Standard expansion joint designs (non-metallic)

In general there are two types of non-metallic expansion joints.
Elastomeric types, those installed in systems operating at or below 400 degrees F. And,composite types, those installed in systems operating above 400 degrees F.

ELASTOMERIC TYPES
A solid product with one or more reinforcing plies laminated with an elastomeric material which is vulcanized into a homogenous solid product.

Expansion joints operating continuously at or below 400 degrees F. will generally be of the elastomeric type. The overall thickness and number of reinforcing plies may vary depending upon application conditions and design concept. The elastomeric type provides an inner cover elastomer selected for its resistance to the system gases and operating temperatures, and an outside cover elastomer selected for its resistance to external atmospheric conditions. The inner and outer covers can be the same or different elastomeric compounds depending upon the manufacturer’s design.

The ability of this product to withstand the system operating and excursion temperatures is based upon the elastomer selected by the expansion joint manufacturer.

COMPOSITE TYPE
A layered product that consists of various plies of material which are laid one over the other and are usually bonded, sewn, or mechanically fastened together in the clamp or flange area. This method of construction allows each material layer to function independently of the others.

Expansion joints in systems that operate continuously above 400 degrees F. will generally be a composite type.