LIQUID CHEMICAL REPELLANT WORKWEAR.
We would like to clarify what is Liquid Chemical Repellant Workwear and clear up what is happening in the market.
Objective of Liquid Chemical Repellant:
To render a fabric or material resistant to specific liquid chemicals.
The objective is to prevent liquid chemical spillages from penetrating through the fabric and touching and burning the skin.
It’s a preventative measure and does not make the fabric liquid chemical proof.
Basically a Fluorocarbon Resin is applied together with an extender or booster to the fabric. The end result is a fine film formation on the surface of the fabric through orientation of the chemical molecules that negate the surface tensions on the fabric. This makes a barrier that enhances the repellent to chemical solutions.
Fabrics treated are resistant to:
Caustic Soda (40%)
Nitric Acid (65%)
Hydrochloric Acid (32%)
Sulphuric Acid (24%)
The test method evaluates penetration of these chemicals through the fabric as follows:
20 mls solution is poured onto the fabric via a funnel
If a test substance shows no penetration for more than 10 minutes the fabric is then deemed suitable for acid repellant work wear.
In terms of durability for this type of finish, there are no guarantees. This is largely due to the fact that after care washing methods, garment drying conditions, type of detergents/softener etc. can have significant impact on the desired end effects.
The recommended washing is as follows:
- temperature 60 deg C
- no softener should be used
- garment must be ironed after washing
- mild household detergent can be used
Garments treated this way will conform for at least 20 washes. If you wash your garments twice a week will they be Acid resistant after 3 months? This is washing with a washing machine and following the instructions on the label. I am so pleased every employee who is required to wear liquid chemical repellant clothing has a washing machine and follow the washing instructions.
The ironing reactivates the Liquid Chemical Repelling coating.
There is a misconception that Poly-viscous and Polyester Fabrics are liquid chemical repellant. This is not correct. Read what is written above – it is the coating that makes the fabric liquid chemical repellant. The fabric may not be affected by the chemical, but it is the penetration of the chemical through the fabric that is important. This is only prevented by the coating.
We prefer to use 65/35 Poly-cotton liquid chemical repellant fabric as the cotton absorbs the chemical repellant and it therefore penetrates the fabric giving better protection and will last longer (Note the number of washes above).
A large amount of the liquid chemical repellant fabric sold in Southern Africa is imported from the far east through traders. The fabric may be labeled acid resistant or liquid chemical repellant and have certificates to confirm this. If you believe this then you are asking for trouble. The certification facility must be ISO registered to be trusted Every batch of fabric should be tested for liquid chemical repellant. Notice I said every batch and not every shipment. Every colour and batch in the shipment should be tested. This is too expensive so samples of the fabric should be taken at periodic intervals for testing.
An easy liquid chemical repellant test is to check the penetration of liquids through the fabric. If water penetrates the fabric, so will liquid chemicals. Therefore throw some water on the fabric, if it penetrates the fabric, so will liquid chemicals. This is a quick test that should be done by the end user. If water penetrates the fabric it should be tested for liquid chemical repellence.
Having a report from the Botswana Bureau of Standards saying that samples of fabric have been tested and comply with the standards does not mean that the garments are liquid chemical repellant. All that the Botswana Bureau of Standards is doing is confirming that the sample of fabric supplied for testing conforms to the standard.
The liquid repellent testing facility will not have approved any on-going quality control and it is the responsibility of the purchaser to satisfy themselves that other production batches perform similarly.
Having labels on the garments stating that they comply with the BOBS Standards also does not guarantee that the garment is liquid chemical resistant only that the garment is manufactured according to BOB Specifications
You have been warned, splash test every batch of Liquid Chemical Repellant Work-wear you receive and be safe.