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Safety Sign and Marking Requirements

Introduction

Hazards exist in every workplace, and employers have a responsibility to warn their employees of these hazards. One of the easiest ways to accomplish this is with accident prevention signs.

Two agencies cover accident prevention signs. Occupational Safety and Health Administration (OSHA), which develops, implements and enforces standards, has specifications for accident prevention signs and tags in 29 CFR 1910.145. These specifications apply to the design, application and use of signs or symbols used to prevent accidental injuries or property damage. These specifications do not cover plant bulletin boards, safety posters or any signs designed for streets, highways, railroads or marine regulations. American National Standards Institute (ANSI) is a private organization which creates voluntary standards through consensus. Accident prevention signs and tags are cited in Z535.1-2006, Z535.2-2002, Z535.4-2007, Z535.5-2002.

Sign Classification and Requirements

OSHA and ANSI classify safety signs according to use. Their definitions are very similar.

OSHA has three classifications of signs:

1. Danger Signs—Indicate immediate danger and that special precautions are necessary. OSHA also specifies that the red, black and white colors used for Danger signs be in accordance with ANSI Z53.1-1967.
2. Caution Signs—Warn against potential hazards or caution against unsafe practices. OSHA specifies that the standard color for Caution signs shall have a yellow background black panel and yellow letters. All letters used against the yellow background shall be black. The colors must be in accordance with ANSI Z53.1-1967.
3. Safety Instruction Signs—Used where there is a need for general instructions and suggestions relative to safety measures. OSHA specifies that the standard color for Safety Instruction signs shall be a white background, green panel and white letters. Any letters used on the white background shall be black. The colors must be in accordance with ANSI Z53.1-1967.

Accident Prevention signs are classified by ANSI Z535.2-2002 into eight classes:

1. DANGER—Indicate an immediately hazardous situation which, if not avoided, will result in death or serious injury. Danger is limited to the most extreme situations.
2. WARNING—Indicate a potentially hazardous situation which, if not avoided, could result in death or serious injury.
3. CAUTION—Indicate a potentially hazardous situation which, if not avoided, may result in minor or moderate injury. Caution may also be used to alert against unsafe practices.
4. NOTICE—Indicate a statement of company policy as the message relates directly or indirectly to the safety of personnel or protection of property.
5. GENERAL SAFETY—Indicate general instructions relative to safe work practices, reminders of proper safety procedures, and the location of safety equipment.
6. FIRE SAFETY—Indicate the location of emergency fire fighting equipment.

The other two classifications are DIRECTIONAL ARROW SIGNS and SPECIAL SIGNS.

OSHA is not specific as to sign design for Danger, Caution, and Safety Instruction signs except for purpose and colors. When complying with OSHA regulations, it is important to check under the specific sign requirement with which you are trying to comply.

OSHA also requires that signs be designed with rounded or blunt corners and must be free from sharp edges, burrs, splinters or other sharp projections. The ends or heads of fastening devices cannot be located as to create a hazard.

The size of the sign, height and width of the letters, and viewing distances are all defined by ANSI Z535.2-2002. OSHA does not have specifications like these for signs, and refers to the ANSI standard regarding these technicalities.

Sign Size

The wording on any sign should be concise and easy to read. The size of the lettering must be as large as possible for the intended viewing distance. Minimum letter height for the signal word (Danger, Caution, Notice, etc.) shall be one unit of height for every 150 units of safe viewing distance. Minimum letter height for other words on the sign shall be one unit of height for every 300 units of safe viewing distance (ANSI Z535.2-2002).

Note: Crowding of letters reduces legibility.

Placement of Signs

ANSI rules for placement of signs are:

1. Signs must be placed to alert and inform employees of hazards in sufficient time to avoid the hazard and take appropriate action. Employees should not be in harm's way before seeing the sign.
2. Signs must be placed so that they are legible, do not create a distraction, and are not a hazard in themselves.
3. Signs must not be placed on moveable objects or adjacent to moveable objects like doors, windows etc., which if moved will obscure the sign.
4. Where illumination may be necessary under emergency conditions, the signs should be equipped with emergency (battery operated) illumination or be reflective or both.

Safety Color Coding

OSHA has specific requirements for marking physical hazards in 29 CFR 1910.144:

1. Red shall be the basic color used to mark:
   • Fire protection equipment and apparatus;
   • Danger. Safety cans or other portable containers of flammable liquids, excluding shipping containers. These shall be painted red with some additional clearly visible identification either in the form of a yellow band around the can or the name of the contents conspicuously stenciled or painted on the can (can should also be labeled in accordance with 1910.1200).
   • Stop, emergency stop bars, hazardous machines, stop buttons and other electrical switches used for emergency stopping.
   
   
2. Yellow shall be the basic color for designating caution and for marking physical hazards, such as striking against, stumbling, falling, and getting caught in-between.

ANSI standards for safety color coding are:

1. Safety Red identifies Danger and Stop.
2. Safety Orange identifies dangerous parts of machines or energized equipment.
3. Safety Yellow designates caution. Solid yellow, yellow and black stripes, or yellow and black checkers must be used for maximum contrast with the particular background.
4. Safety Green designates safety, emergency egress, and the location of first aid and safety equipment.
5. Safety Blue identifies safety information used on informational signs and bulletin boards.
6. Safety Purple is not yet assigned
7. Safety Gray is not yet assigned.
8. Safety Black, Safety White, Safety Yellow or combinations of Safety Black with Safety White or Safety Yellow are used to designate traffic or housekeeping markings.

Commonly Asked Questions

Sources for More Information

29 CFR 1910.144, Safety Color Code for Marking Physical Hazards

29 CFR 1910.145, Specifications for Accident Prevention Signs and Tags

ANSI Z535.1-2006, Safety Color Code

ANSI Z535.2-2002, Environmental and Facility Safety Signs

ANSI Z535.3-2002, Criteria for Safety Symbols

ANSI Z535.4-2007, Product Safety Signs and Labels

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