OSHA Caution This Unit Starts Without Warning Sign Stickers

This sign specifically warns workers that the unit will start without any audible alarm, flashing light, or other pre-start warning signal. This is a critical distinction from standard automatic start signs it explicitly tells workers they cannot rely on any sensory cue to anticipate activation. Equipment commonly posted with this sign includes air compressors, pumps, HVAC units, backup power systems, and remote-activated process equipment.

A "Machine Starts Automatically" sign warns that a machine can activate without manual operator input. A "Unit Starts Without Warning" sign adds that there is no pre-start indicator no horn, no light, no countdown before activation. This additional specificity is important for equipment where workers might otherwise expect a warning signal before the unit starts.

This sign is appropriate for any unit that activates automatically and provides no pre-start sensory warning including air compressors, water pumps, HVAC fans, standby generators, remote-activated conveyor sections, and automated process units. OSHA 29 CFR 1910.147 identifies the absence of start warning signals as a specific hazard requiring clear worker communication.

Post directly on the unit on the housing, control panel, and any service or access panel. For units in enclosed utility areas or mechanical rooms, post at the room entry point as well so workers receive the warning before entering the space. Ensure no worker can approach or service the unit without being informed that it starts without any pre-start warning signal.

Yes. This sign supports compliance with OSHA 29 CFR 1910.147 (Control of Hazardous Energy / Lockout Tagout) by communicating the specific hazard that makes lockout/tagout critical the absence of any start warning that would otherwise allow a maintenance worker to react before the unit activates. Posting this sign reinforces the written lockout/tagout program at the point of service.