F.A.Q.

Though we use tools with far less radiation emissions than many competitors, we still perform x-rays only in restricted areas, thus services to be performed in occupied buildings require tenant coordination.  We will take every precaution to ensure a safe and successful imaging service for your project.

We recommend that we first complete a site safety analysis and meeting with management to coordinate a service time that offers minimal impact to your operations.  To get started, you should:

• Notify your office/building manager about the service;
• Coordinate a time when all tenants and service personnel are off site (any floors the penetrations are going through or coming out); and
• Notify us of how thick the concrete surface is.

We are happy to assist you with any step of this process.

Once we are on site, we will review the work area, post signage and tape off access points, and then set up our equipment. During this time, we will need access to all offices and suites on the relevant floors to personally ensure those areas have been vacated.

Yes, we are experienced in using Cobalt 60, a stronger isotope whose limitations are closer to 24" thickness.  However, the use of Cobalt requires certain accommodations due to its size, weight, and radiation emissions.  Contact us to discuss the details of your project needs.  

We have invested in digital CCD technology instead of the traditional film radiography.  It is around 90% more efficient and offers many benefits over the former method, including a drastically reduced radiation output as well as signficantly faster exposure times.  With digital radiography, we no longer need a darkroom for film processing, and processing is done near real time, on the floor where the penetrations are.

X-Ray
Concrete Imaging has invested into digital CCD technology, which offers a significantly reduced radiation signature and emissions over the traditional method; however, x-rays have potential to be harmful and therefore, we take precautions, such as clearing the location, to ensure a safe and successful imaging service. When x-raying is to be performed in an occupied building, we recommend performing a site safety analysis then meeting with management to coordinate our work to minimize disruptions.

GPR
In comparison, the typical power output of a GPR antenna is less than that of a cell phone, so this method presents no health concerns. GPR is a quiet, safe process, so we can accomplish it without interference to your ongoing operations around us.

GPR and x-ray are the two primary methods used for concrete testing, and they vary in safety precautions, cost of service, time needed for performing the service, and site restrictions.  In general, GPR is the most efficient, cost-effective, and non-destructive concrete scanning choice.  It is highly accurate; however, in certain circumstances, x-ray may be recommended for a more accurate picture.  GPR offers a nearly unlimited coverage area and high resolution imaging, but wet or extremely congested decks can scramble the signal and result in low visibility.  While X-ray is less convenient and more time consuming, it offers the best quality imaging.

Yes, we regularly use our equipment to scan concrete columns, walls, and occasionally, even the underside of a floor.  

Ground penetrating radar is an extremely efficient and fast technology.  Large areas can be scanned quickly with ease. Our standard layout for a typical location is 2' x 2', which generally takes about takes about 10 minutes to scan and mark.

Yes, GPR can tell the area where the void is occurring as well as clearly identify its boundaries; however, it cannot determine the depth from the top of the void to the bottom of the void.

No problem!  GPR can scan through any kind of floor covering (carpeting, hardwoood floors, tile, stone, etc.) except fine wire mesh below floor tile, unless there is more than a 1/2″ air gap between the floor covering and the concrete (rigid insulation or foam, thick carpet padding, etc.)

GPR does not determine what type of object is being located; however, our technicians are experienced at using all available data in identifying the type of embedded object that is present.  We first locate and map out the rebar grid.  Rebar, when placed in concrete, has tendency to stay about the same plane, with a typical pattern with 12-to-18 inch centers.  Anything noted that is in between grids, angled to grids, or that have a different return signature than the grid signatures, we regard as a conflict.  Most often, when something is on an angle through a square layout, it will be a conduit. Post tension cables tend to be spaced further apart, depending on the building’s design and whether they are banded or uniform tendons.

Our technicians will not confirm the identity of the item noted, only note it and make you aware where we believe the target is, the direction and depth as per the display rendered from the survey equipment. We magnify these items when we draw out the rendering on the slab to give you a safety boundary; however, we highly recommend an x-ray be performed, if possible, to confirm whether or not you will have a safe path to penetrate.

Our project managers will leave you feeling confident in the survey findings and in your ability to drill or cut without issue.

Though recent advances in GPR hardware and software have improved the technology, some limitations still exist.  These include:

• Radar waves cannot penetrate metal; therefore, if steel storage tanks are present on the site, GPR will not be able to see inside them, nor assess their condition. Further, objects behind steel may be obscured and not observable. 
• Radar performance is driven by the characteristics of the sensor, the targets, and the competing background clutter. An object may be observable at a shallow depth, but the same object may be invisible at a greater depth.  High-conductivity materials, such as clay soils and soils that are salt contaminated, reduce the depth of GPR ground penetration.
• Signal scattering in heterogeneous conditions (e.g. rocky soils) limit performance
• Interpretation of GPR radargrams (the radar image of mineral deposits or a geophysical surface) is not intuitive.  Considerable expertise is necessary to effectively design, conduct, and interpret GPR data.

The accuracy of GPR scans can be affected by several things, including, but not limited to:

• the composition of the concrete structure being penetrated, such as the moisture content and density; 
• the depth of the target; 
• the different velocities of radar signals travelling through different types of materials;
• areas with strong electromagnetic signals; and
• areas containing a complex assortment of objects.

No, we cannot.  We can generally find the utility without much difficulty, but we cannot determine if the piping is gas, or water, etc. However, our experienced technicians can often trace the utility to valve, meter, control box, or other type of signifying marker, thereby determining the utility. 

The size of the area that can be accurately located in one day will vary based on the project site itself.  Often times, vacant fields that are many acres in size can be scanned with great speed as the expected congestion of utilities is low.  On the other hand, a small property located on a busy metropolitan street could be very time-consuming as the anticipated utility congestion is high.

Yes, while metallic utilities are easier to locate, we do locate PVC, fiber optic, concrete, and other non-metallic pipes/cables.

Typical deliverables for concrete x-rays/scans include:

• marking findings (object locations) directly on the structure using chalk, crayon, or tape;
• verbal communication of the findings while onsite; and
• a report that documents each location.  The report will show the scan location in relation to the overall structure, a photograph of the markings on the structure, marked-up photographs detailing the embedded objects,  an electronic illustration of the GPR data/x-ray collected, and a brief discussion of the purpose of the scan and the objects identified.  

Reports (available in .pdf and .doc) are typically produced within 24 hours.  Digital files, including any photographs, x-rays, or other images, are available via e-mail and/or a portable storage device (e.g. jump drive).  

Typical deliverables for utility locating include:

• marking findings on the surface using paint or flags; and
• verbal communication of the findings while onsite.

Typical deliverables for pipline inspection incude:

• photographs and video recording of findings;
• verbal communication of the findings while onsite; and
• a report that documents findings, including trouble spots.

Yes, we pride ourselves on customer service and our ability to meet your scheduling needs.  We are willing to work nights, weekends, or any other time to help you accomplish your project goals.  

Pricing varies based on several factors, including, but not limited to:

• Project location;
• Concrete imaging objective;
• Type of concrete structure we are scanning – hollow core, post tension, slab-on-grade, etc.;
• Amount/quantity of wire mesh, rebar, and/or post-tension reinforcement suspected to be found in the scan area(s);
• Number of locations that need to be scanned and the distance between them; and
• Whether a lift or scaffolding is readily available (if scanning involves a concrete wall or ceiling).

Call or e-mail us today to discuss the details of your project and obtain a free estimate.