ISO 7010:2019 / ISO 3864-1

ISO E021 Protection shelter Sign

ISO E021 Protection shelter Sign means the location of a protection shelter, a hardened or enclosed space people enter and stay in until an outside threat passes. Unlike most green safe-condition signs it directs occupants inward rather than out, anchoring the sheltering half of an emergency plan. It should be used where the cited standard, facility risk assessment, SDS, emergency plan, or written safety procedure requires this hazard or safety message to be communicated.

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ISO E021 Protection shelter Sign symbol
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Reference artwork: Wikimedia Commons · License: CC0

Technical Data

Legal Standard ISO 7010:2019 / ISO 3864-1
Color Codes #009933 / RAL 6032 Signal Green
Viewing Distance 100 mm: approximately 5 m; 200 mm: approximately 10 m; 300 mm: approximately 15 m; 400 mm: approximately 20 m; 600 mm: approximately 30 m.
Review Status approved / last reviewed 2026-07-07
Jurisdiction Scope Global, United States, European Union
Keywords e021, iso 7010, emergency, protection, shelter, indicate, location

Standard Dimensions Table

Sign Size Recommended Visibility
100 mm approximately 5 m
200 mm approximately 10 m
300 mm approximately 15 m
400 mm approximately 20 m
600 mm approximately 30 m.

Where This Sign Is Used

Civil defense networks in countries like Switzerland and Finland mark public blast shelters with it, US communities apply it to ICC 500 tornado safe rooms, and underground mines use it for refuge chambers stocked with breathable air, water, and supplies. Chemical plants designate sealed shelter-in-place buildings for toxic release scenarios, adding directional arrows, capacity panels, and photoluminescent versions for power loss.

In-Depth Guidance

A Safe-Condition Sign That Points Inward

Almost every sign in the ISO 7010 E-series moves people out of a building; E021 does the opposite. Its ISO register function is to indicate the location of a protection shelter — a hardened or enclosed space that people enter and remain in until a threat outside has passed. The pictogram sits on the standard green safe-condition square, so occupants read it with the same trust they give exit signs, but the instruction it carries is stay, not go.

That inversion matters during planning. Fire training conditions everyone to head for open air, yet tornadoes, toxic gas releases, armed threats, and mine emergencies all punish people who step outside. E021 gives the sheltering half of an emergency plan a standardized visual anchor, so the route to protection can be marked with the same rigor as the route to the door.

Where Protection Shelters Actually Exist

Civil defense infrastructure is the original home of this sign: countries such as Switzerland and Finland maintain extensive networks of public and residential blast shelters, and consistent marking is what makes a shelter findable by someone who has never visited the building before. Storm shelters are the other large civilian category — in the United States, tornado safe rooms and community storm shelters built to the ICC 500 storm shelter standard and FEMA safe-room guidance need equally unambiguous marking.

Industry adds its own variants. Underground mines provide refuge chambers stocked with breathable air, water, and supplies for miners cut off from the surface — US coal mines must provide refuge alternatives under MSHA rules — and chemical plants often designate shelter-in-place buildings with sealed ventilation for toxic release scenarios. In every case the shelter only works if workers can locate it quickly in darkness, dust, or panic.

Shelter or Evacuate: Marking Both Answers

Sites exposed to more than one hazard often need both responses available: evacuate for fire, shelter for tornado or gas. The signage system has to keep those instructions from blurring together. E021 marks the protective destination, while zone-warning signs for the natural hazard — tsunami, storm, or similar — mark where the danger applies, and distinct alarm tones tell occupants which plan is in effect at that moment.

Directional versions of the shelter sign, with supplementary arrows along the approach route, deserve the same attention normally reserved for exit routes. Add a text panel at the shelter door stating capacity and the shelter's identifier, and use photoluminescent or emergency-lit signs where storms or incidents are likely to cut power exactly when the shelter is needed.

E021 Versus the Assembly Point

E007, the assembly point sign, gathers evacuees in the open at a safe distance from the building. E021 does nearly the reverse: it brings people into an enclosed, protective structure. Posting the wrong one is not a cosmetic error — sending tornado-threatened staff to an outdoor muster area, or fire evacuees into a sealed room, defeats the plan entirely.

A practical rule: if the danger is the building, mark the way out and the E007 gathering point; if the danger is the environment or an airborne release, mark the way to E021. Training should rehearse both movements separately, because occupants under stress default to whichever drill they have practiced most recently.

Frequently Asked Questions

What does the ISO 7010 E021 protection shelter sign mean?

It marks the location of a protection shelter — an enclosed space designed to protect occupants from an external threat such as a tornado, toxic release, blast, or mine emergency. Unlike exit signs, it directs people to enter and remain inside until the danger has passed or rescue arrives.

What is the difference between a protection shelter and an assembly point?

An assembly point (E007) is the open-air spot where evacuees regroup once clear of the building, used when the building itself is the hazard. A protection shelter (E021) is an enclosed protective space used when the outside environment is the hazard — severe weather, airborne chemicals, or conflict. Many sites need both, marked distinctly and drilled separately.

Is there a standard sign for tornado or storm shelters?

ISO 7010 E021 is the international symbol for a protection shelter and is appropriate for tornado safe rooms and community storm shelters. In the United States, facilities often pair the symbol with text such as STORM SHELTER or SEVERE WEATHER SHELTER AREA, and shelters themselves are commonly built to the ICC 500 standard and FEMA safe-room guidance.

What sign marks a mine refuge chamber?

E021 is the ISO 7010 sign matching that function, since a refuge chamber is a protection shelter stocked with air, water, and supplies for miners who cannot reach the surface. Underground operations typically add high-visibility and photoluminescent route marking through the drifts, because a refuge chamber must be findable in smoke and total darkness.