The Ex sector turns to EVs

Ex-proof vehicles are increasingly used in hazardous areas

By Claire Marchand

When the term electric vehicle (EV) comes up, it usually brings to mind electric cars and possibly buses or other means of urban transportation. Seldom do we see the mention of industrial vehicles, although they represent 60% of the global EV market. Even rarer is the mention of Ex-proof industrial EVs, which are increasingly used in hazardous areas, replacing diesel-powered vehicles.

ex-proof crane Electric vehicles operating in hazardous environments, such as cranes, have to meet the strictest safety reuqirements (Photo: SIOS BV)

What is a hazardous location?

Hazardous locations are places where fire or explosion hazards may exist due to flammable gases or vapours, flammable liquids, combustible dusts, or easily ignitable fibres or flyings, present in the air in quantities sufficient to produce explosive or ignitable mixtures. 

Oil, gas and mining operations are obviously high on the list of hazardous locations but the risk of explosion exists in a variety of other sectors, such as transportation – including aerospace – furniture manufacturing, automotive manufacturing and repair, pharmaceuticals, food processing, grain handling and storage, sugar refineries. 

Electrical and non-electrical equipment that must be installed in such classified locations should be specially designed and tested to ensure it does not initiate an explosion, due to arcing contacts or high surface temperature of equipment. 

EVs have to be Ex-proof too

Today the use of explosion-proof equipment for hazardous areas is mandatory in most countries around the world and is often included in national or regional – European Union - legislation. 

Like any other type of electric vehicles, industrial EVs used in potentially explosive atmospheres – forklifts, tow tractors or cranes, to name but a few – are powered by large-capacity batteries. 

Ex environments multiply the risks

Whether off-the-shelf or specially-designed cells, primary or secondary (rechargeable) batteries are all built on the same model: one or more electrochemical cells that convert stored chemical energy into electrical energy. 

Lead/acid batteries or alkaline (nickel-cadmium, nickel-metal hydride or lithium ion) rechargeable batteries are used in all kinds of small devices, such as computers, smartphones, tablets and cameras. Their large-capacity counterparts are commonly used in transport (EVs, industrial EVs, buses and trucks) and in UPS (uninterruptible power supply) systems. 

IEC and IECEx: mitigating risks 

While the recharging of batteries, large and small, can be hazardous in itself – hydrogen and oxygen are usually produced inside the battery when charging – the risks are much higher in Ex environments. 

This is why, in some cases, the batteries themselves, or the battery pack/box/container have to be designed and build in compliance with the very strict requirements enunciated in standards and specifications, most notably in IEC International Standards developed by IEC Technical Committee (TC) 31: Equipment for explosive atmospheres. This is valid for small-capacity cells as well as for traction batteries (used in EVs). 

Battery-operated devices are submitted to the same constraints. Their design and manufacture must be able to withstand the harshest and most extreme environmental conditions. They have to be well insulated and explosion-proof. 

Certification needed

Designing and building batteries and containers in compliance with IEC International Standards is not enough. To ensure that any piece of equipment meets the required criteria, it has to be tested and certified. Products associated with a certificate of conformity can be used safely in hazardous environments. 

IECEx, the IEC System for Certification to Standards Relating to Equipment for Use in Explosive Atmospheres, is the only truly international Conformity Assessment (CA) System that provides testing and certification for all Ex equipment and installations as well as certifies the skills and competence of individuals working in hazardous areas. 

Increased level of security

Manufacturers who rely on IECEx for the testing and certifying of their equipment, who have their staff go through the steps necessary to obtain a Certificate of Personnel Competence, have that additional level of security that makes a real difference. They know that they operate in the best possible conditions and minimize the risks inherent to Ex sector. 

Access to certificates anytime, anywhere

IECEx has developed mobile applications for iOS, Android tablets and smartphones, that can be found at the Apple App Store and Google Play. They install simplified versions of the main IECEx online Certificate System covering the three Schemes and allow the user to synchronize the Ex mobile apps with the IECEx online Certificate System, as required. The offline mode provides advanced search capability and certificate abstracts (simplified details), while the online version gives the full details of the Certificates. 

For more information on IECEx: www.iecex.com

Gallery
Miretti ex-proof forklift Electric vehicles operating in hazardous environments, such as forklifts... (Photo: Miretti)
ex-proof crane ...cranes... (Photo: SIOS BV)
RICO ex-proof tractor ...or tractors, have to meet the strictest safety requirements (Photo: RICO)