Tolerance on Outside Diameters

Minimum wall thickness for Inch size NB pipes to B. S. 1387-1957 based on nominal working pressure is given in SWG in the following table. Nominal Bore specifications are based on the wall thickness of the pipe. The fittings are designed for the maximum pressure and are hence applicable to lighter series of pipes.

Metric OD pipes
Inch OD pipes
Inch NB pipes
Series
PipeOD
Tolerance
Pipe OD
Tolerance
Pipe NB
Outside diameter
LL
4-8
+/-0.07mm
1/4″-3/4″
+/-0.004″
1/4″
0.533″-0.541″
L
6-18
+/-0.07mm
1″-1 1/2″
+/-0.005″
3/8″
0.674″-0.682″
22-28

+/- 0.1mm

1/2″
0.842″-0.850″
35-42
+/-0.11mm
3/4″
1.056″-1.066″
S
6-16
+/-0.07mm
2″
+/-0.006″
1″
1.332″-1.342″
20-25
+/-0.10mm
1 1/4″
1.673″-1.683″
30-38
+/-0.11mm
1 1/2″
1.905″-1.915″

* Based on a Safety Factor of 4:1

STANDARDS 
Flareless Bite type fittings for Metric 0D pipe sizes are manufactured to DIN 2353 which specifies the dimensions, materials of construction and standard of workmanship for individual components to provide a conforming joint. These fittings also conform to B. S. 4368 which corresponds to the DIN standard for Metric 0D pipe size fittings. There is no parallel American standard for Metric 0D pipe size fittings. Indian standards for Metric 0D pipe size fittings have been formulated in great detail to cover all aspects of their design and performance. IS:8805 – 1978, for instance, covers “General Requirements for Ferrule type Couplings used in Oil Hydraulic Systems.” There are as many as sixteen Indian standards covering virtually all such fittings. The British standard B.S. 4368 for Inch 0D pipe size fittings is not very stringent and leaves it to the manufacturer to decide on the pipe end. The American standard SAE: J 514 has been laid down for the design of individual components and ferrules. The fittings for Inch 0D and Inch NB pipe sizes featured in this catalogue are designed basically on the DIN and IS specifications for the pipe end, and are therefore totally interchangeable with the respective standards. )

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