This article discusses one city’s approach to
preserving the integrity of its infrastructure
through the use of corrosion-resistant piping systems.
Technological developments in centrifugally cast
fiberglass pipes have provided installation advantages
and lifelong benefits to municipalities.
This article describes two case histories:
construction and installation of a fiberglass-reinforced
plastic (FRP) radome and the design,
construction, and utilization of composite FRP/concrete
bridge beams. The shape, structural requirements, and
radar transmission requirements of the radome are
discussed, as are the design, fabrication, and testing of
the composite beams.
After being in operation for some time, cathodic protection (CP) systems at compressor stations, refineries, and other industrial plants can experience problems. For example, the CP potential distribution can change for various reasons, because of isolating flange failures, alterations in pipeline systems, grounding systems, or reinforced concrete foundations. Some areas become underprotected and others overprotected. The extent of CP current required may exceed the capacity of rectifiers, and may also increase interference on foreign pipelines. This article describes the results of corrective measures for these problems.
Designing cathodic protection (CP) systems for
buried piping in power plants and other similar
industrial facilities offers several unique challenges. This
article discusses these challenges and provides case
histories to illustrate the impact they have on CP system
design and operation.
Stress corrosion cracking (SCC) can lead to rapid
and catastrophic failure. Failures often occur with
little or no prior warning. A systematic approach is
needed to evaluate any failure and identify its
cause. This article continues the case histories begun
in Part 1 and illustrate
common features evident in SCC.
Tuberculation in waste water has long been a
concern. Causes are an adverse mixture of water
chemistry, construction materials, microbiological
attack, and flow rate. Low velocity permits
particulates and corrosion products to form
deposits. Accumulated deposition leads to partial or
complete blockage of pipelines, trapping of pigs,
under deposit corrosion, and tuberculation.
Tuberculation reduces flow rate. This article
discusses tuberculation and presents a case study.
Stress corrosion cracking (SCC) can lead to rapid
and catastrophic failure in many different metals
and alloys. Failures often occur with little or no
prior warning. A systematic approach is needed to
evaluate any failure and identify its cause. The case
histories in this article illustrate features that are
commonly evident in various materials that
Mixed metal oxide (MMO) anodes find extensive
use in impressed current cathodic protection
installations. Part 1 of this article covered the electrochemistry, manufacture, and operation of these anodes. Part 2 presents three case
histories showing application of MMO anodes.
Faced with serious concrete deterioration from
biogenic sulfide corrosion within collection systems,
engineers and municipalities are extending the
service life of wastewater conveyance structures with
the use of 100% solids polyamine systems designed
for hydrogen sulfide (H2S) permeation resistance. This article explains how sewer interceptors, manholes, and lift stations were protected using fluid-applied linings.
An electric company tested concrete construction
members from substations in chemically aggressive
environments to determine their load-carrying
capacity after ~35 years of operation. This article
describes the manner in which tests were
performed and summarizes the results.
Components of water treatment plants (WTPs) are
susceptible to corrosion from constant immersion in water
and proximity to chlorine. A case history of corrosion
problems and their treatment at an Army WTP is
presented. Solutions included using high micro-silica
restoration mortar and advanced coal tar epoxy coatings.
The relative value of an aging asset depends on many
parameters, among which are production rate/
continuity and integrity management (IM) costs.
Reducing unplanned shutdowns and IM costs can
maintain or even improve the relative asset value. This
article describes—using data collected over a five-year
period—how having asset corrosion management and
risk-based inspection systems in place
may achieve the above.
Carbonated amine material, often called amine
blush, is the reaction product of the amine
functional curatives in epoxy paint with carbon
dioxide (CO2) and water vapor. This article explains the formation of amine blush and discusses factors controlled by the applicator and those controlled by the paint manufacturer.
Controlling the hardness of the weld heat-affected
zone (HAZ) in sour service is essential to help
prevent sulfide stress cracking. It is important to
evaluate HAZ properties when developing welding
procedures. The behavior of specific alloys during
welding presents roadblocks to HAZ hardness
control. Two cases are presented to show that weld
thermal simulation is an efficient tool for
developing welding procedures for sour service.
This article presents several case histories where
ductile iron (DI) pipeline sections have been
investigated to ascertain the corrosion control benefits
of polyethylene (PE) encasement. The procedures and
results of the investigations are evaluated and
discussed. These investigations demonstrate the
overall effectiveness of PE encasement as a corrosion
control system for DI pipe.