In an everyday context, we use ‘anti-static’ to refer to protection against that clinging effect you get, for example, with clothing when there’s a static charge build-up. In the Ex context, we more specifically talk about dissipation. See dissipative.


Learn more

Blue Retina

LEDs produce blue light which can damage the retina of the eye. Basically, humans do not recognize blue light as dangerous, so we don’t react to strong or excessive blue light exposure by turning away or blinking.

Unfortunately, blue light makes an LED look clean and bright to our eyes. It’s a cheap, and dangerous, way to make a low-powered LED look brighter than it really is (compared to natural white light). High quality LEDs come with test reports showing the wave lengths of the light spectrum they emit. This is an important source of information Atexor uses to select LEDs for its luminaires. High-powered LEDs produce strong light in any case, so filtering blue light needs to be considered.

Candela (cd)

The standard unit of measurement for luminous intensity, candelas are based on the luminous properties of a traditional candle. Technically, a lumen is measure of the energy and time (the ‘flux’) of the light output, whereas a candela is a measure of the energy, time and angle of the light.

Candelas are interesting for scientific research, but when it comes to assessing how the human eye experiences light, candelas are not meaningful. This is why you typically don’t see candelas mentioned with commercial luminaires.


From the French Conformité Européenne (European Conformity). The ‘CE’ label is used by manufacturers to indicate that their product complies with all the applicable rules and requirements, called directives, defined by the European Commission (EC). Ex products, for example, must comply with a wide range of requirements under EC in addition to those set out by ATEX.


Learn more


If something is conductive, electricity can easily travel through it – generally not a good thing in Explosion Hazardous areas. You want very good conductivity in a power cable or an electronic circuit board.

In Ex areas, particularly confined spaces such as tanks and pipes, conductivity is a huge risk. Anything that is electrified and can hold a large static charge, like a metallic ladder, must be grounded. Grounding is the safe escape route for electricity.

This is why Atexor does not use steel magnets, for example. The Atexor Click’n Fix magnets brackets are fully dissipative (anti-static). Atexor also avoids steel frames as a way to re-enforce luminaires, because such solutions are potentially dangerous and require earthing.

Confined space

In the Explosion Hazardous world, so-called confined spaces are particularly full of risks. Confined spaces are completely or partially enclosed with restricted means for entry and exit. Typical confined spaces include pipes, tanks and silos.

These places are not really intended for humans. In addition to the risk of suffocation, workers have to deal potential explosive, flammable or otherwise poisonous vapours.
Ex lighting solutions such as the Atexor tanks sets, need to be carefully planned for confined spaces. Surfaces tend to be corroded and conductive. Taking a normal high-voltage luminaire into a confined space can be deadly.


Short for Color Rendering Index. On a scale from 1 to 100, CRI measures how an artificial light source compares to natural white light, with 100 being essentially identical to natural light.

In the days of incandescent light bulbs, CRI was not such an issue. With LEDs and advanced electronics, however, the light spectrum can vary quite a lot. The light from an LED can be very different from natural light.

This can have a dramatic impact on the colors you see. CRI is like the treble and bass on your stereo. You can turn a yellow banana blue with an LED. If color is really important, such as on a painting job, the luminaires should have a high CRI. Atexor SLAM® luminaires, for example, use LEDs with at least 80 CRI.


Short for Digital Addressable Lighting Interface. This is the fancy name for the standardized interface allowing software-based control of a luminaire’s brightness. It used to be that the only way you could dim a light was with a mechanical knob or switch. With the digital method, you can adjust brightness and other things, like the color of the light, with software.


Within the European Union, ‘directive’ is used to refer to the rules and requirements defined by the European Commission.


To dissipate means to scatter or disperse. In our context, dissipative is an electrical property of the materials we use in Ex luminaires. Put simply, at Atexor, we design products and solutions that allow an electric charge (like static build-up) to flow back to earth in a controlled, safe manner. The last thing you want is a spark from a sudden electrical discharge when you are working in an Ex area. A static charge is like a bucket of water. Dump it out all at once and you’ll likely get yourself wet in the process. Power it slowly, and you stay dry.


The Russian approval body (formally GOST-R). They handle, amongst other things, the customs clearance for imports to Russia. They also control the implementation and application of IEC standards to Ex products sold in Russia.


