A gas-tight chemical protective suit is made up from large pieces of material which are joined by seams. In total there are several meter seams in a suit and these seams do propose a possible weak link in the construction, where chemicals can sneak through.
To prevent the seam from being a weak link, AlphaTec® suits (formerly known as TRELLCHEM®) use a unique seam technology based on stitching, taping and welding which altogether provides a seam with the same chemical resistance as the garment material itself, and sometimes even better.
Looking at the sketch below, the most important part of the AlphaTec® seam construction is the welded on Barrier tape. With this welded on Barrier tape, the Barrier film becomes unbroken, i.e. continuous all over the suit, and thereby guarantees the same or even longer permeation times than the suit material itself. This seam technology is used on AlphaTec® EVO, AlphaTec® FLASH and AlphaTec® VPS suits.
In a traditional seam, made on a material with the Barrier film embedded inside the material, it becomes impossible to seal it, thereby creating a weak spot in the seams, where the chemicals can permeate. This explains the often shorter seam permeation times shown for this type of seams, compared to the suit material itself! See the sketch below: