Detecting Underground Lines

Sweep1: Clearing an area with the two-person safety sweep.

On Sept. 16, 2019, in Farmington, Maine, a damaged and leaking underground propane line fueled a deadly explosion. This catastrophe, and resulting new regulations, have convinced many propane marketers of the benefits of locating, marking, and avoiding underground lines.


The Farmington tragedy motivated Maine’s legislature to enact LD 1892, An Act to Make Changes to the So-called Dig Safe Law, and on March 17, 2020, Governor Janet Mills signed LD 1892 into law.

A letter from the Maine Public Utilities Commission clarifies how the requirement to locate underground propane facilities has changed. Previously, the law required locating only jurisdictional propane systems. To comply, “you must provide the location of all your underground propane facilities, including those considered as ‘non-jurisdictional.’ …Further, you will be obligated to mark these facilities… upon receipt of a notice of planned excavation.”

Along with heightened expectations, LD 1892 has harsher consequences, increasing first-time offense limits to $1,000 and second occurrences within 12 months to $10,000.

On July 1, 2020, Florida Governor Ron DeSantis signed HB 1095, amending the Underground Facility Damage Prevention and Safety Act. Wendy Schaefer of Sunshine 811, a nonprofit that helps utilities dig safely, says in a summary: “The revised law, which establishes new noncriminal violations, enhanced penalties, more enforcement entities and incident reporting requirements, goes into effect July 1, 2020.”

Because of DeSantis’s action, some propane company operators in Florida have voluntarily joined the 811 system, including Blossman Gas’ Orlando location. “Here in Florida, we have joined Sunshine 811, which helps to prevent costly repairs, utility outages, property damage, possible environmental issues, fines and, more importantly, possible injuries,” says Peter Dawson, General Manager.

Inductive streetlight article: Inductive locating when direct-connection is not possible.


Propane operators confirm that unmarked lines are an issue and that electrical strikes are the most dangerous. There are many opportunities to hit private, unmarked electrical lines. Backyards are often minefields of power lines feeding outbuildings, lighting, pet fencing, swimming pools, gas generators and irrigation systems. Damaging or cutting these lines can result in service interruption, injury, downtime, fines, and embarrassment. “For whatever reason, some things just don’t get marked, so we still will use [our preferred] locators, which are easy to use and help us avoid unneeded damage to underground lines,” Dawson says.

The “unneeded damages”, referred to by Dawson, result in real expenses, both direct costs and opportunity costs. A regional executive at a Top 10 propane company, referring only to the repair costs of strikes, recently shared that each hit costs them between $300 and $1,500. Other costs discussed but not factored into that number, such as liability costs, customer goodwill, employee medical expenses, and lost productivity, can pile up quickly as well

While propane operators are the primary focus of this article, they are not the only businesses who deal with the reality of unmarked lines. Because 811 locating efforts typically stop at the meter, any excavator who works beyond the meter also faces the challenge of unmarked lines and can benefit from a practical solution


Propane operator performing the one-person safety sweep.

Whether locating jurisdictional systems, lines from the tank, private lines or verifying marks, the right locating equipment and practices can better protect customers, property and employees. A locating tool that has an ultra-high frequency assists with checking marks and finding all lines, especially when you can’t connect. When a connection point is available, locators with a low-frequency option can help to isolate lines, even in congested areas.

Performing a “safety sweep” using an ultra-high frequency locator is a technique for finding unmarked lines that might be in the dig area. Two types of safety sweeps can be performed, the two-person safety sweep and the one-person safety sweep. Generally, the two-person sweep is preferable. Because propane service technicians typically work alone, the one-person sweep is vital for them.

In addition, some operators also locate their own existing propane lines. “Locates are an important part of our business culture,” says Dawson. “It’s not just about the safety of our customers, the employees and the environment; it also helps to set your business apart. Locating existing lines shows the customer that you are a professional and have the right equipment for the job.”

To Dawson’s point on competitive differentiation, the opportunity for value-add services, like locating propane lines for customers, gives operators another way to say “yes” to the customer. An operator recently shared that he is seeing an increase in locate requests. These requests are in addition to the ones received through 811 for jurisdictional locates. He believes equipping each branch with a locator will improve damage prevention efforts and better serve his customer base.

One possible reason for the increased demand for locating unmarked lines beyond the meter is the uptick in backyard projects. According to Jobber’s Home Service Economic Report: 2020 Review, growth in landscaping, lawn care, and other outdoor services (the green segment) “accelerated in the fourth quarter of 2020, hitting a record 32% year-over-year growth in December

Direct-connect when possible to isolate in congested areas.

Clearly, COVID-19 impacted these types of projects positively, at a time when stay- and work-athome initiatives were the norm, but it looks as though some employees may continue working from home post-pandemic. This could indicate a continuation of increased green segment work, and the need for private line locating, for the foreseeable future.


Operators say the biggest benefit of finding and verifying underground lines with locating equipment is increased safety. Another benefit is that locating protects company assets and customer property. Other advantages are decreased fines and penalties and increased productivity, all leading to a better bottom line.

So, whatever the business, if digging is involved, the chances are that at some point unmarked lines will be a challenge. Identifying them before excavation is worth the time, effort, and investment.

No one wants accidents. No one wants damages. Safety is of utmost importance, and safety is good business.

Matt Monroe is Sales and Marketing Director at Pipehorn, a locating technology provider. Matt has been safety sweeping since 1993. He can be reached at or by calling 205-956-3710

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