Piping, particularly hot services (Steam, Feedwater, Condensate), are engineered systems. The stresses induced on the piping, fittings, and valves are controlled through purposeful routing, hanger locations, and hangar properties. This is very important to the longevity of system components. Thermal cycles and other transients accumulate stress-induced damage with time leading to failure, if incorrectly installed. Plant reliability and personnel safety are dependent on proper implementation of the engineer's design.
Given their status as “engineered components” it is hard to reconcile the lack of attention-to-detail observed in the installation of supports/hangers in many recently inspected plants. In some cases, the contractors have been so sloppy as to not even finish installing the required supports/hangers.
After a support/hanger is installed, the contractor must also follow up to assure it's correctly setup (commissioned). Usually, this necessitates a QC step to assure the installation is correct, followed by documented verification of the “hot settings”, and then documented verification of the "cold settings". Since engineered supports require periodic inspection by the plant O&M team, these as-built documents should be provided to the owner in turnover packages.
It really is indicative of a complete breakdown of a contractor’s hanger/support program when a finished plant has multiple locations where rope and strapping exist instead of the required supports/hangers. These glaring oversights are called “rope hangers” and a clear indicator the pipe support verification process did not confirm the installation against the native design documents.
Contractor: No savings; hangers usually purchased; lost/not installed.
Contractor: Usually not very costly. Owner: Can be costly, because of the outages caused by even small piping failures/leaks.