PRESSURE WASHER PERFORMANCE
Consumers use pressure washers for cleaning exterior surfaces such as decks, driveways, concrete floors, siding, fences, cars, boats, RVs, etc. To ensure the proper selection of a pressure washer, consumers need to understand pressure washer performance.
A pressure washer’s performance is rated by pounds per square inch or PSI, and gallons per minute or GPM. PSI measures pressure and GPM measures flow rate. A pressure washer’s PSI rating is the maximum amount of force (pressure) developed by the pressure washer. A pressure washer’s GPM rating refers to the water flow during one minute of operation. The higher the PSI and GPM, the more cleaning power available and the more articles that can be cleaned.
PW101, Standard for Testing and Rating Performance of Pressure Washers: Determination of Pressure and Water Flow provides for a uniform method of testing and rating the pressure and water flow of pressure washers. The standard applies to pressure washers intended for the household, farm, consumer, or commercial/industrial markets.
PWMA members and other pressure washer manufacturers test their pressure washers in accordance with PW101. By testing pressure washers to PW101, manufacturers can determine the performance of the pressure washer (PSI and GPM).
The following highlights the key testing parameters as prescribed in PW101:
Third-Party Certification Program
Annually, the third party Program Administrator, Intertek, randomly selects pressure washers for testing. A program participant provides Intertek with a list of all their production models of pressure washers. Intertek then purchases the pressure washers from an outlet (e.g., internet, retailer) that sells the pressure washers. These units are tested to verify that they meet the program participants’ certified published performance ratings.
Intertek conducts the testing as prescribed in PW101. Each program participant is required to have at least two models tested; however, it could be three models (one gas unit, one electric unit, one battery-operated). Three sample units of each model is tested so a minimum of six pressure washers are tested.
Intertek provides the program participants and the PWMA office with the test results. If the test models pass the testing performed by Intertek, the program participants can use the PWMA certification seal on their web site, products and product literature. If the tests reveal that the pressure washers do not meet the advertised performance ratings, the program participant is required to re-rate the pressure washers and change all advertisements to reflect the accurate performance ratings.
PWMA members are required to use a third-party certification program using an independent laboratory to conduct testing to evaluate performance in accordance with an industry standard. Pressure washer manufacturers whom are members of other trade associations may use self-certified products which are tested by the manufacturer using testing methods that they deem appropriate.
There are many brands of pressure washers to choose from in the market so consumers need to be educated on pressure washer performance. Advertised PSI and GPM ratings for pressure washers can be misleading. Consumers who purchase pressure washers with a PWMA certification mark on the packaging can be assured that the pressure washer will deliver the psi and gpm that is advertised.
For information on PW101, the certification, selection guidelines, maintenance tips, visit www.pwma.org.