Giving electrical hazards the boot

As I speak with people from different industries about their PPE, I frequently hear disparate views on what safety footwear should be worn to provide protection against various hazards. When it comes to electrical hazards, some say antistatic boots should be worn, while others say non-conductive boots are the way to go. So, which is the right boot to protect against electrical hazards?

Electricity can be a serious workplace hazard, where a safety incident can cause electrocution that often results in death. Just 3 mA can be enough current to cause serious injury. Most people are well aware of its dangers and treat it with due respect. But it’s an invisible hazard and the risk is typically not that obvious, especially in places like construction sites where temporary electrical cables can be severed or exposed.

To help protect workers from this invisible threat, many safety work boots are expressly designed to insulate wearers from exposed electricity. These types of boots are standard attire for electrical tradespeople, but workers in other trades and occupations are becoming increasingly more conscious of the need for this protection.

However, many non-electrical people are getting confused by the jargon used by footwear manufacturers and retailers to describe their products, potentially confusing their customers, or worse - leading them to purchase unsuitable and potentially unsafe boots.

To help sort out the confusion, I spoke with Steel Blue’s Global Sales Manager, Ross Fitzgerald, and Blundstone’s Group Sales and Marketing Manager, Phil Dewis, who both shared some valuable information with me.

“When it comes to categorising safety footwear from an electrical conductivity perspective, there are three general classifications - insulating (also known as non-conductive), antistatic and conductive footwear,” states Fitzgerald. “It’s really not that complicated, but people can often get them mixed up if they’re unsure about the terminology. We have a policy to market footwear on a basis of ‘fitness for purpose’ and this means advising clients on the right boot for the right job. So let’s address each of the categories to help your readers better understand the issue.”

Non-conductive footwear

In discussing non-conductive footwear, Fitzgerald refers to the design philosophy of Steel Blue’s Hi-PA EH (electrical hazard) safety footwear: “These shoes are rated as ‘insulating’, designed to reduce dangers from accidental contact with live electrical circuits or parts of electrical apparatus of 600 VAC or less. However, these shoes are not suitable where antistatic properties are required.”

This is probably where some people get mixed up. Antistatic shouldn’t be confused with insulating or non-conductive. In fact, in some cases they can be quite the opposite. By definition, anti-static means to reduce or eliminate the build-up of static electricity.

Interestingly, to manufacture an insulative boot, Steel Blue removes the antistatic properties of the foot bed, insole, midsole and outsole. For example, a Hi-PA EH series boot is supplied with a nitrile rubber outsole only.

“Our EH series is non-conductive, in compliance with the ASTM F2413-05 ‘Electric shock resistant footwear’ standard,” continues Fitzgerald. “They’re tested at 14,000 V for one minute, with no current flow or leakage current in excess of 3 mA allowed under dry conditions. They’re marked with distinct yellow plugs in the black rubber sole so you can easily identify them as non-conductive.

“It should be understood that non-conductive footwear is intended for use as secondary PPE, to be used in conjunction with primary protective equipment, in environments where there’s a need to reduce the risk of electric shock from accidental contact with live wires.”

Anti-static footwear

“Anti-static footwear is designed to dissipate the accumulation of excess static electricity by conducting body charge to ground while maintaining a sufficiently high level of resistance to protect the wearer from electrical hazard due to live electrical circuits of up to 240 V,” states Fitzgerald. “Typical applications include working with electronics and petro-chemicals, powder coating, spray painting and fire fighting. This footwear is marked ‘AS/NZS 2210.3 Class 1A’ on a label inside the footwear.”

Conductive footwear

“Conductive footwear is intended to protect the wearer in an environment where accumulation of static electricity on the body is a hazard in applications such as handling explosives or similarly volatile materials,” explains Fitzgerald. “It’s designed to dissipate static electricity from the body to the ground to reduce the possibility of ignition of sensitive explosive mixtures or volatile chemicals. Conductive footwear should not be used by personnel working near open electrical circuits and should be worn only in environments for which they are intended. Steel Blue doesn’t produce this type of footwear.”

