Piping fabrication

The refinery operators were in the process of switching feed from the D drum to the C drum when a 45-degree elbow in the feed line ruptured. Investigators later determined that the 6-inch-diameter elbow was made of carbon steel instead of the 5-percent chrome alloy steel required by specifications. It seems that this section of piping was fabricated and installed in 1963. The mistake in piping fabrication was discovered 20 years later. The extent of the fire damage was such that the central unit was down for a period approaching a year and the adjacent units were each down for a few weeks. [21]... 

The chemical engineer must never lose sight of the practical limitations involved in a design. It may be possible to determine an exact pipe diameter for an optimum economic design, but this does not mean that this exact size must be used in the final design. Suppose the optimum diameter were,3.43 in. (8.71 cm). It would be impractical to have a special pipe fabricated with an inside diameter... 

All these changes are typical in the development of any project and in this case result from the reduction of construction hours at the Job site due to the transfer of pipe fabrication to offsite shops and the leveling of the peak staff over a three month period. 

Note of caution When checking estimates, it must be remembered that on sizes 2 1/2 in. and above, the process area pipe is usually prefabricated away from the field and some estimates would show pipe fabricated offsite as material cost. In that case, the cost will include ... 

There are three mid-sized mechanical contractors, qualified to do industrial piping and equipment erection, with demonstrated capability of handling projects requiring more than seventy workers. Two of them also have piping fabrication shops and asked to be considered for the prefabricated piping purchase. All of them asked to bid for the structural steel erection. 

Petersen G. P., A. B. Duncan and M. H. Weichold, 1993, perimental investigation of micro heat pipes fabricated in silicon wafer, ASME J. Heat Transfer, vol. 115, pp.751-756. 

Hydrogen gas producers in the United States and Europe have accumulated decades of experience with transmission pipelines fabricated from carbon steels and currently operate over 1500 km of pipeline [13,49]. Large-diameter piping systems (>2.5cm) used for local distribution of hydrogen gas in large-scale industrial operations also make extensive use of low-alloy steels, such as the chromium-molybdenum steels, particularly for service at elevated temperature. Pipelines and piping fabricated from low-alloy and carbon steels have functioned safely and reliably in hydrogen gas service. 

Piping fabricators are well aware of the problem, and will instead provide a steel boss 1-1/2-inches in diameter by 4 inches long, drilled and tapped for a 1-inch pipe thread. This boss is welded into the pipe elbow as shown in Figure 7-87b. It is a more expensive operation than using an elbow adapter. 

For pipe fabricated to ASA B31.3 steel should be specified to be open hearth, electric furnace or basic oxygen. Alternatively. Thomas steel is acceptable if fully killel or if it. THSts the following... 

RI examining showed that it could be reconditioned. However, another decision was accepted. It was decided to change the whole reactor compartment of this NS by the new one fabricated earlier. The motive for this decision was the following. In the course of this RI fabrication at the Machine-building plant in Podolsk there was faulty change of the SHS pipes fabricated from high-nickel corrosion-resistant steel by the pipes made from common stainless steel of the same size. 

Lee M, Wong M, Zohar Y (2003) Integrated microheat-pipe fabrication technology. J Microelectromech Syst 12(2) 138-146... 

Exfoliation is commonly experienced on exposure of susceptible aluminum alloys to marine atmospheres. Simulation in the laboratory is accomplished by controlled intermittent spray with 5% NaCl containing added acetic acid to pH 3 at 35-50°C (95-120°F) [28]. In practice, severe exfoliation corrosion has been experienced in water irrigation piping constructed of type 6061 alloy [29]. The cause in this instance was ascribed to pipe fabrication methods and presence of excess amounts of impurity elements (e.g., Fe, Cu, and Mn). 

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