Cargo Tank Requirements and Specifications
MC-306 (DOT-406)
Non (low) pressure bulk liquid cargo tank- MC 306 Maximum operating pressure of up to 3 psi
- DOT 406 Maximum operating pressure of up to 4 psi
- Oval or a shaped cross section
- Flat or nearly flat ends
- Aluminum primary material of construction
- Usually multi-compartmented
- Separate manhole for each compartment
- Emergency shutoff drivers side front
- Rollover protection to prevent manholes from opening up on rollover
- Average maximum capacity 9,000 gallons
Contents:
NORMALLY petroleum products, however, may be water or milk
MC-306 and DOT 406 tankers are elliptical when viewed from the rear. By far the most common product carried in them is gasoline or other flammable liquids. They usually have a heavy, built-up top that is hollowed out to contain small spills. These tankers have one or more domes and dome covers, generally one dome per compartment in the tank.
MC-307 (DOT-407)
Low-pressure bulk liquid cargo tank- Pressure up to 40 psi @ 70°F
- Horse shaped shaped cross section
- Flat or slightly rounded ends
- Stainless steel is primary material of construction
- May be insulated. Insulation may hide tank shape may not appear to be horseshoe shaped
- Manway usually center (top) of tank
- Discharge valves usually center (bottom) of tank
- If multi-compartmented, will have a separate manhole for each compartment
- Emergency shutoff drivers side front
- Rollover protection to prevent manholes from opening up on rollover, normally
- center of tank top
- Average maximum capacity 6,000 gallons
Contents:
NORMALLY mild acids, however, may be water, milk, or combustible liquids
MC-307/DOT 407 tankers are a usually a horseshoe shape when viewed from the rear. They carry vegetable oils, syrups, and milk and they also carry solvents, lubricants, mild corrosives, etc. The horseshoe shape tanks are insulated the shape you see is the thin aluminum insulation shell cover. Some of these tankers are uninsulated, appear round with small ridges, and are usually unpainted aluminum if un-insulated. The domes in these tankers are usually in the center of the long axis of the tank, but can be multiples or in other locations.
MC-312 (DOT-412)
Corrosives Cargo Tank- Pressure 5 to 25 psi exterior strengthening (stiffener) rings often visible
- Lined tank usually lined with rubber or plastic
- Round cross section
- Stainless steel is primary material of construction
- May be insulated, insulation may hide tank shape
- Manway usually rear (top) of tank
- Discharge valves usually rear (bottom) of tank
- If multi-compartmented, will have a separate manhole for each compartment
- Emergency shutoff drivers side front
- Cigar shaped tank long, small diameter
- Average maximum capacity 4,000 to 6,000 gallons
Contents:
Corrosives High weight (specific gravity) liquids
Internal Pressure Specifications
| Code | Test Pressure |
| MC 300, 301, 302, 303, 305, 306 | 20.7 kPa (3 psig) or design pressure, whichever is greater |
| MC 304, 307 | 275.8 kPa (40 psig) or 1.5 times the design pressure, whichever is greater |
| MC 330, 331 | 1.5 times either the MAWP or the re-rated pressure, whichever is applicable |
| MC 338 | 1.25 times either the MAWP or the re-rated pressure, whichever is applicable |
| DOT 406 | 34.5 kPa (5 psig) or 1.5 times the MAWP, whichever is greater |
| DOT 407 | 275.8 kPa (40 psig) or 1.5 times the MAWP, whichever is greater |
| DOT 412 | 1.5 times the MAWP |
MAWP (Maximum Allowable Operating Pressure)
In-Service Minimum Thickness for MC 300, MC 303, MC 304, MC 306, MC 307, MC 310, MC 311, and MC 312 Constructed of Steel
| Minimum manufactured thickness (US gauge or inches) | Nominal decimal equivalent for (inches) | In-service minimum thickness reference (inches) |
| 19 | 0.0418 | 0.038 |
| 18 | 0.0478 | 0.043 |
| 17 | 0.0538 | 0.048 |
| 16 | 0.0598 | 0.054 |
| 15 | 0.0673 | 0.061 |
| 14 | 0.0747 | 0.067 |
| 13 | 0.0897 | 0.081 |
| 12 | 0.1046 | 0.094 |
| 11 | 0.1196 | 0.108 |
| 10 | 0.1345 | 0.121 |
| 9 | 0.1495 | 0.135 |
| 8 | 0.1644 | 0.148 |
| 7 | 0.1793 | 0.161 |
| 3/16 | 0.1875 | 0.169 |
| 1/4 | 0.25 | 0.225 |
| 5/16 | 0.3125 | 0.281 |
| 3/8 | 0.375 | 0.338 |
In-Service Minimum Thickness for MC 301, MC 302, MC 304, MC 305, MC 306, MC 307, MC 311, and MC 312 Constructed of Aluminum
| Minimum manufactured thickness | In-service minimum thickness (inches) |
| 0.078 | 0.07 |
| 0.087 | 0.078 |
| 0.096 | 0.086 |
| 0.109 | 0.098 |
| 0.13 | 0.117 |
| 0.141 | 0.127 |
| 0.151 | 0.136 |
| 0.172 | 0.155 |
| 0.173 | 0.156 |
| 0.194 | 0.175 |
| 0.216 | 0.194 |
| 0.237 | 0.213 |
| 0.27 | 0.243 |
| 0.36 | 0.324 |
| 0.45 | 0.405 |
| 0.54 | 0.486 |