Recently, I was performing a ground penetrating RADAR scan for one of my clients in Atlanta, GA. and they were telling me about one of the other firms offering them a lower price to scan for the conduits and tension cables in the slab at another job site. I had been in the building in question a few weeks earlier and it was one of the easier buildings to scan and should not have been an issue for any RADAR firm to evaluate. My client proceeded to tell me that they did call the other firm out and they arrived with the scanning equipment and they noticed that the equipment had no wires and was much smaller than the equipment we use. The equipment which the "less expensive" firm used was not a ground penetrating RADAR unit at all,  but a magnetometer type of equipment which is produced by a popular handheld tool equipment manufacturer. I jokingly proceeded to inquire of my client how much damage occurred from the scans and he shook his head and indicated two conduits were hit and damage was in the neighborhood of $1900 for the repair. So basically the client paid this "cheaper" firm about $100 dollars less for the scan so that they could spend $1900 on repair. This was an expensive lesson learned by my client that I have heard more than once. 

The reason I shared the problem my client had was to illustrate that not all firms are equal and sometimes the lower the cost of a service the lower the quality of equipment and ability. I was personally on a project this week in Alpharetta, GA. where our client asked us to rescan another firms work because he only trusted our scans. The scans in question were overhead so the difficulty was definitely increased but not by an incredible amount. I began my scan with not much hope that the other firms marks were correct because I am well aware of the equipment they use and it is not ground penetrating RADAR. I am also aware that they are a coring firm that started out as a coring firm and later added RADAR imaging as an afterthought.  The client indicated the two areas in question, which were in a very easy building to scan. Before I began I noted the location of the other firms marks prior to making my own and to my surprise the first scan was very accurate. I then proceeded to the second area which had already been evaluated by the other firm. As I began my scan I was suddenly confused by their markings, each line was approximately 2 inches off and one line was not even marked. There was no doubt the unmarked line was slated to be unknowingly cut because it was directly in the area indicated to be cut. Had the contractor placed the hole where the other firm indicated whatever damage which might have occurred would have been left to my client to handle. My client dodged a bullet by not trusting his subcontractors "cheaper" scanning firm because not all firms are created equally. 

When having a scan performed always be wary of the "cheapest" firm just like everything in life you sometimes get exactly what you pay for. Be wary what type of equipment the firm is using because ground penetrating RADAR and physical x-ray are both excellent techniques to evaluate the contents of the concrete--magnetometers and other equipment that pick up the properties of the materials to locate the contents are not. Finally, if the word coring is anywhere in the name of the company use extra caution because they are indicating right up front  that they are not a RADAR imaging firm. 

Follow these precautions and you should be able to avoid the headaches associated with damaging the contents of your concrete floors when cutting and coring. 

Figure 1: The area in question was scanned prior to our arrival. The dashed lines were placed by the coring companies and were noted to be inaccurate upon our evaluation.Our scans are noted as the solid lines with x's contained within.  Also, please note that the line at the bottom and the second area to the left were not even marked by the coring firm. The hole was moved to avoid damaging the contents of the concrete only after we had completed our scans. Had we not reevaluated the area in question there is no doubt damage would have occurred.