Content for the expansion joints blog will include updates to the Ducting Systems and Piping Systems Technical Handbooks, how-to examples for joint selection, maintenance, usage, storage, testing, and when and why you would require an expansion joint in your piping & ducting system.
Insulating Over Rubber Expansion Joints: A Good or Bad Idea?
The practice of insulating over metallic expansion joints to minimize heat loss in a piping system may be common, but it is not a good idea to follow this same practice with rubber expansion joints.
Rubber expansion joints typically consist of synthetic (oil-based) elastomers (ethylene propylene diene monomer [EPDM], neoprene, chlorobutyl, nitrile or clorosulphonated polyethylene-CSM) combined with polyester or nylon and wire reinforcing that provide pressure-restaining capability.
If an end user were to install a typical rubber expansion joint in a system needing insulation to cover the joint in a “hot” application, that individual must consider the probability of failure resulting from heat exposure.