20 in Offset DOT406 Manhole with Nitrile Gasket and Zinc Plated Steel Cover

Betts PAF manhole with integral 406-98 surge suppression pressure relief valve (PRV) is the proven leader for cargo tank longevity, protection, and safety. The 406-98 features a 10 in (254 mm) reclosing PRV that satisfies primary pressure relief for US DOT406 and TC406 cargo tanks. It meets dynamic pressure surge requirements of 49CFR§178.345-10(b)(3)(ii) with less than one-liter leakage as tested per TTMA RP no. 81. The PRV cover doubles as a quick-open inspection hatch with a secondary safety catch. PPVL models include a 6496 P/V normal vent. The offset 20 in (508 mm) clamp ring style manhole has provisions for mounting a bolted vapor recovery valve and liquid level sensor. Manhole and clamp ring are certified and marked per 49CFR178.345-5 with a test pressure of 36 psig. The PAF 406-98 is also available in a self-latch model (part number L863). On self-latch models, a stop bracket holds the PRV at 91°; if left open, tank movement causes the PRV cover to drop and catch semi-closed. The 406-98 PRV must not exceed 212°F (100°C). Stainless steel versions are available with prefix "PPSS". For MC306 cargo tanks, see Betts’ PAF306 surge manholes.Manhole, Nitrile (Buna-N) Gasket, Zinc Plated Steel Manhole Cover, PRV Cover: E-Coated Aluminum, 20 in, Strongback and Latch: Zinc Plated Steel, For 820