BI-Lok Tube Fittings Selection Guide
Proper tube selection and installation are essential elements in providing a reliable leak-free tubing system. The following tables are intended to assist the designer to properly select quality tubing for use with the BI-Lok Series D Dual Ferrule Instrument Tube Fittings. The pressure rating of a fitting assembly is a direct function of the tubing selected. Care should be taken to insure that all tubing OD surfaces are free of scratches and imperfections that could hinder the sealing capabilities of the BI-Lok Tube Fitting. Proper tube selection and installation is the ultimate responsibility of the system designer and user.
Suggested Maximum Allowable Pressure For Stainless Steel Tubing
304 and 316 annealed seamless tubing per ASTM A-269 or equivalent working pressure are based on allowable stress of 20,000 psi between -20° F and 100° F (Reference: ANSI B31.3)
Table 1 | PSI | ||||||||||||
STAINLESS STEEL TUBING | |||||||||||||
Tube OD inch |
Wall Thickness, inch |
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0.01 | 0.012 | 0.014 | 0.016 | 0.02 | 0.028 | 0.035 | 0.049 | 0.065 | 0.083 | 0.095 | 0.109 | 0.120 | |
1/16 | 5600 |
6800 |
8100 |
9400 |
12000 |
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1/8 | 8500 |
10900 | |||||||||||
3/16 |
5400 | 7000 | 10200 | ||||||||||
1/4 | 4000 | 5100 | 7500 | 10230 | |||||||||
5/16 |
4000 | 5800 | 8000 | ||||||||||
3/8 | 3300 | 4800 | 6500 | ||||||||||
1/2 | 2600 | 3700 | 5100 | 6700 | |||||||||
5/8 | 2900 | 4000 | 5200 | 6000 | |||||||||
3/4 | 2400 | 3300 | 4200 | 4900 | 5800 | ||||||||
7/8 | 2000 | 2800 | 3600 | 4200 | 4800 | ||||||||
1 | 2400 | 3100 | 3600 | 4200 | 4700 |
Suggested Maximum Allowable Working Pressure for Carbon Steel Tubing
Carbon steel tubing per ASTM A-179 or equivalent. Working pressures are based on allowable stress of 15,750 PSI between -70° F and 100° F (Reference: ANSI B31.3)
Table 2 | ||||||||
CARBON STEEL TUBING | ||||||||
Tube OD inch |
Wall Thickness, inch | |||||||
0.028 | 0.035 | 0.049 | 0.065 | 0.083 | 0.095 | 0.109 | 0.120 | |
1/8 | 8000 | 10200 | ||||||
3/16 | 5100 | 6600 | 9600 |
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1/4 | 3700 | 4800 | 7000 | 9600 | ||||
5/16 | 3700 | 5500 | 7500 | |||||
3/8 | 3100 | 4500 | 6200 | |||||
1/2 | 2300 | 3200 | 4500 | 5900 | ||||
5/8 | 1800 | 2600 | 3500 | 4600 | 5300 |
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3/4 | 2100 | 2900 | 3700 | 4300 | 5100 |
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7/8 | 1800 | 2400 | 3200 | 3700 | 4300 | |||
1 | 1500 | 2100 | 2700 | 3200 | 3700 | 4100 |
Suggested Maximum Allowable Working Pressure for Copper Tubing
Copper tubing per ASTM B-75 or equivalent. Working pressures are based on allowable stress of 6,000 PSI between -70° F and 100° F (Reference: ANSI B31.3)
Table 3 | PSI | ||||||||||||
COPPER TUBING | |||||||||||||
Tube OD inch |
Wall Thickness, inch | ||||||||||||
0.01 | 0.012 | 0.014 | 0.016 | 0.02 | 0.028 | 0.035 | 0.049 | 0.065 | 0.083 | 0.095 | 0.109 | 0.120 | |
1/16 | 1500 | 2100 | 2600 | 3100 | 4200 | 2900 | |||||||
1/8 | 2700 | 3600 | 5100 | ||||||||||
3/16 | 1800 | 2300 | 3400 | ||||||||||
1/4 | 1300 | 1600 | 2500 | 3500 | |||||||||
5/16 | 1300 | 1900 | 2700 | ||||||||||
3/8 | 1000 | 1600 | 2200 | ||||||||||
1/2 | 800 | 1100 | 1600 | 2100 | |||||||||
5/8 | 900 | 1200 | 1600 | 1900 | |||||||||
3/4 | 700 | 1000 | 1300 | 1500 | 1800 | ||||||||
7/8 | 600 | 800 | 1100 | 1300 | 1500 | ||||||||
1 | 500 | 700 | 900 | 1100 | 1300 | 1500 |
System Temperature
Operating temperature is another factor in determining the proper tubing material and suggested maximum allowable working pressure of a fitting assembly. Temperature stress factors are used to calculate the suggested maximum allowable working pressures at elevated temperatures. Locate the correct factor in Table 4 and multiply this by the appropriate value in Tables 1-3 to obtain the elevated temperature working pressure.
