Torque Requirements

TORQUE REQUIREMENTS

December 17, 2010

T.R.A.-MAGE would like to clarify the information regarding the torque requirement for the T.R.A.-MAGE Clamp-on Snow Fence.  Until recently, the torque requirement for the bolts used to secure the clamp to the standing seam has been 20 ft lb. It was determined, through physical testing, that this amount of torque, when applied to the bolts, was sufficient to secure the clamp to the seam and would prevent failure of the snow fence system.

Because safety is paramount when using a snow retention system, the decision has been made to increase the margin of safety for the Clamp-on Snow Fence systems. This decision has also been made due, in part, to the lack of maintenance programs for the snow retention systems.  Maintenance is the responsibility of the snow retention system owner and should be carried out on an annual basis.  This increased safety margin is achieved by increasing the amount of torque applied to the bolts of the clamp. The current recommended torque for all standing seam clamp bolts is 30 ft lb. This amount of torque has been determined, also through physical testing, to allow for the greatest margin of safety while maintaining the integrity of the roofing product.

It is the recommendation of T.R.A.-MAGE that if a Clamp-on Snow Fence system has been installed using a torque of 20 ft lb on the bolts as reference in the previous T.R.A.-MAGE product binder, section 17, page 1, the torque be increased to the new 30 ft lb requirement during the next maintenance cycle or when there is no snow present on the roof T.R.A.-MAGE does not feel that snow fence systems designed by T.R.A.-MAGE, and currently at the 20 ft lb torque, pose any imminent threat of failure.