StacksVerified U.S. regulatory reference

46 CFR §153.406

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
When Table 1 requires a cargo's containment system to have a restricted gauge, the containment system must have:
  1. (a)A closed gauging system; or
  2. (b)A system that has:
    1. (1)A restricted gauge (e.g., a sounding tube) with an orifice diameter not exceeding 20 cm (approx. 7.8 in.);
    2. (2)A permanently attached gauge cover that is vapor tight when in place; and
    3. (3)A venting system that has either:
      1. (i)Lock open PV valves; or
      2. (ii)Valved bypasses around the PV valves.