The Case of the One Million Gallon Welding Failure

One Million Gallon Water Storage TankThe Problem: 

Water inlet pipes and inlet collar plates contained defective welds that failed on the tank bottom. The tank was originally emptied for interior re-coating and minor improvements. Minor improvements to the tank included welding a pipe extension to each inlet pipe to modify the inlet flow and create silt-stops above the tank bottom. The weld failures occurred as the tank was re-filled with water after a cleanout. The water in the tank emptied rapidly through the openings and created voids under the tank. The failed welds on the inlet pipes were repaired a second time before refilling the tank.

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The Case of the Welder and Poorly Ventilated Toxic Fumes

Welding Fume Mitigation

The Problem:

Welding fume litigation requires testimony to complex scientific issues concurrent with findings from specific medical maladies in neurology, toxicology and epidemiology.  Physical science, engineering assessments and medical diagnosis are expected to converge and form a legal consensus which does not always happen.  The testimony of experts must be complementary from engineers and the medical community for each case, date, process and workplace.  Accurate data about resultant personnel disorders and biological dysfunctions are often not easily exchanged between engineers and medical practitioners. Reports of findings can be biased, misleading and violate common sense.

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The Case of the Failed Dallas Tower Crane

Tower Crane – Defective Diagonal Tube - Welded ConnectionThe Problem:

On a Sunday afternoon, a violent thunderstorm, with high winds between 75 and 80 mph, collapsed a tower crane and killed one innocent person and injured many others. The tower crane collapse extensive property damage to an apartment complex near the 5 story, concrete parking garage construction site.  The construction company and owner claimed the tower crane was properly stowed for the weekend. The tower crane had been in service at the construction site for 15 months prior to the failure event.  OSHA cited the company with numerous safety violations.  Why did the tower crane collapse during the thunderstorm?

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The Case of the Fatally Failed Hinge Pin

Figure 1.  Exemplar Oven with DoorThe Problem:

The subject oven door hinge failed.  The incident chronology indicated a single-event explosion inside the high-temperature and internally pressurized oven while in operation.  The blast occurred on a tray of a mid-level shelf.  At the time of the explosion, the technician had prepared to open the oven door when the hinge pin failed and the door rapidly opened with great force.  The door disengaged from the hinges and knocked the technician across the room, resulting in his death.

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The Case of the Badly Welded High Pressure Hydraulic Cylinders

Hydraulic Cylinder & Failed WeldThe Problem:

The weld between the rod and end-cap of a high-pressure hydraulic cylinder installed on a concrete boom pumping assembly failed in-service. The weld was a Gas Metal Arc Weld (GMAW) installed at an overseas manufacturing facility. The steel for the rod and cap was a fine grained alloy steel Type StE690 (Yield Strength of 100 ksi). The rod and cap were attached to a piston which moved inside the cylinder housing. 

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