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Copper Tube Joints Working Pressure Solder or Brazing Joints Based on ASME Standard B31.9
HVAC Systems and Components
Engineering Materials
Working Internal Pressure for Copper Tube Solder or Brazing Joints Based on ASME Standard B31.9
Copper tube is usually joined by soldering or brazing socket end fittings. Brazing materials melt above 1000°F and produce a stronger joint than solder.
The table below lists soldered and brazed joint strengths. ASME Standard B16.22-specified wrought copper solder joint fittings and ASME Standard B16.18-specified cast copper solder joint fittings are pressure rated the same way as annealed Type L copper tube of the same size. Health concerns have caused many jurisdictions to ban solder containing lead or antimony for joining pipe in potable-water systems. Lead-based solder, in particular, must not be used for potable water.
Alloy Used
for Joints |
Internal Working Pressure, psi |
||||||
Water and Noncorrosive Liquids and Gasesa |
Sat. Steam and Condensate |
||||||
Nominal Tube Size (Types K, L, M), in. |
|||||||
Service
Temp., °F |
1/4 to 1 |
1-1/4 to 2 |
2-1/2 to 4 |
5 to 8a |
10 to 12a |
1/4 to 8 |
|
50-50 tin/leadb solder (ASTM B32 Gr 50A) |
100 |
200 |
175 |
150 |
130 |
100 |
— |
150 |
150 |
125 |
100 |
90 |
70 |
— |
|
200 |
100 |
90 |
75 |
70 |
50 |
— |
|
250 |
85 |
75 |
50 |
45 |
40 |
15 |
|
95-5 tin/antimonyc solder (ASTM B32 Gr 50TA) |
100 |
500 |
400 |
300 |
270 |
150 |
— |
150 |
400 |
350 |
275 |
250 |
150 |
— |
|
200 |
300 |
250 |
200 |
180 |
140 |
— |
|
250 |
200 |
175 |
150 |
135 |
110 |
15 |
|
Brazing alloys melting at or above 1000°F |
100 to 200 |
d |
d |
d |
d |
d |
— |
250 |
300 |
210 |
170 |
150 |
150 |
— |
|
350 |
270 |
190 |
150 |
150 |
150 |
120 |
aSolder joints are not to be used for
(1) Flammable or toxic gases or liquids
(2) Gas, vapor, or compressed air in tubing over 4 in., unless max. pressure is limited to 20 psig.
bLead solders must not be used in potable-water systems.
cTin/antimony solder is allowed for potable-water supplies in some jurisdictions.
dRated pressure for up to 200°F applies to the tube being joined.
Related:
- Chemical Finish Black Oxide for Copper, Mil-F-495
- Copper Plating Specification Mil-C-14550
- Copper Tubing Size Chart ASTM B-88
- Copper UNS Number Alloys Table and Chart
- AWG Copper Wire Size Table and Data Chart @ 100 Degrees F
- Solder Joint Design Information, Formula and Guide
- Solder Joint - Lap Joint Formulae and Calculation
- Solder Joint - Butt Joint Formulae and Calculation
- Solder Joint - Bevel Joint Formula and Calculation
References
- ASHRAE Handbook of Fundamentals, 2021 Inch-Pound Edition