Hydraulic Power Tools

Hydraulic tools use pressurized fluid to run breakers, saws, cutters, drills and other tools. They’re powerful, light for their output and can be used in wet places and near utilities. The same pressure that gives them power can inject fluid through skin in an instant, and a burst hose can whip or spray hot oil. Understanding the pressure behind the tool is the key to using it safely.

• Construction
• Utilities
• Demolition

How hydraulic tools work

• A power unit (a gas, diesel or electric hydraulic power pack, or the hydraulic system of a truck or machine) pumps fluid under pressure through hoses to the tool. The tool turns that fluid pressure and flow into work, and the fluid returns to the tank.
• Typical hand tool circuits run at about 1,500 to 2,000 psi and different flow rates (classes are set by the Hydraulic Tool Manufacturers Association, such as around 4 to 5, 7 to 9 or 11 to 13 gallons per minute). Check the tool and power unit ratings, and make sure they match.
• Common tools include breakers and chipping hammers, rock drills, chain saws, cut-off saws, impact wrenches, grinders, rebar cutters, post drivers and cable cutters. See Rebar Cutters & Benders, Demolition Hammers and Chainsaws.
• Hydraulic tools are used for work around water and electricity, such as underwater and utility work, since there is no electric motor in the tool.

Main hazards

• Fluid injection: a pinhole leak in a hose or fitting can spray a fine jet of fluid at high pressure that penetrates skin. It may look like a small cut or bruise, but the fluid under the skin can cause severe infection, tissue death and amputation. It is a medical emergency.
• Hose failure and whip: a burst or disconnected hose under pressure can lash, spray hot fluid and strike people.
• Burns: hydraulic fluid and components get very hot, over 150°F in some cases. Spills and sprays can burn.
• Electrical contact: a hose or tool that touches an energized line can conduct electricity, unless it is made of non-conductive material. See Overhead Power Lines.
• Tool hazards: the usual dangers of the tool itself, such as flying chips, noise, vibration, kickback and pinch points.
• Fire: leaking fluid on hot engines can ignite. Some fluids are flammable.
• Slips: spilled hydraulic oil makes surfaces very slippery. See Slips, Trips & Falls.
• Environmental harm: spills pollute soil and water. See Spill Response.

Fluid injection: the hidden danger

• Injection injuries can look minor at first: a small puncture, a tingle or a pale spot. Pain and swelling may come later.
• Get emergency care immediately. Tell the staff it was a high-pressure injection. Surgery is often needed quickly to clean out the fluid and save the tissue, and delay greatly raises the risk of amputation.
• Don’t wait, don’t squeeze or wipe it, and don’t try to treat it yourself. See hydraulic hazards and First Aid Basics.

Hose and coupling safety

• Use only hoses rated for the system’s pressure, and keep their length within the tool maker’s limits. Check the label for the working pressure and burst rating. Don’t mix hoses from different systems.
• Use the right hose for the job. Hoses used near energized lines must be non-conductive, dielectric-tested hoses that are marked as such, and used within the test schedule. Standard steel-braided hoses conduct electricity. See When Equipment Contacts a Power Line.
• Inspect hoses before every use: look for cuts, abrasions, cracks, kinks, bulges, blisters, leaks, exposed wire, damaged covers and loose or damaged fittings. Replace, don’t repair, damaged hoses.
• Use proper couplings. Most tools use flat-face (or similar) quick-connect couplers. Connect and disconnect them only when the power unit is off and pressure is released, and match the male and female ends and the correct direction of flow. Use caps on open ends to keep dirt out.
• Route hoses safely: don’t kink or twist them, don’t pull or drag hoses by the fittings, don’t run vehicles over them, and protect them from sharp edges and heat.
• Secure hoses or use whip restraints on long runs and at connections so that a failure doesn’t lash.
• Replace hoses on a regular schedule, even if they look fine, based on age and service, and keep records.

Setting up and using the tool

• Match the tool, hoses and power unit in pressure and flow. Don’t exceed ratings, and use the correct relief valve setting.
• Check fluid type and level, and use the fluid the maker specifies. Keep it clean and don’t overfill.
• Set up the power unit on stable ground, in a ventilated area (gas and diesel engines make carbon monoxide), away from flammables and with a fire extinguisher nearby. See Carbon Monoxide and Fire Extinguishers (PASS).
• Connect couplers fully and check the flow direction before starting. Start with the tool pointed in a safe direction and the trigger or valve off.
• Wear the proper PPE: safety glasses or face shield, hearing protection, gloves, sturdy boots, a hard hat, and a respirator when making dust. See Eye & Face Protection, Hearing Protection and Silica.
• Use two hands and a stable stance for heavy tools such as breakers. Keep control of the hose, and keep others clear. See Hand-Arm Vibration.
• Release pressure and shut down the power unit before changing bits, blades or tools, clearing jams, or disconnecting hoses. See Lockout/Tagout.

• Don’t use a damaged hose, coupler or tool, or a hose with a patch or tape.
• Don’t disconnect couplers under pressure, or force connections that don’t fit.
• Don’t point a tool or hose at anyone, or stand in line with a connection.
• Don’t use hydraulic hoses as handles, tie-downs or lifting devices.
• Don’t refuel a hot power unit, or fill the tank while it is running.

Leaks, spills and fire

• Fix leaks right away. Shut down, release the pressure and replace the leaking part. Don’t tighten fittings under pressure.
• Clean up spills with absorbent pads and dispose of them properly. Keep drip pans under power units. See Oily Rags.
• Don’t let hydraulic oil contact hot exhaust or sparks. Keep the area clear of flammables.
• Use fire-resistant fluids where the maker or the work calls for it.

Maintenance and storage

• Service tools and power units on schedule: change filters and fluid, check seals and pressure, lubricate and clean. Use trained technicians for repairs. See Hydraulic Hazards.
• Store tools and hoses clean, capped and coiled loosely, out of sun and away from chemicals and sharp edges.
• Tag out and report damaged equipment. See Tagging Out Damaged Tools.

Hydraulic tool checklist

• Tool, hoses and power unit match in pressure and flow ratings
• Hoses and couplers inspected; dielectric hoses used near power lines
• Pressure released and power off before connecting, disconnecting or changing bits
• Leaks checked with cardboard, never my hand
• PPE on, including eye, hearing and respiratory protection; power unit ventilated and fire protected
• I know that a high-pressure injection injury is an emergency and needs immediate care

Last updated: October 4, 2026