The Cygnus 1 Ex is Intrinsically Safe, certified to Zone 0, suitable for hazardous areas. There are a number of impressive statements we have used to introduce our Cygnus 1 Ex Ultrasonic Thickness Gauge, but what do they all really mean? Let’s demystify these statements and explain the rules and regulations surrounding the use of equipment in hazardous areas. WHAT ARE EXPLOSIVE ATMOSPHERES? The term Ex is recognized globally for explosive atmospheres and the schemes used to prevent explosions. Hazardous Areas are locations where there is a risk of fire or explosion, due to the presence of ignitable or flammable substances in the air. These substances include gases, vapours, and dusts that are present in the air, at concentrations high enough to produce an ignitable mixture.