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The Role Of ESD Lab Coats In ESD Protected Areas (EPAs)

ESD lab coats are an important factor for employees that work in an electrostatic discharge protected area (EPA). In an environment with high levels of static charge accumulations, ESD lab coats provide a barrier between the wearer and any possible static charges to prevent electrical damage.

Throughout this blog, we will investigate the key features of anti-static clothing and top tips to consider when purchasing.

Purpose Of ESD Lab Coats

To put it plainly, ESD lab coats act as a protective shield from static energy, replacing standard high charging insulative clothing.

General everyday clothing is made from synthetic fibres, which generate a significant amount of charge. Worse for ESD control, the fabric is an insulator so the result can be very hostile: an isolated charged insulator which cannot be grounded.

An insulator restricts charges from flowing and will therefore hold the charge until either neutralised over time (naturally over hours or days) or with an air ioniser (artificially under a few seconds).

In the meantime, your sleeves, waist, etc. may have several thousand volts (a very significant electric field to expose nearby conductors) that may induce charges on nearby isolated conductors. This is the main reason people wear ESD lab coats: so they can shield the insulative clothing and minimise the electric fields generated from their clothing.

Although the ESD Standards do not require ESD lab coats or jackets, it is evident that they are a very practical, safe and efficient asset within the workplace. 

Some even believe, ESD lab coats represent the single most important step to demonstrate commitment to an ESD control programme.

ESD Lab Coat Properties

Unlike the material of non-ESD clothing, most lab coats are fabricated of a dissipative material which incorporates texturised polyester and carbon nylon fibres. The conductive nylon fibres are woven into a chain-link design which provides a continuous and consistent charge dissipation.

From this, the anti-static material shields, creating a “Faraday Cage” effect. This means that any charges generated on the users clothing will be transferred to the inside of the ESD lab coat. 

Finally, all lab coats are groundable and dissipative so when plugged in, they remove all charges to ground preventing static electricity from circulating on or around your body.

Installation & Grounding Of ESD Lab Coats

There are some important areas to highlight when installing an ESD lab coat. Below, you can see the steps taken to ensure you are using it correctly and efficiently:

 

1.      Place the lab coat on and fasten all of the snaps on the front, ensuring that clothing underneath is not exposed. 

Any item of clothing overhanging defeats the purpose of the protective shield.

 

2.      Throughout use of the lab coat, it is essential that the conductive cuff has intimate contact with the wrist skin. 

The conductive cuff should never be allowed to be pulled up and over the shirt sleeve.

 

3.      Ground the ESD lab coat. A common way to ground an ESD lab coat is with a coiled cord either attached to a snap on the waist area of the lab coat or via a wrist strap snapped to the inside cuff of an ESD lab coat. 

If none of these methods are appropriate, the lab coat should be grounded via the person’s wrist removing charges via ESD footwear to ESD protected flooring.

 

What Will Happen If An ESD Lab Coat Is Not Grounded Correctly? 

Due to the lab coat acting as a conductor throughout its use, it is imperative that it be grounded to ensure all electrical charge is dissipated. 

If not grounded, the ESD garment itself is a potentially threatening isolated charged conductor. 

This means that it will be electrically charged and entirely ineffective, risking ESD damage to sensitive parts that might be being worked on.

Testing Of ESD Lab Coats

A critical factor to consider when employing the use of ESD lab coats within the workplace, is the implementation of panel-to-panel conductivity testing. 

It is vital to ensure that portions of the lab coat are not left as isolated charged conductors.

A Resistance Test Kit rapidly measures the resistance of the fabric and ensures panel-to-panel conductivity by placing electrodes on different fabric panels. 

Panel-to-panel conductivity measures the lowest resistance path between the electrodes placed on the sleeve panels.

Using A Static Field Meter

To ensure that an ESD lab coat is low tribocharging (contact electrification process that enables build-up of static electricity due to touching or rubbing of surfaces), a Static Field Meter can be used to measure the electrical charge.

In addition, the Static Field Meter can demonstrate shielding by measuring a charged object and then covering the charged item with the ESD lab coat. 

Being shielded the measured charge should be significantly reduced.

 

Cleaning Of ESD Lab Coats

In order to maintain and clean ESD lab coats, there are a few tips to consider. 

Firstly, always wash the garment cool or warm water, then tumble dry with low heat or leave to hang dry. 

When choosing fabric conditioner, we recommend that you only use non-ionic softeners and detergents when laundering. Do not bleach your ESD lab coats, as this can cause erosion to the carbon threading! 

Secondly, it is imperative that lab coats are not altered in any way. 

The lab coats effectiveness is in fully covering the human body and non-ESD clothes, particularly at the wrists and front of the body. Altering the lab coat in any way will nullify its effectiveness.

The typical useful and effective life of a lab coat under normal wearing and recommended washing conditions is a minimum of 75 washings. Washing can cause approximately 5% shrinkage for each garment.

Finally, please note that washing guidance differs between each manufacturer.

Things To Consider When Buying An ESD Lab Coat

When considering kitting out your EPA, it is highly recommended that an ESD lab coat is accounted for, especially as there are a few misconceptions around what ESD protection one should be wearing. 

For example, many people may ask why they should wear an ESD lab coat if they are already grounded to Earth via a wrist-strap. This is however untrue, mostly due to the common fact that an ESD wrist-strap will not dissipate ALL static charge on the personnel, because of the type of clothing they are wearing.

Here are some things to consider when making a purchasing decision:

Size

When scoping out your company's lab coats, it is important to gauge each employees desired size so that no risks are taken. These risks can include non-ESD clothes being exposed, thus reducing the effectiveness of the lab coat and posing a risk to electrical components.

Embroidery and Material

Most ESD clothing is made from cotton or polyester and then imbedded with a grid of carbon fiber. These fibers effectively create a Faraday Cage around the body of the wearer.

This shields any charges generated from the clothing that could otherwise damage devices that are sensitive to static electricity.

ESD clothing is generally manufactured from manmade fabrics as, unlike natural materials, their fibers won’t break down. This helps to minimise static and make the space even safer.

 

Summary

In summary, we hope that this blog post has given some insight into how ESD lab coats can be extremely beneficial to EPA's and additionally, aided in any purchasing decisions.

There is no doubt that humans generate a substantial amount of static energy, of which, needs to be strictly controlled in an environment working with electrical components. We highly recommend considering ESD lab coats as part of your ESD control programme.

If you require any assistance in acquiring the correct torque testing equipment, give our team a call on 023 8065 0065 or email us at [email protected].

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