Paul Baker, PE, CPD, GPD, is a senior mechanical engineer with Jacobs in Fort Worth, Texas. He has more than 39 years’ experience in the HVAC and plumbing fields. He has been an ASPE member since 2006. Baker is a registered professional engineer in nine states. He would like to acknowledge the peer review provided by Oslin-Nation and Itron Inc. Baker can be reached at firstname.lastname@example.org.
There are many equations for determining the flow in natural gas pipes and the pressure drops associated with those flows, or vice versa. Our intent is to determine the validity of each equation with respect to flow rates that might be encountered by a plumbing engineer.
In the September 2019 Plumbing Engineer article on “Natural Gas Pipeline Systems on Site Distribution – Pipeline Materials and Installation Requirements,” the discussion centered on using carbon steel piping for above-ground installations and polyethylene (PE) piping for below-grade installations.
Purposes of this article, discussion will be limited to pipelines installed in Location Classes 3 and 4 (suburban and urban environments) and in low pressure distribution systems and service lines (downstream of transmission systems) and for pipelines NPS 12 (DN 300) and smaller.
The codes covering higher-pressure natural gas distribution systems are CFR-2011 Title 49, Volume 3, Part 192, Transportation of Natural and Other Gas by Pipeline: Minimum Federal Safety Standards and ASME B31.8, Gas Transmission and Distribution Piping Systems.