reasonable loadbearing properties with a thermal
conductivity similar to the low density polyurethane
material used for pipe and vessel insulation.
This resulted in the first application of a precision
molded polyurethane product for all of the cold and
cryogenic supports in the Algerian LNG plant
(completed in 1976). Following this, the use of high
density polyurethane became widely accepted for
cryogenic supports.
Since 1976, engineering, procurement and
construction (EPC) contractors started to replace
60°/90° woodblocks, as well as some 180° sections,
with high density polyurethane cut from higher
density blocks. However, the compressive properties
of the products were lower than those of the
woodblocks, resulting in increased support lengths.
The use of long 180° sections to provide the
load-bearing lower part resulted in increased steel
requirements. Therefore, low density polyurethane
foam was used for the upper part to help reduce
costs, as this was considered to be within the
insulation contractor’s scope.
This design made another fastening system
necessary, and resulted in the use of cryogenic
adhesives and welding stop-clips to the pipe, etc.
The cryogenic adhesives were often two or three
components that were extremely expensive and
difficult to apply. Application had to be carried out
Figure 4.
PNG LNG.
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by an insulation contractor, resulting in a divided
responsibility regarding the functioning of the support.
The welding of the stop-clips onto cryogenic pipes
had to be carried out by a qualified welder subjected to
strict quality assurance (QA) and quality control (QC)
procedures, negatively impacting the scheduling and
installation time. The connection with line insulation also
presented problems in embedding the stop-clips.
Having seen and experienced a number of problems
regarding the installation of cryogenic pipe supports, it
