This standard contains requirements for the material, design, manufacture and testing of serially produced, refillable Type NGV 2 containers intended only for the storage of compressed natural gas for vehicle operation. These containers are to be permanently attached to the vehicle. Type NGV 2 containers shall not be over 1000 liters (35.4 cubic feet) water capacity. Where the word "shall" is used in this standard, it indicates a requirement . Type NGV 2 containers are designated as follows: Type 1. Metal. Type 2. Resin impregnated continuous filament with metal liner with a minimum burst pressure of 125 percent of service pressure. This container is hoop-wrapped. Type 3. Resin impregnated continuous filament with metal liner. This container is full-wrapped. Type 4. Resin impregnated continuous filament with a non-metallic liner. All specifications as to construction or materials set forth herein may be satisfied by the construction or materials actually prescribed or such other construction or materials as will provide at least equivalent level of performance. Additional tests may be required to evaluate potential failure modes that pertain to the new construction or materials that are not specifically addressed in this standard.