The Nitro-Charged ACR tubes for the HVAC industry are dehydrated, cleaned, charged with nitrogen, then capped to ensure purity, states the company. According to the manufacturer, the tubes are pure enough to be suitable for use in medical gas systems, per ASTM B-280 and B-819. These copper tubes, each 20 feet in length, are available in sizes ranging from 3/8 to 3-1/8 inches O.D.
Cambridge-Lee, P.O. Box 14026; Reading, PA 19612; 800-926-5588; www.cambridge-lee.com (website).