What size of compression fitting do I need?

It is important to understand the difference between 'nominal' dimensions and 'outside diameter (OD)' dimensions. Nominal is the term used to describe most pipe and fitting measurements in the plumbing industry. Nominal refers to the inside diameter measurement of the pipe. The actual inside pipe measurements will vary slightly due to the wall thickness of the pipe, so it is referred to as "nominal" meaning a small variance of size.

The outside diameter (O.D.) dimensions refer to the actual outside diameter of the pipe. The outside diameter dimensions of pipe are a constant size which allow pipe fittings to be used with the same type of piping with multiple grades of wall thickness.

Nominal or standard CTS (copper tube size) can be confusing. It is important to note that the BC series fittings are described by the O.D. – NOT the nominal size.

When a 5/8” compression fitting is ordered, it is designed to work with 5/8” O.D. (0.625”) tubing. Tubing is O.D. controlled and therefore compression fittings will work with any tubing manufactured to the CTS dimension regardless of the wall thickness (For example Type K, L & M copper tubes all have the same 5/8” O.D., but the I.D. varies K = 0.527”, L = 0.545”, & M = 0.569”).

Therefore, when ordering BC series compression fittings for:

1/4” Copper Pipe – Order a 3/8” (0.375”) Compression Size or Part Number size Code No. “06”

3/8” Copper Pipe – Order a 1/2” (0.5000”) Compression Size or Part Number size Code No. “08”

1/2” Copper Pipe – Order a 5/8” (0.0625”) Compression Size or Part Number size Code No. “10”

5/8” Copper Pipe – Order a 3/4” (0.750”) Compression Size or Part Number size Code No. “12”

3/4” Copper Pipe – Order a 7/8” (0.875”) Compression Size or Part Number size Code No. “10”

1” Copper Pipe – Order a 1-1/8” (1.125”) Compression Size or Part Number size Code No. “10”

Size Code – Each 01 = 1/16” Inch

01 = 1/16”

02= 2/ 16” = 1/8”

03 = 3/16”

04 = 4/16” = 1/4”

05 = 5/16”

06 = 6/16” = 3/8”

07 = 7/16”

08 = 8/16” = 1/2”

10 = 10/16” = 5/8”

12 = 12/16” = 3/4”

14 = 14/16” = 7/8”

16 = 16/16” = 1”