Clockwise left to right: Energy efficiency testing of a pump; Notched impact testing machine (used for testing the strength of plastic material); Pump curve development and testing; Calculation of tensile strength and load testing (calculation is used to determine the testing strength of products and plastics)

If a pool is like a human body, then the pump is like the heart. The pump provides the power necessary to circulate water through the skimmers, suctions fittings and piping for proper treatment such as filtration, disinfection, and heating. The health of the pool is critically dependent upon the pump to carry away contaminants for processing and return sanitized water.

To verify that pumps are able to perform this critical role to national public health standards, NSF International provides technical evaluation, claims validation, testing, and certification of pumps to meet the needs of swimmers, facility designers, operators, public officials, and manufacturers.

Since 1960, NSF International has certified over 1,800 pumps to the American national standard for recreational water equipment — NSF/ANSI Standard 50. NSF Certification of pumps involves a series of mandatory and optional criteria to verify if manufacturer claims are accurate, or in need of modification prior to NSF Certification to NSF/ANSI Standard 50. Here’s a closer look at those requirements.

Confirm pump models/designs and project work scope:When NSF begins work with a pump manufacturer we review market goals (regions, functions, energy efficiency, electrical safety, etc.) and product designs and claims (models, self-priming, SVRS, sound emission, etc.) to develop the work scope and project cost. Some manufacturers begin with the minimum required work to enter the market, then, at a later date, add additional layers of evaluations, testing, and services to further their market penetration.

Identification of parts list and supplier disclosure to NSF:NSF project managers work with the manufacturer to assemble the parts list noting part numbers, material types, surface area, and suppliers of the many pump, strainer, and motor components. This information is used to document the testing plan and helps prepare for the production facility inspection.

Corrosion resistance and materials health safety:For the components of the pump that come into contact with water, NSF staff members evaluate the materials for both corrosion resistance and material health safety. Some alloy materials are considered to have sufficient corrosion resistance otherwise, protective coatings or cathodic protection is required. For health effects testing, NSF toxicologists will determine the parts and materials that require further review and/or testing in accordance with NSF-50 Annex A. Annex A provides guidance on the types of tests to be performed, including test methods, exposure water and temperature scenarios, dosing rate and duration. These tests are designed to mimic real life use to ensure the materials that make up the pump do not introduce any unacceptable levels of contaminants into the water.

Evaluation and testing for design and construction:NSF engineers evaluate design, marking, claims, and use conditions. Design aspects include drain plugs, shaft seals, access to moving parts, replacement parts, installation, use and maintenance instructions and required marking on the pump, strainer, and motor data plates.

Strainer system evaluation and testing:Most pumps come with an integrated strainer, but some have a detachable strainer, and some require the installer to source a strainer separately. Therefore, NSF tests and certifies strainers as a stand-alone product or as a system with the pump and motor. Strainers are evaluated for the corrosion resistance and health effects noted above as well as strainer dimensions, minimum open area, and volume, pressure testing and safety, pressure/head loss, installation, use and maintenance instructions and data plate marking.

Hydrostatic pressure safety:Pumps generate pressure in the pool/spa piping system, but they can also be damaged by pressure. NSF testing challenges the pump to 150 percent of its working pressure to safeguard against damage to the pump. NSF is able to test at flows up to 6,000 gpm via our many test tanks and hydraulic rigs.

Pump performance curve:System flow rate is one of the most important technical aspects of safe pool and spa operation. NSF tests pumps to determine water flow rate under a variety of conditions of resistance or system back pressure. This testing provides critical information of flow rate and total dynamic head, which are needed to properly size and operate the system. This information is essential to commercial and residential pool designers and installers, public health officials and end users, helping them select a pump that will provide sufficient pressure and flow.

Self-priming capacity:Some pumps are designed for flooded suction or low lift performance (e.g. the pump is below the water line). However, many pump installations call for the ability to draw water up into the pump. NSF’s pump self-priming test verifies if the pump can self-prime and to what height, helping users verify if the pump can sufficiently lift or suction water and assist in meeting proper pressure and flow.

Energy efficiency testing: Some local utility companies provide rebates to users that install pumps that have been tested as meeting certain energy efficiency guidelines. NSF provides this testing service upon request to meet local and regional energy efficiency requirements such as California Energy Commission and others.

Electrical safety testing: As an Occupational Safety and Health Administration (OSHA)-accredited testing lab, NSF provides electrical safety testing and certification of pumps.  Many jurisdictions require pumps be certified to UL1081 for electrical safety.

Sound emission testing:Some jurisdictions and home owner associations have weighted scale A decibel ratings and requirements. However, they are highly variable in testing setup and methods. Manufacturers and homeowners need a trustworthy and consistent arbiter.  NSF-50 Requirements are being created to standardize testing and evaluation criteria to quantify pump sound emissions. This will provide the infrastructure needed to standardize this requirement.

Safety vacuum release/limiting systems (SVRS/SVLS):The Virginia Graeme Baker Pool and Spa Safety Act (VGBPSSA) requires anti-entrapment products for pool and spa facilities. NSF meets this demand by offering accredited testing and certification to ASTM F2387 and ASME A.112.19.17 SVRS product standards as well as SVLS requirements. 

Variable Frequency Drive and Flow Rate Accuracy VFD/VSD:Some pumps include hardware and software that enable the user to decrease pump speed, which allows users to reduce flow rate and energy usage. However, knowing the flow rate is challenging when the pump’s motor changes frequency and speed, making it difficult to comply with minimum water turn-over rates. NSF can provide tested and verified flow rates that correlate to pump motor rpm (revolutions per minute), speed, and frequency. This provides users more control over flow rate and energy usage without introducing suction and filtration safety issues. The NSF-50 test methods and requirements for this testing and certification are under development.