Metal in the boot

Some people have the misconception that any metal in a shoe, such as a metal toecap or sole plate, renders the shoe ‘conductive’ and therefore unable to protect against electrical hazards. Under normal circumstances, that’s completely wrong.

Dewis explains: “Electricity conducts through metal when it’s in contact with it. But metal toecaps and sole plates, whether they’re steel or aluminium, are enclosed by non-conductive materials - usually leather uppers and rubber soles. So even if someone wearing non-conductive safety boots with steel toecaps accidentally trod on a live circuit, the metal is completely isolated from the electricity.

“Having said that, the condition of the boot has a lot to do with its insulating properties. To ensure they provide the protection they’re designed for, boots need to be kept in good condition. That applies not only for electrical protection, but for all facets of physical foot protection as well. People need to make sure the soles and the uppers aren’t worn or in such poor condition that their safety attributes are compromised. Regular checks to make sure the boots are in good condition are essential. Don’t wait until you see exposed metal before replacing them.

“Safety boots are often worn in harsh conditions, such as construction sites and industrial facilities, so they are likely to take some abuse. Under such conditions, it’s worth sourcing footwear tough enough to endure such harsh conditions. It’s not just a matter of longevity, but more about maintaining the protection for the wearers. Blundstone’s philosophy is to make safety footwear as safe as possible, no matter what the environment. We figure the boots are likely to be subjected to some fairly rough treatment, so we make them tough enough to withstand it and still provide the protection, whether it’s from electrical or other physical hazards.”

Fitzgerald qualifies Steel Blue’s approach to metal in its boots, stating: “Steel Blue manufactures a wide range of safety footwear, some with steel toecaps and others with composite (non-metallic) toecaps. Our Hi-PA range has a composite safety toecap and, because it’s completely non-metallic, we believe it offers advantages over the traditional metal toecap boots. So, for example, if the leather on the front of a boot happens to be worn off, exposing the toecap, it won’t conduct electricity if it comes in contact with a live wire, say if a wearer is working on his knees and his toecaps touch what’s on the ground beneath him.

“It should be understood though that non-metal composite materials don’t have the same cut and penetration resistance as steel toecaps and should not be used around powered, cutting or grinding devices such as nail guns or demo-saws.”

Precautions

Steel Blue issues a number of precautions that wearers should be aware of, when it comes to protection against electrical hazards:

Insulative (non-conductive):

• Electric shock resistance deteriorates rapidly in a wet environment; and
• Excessive wear will decrease electric shock resistance.

Antistatic:

• The introduction of another foot bed may reduce or eliminate the antistatic properties of the boot;
• The boot will not perform its intended function when worn in wet conditions;
• The wearer should test the boots regularly; and
• Ensure that the correct flooring is in use so as not to negate the properties of the footwear.

Informed choice

Dewis is a strong advocate for empowering purchasers to make informed choices: “When it comes to safety, especially for hazardous environments, people purchasing PPE can’t assume things about a boot’s protection. Do some homework to get the best information on what’s right for your specific applications and environments. Most manufacturers have good technical information on their websites. Many also have technical support specialists who can be contacted by phone or email.

“The supply channel also needs to be able to provide reliable advice, so buyers can make informed decisions at the point of purchase. Since a large proportion of safety footwear is sold through retailers and wholesalers, this is where many questions are asked about what’s best for specific applications and environments. That’s why it’s so important for branch sales staff to be well versed in these technical issues.

“Blundstone is committed to educating the channel. We invest a lot of time and resources into keeping branches up-to-date on what protection is provided by our footwear and what’s best for what situation.

“When you’re looking to buy safety footwear, don’t assume things. Ask questions, even if you think you already know the answers. At the end of the day, there are no short cuts for safety. Whether you’re buying footwear just for yourself or for the entire workforce, you must choose the safest option. And because there are so many options to choose from - non-conductive, antistatic, conductive - there is no better approach than to do your homework. Ask the questions and get factual answers on what’s best for your specific environment.”