Safety Symbols

Geoffrey Peckham

Safety symbols, along with public information symbols and function and control symbols, are among the major types of graphical symbols within the scope of ISO TC 145. As part of its work plan, TC 145 is developing an ISO design guideline for drawing safety symbols. This guideline is difficult to write in some respects because the concepts presented in safety symbols do not lend themselves to the same drawing standards that define line widths, shape, and the patterned-on-a-grid system used for symbols found in ISO 7000 and IEC 60417.¹

Safety symbols can be abstract (see Figure 1), but often they are more representational in form (see Figure 2). Currently, the ISO 3864 safety colors and safety signs standard sets forth a vocabulary of surround shape and color to indicate the type of safety sign. In Figure 2, the solid blue circle with a white symbol is a "mandatory action" safety sign, the red circle with a slash and black graphic indicates a "prohibition" safety sign, and the yellow triangle with a black band and black graphic defines a "warning" safety sign. In this way, the combination of a symbol within one of these distinctive colored shapes creates a safety sign in the international vocabulary of signage.

Figure 1. Examples of abstract IEC and ISO safety symbols (hot surface, laser, radiation).

Figure 2. Examples of ISO 3864 safety signs (rotating gear hazard, wear safety gloves, do not touch).

The laser hazard symbol shown in Figure 1 appears in IEC 60417 graphical symbols for use on equipment as symbol no. 5152. In IEC 825-1 Part 1, this symbol appears in the yellow triangular surround shape, thus making it the IEC laser warning symbol (see Figure 3). The Center for Devices and Radiological Health, a department of the Food and Drug Administration (FDA), is the agency that sets the definition for laser classification and labeling in the United States. This agency has given notice that it will not object to the use of safety labels that use the IEC symbol. The word message for each laser classification is identical under both the U.S. and IEC systems. Figure 4 shows a typical Class 2 laser safety label. The only difference between the IEC and FDA standards is in the definition of 3A and 3B laser categories. FDA considers a 1- to 5-mW laser a Class 3A laser, and IEC considers it a Class 3B laser. If a laser falls into this category, the label should note the standard by which the laser's classification is defined, as shown in Figure 5. For a complete set of laser label examples, visit http://www.
hazcomsys.com/catalogs/2001/laser00. html. The U.S. voluntary standard for laser labeling is ANSI Z136.

Figure 3. IEC 825-1 laser hazard label.

Figure 4. Harmonized ANSI/ISO laser safety label using a standardized symbol and word message.

Figure 5. Class 3B laser safety label that identifies the standard used for classification.

Geoffrey Peckham is the president of Hazard Communication Systems (Milford, PA), a company specializing in the design and production of product safety labels. For more information, visit http://www.hazcomsys.com. Peckham is chairman of the U.S. technical advisory group to ISO TC 145 on graphical symbols. He can be reached at gpeckham@hazcomsys.com.