 |
 |
 |
The Virginia Graeme Baker Pool and Spa Safety Act, which established national pool drain safety requirements, was enacted by Congress and the President in December 2007. The act requires that all public pools in the United States must have safety drain covers meeting the ASME/ANSI A112.19.8-2007 standard and that single-drain pools must be provided with a secondary means of preventing bather entrapment. Pools not in compliance by Dec. 19, 2008, must close until brought into compliance. Although the Act is a federal law, enforcement under the U.S. Consumer Product Safety Commission has been left largely to the states.
To make the new standards enforceable at the state level, amendments to the North Carolina Rules Governing Public Swimming Pools have been adopted by the Commission for Public Health. that make compliance with the ASME/ANSI A112.19.8-2007 standard mandatory for all public swimming pools in North Carolina. The amendments further require that pool owners provide documentation of compliance with three key components of the standard. Pools that fail to provide proof of compliance by May 1, 2010 will be required to close until compliance has been documented.
While the federal law seems simple, the drain safety standard is quite complex and difficult to understand. All public pools must comply fully with the standard, but North Carolina’s enforcement will focus on documentation of three key requirements in the standard:
See the Pool Drain Safety Compliance Flow Chart
Usually compliance is documented through an engineering study by a pool contractor or consulting engineer, but the rules do allow pool owners capable of providing the necessary information to document compliance for their pools. The following sections will lead you through the types of information needed to document compliance.
Step 1: Document the Maximum Pump Flow
Since the pitot tube flow meters typically installed on public swimming pools become unreliable with age and may give readings lower than the actual flow, the Rules Governing Public Swimming Pools (PDF, 826 KB) require the maximum flow to be based on the manufacturer’s performance specifications for the pool pump. You will need the name of the pump manufacturer and model number from the data tag on the pump to find the right performance specifications.
Pump performance specifications are available from pool product distributors and many are available on the pump manufacturers’ Web sites. To save you some time, the Division of Environmental Health has prepared a list with the maximum flow for hundreds of commonly used pool pumps. If you can find your pump on the list, print the page and highlight the information for your pump. Enter the pump information on the Drain Safety Compliance Data Sheet.
If your pump is not on the list, you will need to obtain the manufacturer’s pump performance specifications. Pump performance is shown on a graph as a curve. A line drawn straight down the graph at the far right end of the curve will give the maximum amount of water the pump is capable of pumping. If you cannot identify the model of the pump or find the manufacturer’s specifications, the maximum pump system flow will need to be measured using a magnetic flow meter.
Step 2: Document the Size of the Drain Sump(s)
This step usually requires draining the pool or using scuba equipment unless the pool is very shallow. Measurements will be needed to determine the size of cover/grate and to assure the sump is deep enough and wide enough to meet the requirements in the cover/grate manufacturer’s specifications. The diameter of the pipe leaving the sump to the pump must be measured. If you have the original plans for the pool with sump model numbers, you may be able to look up the sump manufacturer’s specifications for these measurements. Photographs of the drain sumps can help provide supporting documentation.
Generally cover/grates are tested and approved for sumps meeting the requirements in Figure 2 in the ASME/ANSI A112.19.8-2007 standard which requires the top (inside) of the outlet pipe to be at least one and one-half pipe diameters below the bottom of the Cover/grate and a clearance of at least one pipe diameter must be provided under all parts of the cover/grate. Check the condition of the sump and frame to assure a new cover can be securely fastened to the frame. Document the sump dimensions on the Drain Safety Compliance Data Sheet.
If your drain has no sump or the sump is too small to meet the separation requirement in Figure 2, you will need to select a cover/grate that has been tested and approved for installation on a shallower sump or without a sump. A “sumpless” drain such as the Paramount SDX Retro, Neptune-Benson Aegis Shield or Bee Safe drain may be an appropriate choice. Another option is to enlarge the drain sump to meet the dimensional requirements.
