Air hose safety is more than using a coupling safety clip or even installing a hose whip-check cable. Safety needs to be considered as a system which includes properly matched products, education, and frequent inspection. Some products, while appearing to be redundancies, can mitigate risk for varying types of hose and coupling failures.
The graphic below shows 5 items that we recommend to make up a safe pneumatic hose system.
First (1) is a safety check valve. These valves are designed to be installed at the air source (compressor, receiver, manifold, etc.) before any valve or coupling. They are designed to ‘check’ and cut off air flow when a surge is detected. A surge in CFM is a sign of a severed hose or coupling blow out. A properly selected and installed check valve will put a quick end to the hazards of an otherwise unchecked and out-of-control hose.
Next (2) is a hose restraint such as a safety whip check (shown), a hose choker cable, or a nylon hose restraint. A properly installed hose restraint will hold the hose in place if a coupling set becomes disconnected or severed from the hose. Hose restraints come in a variety of styles and sizes so make sure that yours is properly matched and well secured. To ensure that the hose does not slip loose, restraints should sit fully extended down the hose rather than just behind the coupling.
Ensure that all valves and pipe fittings (3) are rated for the service and peak pressure rating of your system. Some plumbing valves and couplings have low pressure ratings and are designed for fluid. Ensure that any pipe fittings are rated for air service and use schedule 80 if a higher pressure rating is needed. Inspect all thread connections and use proper sealant when connecting.
The hose coupling (4) should be: a matched set, in good operating condition, and properly installed. Use a locking type coupling where available. Safety clips ensure that Chicago type couplings are properly connected and also prevents accidental disconnection. Couplings can disengage due to vibration in some cases. Accidental disconnection is not only caused by operator error.
The hose assembly (5) is what all of these items are trying to keep in check. Ensure that the hose assembly is not the potential cause itself. Purchase brand name quality hose, as it will be more resistant to weathering and job site abuse. A pressure rating on the hose layline is only valid for the hose itself. The hose coupling is often rated lower than the hose, so ensure that the system does not see pressure beyond the rating of the coupling and clamping method. Inspect regularly, especially for any field-repaired hose assemblies. Discontinue use if the coupling twists inside of the hose, or if any part of the shank is exposed. Do not use duct tape or electrical tape to repair your hose. If a pinhole leak occurs, cut the hose before the leak and install new couplings or a hose mender. Finally, replace hose before a failure occurs to reduce the risk of blowouts and decrease down time.
Education and proper use is equally important with a well designed hose system
The perceived value of a safety clip may increase when information is shared about the potential of couplings becoming loosened by tool vibration.
Education on whip restraint placement can prevent a hose from slipping out of its restraint and causing injury.
Ensure that all operators are aware of the purpose of the system’s safety components and how to properly install them.
Inspect all components for cracks, weathering, and other damage. Tag items removed from service so as not to be confused for spares.
Never carry or lower equipment by its hose or a hose restraint. This can cause the coupling to loosen and can cause damage to the restraint.
Instruct all operators to replace hose safety restraints in the event of a hose failure as the wire or nylon could be damaged.
Setting up a safe hose and coupling system must include information as well as feedback. Safety should be a conversation.
