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.
Product Details
| Assembly No.* | Description | Body Mat'l | Set Pressure** (psig) | Set Pressure** Vacuum (psig) | Flow Capacity Out-breathing | Flow Capacity In-breathing | Dim. A | Dim. B | Dim. C | Dim. D (Threads) | Wt. (lbs.) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 6238AL* | FVA MC306 Normal Vent | Alum. | 0.8 to 1.0 | 0.25 to 0.375 | 1,750 CFH @ 3 psi | 3,350 CFH @ 1 psi | .72" | 4.16" | 2.75" | 1 5/8-12UN | 1.0 lb. |
| 6238SL* | FVA MC306 Normal Vent | 303 SS | 0.8 to 1.0 | 0.25 to 0.375 | 1,750 CFH @ 3 psi | 3,350 CFH @ 1 psi | .72" | 4.16" | 2.75" | 1 5/8-12UN | 2.5 lbs. |
| 6496AL* | PPV DOT406 Normal Vent | Alum. | 1.0 to 1.5 | 0.25 to 0.375 | 1,200 CFH @ 3 psi | 3,350 CFH @ 1 psi | .72" | 4.16" | 2.75" | 1 5/8-12UN | 1.0 lb. |
| 6496SL* | PPV DOT406 Normal Vent | 303 SS | 1.0 to 1.5 | 0.25 to 0.375 | 1,200 CFH @ 3 psi | 3,350 CFH @ 1 psi | .72" | 4.16" | 2.75" | 1 5/8-12UN | 2.5 lbs. |
| * Add letters to part number to designate seal material. See material table below for designation. ** Proper maintenance is required to ensure effective performance of normal vent. Dust, dirt, or residue will reduce the ability of the vent to hold required set-pressure. |
|||||||||||
| Letter | Mat'l | Temp. Range |
|---|---|---|
| B | Buna-N | -40°F to +220°F |
| V | Viton® | -20°F to +400°F |
| EP | EPDM (Black) | -40°F to +260°F |
Additional Options
Betts prides itself in being able to provide products that meet a customer’s specific needs. As a result we do offer modifications to our product standards. While not every request is always feasible, we do our best to meet your specific needs. In many cases this modification is noted by adding a suffix to the end of the standard part number. The following is a non-inclusive list of common options that are available for this product line . If the options listed below do not meet your requirements please contact one of Betts’ Customer Service Representatives for further assistance. Please note that some product modifications may result in extended lead times.
Commonly Requested Options:
Suffix “277” – Normal vent with 35x35x.012 screen. Image 6496AL_277