Glossary · Guards and machine motion
Fixed guard
In machine safety, a fixed guard is a guard attached so that it can be opened or removed only with tools or by destroying its attachment, for example by screws, nuts or welding.
- Machine safety
- Maintenance
In one sentence
A fixed guard can only be removed with tools; it suits hazards that rarely need access, and its fixings must stay with the guard or the machine.
Example
A bolted sheet-metal cover over the belt drive of a CNC machine can only be removed with a wrench during scheduled maintenance, after the machine has been isolated.
How it applies
- Machine safety: A fixed guard is the preferred choice where access is not needed during normal operation. If access is frequent, operators will leave it off; then a movable guard with an interlock is the better solution.
- Design: The EU machinery rules require that the fixing systems of fixed guards remain attached to the guard or the machine when the guard is removed. ISO 14120 gives the design requirements.
- Maintenance: Removing a fixed guard is a maintenance task. The maintenance manual should require isolation, for example by lockout/tagout, before removal and a check that the guard is refitted with all fasteners.
- Technical documentation: Warnings on or near the guard and in the instructions should state that the machine must not be operated with the guard removed.
Fixed guard vs. movable guard
A fixed guard needs a tool to open. A movable guard opens without tools and is therefore normally interlocked with the control system.