Especially on the inside
If you're a typical party rental business you will carry rental chairs for various occasions. You may have some upmarket styles for theme parties, some pristine white for weddings, maybe some padded stock for conferences, and for everything else, you may carry a bunch of steel/vinyl folding chairs.
For years these folding chairs that stack flat and save space have been the industry standard for portable seating and companies usually have between 1,000 to 50,000 or more, available for rent in a variety of colors and condition.
So we ask, "What are the downstream maintenance issues with these chairs?" In particular what is the effect of rust? And how are companies typically mitigating their exposure to risk from chair failure? First, let's look at the design of the folding steel chair.
It is almost always weakest at the "scissor point" or the point where the two folding legs cross and are joined by a rivet. The chair will typically fail at this point when one of the steel tubular legs shears under load - (the joining rivet does not tend to fail).
The reason for this is simple physics - the hole made to accommodate the joining rivet weakens the shear strength of the steel tube causing failure at this point under load. There is effectively less metal in the steel tube at this point and so the structural strength is weaker here.The burning question asked by many rental owners is, "What is the load at which I can expect failure to occur?" There is no simple answer to that - it depends on factors such as the point on the seat that the load is applied (loads closer to the front of the seat place greater force on the scissor point), the downward acceleration of the load, the quality and wall thickness of the tube used and the extent of corrosion present in the steel tube.
As rental owners we can't really control the first two factors (the way load is applied to a chair), but we can consider carefully the latter two when we purchase.
First, consider quality. Buy from a manufacturer who uses high-grade steel and doesn't compromise on wall thickness. (Thinner walled tube is sometimes used to reduce cost and weight in steel chairs).Second, consider the effects of corrosion. Most manufacturers protect the steel tube from corrosion by powder coating it. This ensures that the raw steel is not exposed to the combination of moisture and air which are the ingredients required for corrosion to begin. Or does it?Actually only partially. Powder coating obviously can't stop rusting on the inside of the tube and in areas such as the rivet holes at the scissor point. This is especially true when chairs are washed and retain moisture inside the tubular legs or in the rivet holes. This starts the process of rusting "from the inside out" and visible evidence of it is often seen when brown rusty stains leach out from behind the rivets at the scissor points.The fact that the scissor is the weakest point, and is also the place where internal rusting can begin means that rental owners need to carefully monitor the condition of their chairs because over time rusting here will increase the chances of failure.One of the risks as a rental store is that if a chair breaks with someone sitting on it, even if it was through misuse, any evidence of rusting around the break point could lead to accusations of inadequate maintenance and liability issues which no store wants.Obviously adequate liability insurance is a must but industry players are trying to deal with this problem. Some are choosing to rotate inventory more often (two to three years) so that there is little risk of rust getting a hold on their chairs.
Others are moving away from steel chairs to newer products such as stainless or Aluminum chairs that cost more but provide owners a comfort level because they cannot rust.
Tom Mantyla of Baker Party Rentals in Cost Mesa, CA made this change when he switched his 4,000-chair inventory to Aluminum. He said recently, "Our steel frames would get beat up, rust would show through, and customers would comment that the chairs looked a little shabby. Some of these chairs were not that old. We felt we were fighting a losing battle on the maintenance front and there was always that concern in the back of my mind about rust and my liability."
The New Zealand manufacturer of the "Alloyfold" brand is seeing some uptake. Antony Brett said, "In the six years that we have been in the US market we are seeing a number of customers buying solely because of rust. The litigious nature of your market I think is a factor in this".
McCourt Manufacturing of Arkansas, a manufacturer of a steel chair of some quality is seeing a resurgence of sales from customers who have tried lower cost options and found them more costly in the end.
There is no easy solution to the problem, either way there is a cost involved, either through buying higher priced chairs, more frequent inventory changes or perhaps with more costly insurance. But most in the industry agree that it is worth considering these costs in lieu of an expensive lawsuit.