Quick answer
How is pipework to chilled beams and FCUs insulated against condensation?
The chilled connections to chilled beams and fan coil units are insulated with a vapour-sealed jacket — typically closed-cell or foil-faced sections with all joints sealed — so moisture cannot reach the cold pipe and condense. The insulation is carried continuously to the unit connection, preventing the dripping and staining that occurs where a vapour barrier is broken.
Why do chilled beams and FCUs need special insulation?
Chilled water feeds to beams and FCUs run below dew point, so any break in the vapour barrier lets moisture in. Water condenses on the cold pipe, runs to the lowest point and drips onto ceilings and equipment. The insulation's job is to stop that happening.
What materials are used?
Closed-cell elastomeric foam is common for chilled connections because it is self-sealing and vapour-tight, or foil-faced sections with sealed joints. The material is chosen for its vapour resistance and flexibility around the small-bore connections typical of terminal units.
How is the vapour barrier maintained at the unit?
The insulation is carried right to the unit connection and sealed there, not stopped short. Any valve or fitting is insulated and sealed as part of the run, because a bare fitting is enough to break the barrier and start dripping in an occupied space.
How is the work done in occupied spaces?
Terminal units are in offices and rooms that are often in use, so the work is phased and clean. Access to ceiling voids is agreed with the facilities team, and areas are handed back clean and dry once the insulation is complete and tested.
What happens if the barrier fails later?
A failed vapour barrier shows as damp patches or drips, usually at a joint or where insulation was disturbed for maintenance. The fix is to reinstate the seal properly, not just patch the wet area, so the barrier is continuous again.
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