1.1 This specification covers selection and application requirements for the design of a thermal insulation system used on cryogenic liquefied natural gas (LNG) Type C tanks that can store LNG at a higher pressure than Type A or Type B tanks.

1.2 Methods and materials for installation, including jacketing and vapor retarders, are also detailed.

1.3 This specification shall be applied to LNG fueled and cargo vessel applications as regulated by either the International Code of Safety for Ships Using Gases or Other Low Flashpoint Fuels (IGF Code) or International Code for the Construction and Equipment of Ships Carrying Liquefied Gases in Bulk (IGC Code).

1.4 This specification provides requirements for the properties of thermal insulation and other materials used in LNG Type C tanks as described in IGC Code Chapter 4.19.3 and IGF Code Section 6.4.13.3.

1.5 LNG Type C tanks are described in IGC Code and IGF Code.

1.6 This specification addresses suitable properties of resistance to fire and flame spread for LNG Type C tanks or portions of the tank are located on or above the exposed deck as well in hold spaces that are not maintained permanently inerted (that is, an atmosphere with less than 5 % oxygen).

1.7 The LNG tank operating temperature range addressed by this specification is from a temperature of –259 °F (–162 °C) +0/–9 °F (+0/–5 °C) to ambient temperatures no greater than 113 °F (45 °C).

1.8 This specification does not address the thermal insulation on vacuum jacketed (that is, insulation systems that operate at below ambient pressure) insulated LNG Type C tanks.

1.9 The design of removable/reusable insulation systems is not addressed in this specification.

1.10 Structural design and physical strength of insulation systems are not addressed in this specification. However, the securement of jacketing systems is addressed.

1.11 Insulation system density is not a design criterion considered in this specification.

1.12 Tank-mounted insulated pipe is outside the scope of this specification.

1.13 Units—The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.

1.14 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.15 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.