ISO E018 Turn anticlockwise to open Sign

What the Anticlockwise Arrow Tells You

E018 instructs the user to rotate an opening device anticlockwise — counterclockwise, in American usage — to release it. The ISO 7010 register ties the sign to a specific scenario: the doorknob of a security door on an escape route must be turned in an anticlockwise direction for the opening mechanism to operate. The pictogram is a curved arrow sweeping in the release direction on the green background ISO 3864-1 assigns to safe-condition information.

Security doors are the origin case because they invert normal expectations: their locks, multi-point mechanisms, or knob-operated releases often behave nothing like an ordinary latch, and a person who has never operated the door before gets exactly one stressed attempt to figure it out. The same rotational instruction transfers naturally to handwheels on marine watertight doors, escape hatches, and wheel-dogged closures, where the sign is applied adjacent to the wheel it describes.

Why Rotation Direction Fails Under Stress

In an evacuation, people do not experiment methodically. They wrench a knob one way, feel resistance, and conclude the door is locked — even when a turn the other way would have opened it instantly. Smoke, darkness, gloves, and adrenaline all strip away the fine motor feedback that lets someone sense a mechanism yielding. A rotation arrow placed at the point of operation converts a two-way guess into a single correct action.

Anticlockwise release at least aligns with the ingrained lefty-loosey convention from valves and threaded fittings, which is some help to industrial workers but means little to the general public. On vessels, the stakes compound: turning a watertight-door handwheel the wrong way drives the dogs tighter, and a crew member fighting a hardening wheel in rising water has no spare seconds. Marine safety signage suites consequently make heavy use of both E018 and its clockwise counterpart.

Applying E018 Correctly

Fix the sign immediately beside or on the device it governs — a rotation instruction three meters from the knob it describes helps nobody. Orientation must be preserved as printed; installing the label rotated or mirrored reverses its meaning, which is a genuinely dangerous installation error rather than a cosmetic one. Where the door also needs push or pull information, combine E018 with the appropriate door-operation sign rather than expecting one symbol to carry both instructions.

Verify the arrow against the hardware before and after any locksmith or maintenance work: mechanisms get replaced, and a swapped cylinder or reversed gearbox can silently turn a correct sign into a false one. Evacuation drills are the natural audit — watch whether unfamiliar users open the signed door on the first attempt. If they hesitate or reverse direction, the sign is too small, too far from the knob, or poorly lit for the conditions it must serve.

What does the green anticlockwise arrow sign mean?

It is ISO 7010 sign E018, telling you to turn the knob, handle, or wheel anticlockwise (counterclockwise) to open the device it is mounted next to. It is used on security doors along escape routes and on wheel-operated closures such as watertight doors and hatches, where turning the wrong way can jam the mechanism tighter.

Is anticlockwise the same as counterclockwise?

Yes. Anticlockwise is the British and international English term, counterclockwise the American one; both describe rotation opposite to a clock's hands. ISO 7010 uses anticlockwise in the official sign title, so E018 and a counterclockwise-to-open instruction mean the same thing.

When is the E018 sign required?

ISO 7010 itself does not mandate any sign; the need arises from risk assessment. If a door or closure on an escape route opens by a rotary action whose direction is not obvious — security doors, handwheel-operated hatches, watertight doors — general workplace signage duties in most jurisdictions expect the operating method to be marked, and E018 is the standardized way to do it for anticlockwise release.

What is the difference between E018 and E019?

They are mirror instructions. E018 means turn anticlockwise to open; E019 means turn clockwise to open. Always match the sign to the actual mechanism, and re-check after any lock or hardware replacement, because fitting the wrong one directs users to tighten or jam the device they are trying to release.