The Pendulum Method for Pedestrian Slip Resistance Testing
Contact Sotter Engineering Corporation at 949-582-0889 for field or laboratory British pendulum (or ASTM E 303) tests. Turnaround time for lab tests is normally two-three working days, and the charge for most samples is $230.00 per sample (a sample is one to three representative pieces of the same material). Field test charges are for time and expenses from southern California. We can also annually calibrate your British pendulum in our laboratory (see bottom of page for details).
The world’s best and most sophisticated safety standards and the test method to go with them are in Australian Standards HB198. There are situation-specific safety standards for Pendulum Test Value (PTV) for more than 27 specific situations. Recommended minimum wet PTV’s range from 12 (for dry areas) to 55 (swimming pool ramps and stairs leading to water.) We recommend using these standards to supplement the rudimentary minimum of 0.42 wet dynamic coefficient of friction in ANSI A137.1, incorporated by reference in the International Building Code. That minimum does not protect the building owner from liability, since it requires that the user consider numerous other factors. We recommend using HB198 to allow for those factors.
The British pendulum is the most accepted pedestrian slip resistance test method worldwide. The test is well-proven and long backed by an ASTM (American Society for Testing and Materials) standard that was validated in 1971 by 3500 test results on walking surfaces obtained over more than 25 years. The pendulum received the highest rating for correlation with human traction in a peer-reviewed published scientific study of 11 types of tribometers (friction meters) by the University of Southern California Medical Center.
The British pendulum method is the national standard for pedestrian slip resistance in at least 48 nations on four continents: Armenia, Austria, Australia, Azerbaijan, Belarus, Belgium, Bosnia-Herzegovina, Bulgaria, Cyprus, Czech Republic, Denmark, Dubai, Egypt, Estonia, Finland, France, Georgian Republic, Germany, Greece, Hungary, Iceland, Ireland, Israel, Italy, Latvia, Lithuania, Luxembourg, Macedonia, Malta, Moldova, Netherlands, New Zealand, Norway, Poland, Portugal, Romania, Russia, Serbia, Singapore, Slovakia, Slovenia, Spain, Sweden, Switzerland, Tunisia, Turkey, Ukraine and United Kingdom and has been endorsed by Ceramic Tile Institute of America since 2001. It is also used for indoor and (by ASTM Specification F 2157 – 09) outdoor sports surfaces.
The method for pedestrian slip testing is based on a slightly modified version of ASTM E 303, the British Pendulum method. Data on precision and bias relevant to human traction are available for that method. A precision statement is included in E 303. Some of the bias data are in an ASTM Publication: STP 1424, pp. 112-136. Greater London Council Bulletins 43 and 145 contain validating information dating from publication in 1971 and 1985. The safety criterion specified in those bulletins has become a standard in the United Kingdom, Australia, Dubai, Malta, New Zealand, Singapore, Spain, and other countries that follow British law, and has been in use continuously, with the same numerical safety criteria, since 1971.
Percy A. Sigler at the U.S. National Bureau of Standards developed the pendulum method specifically for assessment of pedestrian traction potential, publishing his results in 1948. Minor modifications to ASTM E 303-93 (2013) and safety standards for pedestrian traction are specified by the United Kingdom Slip Resistance Group in their 2011 publication “The Assessment of Floor Slip Resistance: The UK Slip Resistance Group Guidelines (Issue 4)”. This group (ukslipresistance.org.uk) has members in the UK, USA, and Australia who contributed to the fine-tuning of the guidelines based on experience with the method. Two members of the committee represent the British Governments Health and Safety Executive. One of these chairs the committee.
The pendulum test method and its safety standard have these advantages:
- Developed in the USA by the U.S. National Bureau of Standards
- Specified by ASTM E 303 for decades, with precision data included in the ASTM standard
- Validation [bias] study of 3500 test results over 25 years, accepted by many government agencies internationally, and other published studies
- In continuous use for assessing pedestrian slip resistance since 1971
- International acceptance in courts of law
Other ASTM test methods for wet slip resistance are obsolete and include no safety standards. See C1028.info for more information on the C1028-07 test method, which is NOT endorsed by the ADA and is not appropriate for assessing pedestrian slip risk.
British Pendulum Calibration
British pendulum calibration used to require sending your pendulum over to Europe for a few weeks. The pendulum needs to be calibrated annually, and we can calibrate your British pendulum here at Sotter Engineering in California. Please call (949)582-0889 or email for details concerning British pendulum calibration here in the United States. The price for pendulum calibration is $980.00, plus the cost of shipping to and from our lab (which can be done on your FedEx or UPS account, if requested). This price assumes we won’t need to replace any broken or missing parts on the pendulum. You should supply the pendulum to our lab with a valid slider installed.