From the GMA Techline
Subject: Flash point— A contractor is proposing installation of a PVC geocomposite in a tunnel as a lining. The California Code of Regulations stipulates the nonuse of materials with a flash point of 100°F or less. Would any of the cements/sealers used in installation of this liner have a flash point of 100° or less? (Doug, California)
Reply: The PVC geocomposite you speak of is a PVC geomembrane bonded to a needlepunched nonwoven geotextile. It has been successfully used in a number of major tunnels for waterproofing. There is no adhesive or bonding agent, as the 2 components are adhered to one another during manufacturing. Thus, flash point is not an issue.
That said, there certainly might be a sealant for the geotextile to be applied to the tunnel walls. This could well be an issue in this regard.
To answer your question, we would need to know specifically what sealant(s) are under consideration. Further testing might be required.