DNV has developed the first rules for building and classification of ships carrying compressed natural gas (CNG) and pressurised natural gas (PNG).

Compared to traditional LNG value chains, a CNG/PNG value chain would not require investments in liquefaction, storage and regasification facilities. Cost analysis show that the CNG/PNG concept in many cases will be highly competitive with pipelines and LNG transport for distances up to 2500 - 3000 nautical miles.

The design of CNG containment systems using pressure vessel codes or the International Gas Carrier (IGC) Code leads to heavy containment systems with virtually no lifting capacity left for cargo. The key to the realisation of CNG design is to use modern reliability calibrated design codes that offer the same system safety, but with the use of smaller nominal usage factors on the structural design.

Our CNG/PNG rules are based on DNV-OS-F101 Standard for Submarine Pipeline Systems. This Standard gives a substantial reduction in the thickness of the containment cylinder walls compared to the IGC Code, hence a significant weight reduction., still maintaining the system safety.