Table 6-6.—Minimum Inside Diameter of Tubing
TUBE
6061 ALUMINUM
1/8 HARD STAINLESS
ANNEALED
OUTSIDE
STAINLESS
DIAMETER
WALL
MIN ID
WALL
MIN ID
WALL
MIN ID
1/8
0.020
0.060
0.016
0.070
0.020
0.060
3/16
0.028
0.095
0.018
0.110
0.020
0.115
1/4
0.035
0.150
0.020
0.165
0.028
0.155
5/16
0.049
0.180
0.022
0.225
0.035
0.225
3/8
0.049
0.240
0.025
0.290
0.049
0.270
1/2
0.065
0.330
0.028
0.400
0.058
0.380
5/8
0.083
0.420
0.035
0.485
0.065
0.475
3/4
0.095
0.530
0.042
0.610
0.083
0.590
1
0.065
0.830
0.065
0.840
0.083
0.800
All measurements are in inches.
24-degree angle of fitting body seat, should be
PROOF PRESSURE TESTING
smooth, free from scores, and should not show
lengthwise or circular cracks. Crazing cracks in
Tube assemblies that are fabricated according to
finish are not harmful to safety or function of fitting.
the instructions in Aviation Hose and Tube Manual,
Minimum internal tube diameter should not be less
NAVAIR 01-1A-20, should be proof pressure tested to
than values shown in table 6-6.
twice the operating pressure of the system in which
they are to be installed, provided the operating
Table 6-7.—Alternate Cleaning Solvents for Tubing and Tube
pressure is greater than 50 psi. Tubing, installed in
systems having an operating pressure of less than 50
Assemblies
Cleaning Solvents
Specification
Dry Cleaning Solvent
P-D-680
Trichloroethane, 1.1.1
MIL-T-81533
Trichlorotrifluorcethane
MIL-C-81302
Only MIL-C-81302 is approved for cleaning
oxygen systems.
psi must be proof pressure tested to a minimum of 100
psi. Vent tubes or drain tubes do not require proof
pressure testing.
The fluid medium for proof pressure testing of all
tube assemblies except oxygen systems should be a
liquid medium such as hydraulic fluid, water, or oil.
Oxygen tubing should be tested using dry nitrogen
and inspected for leaks while the tubing is submerged
in water.
CLEANING TUBING AND TUBE
ASSEMBLIES
All tubing and tube assemblies must be cleaned
after fabrication to prevent contamination of the system
in which they will be installed. Dry-cleaning solvent
P-D-680, Type II, is the preferred cleaner, but the
alternate cleaning solvents in table 6-7 maybe used.
6-14
