• Google+
  • LinkedIn
  • Twitter
  • Facebook
Resources

NPT Pipe End Pressure Ratings, ANSI/ASME B 31.3 - Table 6

  316 Stainless Steel  Brass  Carbon Steel
NPT/ISO
Pipe Size
Size Male Female Male  Female  Male  Female
    psig bar psig bar psig bar psig bar psig bar
1/16" 1 11,050 760 6,750 460 3,350 230 11,050 760  6,750 460 
1/8" 2 10,050 690 6,550 450 3,250 220 10,050 690 6,550  450 
1/4" 4 8,050 550 6,650 460 3,350 230 8,050 5500 6,650  460 
3/8" 6 7,850 540 5,350 370 2,650 180 7,850 540 5,350  370 
1/2" 8 7,750 530 4,950 340 2,450 170 7,750 530 4,950  340 
3/4" 12 7,350 510 4,650 320 2,350 160 7,350 510 4,650  320 
1" 16 5,350 370 4,450 310 2,250 150 5,350 370 4,450  310 
1-1/4" 20 6,000 410 5,000 350 2,500 170 6,000 410 5,000  350 
1-1/2" 24 5,000 340 4,600 310 2,300 150 5,000 340 4,600  310 
2" 32 3,900 270 3,900 270 1,900 130 3,900 270 3,900  270 
Reference: bar = .0690 X psig  To obtain ANSI/ASME B 31.1 values, multiply ANSI/ASME B 31.3 values by .94

 

Pressure-Temperature Derating Table

Stress Factors For Determining Tubing Pressure Ratings at Elevated Temperatures

Instructions

To determine maximum allowable working pressures for tubing at elevated temperatures, multiply the applicable tube’s maximum allowable working pressure from Tubing Allowable Work Pressure Tables  by the corresponding temperature stress factor from Pressure-Temperature Derating Table below.

Temperature Stainless Steel   CarbonSteel  Copper  Monel®400
°F °C 304SS 316SS      
    100
38
    1.00
    1.00
            1.00
     1.00
1.00
200 93 1.00 1.00 .96 .80 .88
300 149 1.00 1.00 .90 .78 .82
400 200 .94 .97 .86 .50 .79
500 260 .88 .90 .82 n/a .79
600 316 .82 .85 .77 n/a .79
700 371 .80 .82 .73 n/a .79
800 427 .76* .80* .59 n/a .76
900 482 .73* .78* .41 n/a .43
1000 538 .69* .73* .16 n/a n/a
1200 649 .30* .37 n/a n/a n/a

* The precipitation of chromium carbides potentially resulting in intergranular corrosion may occur when exposed to operating temperatures above 800°F. Consult the factory for further information.