Jet Mole Piping

Proper Procedures For Operating A Jet Mole, 9 do’s and don’ts

Key Takeaways From PFC's Jet Mole Rig Procedure

  • Jet mole rigs are powerful pieces of equipment employing high-pressure water jets to clean surfaces. At Precision Fabricating & Cleaning (PFC), we use these rigs to validate piping systems.
  • Operating a jet mole rig requires strict adherence to Technical Procedure (TP) 142 - System Validation - Jet Mole Method, which is certified by AS9100 and ISO 9001, two quality management system standards.
  • The greatest hazard surrounding a jet mole rig is the speed of the water jet, which can travel up to and exceed 3,300 kilometers per hour, making them potentially fatal if used improperly.
  • All jet mole systems must incorporate at least one fluid shut-off or dump device (called a Dead Man Switch) for emergency shutdowns in case of system failure.
  • Most jet mole operations require two workers – one to operate the lance/gun or delivery hose of the jet mole rig, and the second to keep an eye on the rig, first operator, and area for possible problems.
  • Strict don’ts must also be followed when using a jet mole rig such as not commencing any operation without warning signs or personal protection in place nor running any equipment with leakage without rectifying it first or attempting to tighten any pressure joint while under pressure etc., leaving site only when safe to do so.

One of the most important cleaning services we offer for piping systems at Precision Fabricating & Cleaning (PFC) is high pressure water using a jet mole rig. While this equipment is extremely effective at its job, it’s also highly dangerous if the operator and nearby personnel don’t follow proper procedures.

That’s why at PFC, we follow a standard called Technical Procedure (TP) 142 - System Validation - Jet Mole Method. By adhering to it, we ensure the utmost safety, not just for our team of operators, but also for the entire floor, the equipment, and the piping systems being cleaned.

To communicate the lengths that PFC goes to maintain safety according to industry standards, we’ve written this article explaining exactly what a jet mole is, its dangers, and what we do and don’t do in the course of operating one.

What Is A Jet Mole?

Jet mole” is an informal term for a high-pressure water jetting unit. It shoots highly pressurized water in a steady stream for the purpose of cleaning dirt, dust, grime, and other forms of contamination from widespread surfaces. We use them at PFC to validate (clean out) piping systems.

What Are The Dangers Of Operating A Jet Mole?

Operating a jet mole rig improperly is extremely dangerous, since exposure to the high-pressure water coming out of it can cause serious injury or even death.

The greatest hazard surrounding a jet mole rig is the speed of the water jet, which can travel up to and exceed 3,300 kilometers per hour. Such a fast-moving stream of water is powerful enough to slice through solid materials, including parts of the human body.

Even injuries that appear to be relatively minor can be fatal. This is because harmful microorganisms can enter the body through the injury site, along with air, water, and debris. Thus, small injuries like abrasions can become infected and turn deadly, if untreated.

What Is Technical Procedure (TP) 142 - System Validation - Jet Mole Method?

At PFC, we follow a series of strict processes and checklists outlined in Technical Procedure (TP) 142 - System Validation - Jet Mole Method. TP 142 defines the techniques and processes to be used for in-house, manually operated high-pressure water jetting equipment for validating piping systems. It has been certified by AS9100 and ISO 9001, which are quality management system standards adhered to across several different industries.

The reason we follow TP 142 is we take the potential dangers of operating a jet mole rig very seriously. As such, we want to maintain the utmost levels of safety for our crew, but also for the equipment we’re operating and the system we’re cleaning. TP 142 provides us with the guidelines to do just that.

Do’s For Operating A Jet Mole Rig

Below is a list of “do’s” - that is, steps that PFC follows in our compliance with Technical Procedure (TP) 142 - System Validation - Jet Mole Method.

  • Erect barriers and rope off the clear area.
  • Erect warning signs.
  • Check the fluid levels on the engine, gearbox, and pump (lubrication oil, fuel, and water, respectively).
  • Lay out the equipment and visually inspect it for damage (hoses, connections, etc.).
  • Assemble the equipment, checking all joints.
  • Ensure that the filters are clean.
  • Fully prime the equipment and bleed where necessary.
  • Fit the gun or lances and/or control valves. Visually check that the correct size and type of nozzle is fitted for the application.
  • Increase the pressure slowly until the operating conditions are reached.
  • Re-check the hose couplings and joints for leaks.
  • Ensure that all operators are wearing suitable protective clothing and are correctly positioned.
  • Ensure that ail pressure in the lines is released during a shut down.

In addition to the above basic steps, we also go even further to meet the safety parameters set out by TP 142.

For example, all jet mole systems must incorporate at least one fluid shut-off or dump device (called a Dead Man Switch). This is so that the operator can shut off the water jet at any time by releasing pressure on a trigger, switch, or foot valve pedal. However, if this dump valve fails, the second operator must be able to perform an emergency shutdown on the water pressure system.

That’s why most jet mole operations require two workers: the first to operate the lance/gun or delivery hose of the jet mole rig, and the second to keep an eye on the rig, the first operator, and the surrounding area for potential problems.

We also make sure that certain safety components are ready and in place on the lance/gun or delivery hose before the start of the operation. These include a stinger, a distance indicator on the flex lance, and a backout preventer - all of which work together to help the operator keep the high-pressure water jet under their control.

Don'ts For Operating A Jet Mole Rig

Just as there are things that jet mole operators should do, there are also plenty of things they shouldn’t. That’s why we also have a list of “don’ts.”

  • DO NOT commence any jetting operation until the warning signs are on and the operating area is roped off.
  • DO NOT operate the jet mole rig without first donning suitable personal protection for eyes, head, hands, feet, and body.
  • DO NOT run any equipment with leakage whatsoever without rectifying it first.
  • DO NOT attempt to tighten any pressure joint while the equipment is under pressure.
  • DO NOT operate with guns and control valves not functioning correctly (leaking or failing to shut off).
  • DO NOT operate with badly worn or undersized nozzles.
  • DO NOT continue to operate if any unauthorized personnel enter the operating area.
  • DO NOT leave a high-pressure water jetting unit running unattended.
  • DO NOT leave the site in a dangerous or untidy condition.

PFC Follows Proper Procedures For Cleaning Using A Jet Mole

At PFC, safety and integrity our most dearly held values. As such, we will always make every effort to follow the proper procedures for cleaning using a jet mole.

To experience this part of our expert cleaning and testing services, contact us here.

About PFC: Precision Fabricating & Cleaning is an innovative, highly qualified company with unique capabilities to accomplish a wide range of industrial testing and Precision Cleaning services, specializing in Hydrostatic Testing, Oxygen Cleaning Service, Cryogenic & Cold Shock Testing, Mobile Field Cleaning, Passivating/Passivation, High Purity Cleaning, Ultrasonic Cleaning, and so much more.


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