What is the smallest size Type K copper tubing that can be used for a 90-foot

This option describes a specific pressure system but does not provide a tubing size. While it specifies the conditions under which the piping operates, it fails to indicate a physical size, making it irrelevant to the question of minimum tubing dimensions.

While 3/4 inch tubing may seem adequate for smaller runs, it is insufficient for a 90-foot length carrying 195 cubic feet per hour. This size would likely result in a pressure drop that exceeds acceptable limits for the given flow rate, potentially leading to inadequate gas delivery.

Though 1 inch tubing would effectively handle the flow rate, it represents a larger size than necessary for this application. Utilizing larger tubing than required can lead to increased material costs and may not be the most efficient choice for this particular gas flow requirement.

Similar to the previous option, 1 1/4 inch tubing exceeds the minimum size needed for this system. While it would accommodate the flow rate comfortably, it is unnecessarily large, leading to greater expense and potential installation challenges without providing additional benefits.