Verify that multiple drains are separated by at least 3 feet measured on centers. The standard requires all cover/grate manufacturers to specify that at least a 3-feet separation be provided between drains or that drains closer than 3 feet apart must be located on separate planes such as one on the floor and one on the wall. The U.S. Consumer Product Safety Commission has indicated that drains closer than 3 feet apart are considered a single drain, so it is not necessary to move existing drains as long as a secondary method of preventing bather entrapment (PDF, 40 KB) is provided on the pumping system.
Step 3: Select an Approved Cover/Grate
Now that you know the maximum pump flow and the size of cover/grate that will fit your sump, you must find a cover grate that will fit the sump and safely handle the pump flow with one drain completely blocked. For one and two-drain pumping systems, this means each cover/grate must be rated to handle more water than the pump can pump. The Environmental Health Section has prepared a table of approved cover/grates to help you with this selection.
Download Table of Approved Cover/Grates
If you find an approved cover/grate that will fit your drain sump and is rated above the maximum pump flow for your pump, installing the new covers in accordance with the manufacturer’s instructions (PDF, 12 KB) should bring your drains into compliance. Check the manufacturer’s installation instructions before you purchase cover/grates because some limitations such as covers approved for bottom-only use or use only on multiple drains may apply. Save the manufacturer’s certificate of compliance and installation instructions that should be packaged with the cover/grate to prove your drains are in compliance. The new cover/grates will have an expiration period by which the cover/grates must be replaced with new covers. Make a note of that for your records.
If none of the cover/grates that fit your drain sump(s) will handle the maximum flow of the pump, you can:
Documenting Flow Reduction (if needed)
The actual flow rate through the pumping system will be less than the maximum flow for the pump because of flow losses due to friction as water flows through pipes, fittings, valves, filters and heaters. This friction loss can be measured or calculated as head loss expressed as feet of head. Having an engineer to calculate the head loss or a pool contractor to measure the total dynamic head loss and establish the reduced flow for the pumping system may improve the selection of cover/grates that can be used.
Alternatively the maximum flow for the pumping system can be measured using a magnetic flow meter with all recirculation valves fully opened and with a clean filter, strainer and skimmer baskets. Flow measurements should be witnessed by the local health department or attested to by a third party such as an engineer or pool contractor. There are also pre-set flow-limiting valves that will limit flow through a pipe to a certain level. If only a slight flow reduction is necessary and the turnover rate requirements for the pool can be met, installing a flow-limiting valve may be an option to improve the selection of cover/grates that can be used.
Step 4: Don't Forget Skimmer Equalizers
The U.S. Consumer Product Safety Commission has ruled that the skimmer equalizer tubes, usually located beneath the skimmer openings, are submerged suction outlets and must be covered with cover/grates meeting ASME/ANSI A112.19.8-2007. The standard does not speak specifically about skimmer equalizers.
Another suction outlet safety standard, ANSI/APSP-7, which applies to all new construction, states that a skimmer equalizer shall be protected by a listed suction outlet cover/grate with a flow rating equal to the maximum system flow divided by the number of skimmers when piped through a common suction line, or the maximum flow rating of the skimmer (usually 55 or 75 gallons per minute), whichever is greater. The Environmental Health Section requires that skimmer equalizers comply with ANSI/APSP-7.
Additional Requirement for Single-Drain Pumping Systems
Both the Virginia Graeme Baker Pool and Spa Safety Act and the amended N.C, Rules Governing Public Swimming Pools require that pumping systems that have a single main drain, other than an unblockable drain, must have a secondary method of preventing bather entrapment (PDF, 40 KB). If your pool pumping system draws from a single drain that has not been certified as unblockable or multiple drains located closer than 3 feet apart, you must provide one of the following secondary means of preventing bather entrapment:
All single-drain public swimming pools in North Carolina were required to install safety vacuum release systems in 2004. If you complied with that requirement, you already have the required secondary means of preventing bather entrapment.
Updated: August 1, 2019