Limits of Human Exposure to Radiofrequency Electromagnetic Fields in the Frequency Range from 3 KHZ to 300 GHZ - Safety Code 6

7. Warning Signs

7.1 Design of the Recommended Warning Signs

Three warning signs described here are suggested for use. These signs or reasonable alternatives shall be used. The suggested signs are designed to indicate the nature and degree of hazard associated with a given device or location. The nature of the hazard is indicated by the symbol, and degree of hazard is indicated by the shape and colour of the sign. The warning signs and their meaning are given below. The size of the sign shall be appropriate to the conditions of use, such that it is clearly distinguishable, being either illuminated or employing reflective materials as necessary.

• The CAUTION sign is BLACK text and symbol on a YELLOW background.
• The WARNING sign is BLACK text and symbol on an ORANGE background.
• The DANGER sign is RED text and symbol on a WHITE background.

The CAUTION sign is not generally used for area demarcation, but it may be placed on devices to indicate that they produce RF fields. All RF devices for which regulations have been promulgated under the Radiation Emitting Devices Act have the CAUTION sign as part of their labelling requirements. For example, all microwave ovens complying with the Microwave Oven Regulations have the Caution sign attached. Both the WARNING and DANGER signs are used for identifying hazardous devices and for area demarcation.

7.2 Area Demarcation

1. A WARNING sign shall be placed at the entrance of any zone within which a survey has shown that RF levels exceed those specified in Section 2.2 but are less than those specified in Section 2.1. The WARNING sign indicates that restricted occupancy is allowed for RF and microwave exposed workers within its boundaries. It shall be located wherever it is necessary to indicate a recommended occupancy time. In such cases, the WARNING sign shall be accompanied by words such as "Warning Radiofrequency Radiation - Maximum Occupancy Time (t) Minutes" and the French equivalent, where t is determined according to the limits specified in Appendix II, taking into account 0.1 h averaging time.
2. A DANGER sign shall be placed at the entrance of any zone where the field levels are in excess of those specified in Section 2.1. The DANGER sign thus indicates a DENIED ACCESS zone. When used for area demarcation, the DANGER sign shall be accompanied by words such as "Danger Radiofrequency Radiation - Do Not Enter" and the French equivalent.
3. The signs shall be clearly visible and identifiable at all viewing distances where either significant exposures can occur or at the entrances to restricted area zones.

7.3 Signs for the Labelling of Devices

When the signs are used for labelling a device, the following recommendations apply:

1. A WARNING sign shall be applied to any device, under development or in use for any industrial, scientific or medical purposes, if the device produces exposure levels that exceed those specified in Section 2.2 but are below those specified in Section 2.1. The WARNING sign shall be applied to a device if misuse or failure could cause RF radiation injury.
2. A DANGER sign shall be applied to any device under development or in use for any industrial, scientific or medical purposes, if it produces exposure levels in excess of those specified in Section 2.1. Furthermore, even though exposure levels are below those specified in Section 2.1, the DANGER sign shall be applied if failure of the device could cause serious RF radiation injury or death.

Area Demarcation

	Caution Radiofrequency Radiation Area of Unrestricted Occupancy Minor Injury Possible from Misuse
	Warning Radiofrequency Radiation Area of Restricted Occupancy (RF Workers Only) Serious Injury Possible from Misuse
	Danger Radiofrequency Radiation Area of Denied Occupancy Critical Injury or Death Possible