Mainline Valve Spacing
Returns the required maximum sectionalizing block-valve spacing by class per 49 CFR 192.179, the minimum valve count for a route, and rupture-mitigation-valve (RMV) applicability under the 2022 Valve Rule (§192.634).
Class & Route
mi
RMV Applicability (2022 Valve Rule)
in
Engineering Basis
§192.179(a): each point must be within {Class 1: 10, Class 2: 7.5, Class 3: 4, Class 4: 2.5} mi of a sectionalizing block valve.
Maximum valve-to-valve spacing = 2× that = {Class 1: 20, Class 2: 15, Class 3: 8, Class 4: 5} mi.
Valves for a route = ⌈route ÷ max spacing⌉ + 1 (valves at both ends).
RMV (or equivalent) required for new / entirely replaced onshore lines, OD ≥ 6 in, installed after 2023-04-10 (§192.179(e)/(f), §192.634).
The regulatory maximum is a ceiling — terrain, crossings and drain-down may force closer spacing.