ANSI Z535.4-2011(R2017)

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This standard sets forth a system for presenting safety and accident prevention information through product safety signs and labels. It consolidates a number of previous graphic approaches into a common design direction selected to present product hazard information in an orderly and visually consistent manner.

This Standard sets forth requirements for the design, application, use, and placement of safety signs and labels on a wide variety of products.


The purposes of this standard are to:

  1. Establish a uniform and consistent visual layout for safety signs and labels applied to a wide variety of products,
  2. Minimize the proliferation of designs for product safety signs and labels, and
  3. Establish a national uniform system for signs that communicate safety information.

Application and Exceptions

This standard provides guidance to for manufacturers, employers, distributors, and others who have a desire to communicate safety information via product safety signs and labels.

ISO-Formatted Safety Signs Product safety information may be conveyed by ISO formatted safety labels in compliance with ISO 3864-2.

Should any of the requirements of this standard conflict with federal, state, or municipal regulations, such conflict shall not invalidate other requirements of this standard.

Safety Alert Symbol

A symbol that indicates a hazard. It is composed of an equilateral triangle surrounding an exclamation mark. The safety alert symbol is only used on hazard alerting signs. It is not used on safety notice and safety instruction signs.

  • Safety Alert Symbols

(A) for use with DANGER signal word; (safety white triangle, safety red exclamation mark, safety red background)

(B) for use with WARNING signal word; (safety black triangle, safety orange exclamation mark)

(C) for use with CAUTION signal word; (safety black triangle, safety yellow exclamation mark)

(D) and (E) for use with DANGER, WARNING, or CAUTION signal words; ([D] is a safety yellow triangle with a safety black border and safety black exclamation mark; [E] is a safety yellow triangle with a safety black exclamation mark and a safety yellow border around a safety black band)

Note (D) and (E) are provided to allow for consistency with certain ISO standards such as ISO 3864-1 and ISO 3864-2

Safety Symbols

  • Safety Symbols

Safety symbols are graphic representations chosen to clearly convey a specific alerting message without the use of words. The conveyed message of a safety symbol is to describe the type of hazard, potential consequences of the hazard, or evasive/avoidance actions to be taken. When used, the Safety Symbol shall be compatible with the word message.

The Use of Safety Symbols

Well-designed safety symbols can often communicate hazard information quickly and across language and literacy barriers. The ANSI Z535.4 standard allows for signs with a word-message-only format, a symbol-only format, or a combination of symbols and text. When deciding whether or not to use safety symbols to complement or replace words, factors to consider include the risk of critical confusion, the clarity and speed of communication, space availability, and translation and literacy issues.

Signal Words

ANSI Signal Words

Are defined as the words used in the signal word panel. The signal words for hazard alerting signs are "DANGER," "WARNING," and "CAUTION." Safety notice signs use the signal word "NOTICE." Safety instructions signs use signal words that are specific to the situation

DANGER Indicates a hazardous situation that, if not avoided, will result in death or serious injury. This signal word is to be limited to the most extreme situations.

WARNING Indicates a hazardous situation that, if not avoided, could result in death or serious injury.

CAUTION Indicates a hazardous situation that, if not avoided, could result in minor or moderate injury.

NOTICE Indicates information considered important, but not hazard-related(e.g., messages relating to property damage). the safety alert symbol shall not be used with this signal word.

(NEW) SAFETY INSTRUCTIONS or similar words Indicate a type of safety sign, or a separate panel on a safety sign, where specific safety-related instructions or procedures are described. More definitive signal words are encouraged, where practical (e.g., SAFE SHUTDOWN PROCEDURE, SAFE OPERATING PROCEDURES, BOILER SHUTDOWN PROCEDURE, LOCKOUT PROCEDURE, SAFE INSTALLATION INSTRUCTIONS, EMERGENCY SHUTDOWN INSTRUCTIONS). The safety alert symbol shall not be used with this classification of a signal word. This signal word may also be used as a heading for a safety instruction panel incorporated into a hazard alerting sign to convey lengthy instructional information.

Letter Size Legibility

Determining the safe viewing distance of a sign depends upon many factors, including:

  • Lighting, background, letter type and visual acuity.

Other factors to consider in determining sign size, include:

  • The complexity of the message, the reaction time necessary, and the angle the sign will be seen from. In many situations, it is better to use multiple signs that are strategically positioned instead of one large one.

Many times letter size may need to be larger than the values shown on the graphic for a variety of reasons:

  1. To make the sign more noticeable from other information displayed in the area.
  2. To enable legibility under low light, or other poor viewing conditions.
  3. To alert persons sooner than the minimum safe viewing distance.
  4. To convey special importance for portions of the message.
  5. To improve legibility for persons who have vision problems with small text.

Example of text message letter heights and *minimum safe viewing distances.

* Minimum safe viewing distance refers to the closest distance a person can be to the sign and still have time to follow the safety sign's message to avoid the hazard.
  • Letter Size Legibility Chart
*0.08" (8 point / 2mm) type is the suggested minimum type size for use on product safety signs, except for small products, 0.06" (6 point / 1.5mm) type may be used.

Model of Events Resulting from a Hazardous situation.

  • Model of Events Resulting from a Hazardous situation.

Signal Word Selection

Determination of Risk: for hazard alerting signs, the signal word is selected according to the risk presented by the hazardous situation that the safety sign addresses. In other words, signal word selection is based on the risk posed if the safety sign is not followed.

The risk is determined based on:

  1. worst credible severity if an accident occurs;
  2. probability of an accident if the hazardous situation occurs (i.e., if the safety sign is not followed); and
  3. probability of the worst credible severity occurring.

Signal Word Selection Matrices

The following matrices show the signal words and colors that are assigned for each combination of accident probability, worst credible severity, and probability, of worst credible severity.

  • Signal Word Selection Matrices
  • Signal Word Selection Matrices does not recommend or specify the use of a specific safety sign because it does not have knowledge of the hazard(s) our customers are identifying. It is the customer’s sole responsibility to identify the hazard(s) that may be present and select one or more signs (stock or custom) that accurately identify their specific hazard(s) and complies with any applicable federal, state or local laws or regulations, any worksite specific rules or regulations and/or any applicable safety standards (including, without limitation, ANSI and/or OSHA standards). disclaims any and all liability (excluding liability for our Product Warranty contained in our Terms and Conditions) for any sign selected by a customer and shall not be responsible for any personal injury or property damage resulting from the use of signs purchased from it or for the independent interpretation made of any applicable federal, state or local laws or regulations, any worksite specific rules or regulations, and/or any applicable safety standards (including, without limitation, ANSI and/or OSHA standards). Customer shall indemnify and hold and its corporate parent and its officers, directors and affiliates harmless from and against any and all claims, loss or expense (including attorneys’ fees) arising from or related to the purchase and use by customer or any third party of any sign purchased by customer from

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