Betts Manhole Cover Vent - Vent In/ Pressure Out6496ALB
406 and 306 Pressure/Vacuum Normal Vent
- Dual Purpose Vent
- Roll Over Protection
- Compact Design
- Interior Mount
A normal vent designed for use on MC306 & DOT406 cargo tanks. Model 6496 has a pressure setting per 178.346-3(b)(2) of “not less than 1 PSIG” and a vacuum setting per 178.346-3(c)(2) “no more than 6 ounces” which allows for efficient recovery of vapors during closed system loading and off-loading. Unique roll over protection retains product at any attitude of rollover. Vent is flow tested and marked.
NOTE: While normal vents provide limited vapor venting during loading/unloading, it is recommended that positive vapor valves (typically air operated) be provided when loading/unloading with the manhole closed. If positive vapor valves are not used, insure normal vent is functioning properly or open manhole cover before beginning loading/unloading. Failure to do so may result in head reversals or other tank failure.