Table 9-5.--Class P-3a Special Brazed Joint Categories
SURFACE SHIPS
SYSTEMS SERVICE
SUBMARINES
Category
2.375" O.D. and Larger & above
2.375" O.D. and Larger & above
A
Steam and Steam Drain Sys
300 psi
300 psi
NA
B
Sea Water Sys Subject to
(1)
Submergence Pressure
NA
C
Missile Booster Suppression Sys
1.315" O.D. and Larger
D
Hydraulic Sys
1.660" O.D. and Larger & above
2.375 O.D. and Larger & above
600 psi
600 psi
(2)
E
2.375" O.D. and above
Lube Oil Sys
2.375" O.D. and above
F
Flammable or Lethal Fluid Sys
0.840" O.D. and Larger
2.375" O.D. and Larger
(e.g., Gasoline, Cleaning Fluids,
(3)
(3)
JP-5, Fuel Oil, Oil Sys other
than Hydraulic, Lube Oil and
Freon
G
0.840" O.D. and Larger & above
2.375" O.D. and Larger & above
Oxygen Sys
10 psi
10 psi
H
0.840" O.D. and Larger & above
Air Sys (including compressed
2.375" O.D. and Larger & above
600 psi
600 psi
(4)
Fixed CO2
I
0.840" O.D. and Larger
0.840" O.D. and Larger
Other systems where specified
by NAVSHIPS
Inspection Requirements: (See 7.3.1.)
Ultrasonic inspection is required on all brazed joints of sizes and pressures shown for the various categories in this table
except ultrasonic inspection is not required on freon (halocarbon) refrigerant systems.
NA = Not applicable
NOTES TO TABLE 3-1
(1) Joints in systems, 0.840" O.D. and larger, subject internally to sea water at submergence pressure where failure of
the joint would result in direct internal flooding within the full and which normally operate at depths in excess of 200 feet.
(2) Joints in the following hydraulic piping having a system design pressure above 600 psi also require ultrasonic
inspection.
a. Tubing and piping 0.830" O.D. and larger in supply mains which supply components in more than one compart-
ment, and in the branch supply lines from these mains up to the first isolation valve in the branch.
b. Tubing and piping 0.840" O.D. and larger, failure of which could result in simultaneous loss of normal and
emergency modes of control for any steering or diving control service.
c. Piping, 0.840" O.D. and larger, in the emergency sea water valve control system necessary to ensure the integrity
of the independent system (this includes all joints from the hydraulic actuator for the sea valve to the isolation
valve(s) in the branch line(s) serving the flood control and normal operating station).
(3) Joints excluded from this category include those in segments of piping within their respective tanks, piping passing
through tanks which contain identical fluid, and all sounding tubes, air escapes, vents and overflow piping.
(4) This includes low pressure MBT blow piping external to the pressure hull which is designed for external
pressure greater than 600 psi.
9-11