Skip to content

Safety Signs

April 22, 2014


The material in this post is extracted from Chapter 8 of the book Plant Design and Operations.

Guidance as to the types of signs and their meanings is provided below.


Prohibition signs mean “You must not” or “Do not do . . .” or “Stop”. Signs of this type have a red circle, a white interior and a red bar, as illustrated in Figure 8.3.

Figure 8.3
Prohibition Sign

Prohibition Sign

The sign can be supplemented with more specific information, as illustrated in Figure 8.4.

Figure 8.4
Prohibition Sign with Information


Other examples of prohibition signs include:

  • No smoking;
  • No open flames;
  • Non-potable water;
  • Do not enter;
  • Do not fish; and
  • Do not use crane for personnel transfer.

Mandatory Action

Mandatory signs mean “You must do . . .” or “Carry out this action” or simply “Obey”. They are often used when special PPE (personal protective equipment) is required.

Signs of this type use a blue circle. Figure 8.5 shows that safety gloves are required.

Figure 8.5
Mandatory Sign


Other examples of mandatory signs include:

  • Hearing Protection Required;
  • Wash Hands;
  • Chock Wheels;
  • Ground Fuel Truck;
  • Hard Hat Area;
  • Doors Must Be Kept Closed;
  • Goggles Required; and
  • Face Shield Required.


Warning signs are yellow triangles using black lettering, as illustrated in Figure 8.6, which is to do with electrical hazards.

Figure 8.6
Warning Sign


Other examples of warning signs include:

  • H2S Gas;
  • Corrosive Liquids;
  • Radiation;
  • Equipment Automatic Start;
  • Open Trenches;
  • High Temperature;
  • Flammables;
  • Explosives; and
  • Danger High Voltage.

Safe Condition

A green square or rectangle indicates a safe condition, a means of escape or the location of safety equipment, as illustrated in Figure 8.7.

Figure 8.7
Escape Sign


Other examples of Safe Condition signs include:

  • Emergency Shower Station;
  • Emergency Eyewash Station;
  • Potable water;
  • Emergency Shutdown;
  • First Aid; and
  • Trash.

Fire Safety

A red square or rectangle is to do with fire safety, as shown in Figure 8.8.

Figure 8.8
Fire Sign

Fire Sign

Leave a Comment

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s

%d bloggers like this: