Pinpointing a gas leak isn’t complicated—drill a hole through the pavement, drive the rod through the soil, insert a tester and move to the next spot until you detect the highest level of gas. But determining exactly how you’re going to dig the hole—or, more precisely, with what—can be more complicated. Wrapped into the decision is everything from efficiency to response times to workers’ compensation.

Gas leaks happen everywhere in all types of pipelines, including PVC and cast iron pipes that wear over time. Corrosion, broken or loose couplings and freeze/thaw cycles are among the quiet culprits.

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Whether crews need to drill five holes or 20, the faster they can do it the quicker they can get a rating and track down the leak. It goes beyond sheer numbers for utility companies; arming crews with the right drill can be a big factor in determining whether your business saves or loses money, customers remain happy and employees stay healthy.

One Method, Three Options

Short of ripping up entire sections of the street, the first step utility companies need to take to pinpoint a gas leak is to drill through the pavement. A rock drill is the best tool for the job. The key is to select the right type of rock drill for your company.

There are three configurations for rock drills that, at a basic level, operate exactly the same. The bits rotate while an internal hammer rapidly moves up and down and strikes the top of a bit to drive it into the ground. While an operator holds some drills in place, others are affixed to a frame. But what really sets these drills apart from each other goes deeper than who or what is holding the machine.

Let’s Rock

Handheld rock drills have been around since the early 1900s. The compact machines are operated by one person, weigh an average of 60 pounds and are most often pneumatically powered. In the past, the handheld rock drill has been the most widely used configuration for drilling holes to pinpoint gas leaks, mainly because of their low initial cost. In addition, the small size allows operators to place them into the back of a truck for transportation from jobsite to jobsite. But the benefit of the low initial cost starts to crumble like dirt falling back into a hole when operators begin sustaining back and arm injuries due to intense, repetitive jolting from the machine.

A Framed Solution

Frame-mounted configurations also are pneumatically powered, but hold the drill in place for precise, consistent drilling. Operators simply pull a lever and the drill goes to work. Most manufacturers equip the frame with wheels for easy maneuverability from one location to the next. For transporting from site to site, many units can be lifted by hand into the back of a truck, and those that are too heavy for safe loading by crewmembers can be placed into the back of a truck easily with a forklift or small loader. These drills are a little more expensive, but they’re easier to operate and just as easy to move.

Taking a Load Off

The most expensive configuration is the rock drill that is affixed to the bed of a truck or mounted to a specially designed trailer. These drills cost nearly nine times more than frame-mounted rock drills and 35 times more than the handheld models. These types of drills are typically powered by hydraulics. Once the truck or trailer is in place, the operator pulls a lever to lower the drill to the ground, then pulls another lever to start drilling. The drill also is equipped with a small auger, so once the bit drills through the pavement, the operator can swing it out and use the auger to drill through the soil to get down close to the pipe. These units eliminate loading and unloading altogether, but are somewhat limited in terms of where they can go; homeowners do not want trucks rolling over their lawns, and these drills can’t be used at all in confined spaces.

While the three tools operate the same way, their effects on operators and company pocketbooks can vary greatly. Drilling it down to the best option goes beyond the price tag.


Rock drills are simple and effective, but their powerful design may be their biggest downfall. The more operator involvement, the higher the risk of injury, and as the risk of injury rises, so does the likelihood of paying out more for those injuries.

Rock drills operate with a percussive motion that produces vibrations. When these vibrations are transmitted to the operator, as mentioned before, they can lead to repetitive strain injuries to the hands, arms and back. Prolonged use can cause carpal tunnel syndrome and reduce blood flow to the hands, which is also known as hand-arm vibration syndrome. These injuries make completing even the simplest of tasks, like holding a fork or gripping a steering wheel, challenging. Prolonged exposure can even cause nerve damage. The risk is so great that some countries limit the use of handheld rock drills to just 20 minutes in an eight-hour time period.

Spring-dampened handles featured on some handheld drills absorb vibrations to reduce the risk of injury. But, these handles simply can’t absorb all the vibrations, so the risk of injuries occurring over time is still present.

