We generally categorize signs into three types:

Mode refers to a socially organized set of semiotic resources for making meaning. Examples of modes include image, writing, layout, and speech among others.

Guide Signs These signs are square or rectangular shaped, and are green or brown with white lettering. They show directions and distance to various locations, or areas such as cities, air ports, state lines; or to special areas such as national parks, historical areas or museums.

• Iconic signs – icons are signs where meaning is based on similarity of appearance.
• Indexical signs – Indexical signs have a cause-and-effect relationship between the sign and the meaning of the sign.
• Symbolic signs – these signs have an arbitrary or conventional link.

Semiotics, also called semiology, the study of signs and sign-using behaviour.

These 4 important safety signs can be broken into categories: Prohibition, Warning, Mandatory and Emergency.

Hazard pictograms (symbols)

• Explosive (Symbol: exploding bomb)
• Flammable (Symbol: flame)
• Oxidising (Symbol: flame over circle)
• Corrosive (Symbol: corrosion)
• Acute toxicity (Symbol: skull and crossbones)
• Hazardous to the environment (Symbol: environment)

Red: Red is reserved for danger signs and labels. Green: Green is safety related and means there is no danger present. This color is commonly used for first aid signs or signs indicating exits. Blue: Provides information about a particular item or area.

Blue

Safety Color Coding Labels and Tape

The color of safety

• Red: Fire protection equipment. Danger, high risk of injury or death.
• Orange: Moderate risk of injury. Guarding devices.
• Yellow: Caution statements. Minor risk of injury.
• Green: Safety equipment or information. First aid equipment or location.
• Blue: No immediate hazard.
• Red – combustible materials. Yellow – oxidizers.

RED

Safety inspection checklists are paper-based or digitized forms used by safety officers to inspect and identify workplace hazards that can cause potential harm to people, processes, and the environment.

OSHA and Safety Colors The standard maintains that red and yellow must be used for marking physical hazards. Red must be used for fire-related hazards, as well as emergency switches, bars, and buttons on hazardous machines.

The American National Standards Institute (ANSI) and the International Safety Equipment Association (ISEA) have set forth some important guidelines in high visibility apparel as part of the ANSI 107/ISEA 107 standard. The three accepted colors of high visibility apparel are yellow-green, orange-red, and red.

According to the ANSI 107 standard, acceptable high-visibility colors include fluorescent yellow-green, fluorescent orange-red and fluorescent red.

Safety color coding is used identify physical hazards, the location of safety equipment, protective equipment, signs, and markers. Safety color coding should not be used as a substitute for engineering or administrative controls to eliminate identifiable hazards.