What is a piping isometric drawing?
- A top view of every line in an area, drawn to scale
- A three-dimensional view of one line, not to scale
- A side view of one piece of equipment and its nozzles
- A schematic of the instruments and control loops only
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B. A three-dimensional view of one line, not to scale
An isometric shows a line in three dimensions on one sheet, with horizontal runs drawn at 30 degrees from horizontal and vertical runs drawn vertical. It carries the dimensions and bill of material but is not to scale.
Reference: Piping isometric drawings
Starting at which nominal pipe size does the outside diameter of steel pipe equal the nominal size?
- NPS 14
- NPS 8
- NPS 12
- NPS 10
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A. NPS 14
Through NPS 12 the outside diameter is larger than the nominal size (NPS 12 is 12.75 in OD). From NPS 14 up, the OD equals the nominal size. NPS 12 is the tempting answer because it is the last of the small-pipe series.
Reference: ASME B36.10 pipe dimensions
A 45-degree offset has to move a line over 14 in. Using the constant 1.414, what is the center-to-center travel?
Answer in in.
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19.8 in
Travel = offset x 1.414 = 14 x 1.414 = 19.80 in.
Reference: Pipe offset constants (right-triangle trigonometry)