Fitting Selection

The following conversion chart provides information to help select the proper size barbed fitting and matching thread for your application.

All nominal barbed fitting designations for this website represent the inner diameter (ID) of the tubing for which the barb is designed to fit, e.g. a 1/4″ barb is designed to fit a 1/4″ ID tube. The actual inch or millimeter dimensions represent the outside diameter (OD) of the barb – slightly larger than the tubing ID to insure a proper seal.

Nominal Inch

Actual Barb OD (Inch)

Actual Barb OD (mm)

Matching Thread

Nominal Millimeter

1/8″ 0.160 4.01 4 mm
5/32″ 0.180 4.52 4.4 mm
3/16″ 0.250 6.35 6 mm
1/4″ 0.290 7.24 7/16″ 20 UNF 6.5 mm/7 mm
5/16″ 0.340 8.71 1/2″ 16 UNF 8 mm
3/8″ 0.390 9.96 5/8″ 18 UNF 9 mm /9.5 mm /10 mm
7/16″ 0.440 11.48 11 mm
1/2″ 0.530 13.51 3/4″ 16 UNF 13.5 mm

Column Definitions:

Nominal Inch:  Barb size designated to match the ID of beverage tubing.

Actual Barb OD (Inch):  The actual outside diameter of the barbed fitting in decimal format in inches.

Actual Barb OD (mm):  The actual outside diameter of the barbed fitting in millimeters.

Matching Thread:  The unified thread standard that is normally used with a nominal inch fitting, e.g. a 1/4″ nut has a 7/16″ 20 UNF thread count.

Nominal Millimeters:  Best practice conversion of inch-based fittings onto metric-based beverage tubing, e.g. 1/2″ barb fittings can be used on 13.5 mm OD beverage tubing.

Clamps

Clamp

Clamp Range (Inches)

Clamp Range (mm)

0123 .386 – .484 9.8 – 12.3
0133 .425 – .524 10.8 – 13.3
0145 .472 – .571 12.0 – 14.5
0157 .520 – .618 13.2 – 15.7
0170 .571 – .669 14.5 – 17.0