Quality Blog

Quality Blog Introduction


EPR’s project management, consulting, and restructuring experience is highly varied. A project managed poorly during construction may have many problems, like safety, schedule, over-runs, etc... However, plant quality is the most significant determinant of the forward value of the asset (plant).

This blog is not presented as reference material with deep technical precision, it's assumed the audience understands the technical basis for the observations. However, our intention is to bring a discussion level perspective of how construction quality impacts an owner, with enough technical content provided for context. If the reader wants to know more about a technical subject (i.e. PWHT of P91) please refer to the reference codes, standards, and specifications for your project (i.e. ASME).

EPR believes a serious discussion is needed in our industry about project construction quality. Hopefully, this is a positive addition to that dialogue…

To discuss your project needs, please contact EPR...

Uncured Coatings


One of the more interesting construction defects observed at a plant in Asia is a nearly universal application of coatings that did not cure.

As background, modern "paint" used in a power plant is a complex engineered product often applied in two or three layers. This is because each layer has a purpose. For example, inorganic zinc is often used as a primer, but not suitable as a top coat. Similarly, epoxy is used as a second coat, but not a top coat because it is poor at enduring UV unlike a urethane. 

Each of the layers must be properly mixed, and usually is catalyzed with a hardener. The proportion of hardener to base product is very important. Too little, the coating never cures and perpetually stays soft. It's a failed coating. Another important factor is to keep water (rain and condensation) from the coating components.  Water affects curing also.

At the plant in question, easily 70% of the coated plant (large coal plant) had coatings that were not cured.  To test this defect, ASTM has a MEK (Methyl Ethyl Ketone) wipe test which roughly involves a clean cloth, a little MEK, and... Read more

Contractor Savings

None.

Repair Costs

Collosal.  Left unrepaired...

"Old School" Steam Drains


Keep in mind, this is a new plant in operation about one year, in a location where quality plants are built routinely...  Yes, this is a NEW plant built to contemporary codes and standards by a large international EPC contractor.

During EPR's review of the Facility, this system is perhaps the single most compelling example of inferior design in the plant.  While not the most cost intensive, the effects are broad reaching.  The open trench design belches hot condensate on steel, electrical hardware, and other equipment leaving the plant to look ready for decommissioning.  O&M personnel are left to perhaps unknowingly assume that facility condition is not important to the owners; how could it be, look at this?  In so many ways this is not consistent with the Facility purchased.

The condensate collection system of trenches and transfer sumps has experienced critical deterioration. Serious failures in the concrete infrastructure include trench through-cracks, cementitious erosion, advanced concrete spalling and scaling, sub-grade undermining, differential settlement, and accelerated... Read more

Contractor Savings

Perhaps $500k.

Repair Costs

Unknowable, but very significant.  Violates Environmental permit, among other problems.

Pillars of Salt & Sand (and Plastic)...


Piers are structural. This necessitates that they are installed correctly with every detail.

As with most construction defects, this is a simple problem of unskilled and unsupervised workers. The problem is compounded by a contractor culture that allows a QC program to run as a "paper" generating endeavor completely disassociated from the facts of field performance. In many cases, it's clear that there is no inspection. This is such a case...

Grout must be installed where to concrete conditions conform to the manufacturers recommendations to assure a strong bond between the materials (concrete and grout).  Typically, this involves a rough surface, clear or debris, and free of any existing concrete surface coating, and similar.

Well, in this case, it's hard to imagine how these piers ended up with plastic bags being embedded at the bonding joint, among other concerns.

One certainty, there was no engaged contractor QC or owner involvement.

Contractor Savings

Essentially none...

Repair Costs

In the future, the piers will need to be re-grouted as routine maintenance.  Unknown cost.

The Lawrence Welk Show


EPR performed a verification of final completion on a large coal plant in a developing country.  

A critical system in any power facility is its instrument air (IAS), because a loss of instrument air means a loss of control in many instances.  Further, IAS is expensive because air compressors take a material amount of parasitic load in addition to the drying needed to wring out any moisture.

In this facility thousands, or perhaps more, IAS leaks were observed.  This is due in part to unqualified installers and also the lack of tools necessary to tighten the joints.  Tubing systems are fantastic because they are high pressure, install quickly, and durable if installed correctly.  However, contractors often underappreciate that a tubing system is a technical installation that require the workers to be trained.  In this plant it was apparent that any joint which did not leak, was purely an accident, because the recommended OEM installation practices were simply not followed.

This will cost the Owner hundreds of thousands per year in additional compressor usage (power and increases... Read more

Contractor Savings

No Savings.  Probably cost more with unqualified personnel.

Repair Costs

Really not possible to repair all leaks.  Owner Cost will be severeral $100k/year for plant life.

Rupture Disk Vent Safety


During a plant final completion punchlist walkdown, the EPR team observed a serious condition with steam rupture disk vent stack locations. The discharge point was face-high at an operator's platform.

These disks relieve pressure from a very large "reservoir" LP header at about 800F and perhaps 250psig. At some prior point, during early operations or commissioning these disks relived. The energy from this release had ripped insulation and metal jacketing from the above cold-reheat piping which was later partially repaired. However, the insulation is still imbedded in structural steel and other equipment in the area from the force of the release.

