ANSI Z535.3-2022: Criteria for Safety Symbols

Construction site with sign posting colorful safety symbols adhering to ANSI Z535.3-2022 criteria.

What is yellow, green, red, or blue? The answer is a safety symbol, which ANSI Z535.3-2022: Criteria for Safety Symbols outlines.

The ANSI Z535.3-2022 Standard for Safety Symbols

ANSI Z535.3-2022 provides criteria for the design, evaluation, and use of safety symbols to identify and warn against hazards and personal injury. The goal of this American National Standard is to promote the adoption of effective safety symbols for safety communication and supply a procedure to do so. The standard defines a safety symbol as a configuration that includes an image, with or without a surround shape, that communicates a message (usually a hazard or precaution to avoid a hazard) without words.

Image effectiveness includes consideration of a simple and recognizable graphic design, such a pictograms, pictorials, or glyphs, of safety symbols and ability to communicate the intended message, which is critical for accident prevention and personal protection. Images consideration include symmetry, direction, arrows, representation of the human figure, hand profiles, feet, proportion and form ,use of determinants, and use of supplementary text or training. Word only signs are not as effective as signs with symbols, and thus signs with safety symbols promote more rapid communication of the safety message and greater safety for the U.S. population. ANSI Z535.3-2022 is created for the diverse U.S. population that has a range of reading and word comprehension skills.

Safety Symbols

Safety symbols typically consist of a safety black image on a white background without color or a surrounding shape. There are however two exceptions when a surround shape is required: the Safety Alert symbol (an exclamation mark in an equilateral triangle) and the Prohibition symbol (a circular band with a diagonal slash through it). ANSI Z535.3-2022 states there are four types of safety symbols that communicate different messages: Hazard Alerting, Mandatory Action, Prohibition, and Information.

  • Hazard Alerting conveys information primarily related to the nature of hazards. This symbol should be drawn within a safety yellow equilateral triangle with a safety black ban.
  • Mandatory Action: conveys actions that should be taken to avoid hazards. This symbol should consist of a safety white image within a solid safety blue circular surround shape if a surround shape or color is desired.
  • Prohibition: conveys actions that should not be taken. The symbol consists of a circular band with a diagonal slash at 45 degrees from upper left to lower right and is used to indicate Prohibition. The Prohibition symbol consists of a safety black image, safety red circular band with slash, and safety white background.
  • Information: conveys a safe condition (equipment location, egress, permitted actions) or fire safety (fire equipment location). When conveying a safe condition, the symbol consists of a safety white image within a safety green square or rectangular background if surround shape or color is desired. When conveying fire safety, the symbol should consist of a safety white image within a safety red square or rectangular background if a surround shape or color is desired.

History of Safety Symbols

From 1906 to 1910, one out of every four immigrant steel workers were killed or injured working on the job in the United States. In fact, the accident rates for immigrants at the South Works steel mill were double those for English speaking workers. Steelmaking was not only highly hazardous work for immigrants who did not read or speak English, but also for literate professionals. A lack of safety standards and poor visual communications only exacerbated the already dangerous work in steel mills during the Progressive Era (1900-1917).

Journalists helped expose the horrendous, unsafe working conditions in factories, which led to reforms in the workplace, including the implementation of safety symbols. In 1914, the Worker’s Compensation Bureau released first publication about the importance of safety signage: “Signs and Slogans.” The pamphlet maintained safety signs were crucial in the workplace, and it also advocated for the use of DANGER safety signs in the languages of the workers. It did not, however, provide any standard format or guidelines for safety symbols.  

Due to the growing industrial revolution and increase of accident rates, safety signage standards were introduced in 1941.That year saw the first publication of ASA Z35.1 Specification for Industrial Accident Prevention Signs, which outlined specifications for safety sign design and introduced standard formats for DANGER signs, CAUTION signs, NOTICE signs, and EXIT signs. Almost a century later, ANSI Z535.3-2022 extensively details the procedure of designing, evaluating, and using safety symbols.

ANSI Z535.3-2022: Criteria Safety Symbols is available on the ANSI Webstore.

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