Added safety needed for hydroexcavating in oilfields because of volatile fluids being used.

As much as it increases the margin of safety, hydroexcavation can be dangerous work due to the use of high-pressure water and air, and the fundamental dangers of excavation work. For those hydroexcavation contractors who also do work in the oil and gas industry, the presence of petroleum serves to compound those risks, according to Gary Toothe, the training manager for Federal Signal’s Environmental Products Group.

His workshop for hydroexcavating in oilfields lasts an entire day and starts with the basics. “We’re not trying to create liquid soup,” he stresses. “The high-pressure water is used to assist in the removal of the dirt. If the vacuum can remove the dirt on its own, you don’t need any water.”

Even if you are well versed in hydroexcavation, working in the oil and gas business requires specialized knowledge and training.

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The presence of gas and oil on a hydroexcavation site brings with it explosive risks not normally encountered in the field, which requires flame-resistant clothing as a start. Due to the risk of explosion, all potential sources of static electricity must be eliminated on the work site. “Your truck has to be spick and span, and you have to do assured grounding,” says Toothe. “No competent contractor is going to allow you on an active well site unless you can prove that there’s not going to be any electrical potential buildup on your equipment.”

The static charges are possible due to the friction of water, air and the vacuumed material flowing against the hoses, lances and tanks. “It is enhanced by the presence of petroleum, which is notorious for sucking moisture out of the air,” says Toothe. “If there’s a hydrocarbon component, you have the potential to create static electricity.” OSHA and well owners require assured grounding for all equipment in such work areas.

The risk of static discharge around petroleum products has been known since the 1950s. Three large oil tankers were damaged or destroyed in separate incidents in December 1969 involving static discharges during waterjetting, resulting in four deaths.

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Oilfield or not, special precautions in the form of equipotential mats are required if there are underground power lines in the area to prevent workers from electrocution hazards. “If you touch an underground electric power line and you’re not on an equipotential mat, you’re taking your life in your hands,” says Toothe. The mat clips onto the truck, which prevents electrocution by preventing the person from becoming grounded. “Regardless of the voltage you touch, it will not hurt you if you are standing on the mat.”

It also protects against injury from step potential: voltage that can be present in the ground around electrical equipment.

Other safety measures are needed to protect against dangerous fumes that petroleum products can produce. “You can blow a lot of contaminants out your blower, so atmospheric monitoring prior to and during the hydroexcavation becomes very important,” says Toothe. “You should have a pretty good idea of what’s there by working with your customer. Hydroexcavators are used to clean hydraulic fracturing tanks and to clean underneath drill rigs. There could be materials in there that have both a bad flammability component and vapor component, especially on a sour well, such as hydrogen sulfide, which is both flammable and toxic.”

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He recommends an OSHA-certified “competent person” on every hydroexcavation job as a best practice. “That person can pass on everything OSHA has learned over the past 40 years and keep people safe. If you’re going to put people in a hole more than 4 feet deep, you are required to have a competent person on site.”

Hydroexcavation for the oil and gas industry requires added training, but it can be worth the added effort, according to Toothe. “It’s a very lucrative field. If you do your homework, you can make a lot of money.”

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