Determining the amount of oil and water in a manhole used to be cumbersome and time consuming for Con Edison's field crews. Recently, the utility equipped some of its service trucks with a new product called the Water-Oil-Level-Flexible-Tape or WOLFTape from L&M Associates (Elmwood Park, New Jersey). Now field workers can measure the amount of dielectric fluid in a manhole in 10 seconds or less.

“When we are working on a manhole near a busy street, this product helps us to get the job done quickly and then move out of harm's way,” says Jamilah Saunderson, a first line supervisor for Con Edison in Astoria, New York.

To use the product, workers simply tear open the individually sealed package, drop one end of the tape in the manhole and then pull up the tape to check the oil level. The tape, which has an orange-colored layer containing urinine dye on one side, is extremely water sensitive and turns fluorescent yellow when it comes in contact with water.

Eliminating Guesswork

The tape is treated with nontoxic dye, and when it absorbs the dielectric fluid in the manhole, it becomes dark orange. The portion of tape that has come into contact with water turns bright yellow to indicate the depth of the water. The tape is marked in both 1-inch and 6-inch increments, which makes it easier for the field crews to produce an accurate measurement. After the workers measure the amount of water and dielectric fluid in the manhole, they can refer to a conversion chart to calculate the spill volume for various-sized manholes.

Correct Response

By helping field crews to measure the correct amount of dielectric fluid in a high-voltage transmission manhole, the tape enables workers to develop the appropriate remediation response. Without the tape, because 1/16 inch of oil can look the same as 12 inches, field crews can miscalculate when estimating the amount of dielectric fluid. This can lead to an unnecessary and costly site remediation or a lack of a proper response, which can be hazardous.

Having accurate measurements makes it easier for the utility to determine what size tanker is needed. By getting information quickly to a supervisor or planner, crews can get the right-sized tanker to the site more quickly. It also helps to generate more accurate spill reports to the regulatory agencies.

Moving Forward

Con Edison worked with L&M Associates to develop WOLFTape, and crews have been using it out in the field for the past two months. The company's managers are training the field employees how to use the product.

“So far the field crews haven't had any difficulty using the product, and it's helped them to be safer and more efficient in the field,” says Paul Katchen, a project specialist for Con Edison.

WOLFTape is now patent pending and carries a trademarked name, says Kevin Silver, principal for L&M Associates. Silver says utilities have suggested that the product would be beneficial for usage not only in manholes, but also in transformer vaults.

“During our development, I kept thinking this product is a real winner, so much so that I decided to seek patent protection,” he says. “The initial response from Con Edison was incredibly positive. We have recently demonstrated WOLFTape to other utilities in the Northeast and were pleasantly surprised to learn just how well it was received.”

At Con Edison, the WOLFTape has improved workers' productivity, as well as improved the accuracy of their initial spill reports, allowing them to spend less time measuring dielectric fluid and more time expediting remediation.

Editor's note: Jamilah Saunderson can be reached at, and Paul Katchen can be reached at