Whether you’re new to specifying equipment for use in hazardous areas or simply looking to refresh your understanding, this White Paper will cover some of the fundamental considerations you should consider when handling a project which involves a potentially explosive atmosphere. While Raytec, and some of the content within this White Paper, is focused on lighting equipment, much of the same consideration should be given to any electrical equipment being used in a hazardous area.
What is a Hazardous Area?
A hazardous area can be defined as any location where there is a risk of an explosion. It is important to know that they can exist in any workplace. Typically, this includes oil rigs, refineries, chemical production facilities, and food production sites to name just a few, but there are other less obvious applications that require hazardous area equipment. Raytec have been involved in projects requiring hazardous area lighting from football clubs to cemeteries!
Specialist lighting plays an important role in the safety and efficiency for many businesses where hazardous areas are present, so it is important to know when and why this type of lighting is required.
Why is Hazardous Area Lighting Required?
Where there is potential for an explosive atmosphere, special precautions are needed to prevent fires and explosions. Lighting, as well as other electronic equipment, needs to be purpose-designed for use in hazardous areas to prevent a spark from occurring and igniting any flammable substances.
For an explosion to occur, there are three components that need to be present;
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.
Although every application is different, for the ease of monitoring and specification each hazardous area is classified as a particular level or “zone”. Zones define the type of explosive atmosphere, as well as the likelihood of an explosive atmosphere being present. The risk also depends on how long the hazard is present.
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, mists, and dusts there are three zones.