FAQs from the ACCT Installation Standards Committee

Technical Bulletins,

In order to get the full strength from each of the cable clamps or ferrules gripping the wire rope, the clamps and ferrules must be loaded equally. The farther the clamps or ferrules are apart, the greater chance that the two cables between them will not be parallel. This will cause one clamp to be loaded before the other and slippage will occur at a lower load. The manufacturers' specifications must be followed, if available, when using any materials for challenge course construction.


On a zip wire (static belay) the vertical force is created by the participant only, thus it is 1/2 of the expected vertical force generated by a dynamic belay. With a dynamic belay the vertical force of the belayer doubles the vertical force of the participant on the horizontal belay cable. This makes it possible to tighten the zip wire twice as tight as regular horizontal belay cables. (See Appendix D.)

Under normal conditions, one might expect wire rope to last 10-15 years. However, there are a wide variety of factors that affect the life of wire rope. Harsh environments, such as salt water, industrial pollution, and high use, can significantly reduce the life of wire rope. For retirement criteria, refer to Standard C2 in the ACCT Inspection Standards.

All treatments used for poles are toxic in one way or another. Penta is the most common treatment used for Southern pine utility poles. The name is short for a treatment called Pentachlorophenol, a chemical treatment that uses a petroleum medium to make it adhere. It is mainly the petroleum that is a skin irritant. After a number of years, the surface of Penta poles becomes less oily and therefore better for skin contact. On challenge courses, Penta poles are best reserved for use where there is low potential for this direct skin contact (some tower designs, Zip Wire end poles, support poles for some low element cables, etc.). When in doubt, verify that state environment and health regulations allow the use of Penta poles for a challenge course.