The Pipeline and Hazardous Materials Safety Administration (PHMSA) exempts the following types of pipelines from having a DIMP:
(1) Individual service lines directly connected to a production line or a gathering line other than a regulated onshore gathering line as determined in § 192.8;
(2) Individual service lines directly connected to either a transmission or regulated gathering pipeline and maintained in accordance with § 192.740(a) and (b); and
(3) Master meter systems.
Small liquefied petroleum gas (LPG) distribution pipeline operators that serve fewer than 100 customers from a single source are only required to have a simplified DIMP as outlined in 49 CFR 192.1015. Note, LPG distribution operators that have multiple tanks connected together via a common manifold are considered a single source.
All other distribution pipelines are required to have a DIMP. PHMSA in Interpretation: PI-11-0008 (Date: 04-19-2011) operators of distribution, gathering, and transmission lines whose system includes “farm taps” meet the definition of a distribution line and must have a DIMP covering these facilities. (Interpretation Response | PHMSA (dot.gov))
PHMSA has a resource page with additional information on DIMP-
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