In the spring of 2007, I was contacted by Coleman-Wichita and asked about testing the thickness of metal. I advised them that I had an ultrasound machine that would test the thickness to .001 inches up to 6 inches thick. (Please see Thickness Tester) We are able to test the thickness of this metal from the outside and then make a determination as to how bad the pole is.
There was a pole that had already fallen in the back lot. These poles were steel and approximately 50 feet tall with large lighting fixtures on the top. The fear of another pole falling and landing of vehicles or even worse landing on an unsuspecting person was something that needed to be dealt with.
Pole #6 was already down. We did some quick measurements on it and found the thickness to be between .065 and .090. I would consider this the breaking point on these poles obviously because that is where it broke. Therefore we set a minimum safe thickness at .100 inch thick. The following images will show what we found.
Light Pole #7
In a visual inspection we could see that this pole had rusted from the inside out and in several places it had rusted completely through to the outside.
We took thickness reading in areas away from the rusted through places and the chart shows what we found. In looking at the chart, the 0 indicates the very base of the pole and the numbers thereafter indicate inches up from the bottom. Measurements were taken on all four sides of the pole.
As can be seen in the chart, the south side of this pole is less that 1/16th inch (.067). This pole needs to be replaced.
This pole has break-through in several spots.
Closer view of the damage.
Light Pole #8
This is another pole that has obvious defects. There were places on this pole that were less that .067 inches thick. Also the chart shows that almost the entire bottom 5 inches of this pole were less than .100 inches thick. This pole should also be replaced.
This pole is also showing damage to the point of break-through.
Other side of same pole with hard to see instances of penetration.
Light Pole #9
The visual inspection on pole #9 shows again obvious damage from rusting from the inside out. This pole sets next to the guard shack and there was some concern on which way it would fall if and when it did fall. As can be seen the damage was quite significant and the chart shows places that were less than 1/16th inch thick.
View of significant scarring/damage.
In all, we tested 39 poles in the parking lot. Of those 39 poles, we found 9 that had several places that were less than .100 inch thick. We recommended that these poles be replaced or repaired.
Also we suggested that there should be a vent hole drilled in the base of all of these poles, the wire connection cover should be pulled and the inside of the base should be sprayed with some sort of rust inhibitor.
What was taking place was the rain entering the top of these poles and then there was no way for it to get out. So over time the bases were rusting from the inside out and no one would ever know there was a problem until one fell, as was the case here.
This is just another service in the field of Predictive Maintenance that is now offered by Peterson Predictive Maintenance.