Type NGV 2 containers are designated as follows:
a) Type 1: metal;
b) Type 2: resin-impregnated continuous filament with metal liner with a minimum burst pressure of 125% of service pressure. The container is hoop-wrapped;
c) Type 3: resin-impregnated continuous filament with metal liner. The container is full-wrapped; and
d) Type 4: resin-impregnated continuous filament with a nonmetallic liner.
Conformable container types are designated as follows:
a) CT1: container or assembly of a non-spherocylindrical or non-spherical (i.e., irregular) shape without a protective shell (i.e., outside wall containing gas pressure);
b) CT2: container or assembly of possibly irregular shape within a conformable protective shell that is acting as a shield and not directly assisting the inner container with containing gas pressure; and
c) CT3: container or assembly of possibly irregular shape within a conformable protective shell that is acting as a shield and directly assisting the inner container with containing gas pressure.
The conformable container types are an additional identifier that is used in combination with the container type. A conformable tank is designated based on the design as a Type 1 (metal) to Type 4 (resin-impregnated continuous filament with a nonmetallic liner) with the additional conformable type identifier. For example, a Type 4 CT2 container would be required to meet the criteria for a Type 4 container as well as the criteria specified for a CT2 container.