This is mandatory and must be completed before verification of the Pendulum or testing can commence. Each time the pendulum is disassembled and re-assembled or when testing at a new site the zero must be set. Majority of Slip Resistance standards mention setting the zero, including: UKSRG, BS7679-2:2002+A1-2013, BS En13036-4:2011 and, CEN/TS 16165:2016.
How to set the zero:
1. Make sure the pendulum arm clears the surface. Ensure the pendulum arm is locked securely in the mechanism before continuing.
2. Rotate the pointer anti-clockwise until the counter-balance rests on the nylon stopper and is parallel with the pendulum arm.
3. When ready, release the pendulum arm so that it swings freely. Catch the pendulum arm as it returns downwards. Place the pendulum arm back in the release mechanism.
Does the pointer read Zero?
If the pointer reads zero (0), place the pendulum arm into the lock mechanism and repeat the process 3 times for verification or test purposes. Once complete, the Pendulum is ready for Verification or testing at a new site.
The pointer does not read zero, friction rings need to be adjusted:
• If the pointer goes above zero, then the friction rings need to be tightened by rotating them very slightly in a clockwise direction.
• If the pointer is below zero on the scale plate, then the friction rings need to be loosened to reduce friction on the spindle. Move the friction rings very slightly in an anti-clockwise direction.
Once the friction rings have been adjusted, release the pendulum arm so that it swings freely. Catch the pendulum arm as it returns downwards. Place the pendulum arm back in the release mechanism.
Does the pointer read now zero?
If Yes, return the pointer to the nylon stopper and repeat the process 3 times. If no repeat the above process until zero has been achieved 3 times consecutively.
Please Note: If you move to a new test location, the instrument must be ‘zeroed’ prior to use. This ensures accurate, reliable and repeatable results.
For more information please download Setting the Zero Flow Chart or watch the video below: