JR Clancey recently sent out the Rigging Report via email. JR Clancy moved their Rigging Report to email so that end user can get more information and photos with out consuming enmormus amounts of paper. This show that JR Clancy is aware that the envoirnment matters and are doing their part to reduce paper usage.
Included in the Rigging report is an article about being cofused about the correct chains for rigging which we have included here.
There is a lot of confusion about chain usage in theatrical rigging. The biggest issue is the “Not for Overhead Lifting” statement associated with some chains. The chain folks define “overhead lifting” as moving a load by mechanically changing the length of the chain. Typical examples are “come alongs” and chain hoists. In both cases there are metal “teeth” making repeated physical contact directly on the chain. This creates wear and stress on the chain, and suitably rated chain is essential.
However, dead hanging and trim chains are simply “suspension” applications, not “lifting” applications. Grade 30 proof coil chain is suitable for this application. This is backed up by an OSHA letter concerning slings (another suspension application) stating “Proof coil and high test chains should only be used in accordance with the manufacturer’s recommendations.” The manufacturer of J. R. Clancy’s grade 30 proof coil chain specifically allows the use of their chain for dead hanging and trim chains. This is a sensible, reliable approach that has been used for many years. There is no reason to spend more money, and have to deal with the challenges of working with hardened chain.
For more information, the links on the left take you to a paper we wrote on chain, and a new article from ESG (Entertainment Structures Group, who provide professional engineering services for our industry).
Download the complete article: ESG Trim Chain Article. To learn more about JR Clancy and their rigging products, visit their website at www.jrclancy.com.