Pendulum Slip Risk Assessments in the Workplace

Copyright (c) 2010 Ianson Internet Marketing

BS 7976: 1- 3 2002; "The Pendulum Method" describes the operation of the TRL (Transport Research Laboratory) Pendulum for slip resistance testing. Originally designed to replicate the actions of a slipping foot, the pendulum skid tester was subsequently adopted extensively for the testing of road surfaces. The BS 7976 pendulum slip testing method remains the only test method expressly recommended by the HSE. This is in part due to its extensive history in slip risk assessment and strong correlation to slip incidents. The pendulum slip test remains one of the few methods to accurately recreate the hydrodynamic squeeze film generated in a slip in wet conditions. Though the pendulum slip tester is somewhat awkward to use and requires an experienced operator it is considered the best method of pedestrian slip testing and is used extensively in legal proceedings. Operation The device swings a rubber slider mounted on a weighted 'foot' from horizontal, striking the floor surface near vertical and subsequently providing a reading as the foot swings back up. The dynamic coefficient of friction of the surface has a measurable effect on the Pendulum Test Value (PTV), previously known as the Slip Resistance Value (SRV). Prior to pendulum slip testing being conducted, full slider calibration is carried out. Sliders are initially prepared or 'faced' by swings over 400 grit sandpaper and lapping film, tests are then conducted on lapping film and float glass before results are compared against known values. In addition to check testing, before and after every direction/condition measured, the pendulum foot is swung 3 times without striking the surface. The zero can be adjusted as necessary and any discrepancy can be investigated. Once the pendulum slip tester is assembled, check tested, levelled and zeroed, testing can commence. The pendulum height is adjusted as necessary to ensure a slider contact length of 126±1mm along the floor surface. Tests of the floor surface are conducted parallel, at 45 degrees and perpendicular to the direction of foot traffic in dry and then contaminated conditions. The contaminant is often water; however it is advised that the contaminants likely to be found in normal use are used. In the past we have conducted tests with icing sugar, oil, MDF dust, mayonnaise, cement, flour, soap, ketchup, even chocolate. Sampling & Results 8 measurements are taken in each direction and each condition. The first 3 measurements of each run are discarded as the slider is mounted freely and requires adjustment. The average of the remaining 5 readings is calculated and an average dry and wet/contaminated result produced. The HSE classify risk of slip from 4S PTV as follows; 0-24 High (approx 5%) 25-35 Moderate (approx 0.5% to 0.005%) 36+ Low (approx 0.0001%) Sampling should be conducted across all surfaces of differing material, wear, cleaning regime or age. The BS 7976 standard states that "at least four tests should be carried out but in larger areas one test per 250m2 is appropriate". Sampling should identify areas of different slip resistance and provide evidence of uniform PTV's across similar areas. It should be noted that it is not as simple and straight forward as conducting BS 7976 pendulum testing and signing the floor off as a 'low risk of slip'. Many external factors can significantly affect the frictional demands of pedestrians using the surface. The HSE have developed a robust risk assessment method in the "Slips Potential Model" which should be used in conjunction with any slip resistance measurement.

Advantages The pendulum remains the only method expressly recommended by the HSE for slip resistance measurement. Factors contributing to its success are; An extensive history of correlation between PTV's and slip incident data. The method is widely accepted by experts as the most accurate method of measuring slip resistance in situ. The accurate modelling of the hydrodynamic squeeze film formed in a contaminated slip. This allows the method to take into account the hydraulic uplift effects which have a critical impact on slip resistance. Portability and versatility, the pendulum tester can be used to test discrete areas down to 126mm, slopes up to 10 degrees, stairs with a variety of dry and wet contaminants. Different rubber compounds can be used to represent the likely traffic types. Industry recognition means the pendulum method can be used for specification and certification of flooring surfaces as well as forensic investigation. Pendulum testing provides strong evidence that statutory obligations have, or have not, been fulfilled.

Disadvantages The pendulum is not used universally for the following reasons; Operation requires experienced technicians to obtain reliable results. Mistakes made by those with inadequate training can significantly affect results. The requirement for trained and experienced operatives means the method is often expensive. Purchase and upkeep of the pendulum tester is also very expensive. Testing takes around 30-45 minutes per sample due to the complex procedure. This is far longer than alternative, less accurate, test methods. Conclusion BS7976 pendulum testing remains the most accurate and most widely recognised measurement of slip resistance. Whilst relatively expensive in terms of time and money the method produces highly accurate results suitable for risk assessment, floor specification and certification and legal proceedings. Grip Potential is an independent consultancy providing pendulum slip testing as part of their holistic approach to slip risk assessment. Staff have extensive experience using the pendulum as a basis for risk assessment and can offer unbiased advice on risk mitigation measures. To arrange an assessment call 0845 163 0 163 or email info@grip-potential.com. Further information can be found on Grip Potential's website www.grip-potential.com and the HSE's slips mini site www.hse.gov.uk/slips. Additional info sheets available include BS 7976 The Pendulum Method and slip risk reduction tips.

Related Articles

• Make Money At Home - Business Ideas to Make Money At Home
• Easiest Way To Make Money - What Is The Easiest Way To Make Money?
• Kaizen - Solving a Mission Impossible in 3-5 Days
• Do We Really Need Corporate Speak?
• Are You Committed Or Interested In Growing Your Business?

HTML Ready Article. Click on the "Copy" button to copy into your clipboard.

