Anchoring Inflatable Games and Size of Stakes
A few days ago another terrible accident involving flying inflatables occurred in South Carolina. Five children were injured with two of them sustaining serious injuries. This is a tragedy that could have been worse but is one that we all must do our best to avoid.
From the reports it appears that the inflatables were anchored to the ground but clearly the anchoring was insufficient for the environment. The anchors may have been too small, not deep enough, or the ground may have been too soft. Over the past year I have noticed that most people severely underestimate effect of wind speed on an object.
The pressure of the wind is directly related to the square of the wind’s speed.
The formula is: pressure = ½ air density x Speed2
Here’s an example demonstrating the effect of a change in wind speed by 5 mph:
10 mph to 15 mph:
10 mph = 10 x 10 = 100
15 mph = 15 x 15 = 225
(225-100)/100 = 1.25 or a 125% increase in pressure caused by a 50% increase in speed!
15 mph is not a lot of wind. Mother Nature is serious. Three times this week I’ve had someone use the word “crazy” when they asked for anchoring recommendations. Good 1” stakes at least 18” submerged in stiff ground are your best tools for anchoring.
Members of ASTM International with inflatable manufacturer members like Happy Jump have been working closely to improve standards to reduce and, hopefully, eliminate these incidents. We need everyone in this industry involved to help. Be a part of increasing inflatable safety.