It is a serious safety concern when a standard design platform for personnel access is above the vent stack. If any personnel would have been located on the platform during this release, they would have no doubt been seriously injured or a possible fatality would have occurred.

Contractor Savings

Minimal

Repair Costs

Minimal.  However, potential Owner risk is significant.

CEMS Tubing Damage


At a multi-unit facility it was observed that most of the certified emissions monitoring system sample tubing heating circuits indicated open continuity. The heating circuits are important to maintain transported sample temperature needed for CEMS accuracy (emissions compliance).

After a brief investigation it became clear that the installation was performed by construction personnel that did not understand the sensitive nature of the tubing assemblies.

Engineering properly cascaded the OEM requirements of not less than a 20.5 inch bend radius into the construction drawings.  The OEM information was also available to the Contractor staff.  However, the sample tubing was observed to be strained by being conformed to tight radius cable tray, pulled taught over edges of grating, and in some cases poorly tied with nylon ties that broke leaving the tubing to move with the wind.

All these visible defects were in addition to the probability that the equipment was mishandled during installation.  All of the sample lines at each CEMS installation have bend radius below 20.5 inches in... Read more

Contractor Savings

Minimal to no cost savings by performing an unsupervised installation.

Repair Costs

Owner: Difficulty with CEMS certification and continued compliance. Contractor: $50,000/unit to replace.

Electrical Zip(less) Ties


Recently EPR evaluated a facility, which among other difficulty, suffered from a condition that is unusual but serious in that essentially all the nylon cable (zip) ties were defective.  While the zip tie is a wonderful time saving and usually effective component widely used to affix electrical cables, it must remain unaffected by its environment to remain durable over time.

In this instance, the plant was less than two years old and located in a high UV zone.  This defect was so severe that gently touching the installed tie would lead to a brittle failure.  The plant was littered with failed zip ties that had fallen from cable tray systems and cable installations.

One supplier used by the contractor indicated in the technical literature that the ties are compliant with NEC, meaning Nylon, UV, weather, seawater, and oil resistant type from Panduit /T&B or equivalent.  However, those ties have failed almost universally.  While some cursory research was performed on the ties, it is not clear exactly why the ties were brittle and failing, but they certainly all needed replacing.  The real... Read more

Contractor Savings

Negligible material savings.

Repair Costs

Contractor: Somewhat time consuming especially in an operational plant.  Owner: Outage events and unpredicatblity are hard to quantify, but even a single lost generation day is expensive.

Faked Electrical Ductbank


There are several important reasons to concrete encase underground raceway (rigid and PVC conduit) that carry power and control cables.

At a newly completed powerplant, the EPC Contract clearly stated: “All underground cables are installed in underground duct bank consisting of concrete encased duct: Hard polyethylene or rigid galvanized steel conduits as per ANSI C 80.1.” It goes further with detail, but does not allow direct bury cables and also articulates a minimum depth of cover. Engineering understood the implications and cascaded the contract/code requirements into the construction drawing details, which were available to the construction team.

Upon casual observation, the ductbank risers (concrete exposed above grade) did not appear "correct".  Detailed investigation revealed there was effectively no ductbank.  In some cases, rigid conduit was inserted into soil, perhaps 24” deep and then simply ended, leaving a direct bury cable condition.  In other cases, groups of conduit were encased in concrete risers, giving the “impression” a ductbank existed.  However, upon removing 6” of... Read more

Contractor Savings

Certainly some marginal cost was saved, as well as, some time early in the project. Almost certainly not a critical path activity (No LD savings).

Repair Costs

Owner: Unpredictable unit operation. At ~$35,000/day finding/repairing cable problems is costly. Contractor: Full remedy would cost millions.

Rope Hangers


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 really 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... Read more

Contractor Savings

Contractor:  No savings; hangers usually purchased; lost/not installed.

Repair Costs

Contractor: Usually not very costly.  Owner: Can be costly, because of the outages caused by even small piping failures/leaks.

Pipe Rack Bolting


The consequence of structural failure in a power plant is operationally serious, and can be life threatening.
 
When structures are designed for bolted connections usually "high-strength" fasteners are indicated (ASTM A325/A490).  If these bolts are not installed properly, per the standard (AISC/RCSC, or other), the joint does not support the loads expected by the engineer.  So, when loose bolts are observed in completed facilities, it is alarming because it is an indicator the contractors bolting program was flawed.  Properly installed bolts are verified to be pre-tensioned, which practically eliminates nuts backing off for any reason.

So what constitutes proper pre-tensioning?  The code guidelines are specific, however, in simple terms bolts must achieve a certain amount of stretch.  The complicating factor is that pre-tensioning varies depending on manufacturing lot, and environmental conditions like moisture because of variable thread friction.  This means that daily testing (for each lot) is required to determine a "torque value" for the assembly.  If this is not... Read more

Contractor Savings

Little or none.

Repair Costs

Contractor: RCSC arbitration is moderately expensive.  Owner: Risks structural failure and personnel injury.

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