Short for Electro Magnetic Compatibility. Most markets around the world have implemented rules and regulations related to electric and magnetic interference. The basic principle is: do not disturb or be disturbed. For instance, the FM radio and GPS navigator in a car should be able to work at the same time without causing any trouble with signal reception.
Ex-rated equipment sold within the European Union must comply with the EMC directive 2004/108/EC.


Also known as Explosion Proof, Explosion Protected, Ex Proof, Ex Rated – used worldwide as simple ways to say, “Explosion resistance.” Sometimes you may also see ‘flame proof,’ though that term is a bit misleading. In practice, Ex means the product or equipment cannot be a source of ignition or, if it does explode, the explosion is confined and controlled within the equipment.

Think of this like car engines: controlled explosions are used to drive pistons. In normal civilian cars, these are controlled within reasonable levels (for reliability and safety). In racing cars, engines are tuned for maximum power, so you may see flames shooting out of exhaust pipes, and sometimes race engines literally explode.

Ex Zone

Learn more


Short for Ex Certified Bodies. These are organizations who are approved to serve as notified bodies for Ex equipment, facilities and people. The list of ExCBs is maintained by IECEx and available on their public website

Floodlight High powered luminaires used to illuminate particularly large areas.

GOST-R Former state approval agency in Russia. See EAC.

Hazardous Area

This can mean the area in question has any type of hazard. But in the Ex world, this is short-hand for a number of phrases, including:

  • Explosion Hazardous
  • Explosion Hazardous Area
  • Potentially Explosion Hazardous Area

The important thing here is for people who work in such areas to understand what equipment is safe to use, and for manufacturers to know how to make products rated for these areas


Short for International Electrotechnical Commission. This is the all-important, internationally recognized authority that maintains International Standards related to electronics.

Countries around the world participate in the arduous task of creating unified standards for a very wide range of industries, including those for Explosive Atmospheres.

Although the standards are unified, interpretation may vary from market to market. Local Ex authorities make their own interpretations, which can lead to confusion for both manufacturers and buyers of Ex equipment. In such cases, organizations – manufacturers, notified bodies, etc. – may make recommendations to change IEC standards to help eliminate conflicting interpretations.


Learn more

Intrinsic safety

Learn more


Short for South Korea Occupational Safety and Health Agency. Like INMETRO in Brazil, this is the local authority responsible for Ex product imports and distribution.

LED Short for Light-Emitting Diode. The go-to modern day light source, LEDs have come a long way from their humble beginnings as little red indicators. In addition to visible light, they can be used to generate infra-red and even ultra-violet light.

LEDS have many advantages over other light sources, including low energy consumption and longer lifespan.

LED technology has advanced very quickly, particularly in the last decade. Like we have seen with computer processing power, the lumens an LED can produce has gone through the roof. For Ex luminaires, this is a mixed blessing: we can make very bright luminaires now, but the risk of them igniting particles in the air has to be factored into the design equation.

Light fixture

Light fixtures (UK English ‘light fittings’) in the everyday context refers to the whole luminaire – the light-emitting element (lamp or LED), the housing, the stand or mount, and the electrical wiring.

However, with lighting solutions used in Ex areas, at Atexor we talk about the fixture (fitting) separate from the luminaire. The Ex luminaire is the light emitting element(s) plus the control unit (electronics) and enclosure around it. The Atexor luminaire is modular by design so that it can be used in a variety of configurations. Where a normal household light fixture is designed for one mounting option – floor, ceiling or wall – an Atexor Ex luminaire might be suitable for all three depending on the bracket and fitting options available.

Lumen (lm)

This is the standard unit of measurement for brightness or ‘luminous flux.’ With incandescent bulbs, we used watts (energy consumption) to indicate the brightness of a bulb. As more energy efficient technology became available, however, watts were no longer a clear indicator of how much light you actually get out of a luminaire.

So today we indicate the brightness of a luminaire in lumens. As an example, a traditional 40-Watt incandescent bulb produces between 400 and 500 lumens. A comparable LED bulb in terms of lumens may consume as little as 5 Watts.


A general term for any light-emitting product. We tend to use this term in the Ex business because it covers all types of lighting solutions. In modular systems, using this term also allows us to address properties of a luminaire separate from those of, for example, cables and mounting brackets which have their own special properties for Ex areas.

Lux (lx)

This is the standard unit of measure of illuminance, or how much light is hitting a given surface. Since we know that one lux is equal to one lumen per square meter, we can calculate how much light (lumens) is needed to illuminate a given space.

