“It’s just a piece of plastic. How hard can it be to comply with VGB?”
A friend asked this question during the chaotic rollout of the Virginia Graeme Baker Pool and Spa Safety Act, and I nearly fell out of my chair. He had no idea — not yet. He is a successful engineer designing sophisticated pool equipment, so to him a drain cover was little more than a piece of plastic and two screws. This was in the spring of 2008, when drain cover manufacturers and test labs were working 24/7 to meet the impossible timeline set by the U.S. Congress.
As the drain-cover standard is being updated, it is becoming increasingly the case that VGB Act compliance requires more than certified pieces of plastic held in place by two screws. It takes the proper pairing of product with the hydraulic system and sump structure. Currently, the law states that all drain covers sold in the U.S. must be third-party tested and certified as compliant. But the drain-cover standard named in the VGB Act is being rewritten and is expected to require that, in addition to being compliant out of the box, drain covers must be installed to manufacturer specifications for it to comply in the pool.
Plasterers play a crucial role in ensuring that pools and spas remain safe and VGB-compliant after renovations. With just a few steps, this can be achieved easily.
Today the core aspects of VGB are fairly common knowledge.
It is well understood that VGB requires putting drain covers through rigorous, third-party testing before they can be certified as complying with the federal pool and spa safety law. Most also know that drain covers must be rated to accommodate flows higher than the pumping system will generate. And pools with only one blockable drain need a secondary device or system designed to prevent suction entrapment, such as gravity drain systems or safety vacuum release systems.
But because drain covers look deceptively simple, even to experienced pool professionals, we keep seeing some errors in the field. For instance, small, blockable drain covers meant for lower flows sometimes are installed in systems with modern, high-powered pumps. What especially scares me is the disconnect that seems to occur when a powerful, variable-speed pump is sold with incompatible VGB drain covers.
Most variable-speed pumps have the capability to move more than 140 gallons per minute on pools built to modern pool standards. Think about the millions of pools built since the mid-1990s: They have spas that spill over and contain powerful therapy jets, or waterfeatures and, the granddaddy of them all, vanishing edges. Generally speaking, these require very high flow rates. Additionally, any pool with multiple return-line valves also carries the potential for extra high flow, because those valves are begging to be turned by unsuspecting pool owners, visitors or children who don’t realize they’ve opened the flood gates.
For this reason, properly replacing a drain cover involves more than choosing just anything with a VGB stamp. Instead, the model must be suitable for the specific pool being plastered or replastered. That also means that, if there’s a variable-speed pump, the drain must be rated to accommodate the pump’s highest possible flow — not the rate at which it is expected to run most of the time.
The all-too-frequent failure to do this is what I call the compliance gap. To avoid this, consider who is selecting your project’s drain covers. If not you, who are you trusting with your customers’ safety? This is the compliance gap we need to plug immediately.
STEPS TO SAFETY
Assuring compliance on existing pools and spas can be particularly challenging for plasterers, who likely don’t know how each project was built and plumbed during original construction.
But plasterers can take some steps to help them choose the right drain cover. First, looking up the pump manufacturer’s published performance curve for the particular model is an effective way to find the potential flow. Once that is known, a drain cover with a higher flow rating can be selected.
But that doesn’t cover all the bases. In addition to flow rating, sump depth presents another compatibility issue.
The space between the drain cover and the suction pipe opening that feeds the pump is referred to as the sump. This can be formed out of stainless steel, molded plastic or even concrete, which is called a field-built sump in the drain cover standard. Regardless of how the sump is formed, the depth of this opening is important to know, because most drain cover manufacturers specify a minimum sump depth for their products to be safe. And while the VGB Act does not stipulate minimum sump depth, it does require adherence to the manufacturer’s specifications.
We commonly see minimum clearance requirements of 3 inches, while larger drain-cover installation instructions often mandate that the clearance be equal to 1½ times the suction pipe’s diameter. Some manufacturers will add another specification — a minimum depth around the edge of the sump, by the drain-cover frame.
Some covers don’t require any clearance, the best example being manufactured spa bulkhead fittings where the drain cover attaches directly to the suction pipe fitting. This concept is not limited to bulkhead fittings — many retrofit drains are suitable for installation on zero-depth sumps.
The sump-depth requirement is important to understand and follow, because water moving between the cover and the pipe can cause hair to twist and tangle, which is why flow ratings are determined through third-party testing. Drain cover flow ratings are largely driven by how hair enters the suction pipe after passing through the cover. If a cover is designed for a 2-inch clearance and is then installed directly over an open pipe, hair and water will be concentrated within too tight an opening, causing a potential hair-entrapment hazard.
Most drains must stick up from the floor to make it harder for a body to completely block them and form a seal. (Although a seal is still possible, which is why we need more than one blockable drain for all new construction.) This is why it is common for drain covers to come with what is called a riser ring, which raises the cover up from the floor.
Regardless of how many blockable drains are installed, the riser rings must always be used as instructed by the manufacturer.
Achieving verifiable VGB compliance is more complicated than it appears, and it doesn’t begin and end with the drain cover manufacturer and installer.
Everyone in the pipeline must speak up and help. The first line of defense will always be the person with the screwdriver, but that can be anyone. Those who install drain covers should look at the requirements for each pool and not just select VGB Act covers based on color, style and price.
Closing the compliance gap begins by asking the right questions and providing compatible drains for the pumps and sumps in a specific installation. PSN
Steve Barnes is the director of science and compliance with AquaStar Pool Products in San Diego. He also is chairman of the APSP Technical Committee, overseeing the organization’s various standard-writing committees. He has held that post for 12 years and been involved with the drain cover standard since 2002. His earlier experience included drain-cover design.