Stainless Steel NPT Screwed Pressure Fittings

NPT (National Pipe Tapered) Fittings are a U.S. standard that use a tapered thread profile to create a mechanical, wedging seal between male and female fittings. This enables the threads to seal tightly but also creates gaps that require a thread sealant to ensure a leak-free connection.  

  • Stirlings stocks a range of NPT Screwed Pressure Fittings, including Seamless TBE and TOE Nipple, Round Coupling, 3 Piece Union, 90 Degree Female Elbow, 45 Degree Female Elbow, Female Tee, Hex Cap, Hex Nipple, Hex Plug and Round Cap Fittings.

  • Reducing NPT Fittings products include Reducing Hex Tee, Reducing Hex Bush, Reducing Hex Nipple, and Reduced Coupling Fittings.

  • NPT Fittings are stocked in Austenitic Grade 304/L, 316/L and Duplex 2205. 

  • Stirlings stocks 150LB and 3000LB NPT Fittings in sizes from ⅛ inch (6mm) to 3 inches (80mm) and 150LB and 3000LB Reducing NPT Fittings from ¼ x ⅛ inch (8mm x 6mm) to 2 x 1 ½ inches (50mm to 40mm). In addition, Seamless Pipe Nipples in Schedule 80 and 80S from ⅛ inch (6mm) to 6 inches (150mm). Everything currently in stock is specified in the tables below. 

  • Anything not currently in stock/Market Available can be obtained via indent.

     

● Stocked Item ○ Market Available

316 NPT Screwed Fittings

Size - Nominal Round Union 90º Elbow 45º Elbow
Inch (NPS)
 mm (DN)
 Coupling 3 Pce Female Female
    3000lb 3000lb 3000lb 3000lb
    FNCF316 FNUC316 FNE9316 FNE4316
⅛ 6 ○ ○ ○ ○
¼ 8 ● ○ ○ ○
⅜ 10 ● ○ ○ ○
½ 15 ● ● ● ●
¾ 20 ● ● ● ●
1 25 ● ● ● ●
1¼ 32 ● ● ● ●
1½ 40 ● ● ● ●
2 50 ● ● ● ●
3 80 ● ○ ● ○

 

 

Size - Nominal Tee Cap Hex Hex Hex Round Hose
Inch (NPS)
 mm (DN)
 Female Female Nipple Nipple Plug Cap Tail
    3000lb 3000lb 3000lb 6000lb 3/6000lb 3000lb 150lb
            316    
    FNTE316 - FNNX FNNX FNPX FNRC3 FNHT
⅛ 6 ○ ○ ● ○ ○ ○ ○
¼ 8 ○ ○ ● ○ ● ○ ○
⅜ 10 ○ ○ ● ○ ● ○ ○
½ 15 ● ● ● ● ● ● ○
¾ 20 ● ● ● ○ ● ● ○
1 25 ● ● ● ○ ● ● ○
1¼ 32 ● ○ ● ○ ● ● ○
1½ 40 ● ● ● ○ ● ● ○
2 50 ● ● ● ○ ● ● ●
3 80 ● ○ ● ○ ○ ○ ○

Size - Nominal Nipple Nipple
Inch (NPS)
 mm (DN)
 TBE TOE
    SCH 80 SCH 80
       
    FNNB316 FNNO316
⅛ 6 ○ ○
¼ 8 ○ ○
⅜ 10 ○ ○
½ 15 ● ○
¾ 20 ● ●
1 25 ● ●
1¼ 32 ● ●
1½ 40 ● ●
2 50 ● ●
3 80 ○ ○

 

 

 

Size Nominal Reducing Tee Hex Red Bush Hex Red Nipple Reduced Coupling
Inch (NPS) mm (DN) 3000lb 3/6000lb 3000lb 3000lb
    FNTR316 FNRB316 FNRN316 FNRC316
¼ x ⅛ 8 x 6 ○ ○ ● ○
⅜ x ⅛ 10 x 6 ○ ○ ● ○
⅜ x ¼ 10 x 8 ○ ● ○ ○
½ x ⅛ 15 x 6 ○ ○ ● ○
½ x ¼ 15 x 8 ○ ● ○ ○
½ x ⅜ 15 x 10 ○ ● ○ ●
¾ x ⅛ 20 x 6 ○ ○ ● ○
¾ x ¼ 20 x 8 ○ ○ ● ○
¾ x ⅜ 20 x 10 ○ ● ○ ○
¾ x ½ 20 x 15 ● ● ○ ●
1 x ¼ 25 x 8 ○ ○ ● ○
1 x ⅜ 25 x 10 ○ ○ ● ○
1 x ½ 25 x 15 ● ● ● ●
1 x ¾ 25 x 20 ● ● ● ●
1¼ x ½ 32 x 15 ○ ● ○ ●
1¼ x ¾ 32 x 20 ● ● ● ●
1¼ x 1 32 x 25 ● ● ○ ●
1½ x ½ 40 x 15 ○ ● ● ●
1½ x ¾ 40 x 20 ○ ● ● ●
1½ x 1 40 x 25 ● ● ● ●
1½ x 1¼ 40 x 32 ● ● ● ●
2 x ½ 50 x 15 ○ ○ ● ●
2 x ¾ 50 x 20 ○ ○ ● ●
2 x 1 50 x 25 ○ ● ● ●
2 x 1¼ 50 x 32 ○ ● ● ● 
2 x 1½ 50 x 40 ○ ● ● ●

 

 