<!DOCTYPE HTML PUBLIC '-//W3C//DTD HTML 4.01 Transitional//EN' 'http://www.w3.org/TR/html4/loose.dtd'><html><head><title>Articles Back Link | Pendulum Slip Risk Assessments in the Workplace</title></head><body><h3>Pendulum Slip Risk Assessments in the Workplace</h3><br><br> By: Louise G<br><br><p><p>Copyright (c) 2010 Ianson Internet Marketing</P><p>BS 7976: 1- 3 2002; "The Pendulum Method" describes the operation of the TRL (Transport Research Laboratory) Pendulum for slip resistance testing. Originally designed to replicate the actions of a slipping foot, the pendulum skid tester was subsequently adopted extensively for the testing of road surfaces. The BS 7976 pendulum slip testing method remains the only test method expressly recommended by the HSE. This is in part due to its extensive history in slip risk assessment and strong correlation to slip incidents. The pendulum slip test remains one of the few methods to accurately recreate the hydrodynamic squeeze film generated in a slip in wet conditions. Though the pendulum slip tester is somewhat awkward to use and requires an experienced operator it is considered the best method of pedestrian slip testing and is used extensively in legal proceedings. Operation The device swings a rubber slider mounted on a weighted 'foot' from horizontal, striking the floor surface near vertical and subsequently providing a reading as the foot swings back up. The dynamic coefficient of friction of the surface has a measurable effect on the Pendulum Test Value (PTV), previously known as the Slip Resistance Value (SRV). Prior to pendulum slip testing being conducted, full slider calibration is carried out. Sliders are initially prepared or 'faced' by swings over 400 grit sandpaper and lapping film, tests are then conducted on lapping film and float glass before results are compared against known values. In addition to check testing, before and after every direction/condition measured, the pendulum foot is swung 3 times without striking the surface. The zero can be adjusted as necessary and any discrepancy can be investigated. Once the pendulum slip tester is assembled, check tested, levelled and zeroed, testing can commence. The pendulum height is adjusted as necessary to ensure a slider contact length of 126±1mm along the floor surface. Tests of the floor surface are conducted parallel, at 45 degrees and perpendicular to the direction of foot traffic in dry and then contaminated conditions. The contaminant is often water; however it is advised that the contaminants likely to be found in normal use are used. In the past we have conducted tests with icing sugar, oil, MDF dust, mayonnaise, cement, flour, soap, ketchup, even chocolate. Sampling & Results 8 measurements are taken in each direction and each condition. The first 3 measurements of each run are discarded as the slider is mounted freely and requires adjustment. The average of the remaining 5 readings is calculated and an average dry and wet/contaminated result produced. The HSE classify risk of slip from 4S PTV as follows; 0-24 High (approx 5%) 25-35 Moderate (approx 0.5% to 0.005%) 36+ Low (approx 0.0001%) Sampling should be conducted across all surfaces of differing material, wear, cleaning regime or age. The BS 7976 standard states that "at least four tests should be carried out but in larger areas one test per 250m2 is appropriate". Sampling should identify areas of different slip resistance and provide evidence of uniform PTV's across similar areas. It should be noted that it is not as simple and straight forward as conducting BS 7976 pendulum testing and signing the floor off as a 'low risk of slip'. Many external factors can significantly affect the frictional demands of pedestrians using the surface. The HSE have developed a robust risk assessment method in the "Slips Potential Model" which should be used in conjunction with any slip resistance measurement.</P><p>Advantages The pendulum remains the only method expressly recommended by the HSE for slip resistance measurement. Factors contributing to its success are; An extensive history of correlation between PTV's and slip incident data. The method is widely accepted by experts as the most accurate method of measuring slip resistance in situ. The accurate modelling of the hydrodynamic squeeze film formed in a contaminated slip. This allows the method to take into account the hydraulic uplift effects which have a critical impact on slip resistance. Portability and versatility, the pendulum tester can be used to test discrete areas down to 126mm, slopes up to 10 degrees, stairs with a variety of dry and wet contaminants. Different rubber compounds can be used to represent the likely traffic types. Industry recognition means the pendulum method can be used for specification and certification of flooring surfaces as well as forensic investigation. Pendulum testing provides strong evidence that statutory obligations have, or have not, been fulfilled.</P><p>Disadvantages The pendulum is not used universally for the following reasons; Operation requires experienced technicians to obtain reliable results. Mistakes made by those with inadequate training can significantly affect results. The requirement for trained and experienced operatives means the method is often expensive. Purchase and upkeep of the pendulum tester is also very expensive. Testing takes around 30-45 minutes per sample due to the complex procedure. This is far longer than alternative, less accurate, test methods. Conclusion BS7976 pendulum testing remains the most accurate and most widely recognised measurement of slip resistance. Whilst relatively expensive in terms of time and money the method produces highly accurate results suitable for risk assessment, floor specification and certification and legal proceedings. Grip Potential is an independent consultancy providing pendulum slip testing as part of their holistic approach to slip risk assessment. Staff have extensive experience using the pendulum as a basis for risk assessment and can offer unbiased advice on risk mitigation measures. To arrange an assessment call 0845 163 0 163 or email info@grip-potential.com. Further information can be found on Grip Potential's website <A href="http://www.grip-potential.com/">www.grip-potential.com</A> and the HSE's slips mini site <A href="http://www.hse.gov.uk/slips">www.hse.gov.uk/slips</A>. Additional info sheets available include BS 7976 The Pendulum Method and slip risk reduction tips.<br></P></p> <br><br> <b>Author Resource:-></b>  <br><br><b>Article From</b> <a href='http://www.articlesbacklink.com/'>Articles Back Link</a><br></body></html>