Zone 1 (hazardous area)
An area in which an explosive gas-air mixture is likely to occur under normal operating conditions.
Source: Rules and Regulations for the Classification of Mobile Offshore Units, Part 7, Safety Systems, Hazardous Areas and Fire, June 2013, Lloyd’s Register, Global Standards
Place in which an explosive atmosphere consisting of a mixture with air of flammable substances in the form of gas or vapour is likely to occur in normal operation occasionally.
Source: IEC 60079-14:2013, Explosive atmospheres – Part 14: Electrical installations design, selection and erection, Edition 5.0, November 2013. Global Standards