Thread: NPT vs. ID
View Single Post
Unread 01-07-2003, 10:50 PM   #2
BrianW
Cooling Savant
 
BrianW's Avatar
 
Join Date: Jun 2001
Location: Desert City in California
Posts: 631
Default

Heheheh, I do not know how many times I have seen this post.

Defined NPT: "National Pipe Thread." A specification for tapered pipe threads from ANSI (American National Standards Institute). Actually taken from American National Standard Taper Pipe Threads. When listed as NPT-F, indicates female ends.

As the definition states the inside Inside Diameter taperes, therefore not a constant Inside Diameter. Also depending on what is on the other side of that NPT fitting, your inside diameter might be either larger or smaller.

_________________________________________________
Pipe Thread Size | Threads Per Inch | Theoretical I.D. of Ftg.
||||||||||||| 1/16'' |||||||||||||||||||||||| 27 ||||||||||||||||||||||||| 1/16'' ||||||||||||||||
|||||||||||||| 1/8'' ||||||||||||||||||||||||| 27 |||||||||||||||||||||||||| 1/8'' ||||||||||||||||
|||||||||||||| 1/4'' ||||||||||||||||||||||||| 18 |||||||||||||||||||||||||| 1/4'' ||||||||||||||||
|||||||||||||| 3/8'' ||||||||||||||||||||||||| 18 ||||||||||||||||||||||||| 3/8'' |||||||||||||||||
|||||||||||||| 1/2'' ||||||||||||||||||||||||| 14 ||||||||||||||||||||||||| 1/2'' |||||||||||||||||
|||||||||||||| 3/4'' ||||||||||||||||||||||||| 14 ||||||||||||||||||||||||| 3/4'' |||||||||||||||||
|||||||||||||||| 1'' |||||||||||||||||||||||| 11-1/2 ||||||||||||||||||||||| 1'' ||||||||||||||||||
||||||||||||| 1-1/4'' |||||||||||||||||||| 11-1/2 ||||||||||||||||||| 1-1/4'' |||||||||||||||
||||||||||||| 1-1/2'' |||||||||||||||||||| 11-1/2 ||||||||||||||||||| 1-1/2'' |||||||||||||||
||||||||||||||| 2'' ||||||||||||||||||||||||| 11-1/2 |||||||||||||||||||||||| 2'' |||||||||||||||||
_________________________________________________

To answer your question:
Quote:
Originally posted by m3_arun
just wondering...
say there is a barb 5/8"IDx3/8"NPT.

does the 3/8"NPT size mean that the ID is actually only 3/8"!?

if not, then what is the relationship between ID of a hose barb and the NPT size.
As the table indicated the "Theoretical ID" is indeed 3/8". There is no relationship as they are both independent. Whichever is a smaller measurement will determine your max throughput through the fitting.

PS: Html code would of been nice to make a table. Maybe vB code has a table option but the help on the bottom didn't show any.
__________________
Water Cooled Inwin Q500 (Dual Rads: Rad1 = DTEK Pro Core | Rad2 = Blick Ice Estreme, Hydor L30, Dangerden Maze2, Bay Res Typhoon Reservoir, 1/2 " DD Tygon Thick Wall Hose).

Flow: Res, Pump, CPU watervlock, Y into both rads, both rads into res independently.

Athlon XP 1800+ (@ 1731 - 150mhz fsb.), on a Asus A7N266-c, and a Radeon 9000 *waiting for RMA'd Saphire 9800 ultra from Newegg)

Last edited by BrianW; 01-07-2003 at 11:23 PM.
BrianW is offline   Reply With Quote