Intrinsically Safe Lighting in Explosive Environments
By: Derek Box, Contributor
When your employees need portable lighting in order to accomplish their work tasks, it’s important to consider the safety of the lighting equipment they’ll be using – if the environment is potentially explosive. The danger is obvious in the petroleum and chemical processing industries, but many other industries can create explosive atmospheres that are not as obvious but still represent a serious danger.
Examples illustrating this are in facilities that process grains, sugar, metal powders and wood products. In 2018 grain handling facilities in Nebraska and eastern France were destroyed or seriously damaged by grain dust explosions. In 2008 an explosion wrecked a sugar refinery in Georgia, killing 14 people and injuring another 40. Five workers were fatally injured in an iron dust fire in Tennessee in 2011. It is essential to understand the conditions that can create explosive environments and the proper equipment required to enter them safely.
The lighting and other equipment you are using must meet or exceed the standards for the most explosive environment you could face under known or unknown situations. In the United States, Intrinsically Safe (IS) products are tested to the UL 913 5th or 8th edition standards with the UL 913 8th edition being harmonized to the EN/IEC 60079 -01/-11 standard for European Union ATEX certifications and the remaining countries IECEx certifications.
For an explosion to occur, five components must be in place: oxygen, confined space, ignition source, dispersion and a fuel source. These elements make up the explosion pentagon. The three elements needed for a fire — fuel source, oxygen and an ignition source — can create a flash fire within a confined space, resulting in the ingredients for an explosion. Eliminating one of these five elements will prevent an explosion, but eliminating these hazards is not a simple process. Oxygen in confined spaces typically cannot be eliminated. Therefore, managing fuel sources and the use of properly rated equipment to prevent ignition is essential.
As an example, using the ATEX classification system, a Zone 2 environment could quickly become a Zone 1 or even a Zone 0 environment, and your equipment must be rated appropriately as you may not be aware that the environment has changed until it is too late. If you are unsure, analyze the work environment, determine the worst-case scenario, and equip your workers based on that.
ATEX Zones Explained
Three components are necessary to create an explosion:
- Flammable material – A gas, vapor or mist.
- Oxygen – Regular breathable air is sufficient.
- Ignition Source – Extreme heat or a spark.
In a flammable atmosphere environment, special precautions must be taken to prevent catastrophic explosions. All portable lighting must be specifically engineered to avoid a spark from occurring and igniting any flammable vapors or explosive mists. In some cases, these vapors and mists can be colorless and odorless, making them especially dangerous.
Commercial worksites have different hazardous areas classified at a specific level called a “Zone.” All equipment safety ratings must be carefully selected based on the most dangerous Zone it may encounter; therefore, it is critical to identify the Zone in which you will be working.
Let’s take a look at the specific characteristics of each Zone.
Zone 0: An area in which an explosive atmosphere is always present.
Zone 1: An area in which explosive atmospheres are likely to occur during regular operation. This may be due to leakage, scheduled maintenance or emergency repairs.
Zone 2: An area in which an explosive atmosphere does not occur during normal operation, or for a short period of time only. This is usually the result of an accident or other unusual operating conditions.
The quality of your equipment is vital in explosive environments. You must ensure it is manufactured by a reputable company with documented experience in creating intrinsically safe products. The ideal situation would be to purchase all of your IS products from a single manufacturer rather than mixing and matching products from several companies. A single source manufacturer ensures consistent quality and safety across the entire product line. Because of the knowledge, time and expense required to engineer and produce IS products, a very limited number of companies can achieve this. WMHS
Derek Box is Marketing Manager, Industrial Division, of Nightstick, a global brand of professional portable LED lighting products that adheres to the ANSI/PLATO FL 1 standards. Nightstick’s intrinsically safe products are UL 913 certified for Class I DIV 1; most also carry a Zone 0 IIC ATEX and IECEx certification with T3 and T4 temperature ratings. Nightstick has more than 50 safety-rated LED lighting products, from pocket-sized penlights to wide-area floodlights, for use above ground or below ground (www.nightstick.com).
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