IAPMO IGC 193-2019 specifies requirements for the installation of thrust blocking for ductile iron pipe with elastomeric gasketed joints and fittings and PVC piping with solvent cemented or elastomeric gasketed joints intended for cold water building supply and yard piping.

Thrust blocks covered by this standard prevent separation of joints and pipe movement by transferring the resultant thrust force at a bend to the undisturbed soil behind the thrust block.

The bearing strength of the soil is expressed in pounds per square foot. Therefore, the area behind the thrust block must engage enough soil area to resist the resultant thrust force at a change in direction.