Recent tests conducted by an independent, accredited laboratory show that white Tyvek® L1431N fabric has a good chemical barrier performance that provides excellent protection against liquid permeation.

To most people all protective coveralls look the same and selecting the correct one to offer the best protection against liquid penetration and permeation can be a task in itself. In order to factually assess the barrier performance, permeation tests (according to EN ISO 6529 – Method A) were conducted to determine the breakthrough times of commonly-used chemicals with white Tyvek®, MPF (Microporous Film) and SMS (Spunbond-Meltblown-Spunbond) – materials that are frequently used for Type 4, 5, and 6 single-use chemical protective clothing.

Liquid penetration is a physical process whereby a liquid penetrates a fabric by passing through pores or holes in the fabric. Permeation is the process by which a hazardous liquid chemical moves through a protective clothing fabric on a molecular level. The resistance of the fabric to permeation is determined by measuring the breakthrough time and the rate at which the hazardous chemical permeates and is detected on the inside surface of the fabric.

To conduct the permeation test and determine the actual and normalised breakthrough times, 40% sodium hydroxide and 18% sulphuric acid, two commonly used chemicals in the industry, were selected. With a normalised breakthrough time of over 480 minutes with these two water-based inorganic chemicals, Tyvek® offered a barrier 10 times higher than the average MPF results, while SMS showed immediate breakthrough.

Penetration and repellency tests were also conducted according to EN ISO 6530 standard and showed virtually no difference between the three materials, indicating the liquid barrier of the three materials seems to be of equal protection. However, this standard stipulates just one minute of exposure to the hazardous substance, which is rarely the case in working conditions.

When tested for permeation according to EN ISO 6529 - Method A, which determines the resistance of materials to permeation by liquids and gases, it was revealed that white Tyvek® offers long-term protection of up to eight hours for the aforementioned chemicals – much closer to what is needed in real use situation.

Tyvek® is an excellent material because the continuous, strong, high density polyethylene fibres do not shed and it does not contain additives or fillers. This smooth surface repels both liquids and particles, offering a very high chemical barrier in its category. Even after surface abrasion, the fabric retains a high level of barrier because the entire thickness of the fabric constitutes the “barrier” itself. This means that contamination, whether from the person wearing the coverall or the environment that the person is working in, is minimised; therefore offering protection for products or processes. Tyvek® is also extremely durable, highly resistant to tear and abrasion, but still breathable and, because of the smooth surface of the finished fabric, it remains soft to touch and is extremely flexible, not restricting movement.

The range of Tyvek® garments includes Tyvek® Industry, Tyvek® Classic Xpert and Tyvek® Classic Plus, Tyvek® Dual and Tyvek® Labo. Ultimately the ambition for DuPont is to protect every single person in every situation and continuous attention is paid to every detail. That’s the reason why Tyvek® makes the difference.