LNG (Liquified Natural Gas) cargo inspection, and storage tank calibration Services.

Intertek provides expert LNG inspection, testing and calibration services for Liquid Natural Gas across the world. Intertek safeguards LNG cargo quality and LNG quantity during the storage, production and transportation stages.

LNG storage tank calibration services

Intertek technical experts provide volume calibration of ship’s cargo tanks and shore-based LNG storage tanks. Accurate measurement determines the financial value of LNG when transferred between ship and shore. Two different methods of tank calibration are used depending upon the type of LNG cargo tank for the vessel; the Moss type or the Membrane type. Calibration takes one day per cargo tank and is conducted at the shipbuilder’s yard while the ship is in dry dock or in the floating condition prior to delivery.

Moss type calibration is by laser, and utilises multiple measurements and volume determination statistics. Membrane tank calibration is by ISO 8311 Method, referring to the International Standard ISO 8311 for refrigerated light hydrocarbon fluids. LNG liquid natural gas tanks are calibrated by physical measurement using steel tape with strings or a portable handy laser which has traditionally been applied for many membrane tanks with approval of government regulatory authorities Korea, Japan, India, Indonesia, Malaysia, Oman, Qatar and other nations.

LNG cargo inspection services

• LNG Volume Measurement: To obtain an accurate LNG volume measurement, the opening and closing measurements are conducted by an Intertek Surveyor using the ship’s equipment, along with the LNG ship’s tank table of cargo tanks, for considering proper corrections to the LNG ship’s condition.
• Sampling LNG: Generally, a continuous LNG sampling system is used and sampling is conducted during full rate pumping by an experienced Intertek LNG Surveyor. The Surveyor takes great care to ensure no air enters into the LNG sample bottle.
• Laboratory Analysis of LNG Samples: The LNG liquified natural gas samples are analyzed for composition, purity, sulfur and BTU value at an Intertek laboratory by using gas chromatography, often fitted with multi-columns to separate the components. To determine composition of the LNG sample gas, a chemist analyzes the reference standard gas and the sample gas twice, per GPA (Gas Process Association) protocol.