Model PAF 412-5.0, 20″ Offset Manhole. DOT 412 Pressure Relief Device

Model PAF 412-5.0 is a 10″ (254mm) aluminum surge suppression spring loaded re-closing pressure relief device for use as a cargo tank’s primary pressure relief system. The PAF is mounted to a clamp-ring style manhole. Designed to be used on DOT412, TC412 and TC423 cargo tanks with a MAWP of 5.0 psig, the PAF 412-5.0 meets the requirements of 49CFR §178.345-10 and §178.348-4. Relief vent meets the 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 offset 20” (508 mm) clamp ring style manhole has provisions for mounting a bolted style vapor recovery valve and liquid level sensor. Manhole and clamp ring are certified and marked in accordance with 49CFR178.345-5 with a test pressure of 36 psig.

The LPVQ version includes a 6705 normal vent installed and meets the requirements of 49CFR178.345 for use with DOT412 applications.

The IVAQ version includes a 6234 in-breathing vent installed and meets the requirements of CSA B620-20 clause 5.6.11 and clause 5.10.5 for use with DOT412, TC412 and TC423 applications.

The manhole’s overall height is 3.56″ from the top surface of the manhole collar.

Manhole Assembly Part Numbers:
      LPVQ820CXB – 7535ALB pressure relief device with 6705ALB normal vent. 304 stainless steel 20″ offset manhole with provision for mounting a bolted style vapor recovery valve and liquid level sensor.
      LPVQ820CXB442 – Same as LPVQ820CXB but adds welded pins and padlock tabs on clamp ring and padlock loop on strongback for security.
      LPVQ863CXB – Same as LPVQ820CXB but adds self latch mechanism.
      IVAQ820CXB442 – 7535ALB pressure relief device with 6234AL in-breathing vent.  304 stainless steel 20″ offset manhole with provision for mounting a bolted style vapor recovery valve and liquid level sensor. Includes welded pins and padlock tabs on clamp ring and padlock loop on strongback for security.

7535ALBN – PAF 412-5.0 Aluminum Relief Vent Assembly w/ nitrile seals
      Set Pressure: 6.0 to 6.6 psig (41.4 to 45.5 kPa)
      Rated Air Flow: 263,124 SCFH at 7.5 psig (7,450 SCMH at 52 kPa)
      Liquid Flow Capacity: 1,426 gpm at 7.5 psig (5,398 lpm at 52 kPa)

Alternate seals are available as-well-as a steel zinc manhole option.