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
What is the purpose of a balancing valve in a hydronic branch?
- To stop water from flowing backward in the branch
- To relieve pressure if the branch becomes isolated
- To shut the branch off quickly in an emergency
- To set the flow so each circuit gets its design gpm
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D. To set the flow so each circuit gets its design gpm
Water takes the easiest path, so short circuits would get too much flow and distant ones too little. Balancing valves add measured resistance so every terminal unit gets its design flow.
Reference: Hydronic balancing