By Mike Crews
Q: How can I ensure safe installation when hanging loads in tents?
In today’s world of tenting, demand for high-end decorating is at an all time high. Many renters are asked by the decorator, light company or audio company, “How much weight can I hang in the tent?” The response should include both how much weight can be hung and how it can be hung safely. This is based on the type of tent being used. Is it a conventional rope and pole tent, engineered structure, tension structure, trac-system or frame tent?
The process for determining the loads for engineered structures or trac-systems is driven by structural evaluations. For engineered structures, the amount of weight allowed and the exact attachment points are specifically stated. Normally these suspension points are at the ridge and at equal points on either side of the ridge. While the predetermined weight can be hung from specific points, it can also be uniformly distributed along the length of the rafter. The loads can vary from 500 to 1,000 pounds at the ridge and from 250 to 500 pounds at the other two points. The concentrated load could be higher or lower depending on the manufacturer.
Trac-systems are slightly different in that they are a bit of a hybrid. They have characteristics of both an engineered structure and a typical frame tent. Where you suspend the load will be similar to that of an engineered structure, but the load itself tends to be less. These loads can be from 50 to 100 pounds at each location.
Tension pole structures have a different characteristic all together. When suspending the concentrated load independently from each pole, you create an axial load. So long as the connection point maintains the proper sheer and the weight is uniformly distributed, the load could be anywhere from 100 to 3,000 pounds. It is simply a measure of allowable load minus design load. When creating a truss rigidly between two of the center poles, there is a positive/negative effect. Typically the center poles are designed to move independently. By adding the truss you are creating a moment at this location. It’s similar to holding a sledgehammer close to the head with your arm extended in front of you. Now move your hand to the opposite end of the hammer—you can feel the dramatic load shift.
Remember, it is ultimately the responsibility of the tent installer to contact the manufacturer and get the proper information on engineering to ensure the safest installation possible.