Table 4 | ||||
STRESS FACTORS | ||||
Temperature |
304 Stainless Steel | 316 Stainless Steel | 1 Copper |
|
°F |
°C | |||
-325 – 100 | -198 – 38 |
1.0 | 1.0 | 1.0 |
200 | 93 | 1.0 | 1.0 | 0.97 |
400 | 204 | 0.93 | 0.96 | 0.45 |
600 | 316 | 0.82 | 0.85 | |
800 | 427 | 0.76 | 0.79 | |
1000 | 537 | 0.69 | 0.76 | |
1 Maximum recommended usable temperature 300°F (150°C). |
Pipe End Pressure Rating
Fittings with both Tube End and NPT/ISO threaded pipe end connections have different pressure ratings. When specifying these types of fittings, please refer to the chart for the maximum allowable pressure ratings. A thread sealant must always be used when using NPT/ISO connections.
Table 5 | PSI | |||
PIPE END PRESSURE RATINGS | ||||
NPT/ISO size | 316 Stainless Steel | Brass | ||
Male | Female | Male | Female | |
1/16 | 11000 | 6700 | 5500 | 3300 |
1/8 | 10000 | 6500 | 5000 | 3200 |
1/4 | 8000 | 6600 | 4000 | 3300 |
3/8 | 7800 | 5300 | 3900 | 2600 |
1/2 | 7700 | 4900 | 3800 | 2400 |
3/4 | 7300 | 4600 | 3600 | 2300 |
1 | 5300 | 4400 | 2600 | 2200 |
1-1/4 | 6000 | 5000 | 3000 | 2500 |
1-1/2 | 5000 | 4600 | 2500 | 2300 |
2 | 3900 | 3900 | 1900 | 1900 |
SAE Straight Thread End Pressure Rating
For the 2straight thread connection, refer to the table below for the allowable working pressure.
PSI | ||
1SAE STUD END PRESSURE RATING | ||
Thread size | 316 stainless steel | |
Nonpositional | Positional | |
5/16-24 | 4568 | 4568 |
3/8-24 | ||
7/16-20 | ||
1/2-20 | ||
9/16-18 | 3626 | |
3/4-16 | ||
7/8-14 | 3626 | 2900 |
1-1/16-12 | ||
1-3/16-12 | 2900 | 2320 |
1-5/16-12 | ||
1 SAE J1926-3 |
||
2 Part number DCU, DCUZ, DCO, DCF, DLO, DHB and DHO |
AN 37° Flared End Pressure Rating
For the 2AN 37° flare end connection, refer to the table below for the suggested maximum allowable working pressure.
PSI | ||||||||
1AN END PRESSURE RATING | ||||||||
Thread size | 316 stainless steel | Brass | ||||||
5/16-24 | 3000 | |||||||
7/16-20 | ||||||||
1/2-20 | ||||||||
9/16-18 | ||||||||
3/4-16 | ||||||||
7/8-14 | ||||||||
1-1/16-12 | ||||||||
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