1. Typical Project Services Offered:
Basic water, sewer, steam, oil, gas, chemical, cooling water or process water pipeline leak detection, field marking of leak locations with a summary report in electronic and hard copy formats.
Optional: 2nd pipeline within same corridor, street or pathway leak detection (typically primary water pipeline and secondary sewer pipeline or vice versa.)
Optional: Pipeline exterior erosion void detection
Optional: Exterior erosion void detection and characterization for depth and volume
Optional: Prioritization of each anomaly based upon plume size, void existence, void size and potential public disruption or subset of these characteristics per Client requirements.
Optional: Isolated sinkhole detection and characterization for depth and volume
Optional: Expanded report documentation with visual & IR imagery data of each anomaly for future comparison and size growth trends.
Optional: Follow up repeat reports with all data correlated with original report information
Optional: Non-invasive. No-trenching repairs of many types of pipelines carrying a variety of products using surgical multipart chemical grouting (not concrete)
Optional: Independent repair certification after client repairs
2. What size, material and type (e.g. water, sewer, pressure, gravity) are these tools most suited?
EnTech has successfully used its various remote sensing pipeline leak and erosion void detection and repair systems on water, sewer, wastewater, steam, oil, gas and chemical pipelines in urban, rural and industrial environments. We have actual experience in copper, cast iron, steel, various plastics and concrete in both underground and above ground scenarios. We have produced results covering <8”, 12”, 16”, 24”, 36”, 48”, 72”, 96”, and 108” pipelines. Sewers have been in both gravity and pressurized systems.
3. What advantage do your tools have over other types of void detection techniques?
Our systems are designed to work on all types of pipeline systems with:
No modifications to the system
No attachments to the system
No stopping of traffic
Usually no parking control
No need to be over the pipeline
Depending on the system under investigation, leak detection depths have reached 93ft with
regular water and sewer pipeline investigations to depths of 15-20ft.
Investigations may be performed either during the day or nighttime hours
Production rates for van mounted systems range 5 to 10 miles per shift
Data collection rates for helicopter mounted systems range 50 to 100miles per shift
4. Are there any limitations of the tools provided by your company? If so what are they?
Although the various techniques appear to overlap in their capabilities, each technique measures a different physical property. It is recommended that the infrared phase be performed first, because it can cover the most area at the lowest unit cost. Its accuracy depends upon the energy flow characteristics of soil, the potential buried pipelines and their contents. It is usually our most accurate and widely used Non-Destructive Testing technique. The IR works best under dry conditions with no ponded surface water. The microwave (GPR) based investigation techniques can use various antennae for various depth of penetration requirements. The GPR performs very well under most site and weather conditions, except when ground geology contains a great deal of clay or is highly conductive.
5. Can you provide indicative order of magnitude costs for your techniques?
All of EnTech’s proprietary techniques are designed to be extremely efficient in performing high volume investigations. It is recommended that the IR phase be performed first, because it can cover the most area at the lowest unit cost. In large volume with basic reporting requirements, the cost of IR based leak and erosion void investigations have been as low as $0.20 per ft.
6. What factors should be considered in developing its procurement plan for void detection services to achieve the best value/money outcome?
Large volume lengths of pipelines allow for the lowest unit cost
If small pipeline lengths are to be investigated, EnTech can provide investigation services and report generation to meet client specifications
Most sinkholes are formed when water mains form corrosion holes allowing water to channel through the ground soils and migrate into the sewers and flow away unseen. EnTech’s remote sensing leak detection and erosion void detection systems may allow both the water and the sewer mains to be investigated during the same inspection at a minimal additional cost. These combined costs can then be split between agencies for lower final costs.
Is there a minimum size project that EnTech pursues?
• EnTech will consider projects of all sizes.
• We do not have a set pricing schedule.
• We normally quote a Mobilization/Demobilization fee plus a unit price per length or unit price of the investigation area
• We will also propose by lump sum.
• We believe that we are unique in our lump sum pricing by assuming the risk for many uncertainties or contingencies.
• In over 30 years of projects and thousands of lump sum projects, we have never asked for a change order.
• Our general pricing is dependent upon location and volume of areas to be investigated.
We occasionally have a client that doesn’t know the location of all of their existing utilities. Existing maps either have been lost or destroyed, or they are inaccurate. Recreating mapping for these clients would likely involve mapping wide areas rather than right of way or utility corridors. Do you have a minimum area (in acres) that you fly and perform utility mapping services? I assume that the congestion of utilities in an area affects your fee but is there some sort of $$/acre range, and a minimum area that you would mobilize to perform. Does your fee vary depending on the types of utilities that you map (one fee for just sanitary sewer, an additional fee to add water mains, additional for private conduits, etc.?)
• EnTech can use any and all of the information supplied by our Clients.
• On occasion we do not receive any drawings or information, other than to “Look here”.
• Pricing will depend upon the specific project.
When you perform utility locating services, do you also locate service lines? It is very challenging to locate water services in the field, and even more challenging to identify active vs. abandoned services. I assume that you can’t distinguish between active and abandoned water or sewer services, but can your equipment locate these services?
• EnTech can locate both water and sewer service lines.
• We cannot tell if they are active or abandoned.
• Pricing will depend upon the specific project.
How do your fees compare for performing utility locating services along a corridor compared to leak detection along a specific utility? Also, if there are two utilities running parallel and an anomaly is located, do you have the capability to distinguish which utility is responsible?
• Pricing will depend upon the specific project.
• Determining which pipeline or utility is leaking in a crowded corridor is dependent upon local conditions.
How accurate are the resulting depth calculations?
• Using GPR – ~ +/- 6 inches to depths of 15 ft.
• Using IR – Depth cannot be estimated.
What are the depths of penetration given any flight height?
• Using GPR – Must be in contact with ground
• Using IR – from 12,000 feet of elevation we have investigated ~1,000 acres locating brine leaks from oil wells at a confirmed depth of 93 feet.
How wide a swath does a single line of flight cover?
• Variable depending upon lens used. Example 600 ft. of elevation gives a 200 ft. wide swath with 4 inches per pixel resolution.
Does the soil moisture or type of host rock make a difference?
• Using GPR – Highly conductive or clay soils restrict depth of penetration
• Using IR – not a problem
Does the technology show metallic or other underground anomalies?
• Using GPR – Yes
• Using IR – Yes
Are there other limiting factors that would make the technology less than ideal for my application?
• IR is the recommended application, but surface topography such as trees, large rocks, etc., may present problems
