Emergency stop button
Identifies an emergency stop button.
Understanding this sign
Green square or rectangular signs identify emergency escape routes, safety facilities, and rescue equipment.
Follow the complete wayfinding system and local emergency plan. A symbol alone does not establish a safe route.
Sign Versus Actuator: What E020 Actually Is
E020 is a location marker, not the control itself. The ISO 7010 register gives it a single job — to indicate where an emergency stop button is — and it does that with a white pictogram on the green field used for emergency-equipment signs. Anyone scanning a machine hall for a way to kill a runaway process is looking for this sign first and the button second.
The actuator it points to follows a different color logic entirely. Machinery standards, IEC 60204-1 and ISO 13850 among them, established the familiar red mushroom-head pushbutton against a yellow background as the emergency-stop convention, with latching behavior so the button stays engaged until deliberately reset by twisting or pulling. Green sign, red-on-yellow device: the sign says where, the colors on the device say what.
Why the Location Needs Marking at All
On a compact bench machine the operator can see the red mushroom from the working position and E020 adds little. The sign earns its place on larger installations: packaging lines with stop stations every several meters, conveyor runs equipped with pull-wire stops, robotic cells with buttons at each access gate, test benches, escalators, and fuel dispensing forecourts. In these environments the person who needs the stop is often not the operator — a passer-by watching an entanglement unfold must find a control on equipment they have never used.
Height and sightline decide effectiveness. Post E020 above or immediately at each stop station, high enough to be seen over intervening machinery and trolleys, and repeat it at every station rather than only the nearest one to the control panel. Along pull-wire conveyor stops, periodic signs remind people the entire wire is the actuator, a fact non-operators rarely know.
Emergency Stops in the Safety Hierarchy
An emergency stop is classified in machinery-safety practice as a complementary protective measure. It exists for the situation that inherent safe design, guarding, and interlocks failed to prevent, and it depends on a human noticing the event, reaching the button, and pressing it — all after the harmful motion has begun. A machine that is only safe because someone might hit the e-stop in time is not a safe machine, and no quantity of E020 signage changes that.
The sign nevertheless supports the measure's one advantage, speed of human intervention, and it pairs naturally with related markings: W018 warns of automatic start-up on equipment that can restart without warning, while lockout points for maintenance energy isolation are a separate system that an e-stop never substitutes for. Pressing the mushroom stops the hazardous motion; it does not make a machine safe to reach into.
Keeping the Marked Stops Functional
Emergency stops degrade quietly. Buttons get obstructed by added guarding or stacked materials, pull-wires stretch out of tolerance, and reset procedures drift into folklore known to one shift only. Function tests of each stop station belong on the planned maintenance schedule, and the walk to each station is also the moment to confirm its E020 sign is present, clean, and visible from the directions people would actually approach.
Discipline about placement protects the sign's meaning. Marking ordinary stop or power-off controls with E020 teaches the workforce that the symbol sometimes points to non-emergency hardware, an association that costs seconds during a real event. Reserve it for actuators that meet the emergency-stop requirements of the machinery standards, and let normal controls carry normal labels.
Where you will see E020
Packaging lines with stop stations every several meters, conveyor runs with pull-wire stops, robotic cells with buttons at each access gate, test benches, escalators, and fuel dispensing forecourts are where the sign earns its place, since the person needing the stop is often a passer-by rather than the operator. It is posted above or at each stop station, high enough to be seen over machinery and trolleys, and repeated periodically along pull-wire conveyor runs.
Common questions about E020
What does the E020 emergency stop button sign mean?
It marks the location of an emergency stop actuator so that anyone — operator or bystander — can find it quickly during a dangerous event. The sign itself is green and white per ISO 7010; the button it points to is the red mushroom-head on a yellow background required by machinery standards such as IEC 60204-1.
Why is the emergency stop sign green when the button is red?
They follow two different color systems. ISO 3864-1 uses green for signs indicating safe conditions and the location of emergency equipment, which is what E020 does. The device colors come from electrical machinery standards, which reserve red-on-yellow for the emergency-stop actuator itself. The green sign helps you find the red button.
Does every machine need an emergency stop button?
Most powered machinery under regimes like the EU Machinery Regulation must have an emergency stop function, with limited exceptions such as some hand-held tools and machines where a stop would not reduce the risk. Whether the location then needs an E020 sign is a risk-assessment question — it matters most where stations are numerous, distant, or used by people unfamiliar with the equipment.
Can an emergency stop replace machine guarding?
No. Safety standards treat the e-stop as a complementary measure that backs up, but never substitutes for, safe design, fixed and interlocked guards, and other engineering controls. It only works after a person has noticed the danger and reached the button, which is too late to rely on as the primary protection.
Reference details
| Symbol code | E020 |
|---|---|
| Sign family | ISO Emergency Signs |
| Standard reference | ISO 7010:2019 / ISO 3864-1 ISO Online Browsing Platform: E020 |
| Screen color reference | #009933. Screen colors are not a production color specification. |
| Download formats | SVG reference artwork; a 1024 × 1024 pixel PNG conversion on a white canvas. |
| Record date | · How to interpret our dates |
| Page updated |
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Sources and artwork credits
- Artwork source
- Wikimedia Commons file page
- Creator credited by source
- Clemenspool
- License
- CC0
- Source metadata checked
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