Handheld drill operators also can suffer from injuries that are not caused by vibrations. Since most bits are slightly flared at the end, they can get caught up on the material that has fallen around it. As the operator keeps the drill running while lifting it up, the bit can catch on this material and cause the drill to jerk. This, along with the holding the sheer weight of the machine can lead to back injuries.

Frame-mounted and truck-mounted drills have no limits on usage. The frame on the unit holds the drill in place as it operates, transmitting vibrations to the frame instead of the operator. And if a bit becomes stuck, operators simply flip a lever and the drill backs the bit out of the hole, transmitting any jerking motion to its frame. While they might initially cost more than a handheld model, they are both safer options that will likely pay for themselves when compared to the costs associated with workers’ compensation.

To further avoid injuries, look for features that aid in maneuvering handheld and frame-mounted drills from one site to the next. For example, some frame-mounted units are equipped with a lifting bale, which provides a balanced picking point for loaders and forklifts so crews don’t have to lift the unit.


Drilling holes faster allows crews to find leaks more quickly so potential hazards can be minimized and crews can move to the next project. Because fame-mounted drills don’t fatigue like handheld drill operators, they maintain consistent pressure whether it’s the first hole or the tenth. This allows frame-mounted drills to drill up to four times faster than handheld models. When pinpointing leaks, that speed could be the difference between hours and days.


When in search of leaks, operators must be careful not to damage nearby water and electrical lines, or the gas line itself. Precision is crucial.

Handheld models are relatively easy to position, but if the operator doesn’t maintain enough pressure, the drill can bounce around, reducing control. Both frame-mounted and truck-mounted models keep the drill steady during operation.

While the compact handheld drill can be easy to position, even in limited access areas, lifting a 60-pound machine out of the hole and moving it from one spot to the next leads to operator fatigue and injuries to the back, shoulders, legs or feet.

Frame-mounted models are easier to maneuver and position. The frame holds the drill’s weight and the frame’s wheels allow operators to easily move it from one spot to the next. The drills also are compact enough to maneuver into limited access areas.

While truck-mounted drills obviously are the easiest to transport from site to site, moving the rig into congested areas near cars and curbs can be challenging or nearly impossible. The units take up a lot of space, which, in some cases, requires entire lanes of traffic to close and disrupts traffic flow. The large size of the rig also could be tough to position, particularly without directional guidance.


Handheld drills vibrate intensely, so keeping them aligned while maintaining the appropriate pressure can be tiresome and challenging, particularly for operators with less experience. If the operator uses too little pressure, the drill could bounce, which not only reduces control and transmits vibrations to the operator, but also causes damage to the bit. Too much pressure slows the bit down, causing it to get stuck and become damaged. In addition, drills become misaligned when operators lean too far to either side. That affects the bit’s normal rotation, which reduces efficiency and might damage the bit.

Overall, frame-mounted and truck-mounted drills are easier to operate and maintain. The frame holds the drill in place so it remains properly aligned and helps the drill maintain consistent pressure.

Pneumatic drills are relatively easy to care for and, if issues arise, operators can open them up and have a look right on site. Truck-mounted drills are powered by hydraulics that require O-rings and seals. Once exposed to dusty environments, these units are likely to fail. They also require regular maintenance like filter changes and fluid replacement, and when repairs are needed they are typically more expensive than pneumatic units.

Middle of the Road, Way Out Ahead

Frame-mounted models may just be the best of the safety, cost and productivity worlds. They practically take the operator out of the equation, drastically reducing the risk of injuries, and that equates to fewer workers’ compensation claims. They are easy to operate and maintain. They are also small enough to operate in minimal access areas, yet powerful and fast enough to pinpoint leaks quickly.

While it might seem like a huge factor when choosing a drill, consider this: The cost of just one workers’ compensation claim likely will be much more than the difference between the costs of a handheld rock drill and a frame-mounted unit.

 That’s important because, the fact is, it could take five holes or it could take 20, and you want to make sure you’re maximizing the positives and minimizing the negatives every time a bit touches a road or sidewalk surface. It doesn’t have to be a complicated choice, but it can be a smart one.