Think of lux as watering a lawn with a hose versus a sprinkler. Just running water (max lumens) out of the hose gets just a small area very wet. Using a sprinkler spreads the water out over a larger area, giving equal amounts of water (lux) to the lawn.

Machine lamp Sometimes used as a general term for workplace luminaires, machine lamps are luminaires that are permanently fixed to a piece of equipment. Instrument cabins, for example, may have machine lamps that are fixed to the inside of the cabin to make servicing the instrumentation easier.


Short for National Supervision and Inspection Center for Explosion Protection and Safety of Instrumentation. NEPSI is one of the notified bodies specializing in testing and certifying Ex equipment for the China market.

Notified body A notified body is a government-approved organization in that is allowed to certify that products, processes, people and organizations comply with a given regulation or standard for EX areas within the EU (ATEX directives). Government authorities control and audit notified bodies in most countries, though the exact setup is not always so clear. However, there are mechanisms in place just about everywhere to help resolve conflicts of interest and ensure notified bodies remain objective and trustworthy.

For IECEx approvals, we talk about Ex Certified Bodies (see ExCB). The list of approved ExCBs is maintained by IECEx.

op is These letters are used to indicate a product complies with the safety standards for optical radiation (also called ‘optical irradiation’). High-powered LED luminaires can create an ignition source if they are not designed to take into account the radiated energy of the LEDs. This can be a significant risk as LED technology continues to increase the power generated by each diode. For more information, please see LINK.


Short for Restriction of Hazardous Substances. This European Union directive puts very strict rules on the use of dangerous substances in electronics, such as lead and mercury. All products, including spare parts and cables, sold in the EU must adhere to these rules.

The RoHS does not currently have a marking of its own. It is assumed that if a product uses the CE mark, it complies with the RoHS directive. ATEX directives do not add additional RoHS requirements.

Safety lamp

Back in the day, coal miners started calling lanterns with an enclosed flame “safety lamps.” Open flames in coal mines were a big problem, regularly causing deadly explosions. Attempts to help mitigate explosion risks stretch all the way back to the 1700s.

One of the more successful early types of safety lamps is the Davy lamp, invented by Humphry Davy in the early 19th century. In these lamps, the open flame is surrounded by mesh material that can, at least temporarily, prevent the flame from extending too far or getting hot enough to ignite flammable gases in the surrounding atmosphere.

Nowadays we would call these Ex luminaires for mining operations, but the term ‘safety lamp’ is still quite common and widely understood in the mining industry.

Safety light

This is a common term used to refer to many different types of lights, from a yellow light on a traffic barrier to a red light on the back of a bicycle. Unfortunately, the term is sometimes also incorrectly used to denote Ex luminaires. In the Ex world, we prefer to emphasize the fact that safety is always more than just a single piece of equipment. People, products and places together make (or break) safety.

Temperature class Temperature class (also known as ‘T-rating’) defines the explosion hazard type for the Ex product. The class, from 1 to 6, indicates the highest temperature allowed without igniting anything in the area. Class defines risks of a zone in a given area.

The temperature class schema was created to help simplify the discussion around safe temperatures in Ex areas. Think of it as a standardized communication protocol, like SMS for text messaging. If you have an area classified as T4, you know you can use T4 rated products.

The classes are defined separately for gas and dust hazards by IEC standards 600079-10-1 (gas) and 600079-2 (dust). The temperature restrictions for gas apply to the whole product, inside and out. The dust classes only concern the hottest outer surface temperature.
An important side note here: currently the standards do not cover areas where both gas and dust explosion risks are present.


Short for Underwriters Laboratories. UL are the leading authorities in the United States certifying product compliance with quality, safety and other standards. This includes all Ex-related certifications. Products that have passed the rigorous certification tests get a unique certificate number and permission to use the “UL” label on product.

UL listing

See also UL. The UL listing is a collection of products that UL, a widely respected certification body, has tested and certified. UL actively maintains this list, meaning it audits products it has already certified and may remove them if the product manufacturer fails the audit.


Short for Waste Electrical and Electronic Equipment. Within the European Union, the WEEE directive lays out rules for collecting and recycling waste from electronic devices, from industrial equipment to household appliances and toys. Compliant products must carry the WEEE recycle bin logo.