Westlake Pipe & Fittings' GVS-90 gas venting product family features a complete system of pipe, fittings and accessories suitable for appliances with flue gas temperatures up to 90˚C. Our GVS-90 pipe is manufactured to Schedule 40 dimensions and our GVS-90 fittings are manufactured to Schedule 80 dimensions, ensuring compatibility with other systems. This Type BH Class II B venting system is certified to ULC S636 standards.