It was May 2011, and the pool season was about to begin.
Aquatics facility operators across the country were in high gear,
preparing to open seasonal pools 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 1 million suction
outlet covers sold by 10 manufacturers, all of which had been
installed within the past 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
“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
The news threw the industry into chaos: Pool managers and service
technicians tried frantically to accommodate the massive recall,
while manufacturers and distributors cleared the channels of
“tainted” product and hurriedly began producing
Across the country, many pool operators 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.
One year later, an update to the language that governs drain-cover
production is in the works. In the meantime, test labs follow CPSC
requirements that supplement the drain-cover standard. But getting
beyond the controversy to examine the actual workings of drain
covers is still no small feat.
Nevertheless, it’s critically important that industry
professionals understand what these products do, the current
standard and testing regulations governing them, and where
Though 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 out, via gravity, a pool (or spa) drain
functions 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 suction 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. When this
happens, water is no longer fed into the pipe, and a powerful
vacuum forms, pinning down whatever is causing the blockage. Other
types of entrapment result when hair, limbs or objects connected to
an individual enter the outlet and become stuck.
The covers act 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. Compliant covers must
address the five types of
entrapment, each caused by slightly different combinations of
proximity, access and suction. To accomplish this goal,
manufacturers must attend to several aspects of the product’s
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 often are needed to provide power for features
such as waterfalls and spa jets.
BHole size /
In concert with appropriate flow rates, properly designed openings
help prevent fingers, jewelry 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
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.
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.)
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.
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
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. (Last year,
it was replaced by ANSI/APSP-16.)
The standard first came under fire in 2010 amid allegations of
misconduct in the testing. Broadcast network ABC and the
Chicago Tribune publicized the issue, and Sen. 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 of the labs approved to
conduct the testing required under ASME/ANSI A112.19.8-2007, but
lab officials claimed the standard’s language was too vague.
Some accused the International Association of Plumbing and Mechanical
Officials — 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
The standard writers concurred and began a rewrite to fill in the
gaps. That rewrite is currently in its final stages.
The rating discrepancies leading to the recall involved two
controversial areas: the body block and hair-entrapment
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 under review 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.
The 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-pound 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. To meet the standard, the force needed cannot surpass the
maximum allowed for drains of its size. For example, when testing
an 8-inch drain cover, the body-blocking element must be removed
with 15 pounds 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 sizable — and,
presumably, stronger — the person would have to be to block
Most of the problems leading to the recall centered on the
body-block 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 because this configuration is still
relatively rare. The affinity law that causes variable-speed pumps
to be so efficient 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 will be included in the forthcoming version of
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 used, no matter the size of the outlet, to represent
an adult male in the 99th percentile of size.
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 states 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, another
vertically, resulting in different readings.
The upcoming version of ANSI/APSP-16 is expected to
stipulate the methodology in more detail to achieve consistent
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
pool walls or floors. 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 to be used. The CPSC specified that this happen during the
retesting that led to the recall, and the upcoming standard will
make that language clearer and more specific.
Hair entanglement has been the most challenging type of entrapment
to test for, and the protocols have yielded inconsistent results,
placing them on the CPSC’s radar.
The 1987 version of the ASME/ANSI 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 entangled and/or entrapped by suction.
In 2007, it became apparent that the ponytail test was insufficient
because a swimmer’s hair wouldn’t always be tied back.
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
entangled within the holes on the cover. 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 pounds, the drain fails.
It’s important to note that if even one or two hairs become
snarled, it may require a minimum of 10 pounds to remove
Developing effective hair-test methods has been difficult because
hair is an unpredictable material and generally won’t
replicate the same pattern from test to test.
Additionally, the standard, once again, proved vague. 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 standard stipulated use of 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.
The updated version of the standard likely will 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-pound weight, in order to
eliminate stiction from the equation. Standards writers hope this
change also will remove the inaccuracy and vagueness of the gauges
that had been used. Technicians must 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
Final revisions to the current standard are expected later this
These video captures show Steve Barnes,
product manager, safety and compliance with Pentair Aquatic Systems
and chairman of the APSP Technical Committee, trapping off on a
compliant 12-by-12-inch drain cover to study body entrapment. By
pushing himself down, Barnes was able to apply 95.8 pounds of
downward force onto the grate. He was able to release with 5.6
pounds of force. Tests such as this have confirmed that skin
behaves similarly to the body-blocking element, but it is slightly
more likely to adhere to the cover and easier to remove. Some hope
to find a closer match to human skin.
Editor’s Note: This article originally
appeared in Aquatic International’s sister
publication, Pool & Spa News, which would like to
thank the following experts for their contributions: Steve Barnes,
Pentair Aquatic Systems; 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