Shutting down a machine does not automatically make it safe to work on. Hydraulic pressure or compressed air may still be trapped somewhere in the system, posing a risk to anyone servicing the machine. This stored energy is why lockout/tagout, commonly called LOTO, matters for fluid power equipment. A proper procedure identifies every hazardous energy source, isolates it, addresses stored energy, and verifies that equipment is actually deenergized before work begins.
Why is LOTO Different for Hydraulic and Pneumatic Equipment?
Hydraulic and pneumatic systems create an extra challenge because energy can remain in the machine after its primary power source is disconnected. OSHA 29 CFR 1910.147 recognizes these types of energy as hazardous energy sources, and notes that turning off the machine is not always enough to make it safe for service.
Depending on the equipment used in a facility, a fluid power LOTO procedure may need to address electrical power to pumps and compressors, hydraulic pressure, compressed air, and other stored pressure. OSHA’s lockout/tagout standard requires potentially hazardous stored energy to be relieved, disconnected, restrained, and otherwise rendered safe before servicing begins.
What Are the Basic LOTO Steps?
The exact procedure should be developed for the specificities in each workplace, but OSHA establishes a general process for controlling hazardous energy. The process generally looks like this:
- Prepare for shutdown by identifying hazardous energy involved and how it will be controlled.
- Shut down the equipment following manufacturer procedures.
- Isolate energy sources by operating the appropriate disconnects and line valves.
- Apply lockout or tagout devices according to the company’s energy control procedure.
- Control stored energy by relieving, disconnecting, restraining, or blocking it.
- Before starting work, confirm that the equipment has been isolated and deenergized.
Always double-check that the equipment is actually deenergized before working on it.
How Do You Deal With Stored Hydraulic Pressure?
Controlling stored hydraulic or pneumatic energy may involve bleeding pressure from the circuit, addressing accumulator pressure, lowering components to a safe position, or mechanically blocking equipment that may move during service. Never rely on a control valve alone to hold a load while someone is working on a machine. If pressure can build back up while maintenance is underway, OSHA requires continued verification until the work is complete or the possibility of hazardous reaccumulation no longer exists.
How Do You Lock Out a Pneumatic System?
Pneumatic equipment presents similar concerns to hydraulic systems. Closing the main air supply stops new compressed air from entering the system, but it does not guarantee that there is no air already trapped downstream. A proper isolation setup may include a lockable air supply valve that can be secured in the safe position and a method for releasing downstream pressure. Before work begins, the lockout procedure should account for air stored in cylinders, air lines, reservoirs, and accumulators.
What LOTO Equipment Might a Fluid Power System Need?
Common LOTO equipment includes ball valve lockout devices, lockout hasps, cable lockouts, and other equipment that can be used to block or restrain hazardous movement. The device used has to match the energy-isolating device. A lockout that does not properly fit a valve and hold it in a safe position does not solve the problem.
It is also important to remember that hardware is only one part of LOTO. OSHA requires an energy control program that includes procedures, employee training, and periodic inspections.
Need the Right LOTO Equipment for Your Fluid Power System?
If you’re updating a machine safety setup or preparing for a plant-wide LOTO rollout, Dewald Fluid Power can help you match the hardware to your equipment. We stock ball valve lockout and LOTO safety equipment, including ball valve lockout devices, safety ball valves with integrated lockout provisions, locks, tags, hasps, and related safety hardware.
Dewald also carries safety products for fluid power applications, including velocity fuses and two-hand anti-tie-down systems. If you’re unsure what fits the valves on your equipment, bring your valve information to our Mishawaka counter, give us a call, or request a quote. We’ll help you identify the right hardware for the application.