At The Bidvest Laundry Group we pride ourselves on our excellent service delivery and affordable solutions that cater to a wide range of industries. We are also proud of our ability to dress people for their job functions – especially those whose attire needs to comply with strict health and safety standards because they work in hazardous areas or around potentially harmful substances.
PPE in the workplace
PPE (or personal protective equipment) is equipment that will safeguard someone against health or safety risks at work. The material from which the workwear is made acts as a protective barrier against the hazards which the wearer could be exposed to. The quality of garment manufacturing plays a vital role in the overall level of protection, while a good fit is also crucial for safety and usability. Ill-fitting garments run a higher risk of tearing and can also restrict movement.
How acid resistance is achieved on fabric
An acid-resistant finish is primarily a liquid-proof coating that is not destroyed by the action of acids or other chemicals – it doesn’t allow the cloth to be ‘wetted’ by the acid/s and is therefore ‘resistant’ to it.
Much like applying Scotchgard™ to a couch or Teflon coating to a pan, the standard woven fabric we use for our workwear has an acid-resistant finish applied directly to it, which is then fixed (or stentered) into the material fibres before the garments are made up.
We do a resin finish first, to up the washing temperature, so the fabric can withstand the rigours of the industrial laundry process (typically, both cotton and polyester become unstable at high temperatures without protection). This resin base essentially protects the fibres from the heat, otherwise you would lose stability and see distortion in the shape of the fabric. Over and above the resin, we then add the ‘Teflon coating’ which is really a splash-resistant finish – if you splash liquid/acid on it, it will simply roll off, much like a drop of mercury.
The critical thing to understand with acid resistance is that treated fabric can absorb acid if given the time to do so – what you’re really doing by coating the garment is buying time; giving someone enough time to remove the garment, which is why most acid-resistant workwear comes in the form of dust coats and Conti-suits, finished with press studs instead of zips or buttons, for quick removal.
The main aim of an acid-resistant finish is to preserve the longevity of the fabric. If washed incorrectly, you will damage the coating or wash it off altogether. Acid-resistant garments need to be cleaned in a controlled environment.
Testing for acid resistance
At The Bidvest Laundry Group, we have in-house chemical technicians whose job it is to ensure that we continually offer our customers the best in protective workwear. These teams regularly put our acid-resistant garments to the test to assess, amongst other things, how many washes the protective coating on the fabric can withstand before breaking down.
There is currently no SANS specification for acid resistance, therefore alternate testing is done in the absence of a national standard. The tests are done in accordance to the ISO 6530:2005 and the chemical selection and concentration to the withdrawn DIN32763 standard.
One of the most basic test methods we use to help evaluate the liquid penetration resistance of a single layer of protective clothing is conducted as follows, using Hydrochloric Acid (HCl) 32%:
• The test material is placed tightly over a glass, as the glass provides a viewing window so that the inside surface of the material specimen (collection surface) can be observed during the test.
• A small amount of acid is poured onto the fabric.
• The material specimen passes if the inside surface of the material specimen indicates no presence of liquid after five minutes of exposure to the acid, while the material specimen fails if the inside surface of the material specimen does indicate the presence of liquid during the allotted time.
Why employers need to get it right
Protective clothing will only remain effective if properly maintained and cleaned in accordance with the manufacturer’s instructions – and herein lies one of the main challenges we face as a garment supplier with an in-depth understanding of the chemical industry and their garment requirements.
An acid-resistant coating comes with specific wash instructions in terms of temperature, handling etc, which will determine how long the coating lasts. Not following these instructions could have serious ramifications for employers, as they run the risk of not providing the protection required to keep their employees safe.
Those involved with providing workwear may not always be clear about what the hazards are, so it’s important that you identify, as far as you can, what the workwear is intended to do or protect workers from. We can assist you there by conducting an assessment and advising you on our garment solutions, such as RFID tagging for instance, which can keep track of how many times an acid-resistant garment has been washed.
We can offer you that peace of mind.
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Tel: +27 11 398 5300 (Head Office)