British pendulum

5 Portable devices measuring skid resistance 16.3.5.1 British pendulum 

The British pendulum was designed with the aim of providing a low-cost and portable apparatus for stationary measurements of slip/skid resistance of a surface in the field or in the laboratory. This test method provides a measure of frictional property, micro-texture in particular, of surfaces and may be used to determine the relative effects of various polishing processes on materials or material combinations. 

The arm is released from its horizontal position to swing over a contact path length of 126 1 mm (for horizontal site surfaces, not for laboratory curved specimens for polished stone determination). The contact path length is obtained by adjusting the height of the pendulum arm. 

Prior to the start of taking measurements, the surface is wetted with a sufficient amount of water and then the arm is released without recording the reading. This operation is repeated five times, re-wetting the surface copiously just before releasing the pendulum and recording the result each time. The average of the five values recorded is the pendulum test value (PTV). If the five values recorded differ by more than three units, further measurements are taken until three consecutive values are the same otherwise, the test is repeated in an adjacent location. 

The PTV is defined as the loss of energy as the standard rubber-coated slider assembly slides across the test surface and provides a standardised value of slip/skid resistance (CEN EN 13036-4 2011). 

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Figure 2.6 British pendulum friction tester. (Courtesy of Controls Sri.]...

Surface skid resistance is measured by self-powered mobile devices or towed mobile devices. Spot measurements or measurements over short road sections are usually carried out by the British pendulum or ether portable devices. 

Finally, apart from the mobile devices, portable devices such as the British pendulum (SRT), the Japanese DFT (Dynamic Friction Tester) and the Swedish T2GO and VTI are in use. From the above, the British pendulum has been widely used in many countries around the world and the portable friction testers T2GO and VTI are slowly gaining popularity. 

It has also been proposed (Oliver 1980) that the following equation for correcting PTV (or skid resistance value [SRV] measured by British pendulum) be used when measuring at a pavement surface temperature other than 20°C ... 

The slip/skid resistance values determined by the British pendulum do not necessarily agree or directly correlate with those obtained utilising other methods of determining friction properties or skid resistance. 

ASTM E 303. 2008. Standard test method for measuring surface frictional properties using the British Pendulum tester. West Conshohocken, PA ASTM International. 

Several ASTM standards give methods of pavement testing and methods of result calculation. A British pendulum tester is used to measure surface frictional properties. The pendulum slider is positioned in contact with the tested surface which was previously thoroughly cleaned and wetted. A rubber slider gliding on the surface causes a swing of the drag point, which increases with surface fiic-... 

ASTMD1996-97(2003) Standard Test Method for Determination of Phenolic Antioxidants and Erucamide Slip Additives in Low Density Polyethylene Using Liquid Chromatography (LC). ASTME303-93(2013) Standard Test Method for Measuring Surface Frictional Properties Using the British Pendulum Tester. 

Gathurst Powder, Accdg to Marshall (Ref 1), it is a British permitted expl contg AN 51 K nitrate 6, TNT 18 NaCl 25%. Its.strength by swing of Ballistic Pendulum is 2.41 inches, compared with 3 27 inches for British. Standard Gelignite (60% NG)... 

The British standard, BS 903 Part A89, is not identical because it also specifies the Dunlop tripsometer. A previous version additionally included the Dunlop pendulum which is a compound pendulum shaped to ensure high rigidity, attached by a spindle and ball races to a massive structure. The indentor is 2.5 cm diameter and the test piece a 50 mm square block 25 mm thick. The ISO method is included, but in different format, as Method B and two appendices. 

British Tests. See Physical Tests for Determining Explosive and Other Properties Vol 1 and specifically the following British tests a)Ballistic Pendulum Test, p VII b)Exudation(ot sweating) Tests, p XI c)F7 lest(Figure of Insensitiveness Test) p XII Fragment Gun, p XII d)Friction Sensitivity Tests, p XIII e)Hopkinson s Pressure Bar Test, p XVI and i)Silvered Vessel Test or Waltham Abbey Silver Vessel Test, p XXIV... 

Britonites. Brit coal-mine expls manufd after WWI by the British Explosives Syndicate,Ltd,Pitsea. They used to be on Permitted List, but have now been repealed. The original compn contained NG 26, K nitrate 32.7, woodmeal 41 Na carbonate 0.3%. Later compns were No2, which contained NG 24, K nitrate 30, woodmeal 38 Amm oxalate (cooling agent) 8% and No3, which contained NG 24.5, Na Nitrate 28, woodmeal 35-5 NaCl 12%. Power(swing of ballistic pendulum) was 2.26" for No 2 and 2.17" for No 3, vs 3-2/ for std Gelignite. Limit charge for both No 2 No 3 was 24oz... 

Oynobels. A series of British mining explosives, of which the older type passed the Rotherham Gallery Test and was on the British Permitted List K chlorate 27, NG 32.5, Collod Cotton 0.7, Amm oxalate 29.5 woodmeal 10.3%. Its swing by Ballistic Pendulum was 2.6l inches compared with 3.27 for "Standard 60% Gelignite (Power... 

Crookes, W. 1886. Reports of the British Association for the Advancement of Science, 567. Excerpts, and his diagram showing the giant pendulum swings in element evolution are reprinted in Father, E. 

In the mid-eighteenth century, however, the British Isles experienced a series of severe earthquakes, which created a tsunami that destroyed Lisbon, Portugal, killing tens of thousands of people. Scientists quickly developed an interest in cataloging and understanding seismic events. In the early nineteenth century, Scottish physicist and glaciologist James D. Forbes invented the inverted pendulum seismometer, which gauged not only the severity of an earthquake but also its duration. 

The Izod test is used mostly in the United States and the United Kingdom [British Standard (BS) 2782, Method 306A]. The notched specimen is firmly clamped in a vertical position in a vise fixed in the base of the apparatus (Fig. 1). A pendulum fitted with a striker head of 3.2-mm radius, falling from a height of 0.61 m (ASTM) or 0.31 m (BS), hits the specimen horizontally at a point above the notch. At least 10 samples are required to obtain a satisfactory assessment of impact strength. 

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