Referring to bathtub plumbing...3/4 pipe threads are typically 10 or 14 per inch? What is common? And, what does NC or NF mean?

pipe threads are NPT or if you are old like me IPS


NC is national course (not a tapered pipe joint thread)

NF is national fine (not a tapered pipe joint thread)





1/2" and 3/4" NPT and/or IPS (they are the same) have 14 TPI and a 1 in 16 taper


[www.engineeringtoolbox.com]

I’m an ips guy as well

i'll wager 50:50 you even know what 'B' Cu tube is (was)


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B tube had the same OD as IPS but the wall thickness of Cu, it led to oversized piping and significant flow issues and was discontinued



Edited 1 times.

Oversized ID would lead to lower flow velocities. Just curious, what is an example of oversized piping causing issues?

stagnation - excessive heat loss/gain - increased cost of material (think insulation, hangers, etc)




? why do they not run 3" piping into your home ?

Cost

My question was in the context of copper B tubing not being used anymore. When selecting the appropriate size of B tubing,none of the issues when mentioned - stagnation, heat loss, materials, cost will be a factor since, for example, if 1 in B tubing is oversized, 3/4 B tubing will be specified.

The obvious reason that comes to mind why B tubing is not used any more would be the necessity of its own line of fittings since CTS fittings cannot be used.

CTS came AFTER B tube

The problem was lack of education when it came to retrofitting galvanized.

Too many times 3" gal was replaced by 3" B resulting in greatly increased ID ....................


etc etc etc