to meet the standard, the force required to remove the blocking element cannot surpass the maximum allowed for drains of its size. When testing an 8-inch drain cover, for example, the body-blocking element must be removed with 15 lbs. of pull or less, to correlate with the amount of strength reasonably expected of a small child. This allowance increases with the size of the drain cover, following the logic that the larger the drain, the more sizeable — and, presumably, stronger — the person would have to be to block it.

At the end of the day, most of the problems leading to the recall centered on the body-blocking test. Some labs conducted the procedure using a variable-speed pump set on low, which could generate the necessary flow but would not achieve the vacuum pressure seen in most real-world applications, since this configuration is still relatively rare. The affinity law that causes variable-speed pumps to be so appealing actually worked against the objectives of the body-block test: A pump run at half speed only generates a quarter of the pressure, which means in theory it could only produce one-fourth the vacuum.

The practice of setting the pumps on a low speed allowed drain covers to be awarded higher flow ratings artificially, since not enough negative pressure was created to accurately assess them. Pool and spa pumps can produce up to about 26 inches of mercury, enough for the unit to self-prime when placed as high as 10 feet above water level, as is historically required for pump certification. However, a variable-speed pump set on low speed only generates a few inches of mercury — not enough to provide real-world ratings of suction outlet covers.

Today, the CPSC stipulates that pumps be operated at a speed capable of producing 26 inches of mercury during testing, and this language is being included in the new version of ANSI/APSP-16.

The second problem with the body-blocking test arose from the artificial human form, or “element.” Members of the standard-writing committee stated an intent for an 18-by-23-inch element to be utilized, no matter the size of the outlet, in order to represent an adult male in the 99th percentile. However, some testing labs employed a variety of sizes, taking their cues from comments made at a meeting regarding the standard, and from a reference chart pertaining to another aspect of the test. In addition, though the standard stated that the body-blocking element should be positioned in a specific manner, some laboratory technicians didn’t follow this instruction to the letter. One tech might hold the form horizontally while another situated it vertically, resulting in different readings.

The upcoming revision of the standard will stipulate all methodology in great detail so as to achieve consistent results.

Finally, at least one lab was known to have performed the body-block test by affixing drain covers to a sump at the end of a suspended pipe, a scenario that’s virtually impossible in a real-world setting, since suction outlets are always found within a pool wall or floor. Without a flat surface surrounding the opening, it becomes significantly more difficult for the body-blocking element to form a seal. For the past few years, the drain-cover standard has required a simulated pool floor backing plate be used. The CPSC specified that this happen during the retesting that led to the recall, and the new code is being changed to make that language clearer and more specific.

Hair test

The 1987 version of the drain-cover standard called for a test in which a ponytail was placed over a drain to see at what flow rate it would get tangled and/or entrapped by suction. In 2007, it became apparent that the ponytail test was insufficient, since a swimmer’s hair wouldn’t always be tied. A second procedure, the full-head-of-hair test, was added.

These two procedures address different aspects of the way hair strands interact with a drain. A full head of hair can become tangled within the holes on the cover, whereas a ponytail, which has fewer strands, can descend into the openings more easily, and wrap around screw posts.

The wig is made with natural, fine, European blonde hair, which is the easiest to tangle. The ponytail contains human hair that is medium to fine, straight and light brown. The hair is placed on the drain and moved from side to side, with the ends of the strands fed into the fitting for 60 seconds. The technician then holds the base of the wig or ponytail directly against the fitting for an additional 30 seconds, then releases the hair and allows it to float for approximately 30 seconds more. The hair is finally disengaged, and the tech measures how much force is required to extricate it. If the number is more than 5 lbs., the drain fails. It’s important to note that if even one or two hairs become snarled, it may require a minimum of 10 lbs. to remove them.

Hair entanglement has been the most challenging type of entrapment to test, and these protocols have yielded inconsistent results, placing them on the CPSC’s radar. Hair is an unpredictable material and generally won’t replicate the same pattern from test to test. Additionally, the standard, once again, proved to be vague regarding the procedure. Technicians weren’t informed exactly how to position the ponytail or wig: One might hold it in the center, another near a corner, without taking into account where the drain might be pulling water most forcefully. The 2007 version added a pull mechanism, often an air cylinder, which is notorious for causing stiction — a jerky action that changes the speed and force applied during the test. Additionally, the gauges were analog rather than digital, allowing technicians to read them differently, with some rounding up and others down.

The alterations to the standard will likely specify where to hold the wig or ponytail. In addition, technicians will be required to suspend the hair over the outlet cover with an apparatus that utilizes frictionless pulleys and a 5-lb. weight, in order to eliminate stiction from the equation. The standards writers also hope this change will remove the inaccuracy and vagueness of the gauges that had been used. Technicians perform the test with water flowing at progressively higher rates until the drain cover fails. The last flow rate to pass then becomes the maximum rate allowed.

The revised standard is expected in the coming months, however the labs may perform round-robin testing before these changes are released.

Time Lapse

Pool & Spa News would like to thank the following experts for their contributions to this report: Steve Barnes, Pentair Water Pool and Spa; Dominick Conn, Paramount Pool & Spa Systems; Brooks Hilton, Waterway Plastics; Mike Huppert, Hayward Pool Products; Alison Osinski, Aquatic Consulting Services; David Peterson, Watershape Consulting; Bill Rowley, Rowley International; Ron Schroader, Drainsafe/New Water Solutions; and Leif Zars, Gary Pools.