So today I want to talk about rigging. Whether it’s for the flying trapeze or aerials, all rigging shares a basic set of tenets. The first and most important aspect of any circus rigging is safety. In the circus, we go above and beyond the requirements of most regulations. Certain governing bodies, like the ASME or ANSI, provide detailed instructions on maintaining your rigging, and because in the circus we are constantly putting people in the air, we like to top those instructions with some of our own.
Much of the rigging terms will seem familiar to you, the more time you spend around the circus. Carabiners, swivels, pulleys, round slings, etc.; these are just some of the tools we use to keep you safe in the air. But knowing the names of these is just the beginning. Understanding how they work and how to maintain them is the meat of rigging safely.
Every piece of rigging you use has a rating for how much force it can handle, known as a Working Load Limit (WLL). In normal rigging situations – hoisting a piano, for example – you want to give yourself 6 times as much strength as you need for that weight (i.e. you’ll want equipment that can handle 3000lbs for a 500lb piano). However, in circus, we up that to 10 times the strength for the weight. The forces prevalent in circus arts are dynamic, which means they can increase quite a lot as we move. Because the force generated by an acrobat falling isn’t the same as their weight we use a different term: Kilonewton. A kilonewton (kN) is a representation of the force generated by a body in motion. One kN is equal to 224.81 pounds of force. What this all means is that if we assume that an acrobat and his equipment weigh 200lbs, we would want rigging with a minimum rating of 10 kN. Remember, a chain is only as strong as its weakest link.