Physical Property Measurement and Computer Simulated Performance Prediction of Rigid Polyisocyanurate Foam at Cryogenic Temperatures

Abstract

The use of rigid polyisocyanurate (PIR) foam for the insulation of pipework, vessels, equipment, etc., running at cryogenic temperatures has increased slowly over recent years as the advantages of polyisocyanurate (e.g., ease of installation, low thermal conductivity, light weight, etc.) over traditional methods such as cellular glass have become apparent. A major drawback preventing a more rapid acceptance of PIR is that it has not been possible to accurately test key cryogenic properties such as Poisson's ratio and tensile modulus. As a result, accurate modeling of stresses at cryogenic temperatures has not been possible, and some inservice failures have taken place.

This paper presents cryogenic test data on PIR foam, including tensile modulus and Poisson's ratio data which has been measured using a novel technique that allows the precise measurement of these key physical properties. The stresses expected in operation at cryogenic temperatures have been modeled with a view to confirming the technical performance of the PIR foam. The paper focuses on the use of PIR for LNG (liquified natural gas) projects operating at -160°C.

It is believed that this work will give users/specifiers the confidence in the suitability of PIR foams to withstand stresses at cryogenic temperatures. It also gives the foam manufacturer a method of evaluating and optimizing different foam formulations.