A polypropylene flue-gas venting system called Polyflue is now available for Category 2 and Category 4 heating appliances. Officials say this product has a higher safety factor than polyvinyl chloride and chlorinated polyvinyl chloride plastic pipe used on such heating appliances. Polyflue also provides faster and cleaner installations, officials say. The venting system is offered in 2-, 3- and 4-inch-diameter, white-single-wall-rigid and flexible re-liner pipe systems, and comes with a 10-year limited warranty.

Polyflue, 5030 Corporate Exchange Blvd. SE, Grand Rapids, MI 49512; (800) 992-8368; fax (877) 393-4145;