Identifying Zone 0, Zone 1 & Zone 2 Hazardous Areas | Raytec Lighting
Published 16 Jul 2019
uploaded by Chris Dodds - Sales & Marketing Manager Thorne & Derrick
Hazardous Area Zones
Zone | Zone 1 | Zone 2 Definitions
A hazardous area can be defined as any location where there is risk of an explosion – this could include on offshore oil rig or an onshore grain storage facility.
But every hazardous area is different and each has specific requirements depending on the nature of the explosive atmosphere and the elements that are present.
Fundamentally, for an explosion to take place, flammable or explosive gases, vapours, mists or dusts will be present. Then, the level of risk of an explosion is based on the frequency and duration of the occurrence of an explosive atmosphere. This level of risk is represented by classifying the hazardous area zones as Zone 0, Zone 1 or Zone 2 (for gas, vapour and mist atmospheres) or Zone 21 or Zone 22 for dust atmospheres.
In this article we will look at what defines Zone 0, Zone 1 and Zone 2 hazardous area classifications and the considerations for specifying lighting for hazardous zones into each area. But first, we must consider what is likely to cause an explosion in the first place.
There are three necessary components for an explosion to occur;
1. Flammable Substance – this needs to be present in a relatively high quantity to produce an explosive mixture (e.g. gas, vapours, mists and dusts).
2. Oxygen – oxygen is required in high quantities and in combination with the flammable substance to produce an explosive atmosphere.
3. Ignition Source – a spark or high heat must also be present.
Lighting & Hazardous Area Zones
Where there is potential for an explosive atmosphere, special precautions are needed to prevent fires and explosions. Electronic equipment, including hazardous area lighting, needs to be purpose designed for use in hazardous areas to prevent a spark occurring and igniting any flammable substances.
Although every application is different, for the ease of monitoring and specification each hazardous area is classified as a particular level or “zone”. As a result, all hazardous area equipment must be designed with hazardous area zone classifications in mind, as the “zone” governs the level of protection and precaution required. It is essential to know which zone you are working in, so that you can specify the most appropriate equipment.
For gases, vapours and mists the zone classifications are recognised as Zone 0, Zone 1 and Zone 2 areas.
Let’s take a look at what defines each zone…
Zone 0 is a hazardous area in which an explosive atmosphere is present continuously for long periods of time or will frequently occur.
Zone 1 is a hazardous area in which an explosive atmosphere is likely to occur occasionally in normal operation. It may exist because of repair, maintenance operations, or leakage.
Zone 2 is a hazardous area in which an explosive atmosphere is not likely to occur in normal operation but, if it does occur, will persist for a short period only. These areas only become hazardous in case of an accident or some unusual operating condition.
To make this even easier to understand, take a look at the diagram of a typical petrol station above where we have identified the areas that are classified as hazardous area Zone 0, Zone 1 and Zone 2.
Whenever you are filling up your tank you are standing in a Zone 1 hazardous area. That is why the use of mobile phones on petrol forecourts are banned.
You’re phone isn’t rated for use in hazardous areas. Have a think about it next time you’re filling up!
Identifying Raytec SPARTAN
Luminaires for Different Zones
The Raytec SPARTAN range includes dedicated luminaires and light fittings for both Zone 1 and Zone 2 areas as well as industrial applications. The colour of the luminaire body indicates the level of protection.
Zone 1 light fittings are supplied as silver, Zone 2 fittings as dark grey and industrial fittings as white.
All emergency versions, whether Zone 1 or Zone 2 can also be easily visually identified by their red end cap, encapsulating the emergency battery back-up.
The part codes for each Raytec SPARTAN light fitting variant also differ depending on the level of protection required. SPARTAN’s Zone 1 part code begins SPX, Zone 2 SPZ and industrial products having a SPI prefix.
Raytec do not currently offer any lighting solutions for Zone 0 hazardous areas.
This is because Zone 0 usually classifies areas for gas storage or containment, and any lighting required would be used on a small and portable basis for visual inspection, e.g. a headtorch, rather than a dedicated fixed luminaire or light fitting.
Therefore, it is very important to make sure that you are using a suitable luminaire for your application by choosing your fitting based on its suitability for the hazardous area Zone in which it will be located.
ELECTRICAL & PROCESS INSTRUMENTATION EQUIPMENT
FOR EXPLOSIVE ATMOSPHERES
Thorne & Derrick are Specialist Distributors of Hazardous Area & Explosion Proof Equipment with IECEx & ATEX Certifications to the onshore and offshore oil, gas, petrochemicals and process industries.
Key Product Categories: Control Panels | Plugs & Sockets | Isolators | Enclosures & Junction Boxes | Lighting | Control Stations | Motor Starters | Heat Trace Cables & Systems | Gas Detection & Detectors | Fire Detection & Detectors | Heat Detectors | Electrical Heating & Heaters
Also Process Instrumentation Products: Ashcroft Pressure Gauges | ASCO Valves | Katronic Flow Meters | KROHNE Flow Meters | VEGA Level Sensors | Rotronic Temperature & Humidity Sensors | SIKA Pressure Gauges