Q: Which zipper is used on a protective suit?
A protective suit uses a size 8 or size 10 airtight zipper with a double flap, not an ordinary garment zip. The chain is built to hold pressure or to block liquid and particulate ingress, and the slider is designed to compress the two tapes together along their full length. The front placket must run straight, because an airtight zip cannot follow a curve without creasing and losing its seal; the parking area for the slider has to be flat and reinforced.
- Size 8 or 10 airtight chain with a double flap.
- Straight placket only; no curve through the seal.
- Reinforced, flat slider parking area.
The usual pitfall is substituting a size 5 coil because it is flexible and cheap: it leaks at the first test and gives no warning in use. The second is layout. A curved front, a pocket placed across the seal or a seam that crosses the chain will all defeat the closure. Lubricate only with a product approved for the suit material, since a silicone that attacks the coating will destroy the seal it was meant to protect.