Simpler compression joints for more reliable insulation
If you’ve ever read our application manual, attended one of our on-site application training sessions or discussed Kaiflex application with anyone from Kaimann you’ll know that Kaiflex should always be installed under slight compression. What you might not appreciate is just why this is the case.
Every material is affected by changes in temperature, expanding as the temperature increases and contracting when the temperature cools. Any mechanical system that operates across a wide temperature range must be able to accommodate these changes.
Engineering compression joints
A compression joint is something that any contractor who has worked with rigid insulation materials will be well aware of. Most rigid insulation materials have a higher coefficient of linear thermal expansion than the pipe to which they are applied. This means that a gap will appear when the temperature falls and the insulation contracts faster than the pipe.
A compression joint is a simple solution to this problem: insert a small volume of flexible or loose insulation tightly between two sections of rigid insulation. When the rigid insulation contracts and shrinks the flexible insulation expands to fill the gap that would otherwise appear.
Add 5mm to the length necessary and apply under "compression"
Such an approach isn’t without its shortcomings. The different thermal conductivities and moisture resistance performance of the materials used creates a thermal bridge and potentially a weak point in the vapour barrier.
It’s also easy to overlook the importance of creating compression joints and many contractors will omit them entirely – especially when installing insulation on hot pipework.
Compression joints built in with Kaiflex
The inherent flexibility of Kaiflex makes it possible to create a compression joint as part of a standard application process.
Fitting under slight compression – “squeezing” 1.05 m of Kaiflex into a 1 m long gap – means that when the Kaiflex contracts by 5% it will still be long enough to fill the whole 1 m length so no gap will appear between tubes. This is particularly important for air-conditioning and refrigeration pipework where any gap is critical.
For more information on how to install Kaiflex please download our application manual or contact our technical service team.