and Piping Inspections:
enhances system reliability
Joe Maciejczyk, PE, Associate, Structural Integrity Associates
For the first time in 60 years of U.S. Energy Information Administration recordkeeping, electrical consumption in the United States decreased for
two consecutive years, in 2008 and 2009.
The recession certainly played a part in
this, as did Americans’ increased awareness of their energy use and the need
for conservation. Suppliers of all types
of energy have had to accommodate this
As district heating customers have
used less energy, boiler operators have
seen curtailed operation, more hot standby and cyclic operations. This type of
operation poses unique challenges to capital equipment and infrastructure piping –
creating the potential for problems that, if
left unaddressed, could lead to unplanned
outages, unbudgeted expenditures and
disruptions of service to customers.
Typical inspections of boilers
and piping are not designed to identify
these types of problems. They generally
focus on baseloaded operation, such as
the yearly inspection of the boiler and
relief valves by an authorized inspector.
Distribution piping inspections are most
often handled on an exception basis:
When leaks and failures create a forced
Courtesy Structural Integrity Associates.
Failures and unplanned outages of critical infrastructure piping and boilers can be avoided with a
proactive, risk-based inspection program.
outage, they are repaired, and the system
is put back into operation. Cyclic operation exacerbates these issues.
Failures and forced outages can be
avoided, however, with a program of pro-
active boiler and piping inspections and
repairs that are prioritized on the basis
of system risk factors. Conducted during
a normal scheduled outage, this type of
targeted inspection program is crucial to
keeping district heating systems opera-
tional and safe until the next scheduled
Boilers are typically not designed to
handle cyclic operations. Startups and
shutdowns, even though they are within
operating parameters for pressure and
temperature, generate metal temperature
gradients and set the stage for cracking
and through-wall defects – resulting