Pendulum slip (or skid) resistance data are usually expressed as PTV, Pendulum Test Value (or sometimes BPN, British Pendulum Number, or even SRV, Slip Resistance Value). The question has been asked, “What’s the coefficient of friction?” This number (dynamic COF – DCOF) was calculated decades ago at the U.S. National Bureau of Standards, and can … Continue reading “COF vs. Pendulum Test Value (PTV to DCOF conversion table)”