Using Probability to Determine Medical Gas Flow, Part I
Plumbing designers are often called upon to design medical gas piping systems, including oxygen, nitrous oxide, nitrogen, carbon dioxide, medical vacuum, WAGD (Waste Anesthetic Gas Disposal) and medical compressed air. As with any gas piping system, in order to determine pipe sizes accurately, we must first determine the maximum anticipated flow. Then, once the flow has been determined, pipe sizes may be selected using standard tables or by direct calculation using various gas-flow formulae.
However, calculating medical gas flows and pipe sizes, especially for large facilities such as hospitals, can be a rather complicated process. To determine flow, designers have traditionally counted the number of outlets/inlets served by a section of piping without regard to the location of those outlets/inlets, applied a "use factor"