The Pendulum Method for Pedestrian Slip Resistance Testing
The 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 method and its accompanying safety standards (based on accidents on those walking surfaces) is the national standard in a number of countries and has been endorsed by Ceramic Tile Institute of America since 2001.
The pendulum 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 (available from Safety Direct America in pdf format) 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, New Zealand, Singapore, and other countries that follow British law, and has been in use continuously 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 (2003) and safety standards for pedestrian traction are specified by the United Kingdom Slip Resistance Group in their 2005 publication, The Assessment of Floor Slip Resistance The UK Slip Resistance Group Guidelines (Issue 3). 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:
1. Developed in the USA by the U.S. National Bureau of Standards
2. Specified by ASTM E 303 for decades, with precision data included
in the ASTM standard
3. Validation [bias] study of 3500 test results over 25 years, accepted by many
government agencies internationally, and other published studies
4. In continuous use for assessing pedestrian slip resistance since 1971
5. International acceptance in courts of law
Other ASTM test methods for wet slip resistance are obsolete and include no safety standards. ASTM withdrew their static coefficient of friction method C 1028 in 2005. The ASTM methods specifying the English XL and Brungraber Mark II tribometers will be withdrawn by ASTM in September 2006. The United States Occupational Health and Safety Administration (OSHA) in 2006 revoked its safety standard based on the English XL and Brungraber Mark II tribometers due to lack of validation of these test methods.