by Sebastien Viale, Technip FMC, sebastien.viale@technipfmc.com and Barry Meneghelli, Cryogenics Test Laboratory, Kennedy Space Center, barry.j.meneghelli@nasa.gov

The mission of the International Organization for Standardization (ISO) is to create reference standards that identify requirements, specifications, guidelines and characteristics that can be used consistently by manufacturers and users to ensure that materials, products, processes and services are fit for their purpose. Working Groups (WGs), whose memberships include both governmental and non-governmental international organizations, develop these standards.

During the past several years, a joint WG composed of ISO TC 8[1] and ISO TC 67[2] members has been focused on the development of a new standard (ISO 20088) for determining the resistance of insulation materials that are used for Floating Liquefied Natural Gas (FLNG) facilities to deter cryogenic spillage.

The handling, storage and transporting of liquefied natural gas (LNG) requires cryogenic insulation of storage tanks, piping, valves and various other components to keep the LNG at a temperature of -260 °F (-162 °C). Cryogenic Spillage Protection (CSP) systems of various thicknesses and compositions can be applied on top of the carbon steel of the ship’s hull and around piping, valves, etc., as a thermal protective barrier.

With any of these systems comes the need for the best materials to mitigate the risk of a potential spill or fire. The intent of the new ISO standard is to set test parameters that will allow the producers of insulation material to test their products and ensure they will stand up to the types of cryogenic spills, leaks, etc., that may occur on an FLNG.

ISO STANDARD 20088

The new standard is composed of three parts: Part 1-Liquid Spill, Part 2-Vapor Release and Part 3-Jet Release. The Liquid Spill (ISO 20088-1) part of the standard describes a method for determining the resistance of CSP materials due to the release of a large volume of cryogenic liquid onto a material like deck plating. It covers cryogenic release scenarios which can lead to pooling conditions for carbon steel work protected by CSP as a result of a jet release or low pressure release of LNG or liquid nitrogen (LN2).

In comparison, Part 2 (ISO 20088-2) of the standard simulates the effect of cold cryogenic vapor on material such as walls, flanges, I-beams, etc. In this case, the liquefaction of the jet is practically zero.

Finally, the Jet Release (ISO 20088-3) portion of the standard tests the effectiveness of insulation material when a jet of cryogenic liquid impinges directly on insulated ship material as a result of a pressurized release which does not result in the immersion conditions that are present in Part 1.

LN2 was used as the cryogenic medium during the development of the standard since it has a lower boiling point than LNG, is not flammable and can be safely used for experiments by test laboratories familiar with cryogenic safety and the use of proper personal protective equipment when handling cryogenic liquids.

As much as possible, the procedures developed within the standard were designed to simulate some of the conditions that occur in actual cryogenic spillage, liquid release and vaporization, as well as a cryogenic jet release. Operators familiar with cryogenic release scenarios were consulted to ensure that realistic temperature and pressure parameters were embedded within the test requirements of the standard since it was not practical to cover all potential conditions.

The test methods described within ISO 20088 are repeatable and reproducible between test laboratories that include the following:

1. Liquid release
1a. Cybernetix Test Laboratory, France
1b. Komeri, South Korea

2. Vapor release
2a. Cryogenics Test Laboratory, Kennedy Space Center, US
2b. Spadeadam Testing and Research
Facility, UK

3. Jet Fire
3a. Spadeadam Testing and Research
Facility, UK
3b. RISE Trondheim, Norway

Additional work on this standard is focused on the development of a fourth part (20088-4) that discusses testing procedures to cover those cases where insulation materials are subjected to an ignited cryogenic jet. Discussions are ongoing to extend current cryogenic spillage work to future liquid hydrogen use.

The authors wish to thank all members of the joint Working Group (TC8 & TC67) for their time and efforts in developing ISO 20088. Additionally, thanks to all laboratory support personnel at the testing facilities for their assistance in sample preparation and data collection.

References:
[1] Ships and Marine Technology-Participating Members (17): China, Denmark, France, Germany, India, Indonesia, Islamic Republic of Iran, Japan, Republic of Korea, Netherlands, Panama, Russian Federation, Switzerland, Turkey, Ukraine, United Kingdom, United States. Observing Members (13): Australia, Croatia, Cuba, Czech Republic, Finland, Greece, Italy, Malaysia, Poland, Portugal, Romania, Serbia, Slovakia.
[2] Materials, equipment and offshore structures for petroleum, petrochemical and natural gas industries-Participating Members (18): Australia, Belgium, Brazil, China, France, Germany, Ireland, Italy, Japan, Republic of Korea, Malaysia, Netherlands, Norway, Qatar, Spain, Sweden, United Kingdom, United States. Observing Members (4): Argentina, Canada, Romania, Singapore. ■