Factors to consider for cryogenic insulation systems
Published by Leah Jones,
Digital Administrator
LNG Industry,
Cryogenic insulation systems are a highly-engineered combination of materials designed to work in synergy with each other to provide specific benefits to the system’s designed operation. Some of the materials that must be considered are the pipe or vessel material, insulation type and thickness, installation accessories, and protective cladding options. All these products must be chosen carefully in order to get the operational benefits intended from the entire insulation system. However, even when great care is used to select the optimum offering for each of these materials, they are often not enough to provide the long-term system performance an owner, engineer, or contractor requires on cryogenic applications such as LNG. Mastics, membranes, and sealants are often overlooked as a small piece of the insulation system, but, in reality, they are a crucial part of the cryogenic system’s overall design and longevity. In many cases, the mastic, membrane and/or sealant may be the system’s first and last line of defense in protecting it from any number of sources of potential damage.
Purpose and importance of mastics, membranes, and sealants
Arguably, the most important property of mastics, membranes, and sealants in any cryogenic insulation design is their ability to keep water (both liquid and vapour) out of the system. Water is always present and trying to enter the insulation system and may be from sources such as rain exposure or simply latent humidity in the surrounding air. In any case, water can cause several issues if allowed to get into an insulation system. Wet insulation will lose some of its thermal insulating value thus resulting in a less efficient system, costing the owner more money to operate or affecting the temperature regulation and system design. Water can also cause physical damage to the insulation as it expands and contracts on systems that fluctuate between temperature extremes and most importantly can lead to corrosion under insulation (CUI) if the insulation system is allowed to remain wet and is operating within the temperature ranges where CUI is most likely to occur. All these situations can lead to higher operating costs, increased maintenance, and potential harm to the system itself.
Primary vapour barrier mastics and membranes
Primary vapour barriers are a class of product that resists or considerably slows the rate of water vapour transmission through a film over time and have a low permeance value. n cryogenic systems where the vapour drive is from the ambient air toward the pipe or equipment surface, these products are crucial to keeping not only liquid water, but also water vapour out of the system. Using the correct primary vapour barrier product(s) is an essential component of any cryogenic insulation system design. Foster® ButylarTM NXT Vapor Barrier Jacketing is a next-generation, high performance butyl membrane that cryogenic insulation engineers and contractors trust to protect their systems from moisture intrusion.
Sealants and vapour stops
In addition to the use of vapour barrier mastics and membranes on the exterior of cryogenic insulation systems, products such as joint sealants and vapour stops are essential in providing additional protection from the damaging effects of water entering the insulation system. Foster 95-50 Flextra® Sealant is a butyl rubber-based vapour barrier joint sealant that has been successfully used on LNG projects globally to provide protection to insulation systems, while Foster 90-61 Cryolar® 1K Vapor Stop Sealant has become one of the industry’s most trusted products for cryogenic vapour stop applications in LNG systems worldwide.
For decades, engineers, owners, and contractors have depended on the quality and reliable performance of Foster insulation accessory products. The company’s products are trusted industry wide and offer peace of mind that the systems will perform as intended. Protect investments and choose Foster to ensure the systems are operating to their full potential.
Read the article online at: https://www.lngindustry.com/special-reports/10082023/factors-to-consider-for-cryogenic-insulation-systems/
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