Cobham Type 4 CNG Tank – 73 Gallon | 3600 PSI

Is this ASME or DOT rated, and what does that allow me to do with it?

These tanks are DOT-rated to FMVSS 304, the Federal Motor Vehicle Safety Standard for compressed natural gas vehicle fuel containers. This certification restricts them to CNG vehicle fuel storage applications; they cannot be legally used as stationary storage, in other gas services, or filled beyond the marked service pressure and inspection intervals without violating the DOT certification under which they were manufactured.

What is the MAWP and capacity at service pressure?

The service pressure is 3600 PSI (24,800 kPa) and the capacity is 73 gallons. DOT FMVSS 304 tanks like these do not use the ASME term "MAWP"; instead, the service pressure is the maximum working pressure for normal fill operations, and there is typically a higher hydrostatic test pressure used during certification and requalification.

What is the requalification or inspection status?

These tanks require inspection every 36 months or 36,000 miles, whichever comes first, per DOT FMVSS 304. The available units were manufactured in 08/2016 and 03/2017 with service life expiration dates of 08/2036 and 03/2037 respectively, but the listing does not state when the last inspection was performed or how many inspection cycles remain—confirm current certification status and mileage history with the seller.

What should I inspect before putting it into service?

Verify the composite overwrap for any impact damage, cuts, abrasion, or delamination, and confirm the liner shows no signs of fire exposure, bulging, or stress cracking. Check that valves and PRDs are manufacturer-approved components in serviceable condition, confirm the tank has not exceeded its inspection interval or accumulated mileage, and verify the nameplate data matches DOT records. Type 4 tanks are particularly sensitive to impact and UV degradation, so examine mounting points and any areas with compromised outer protective layer closely.