Hydraulic pressure release near miss

By Jerry Fritz, District 5 Employee Safety Representative

Hydraulic Quick Couplers

In the pre-dawn darkness of 5:00 a.m., a maintenance worker was attaching a snow plow to a truck. While attempting to connect the hydraulic quick couplers, he realized the hydraulic fluid was under pressure and he could not attach them without relieving the pressure. Using two wrenches he loosened the hose connection and in doing so, the oil from the hydraulic line sprayed him. He was covered from his chest to his knees and very fortunate the oil did not penetrate skin or spray into his eyes around his safety glasses.

Hydraulic Fluid Injection

Hydraulic fluid injection occurs when a stream of hydraulic fluid, under as little as 100 psi, penetrates your skin. It can occur with other fluids, such as water, diesel or paint, but the issue is the same: a fluid at high pressure pierces your skin and becomes trapped underneath. The first recorded case of this type of high-pressure injury occurred back in 1925, so it isn’t anything new.

When fluid initially hits your skin, it usually feels like a bee sting, a wire prick or a slight shock of electricity. The entry site may be so tiny that it looks like a pinprick, but don’t let the size of the injury deceive you – it can still be very dangerous. It can also look like a cut or tear in your skin.

Within a few hours, you’ll notice some welting and redness, usually accompanied by pain. After six hours, it will usually either be throbbing or feel numb. If left untreated, the tissue in the area of the injury will begin to die, you may experience a serious physical complication called compartment syndrome, and death can even occur. If the injury isn’t treated soon enough, you may end up with an amputation.

Relieving Hydraulic Pressure

The best solution is to eliminate the problem. Talk with your local mechanic for tips on how to eliminate the pressure or check to see if the manufacturer has any recommendations. If there is no way to eliminate the pressure then consider installing high-pressure quick couplers or using a leverage system. If you have no choice but to break a connection to relieve the pressure then cover the link to be loosened and very slowly turn the couple to relieve the pressure. Never attempt this task without proper PPE (gloves, face shield, or other eye protection).