304 & 2205 NPT Screwed Fittings

Seamless Pipe Nipple

Size - Nominal Nipple Nipple
Inch (NPS)
 mm (DN)
 TBE TOE
    304 304
    SCH80S SCH80S
    100MM 100MM
    FBNB3048 FBNO3048
⅛ 6 ○ ○
¼ 8 ○ ○
⅜ 10 ○ ○
½ 15 ● ●
¾ 20 ● ●
1 25 ● ●
1¼ 32 ● ●
1½ 40 ● ●
2 50 ● ●
2½ 65 ○ ○
3 80 ○ ○
4 100 ○ ○
5 125 ○ ○
6 150 ○ ○

 

Size - Nominal Round Union 90º Elbow 45º Elbow
Inch (NPS) mm (DN)
 Coupling 3 Pce Female Female Female
    3000lb 3000lb 3000lb 3000lb 3000lb
    304 304 304 2205 304
    FNCF304 FNU304 FNE9304 FNE92205 FNE304
⅛ 6 ○ ○ ○ ○ ○
¼ 8 ○ ○ ○ ○ ○
⅜ 10 ● ○ ○ ○ ○
½ 15 ● ● ● ● ●
¾ 20 ● ● ● ● ●
1 25 ● ● ● ● ●
1¼ 32 ● ● ● ● ●
1½ 40 ● ● ● ● ●
2 50 ● ● ● ● ●
3 80 ○ ○ ○ ○ ○

 

 

Size - Nominal Tee Tee Hex Cap Hex Hex Hex Round
Inch (NPS) mm (DN)
 Female Female Female Nipple Nipple Plug Cap
    3000lb 3000lb 3000lb 3000lb 6000lb 3000lb 3000lb
    304 2205 304 304 304 304 304
    FNTE304 FNTE2205 - - FNNX3046 FNPX304 FNCR304
⅛ 6 ○ ○ ○ ○ ○ ○ ○
¼ 8 ○ ○ ○ ○ ● ○ ○
⅜ 10 ● ○ ○ ○ ● ○ ○
½ 15 ● ● ○ ● ● ● ●
¾ 20 ● ● ○ ● ○ ● ●
1 25 ● ● ○ ● ○ ● ●
1¼ 32 ● ○ ○ ● ○ ● ○
1½ 40 ● ● ○ ● ○ ● ○
2 50 ● ● ○ ● ○ ● ○
3 80 ○ ○ ○ ○ ○ ● ○

 

 

Size Nominal Reducing Tee Reducing Tee Hex Red Bush Hex Red Bush Hex Red Nipple Reduced Coupling
Inch (NPS) mm (DN) 3000lb 3000lb 3/6000lb 3/6000lb 6000lb 3000lb
    304 2205 304 2205 304 304
    FNTR304 FNTR2205 FNRB304 FNRB2205 FNRN304 FNRC304
¼ x ⅛ 8 x 6 ○ ○ ○ ○ ○ ○
⅜ x ⅛ 10 x 6 ○ ○ ○ ○ ○ ○
⅜ x ¼ 10 x 8 ○ ○ ○ ○ ○ ○
½ x ¼ 15 x 8 ○ ○ ○ ○ ● ○
½ x ⅜ 15 x 10 ○ ○ ○ ○ ● ○
¾ x ¼ 20 x 8 ○ ○ ○ ○ ○ ○
¾ x ⅜ 20 x 10 ○ ○ ○ ○ ● ○
¾ x ½ 20 x 15 ● ● ● ○ ● ●
1 x ¼ 25 x 10 ○ ○ ○ ○ ○ ○
1 x ½ 25 x 15 ● ● ● ● ○ ○
1 x ¾ 25 x 20 ● ● ● ● ○ ○
1¼ x ¾ 32 x 20 ● ● ○ ○ ○ ○
1¼ x 1 32 x 25 ● ● ● ● ○ ○
1½ x ¾ 40 x 20 ○ ○ ● ● ○ ○
1½ x 1 40 x 25 ● ● ● ● ○ ○
1½ x 1¼ 40 x 32 ● ● ● ● ○ ○
2 x ¾ 50 x 20 ○ ○ ○ ○ ○ ○
2 x 1 50 x 25 ○ ○ ● ● ○ ○
2 x 1¼ 50 x 32 ● ○ ○ ○ ○ ○ 
2 x 1½ 50 x 40 ● ○ ● ● ○ ○

 

 

NPT Technical Data

  6 8 10 15 20 25 32 40 50 65 80 100
Unit mm L L L L L L L L L L L L
90º Elbow 32 38 45 52 61 72 82 98 106 134 156 190
Coupling/Socket 32 35 38 48 51 60 67 79 86 92 108 121
Nipple - 26 36 40 48 52 - 60 62 - - -
Union 41 41 46 49 57 62 71 77 86 102 19  
Tee 42 50 56 66 76 88 102 120 128 166 190 228
Hex Cap 16 19 22 28 35 44 57 64 76 92 108 140
Hex Head Plug 16 17 21 22 26 29 35 37 40 46 51 57
Red Socket - - - - 27 28 32 33 38 48 54 60
Hex Red Bush - 14 17 19 22 25 28 29 31 37 38 45
Hex Red Nipple - 57 64 70 76 89 102 114 165 178 203 229

 

  6 8 10 15 20 25 32 40 50 65 80 100
Weight Kg L L L L L L L L L L L L
90º Elbow 0.1 0.14 0.29 0.43 0.69 1.14 1.42 2.63 2.92 5.99 8.88 14.6
Coupling/Socket 0.04 0.05 0.06 0.13 0.19 0.45 0.81 1.07 1.4 2.29 3.38 6.28
Nipple 0.03 0.04 0.05 0.09 0.15 0.47 0.45 0.62 1.03 1.51 2.22 4
Union 0.28 0.28 0.34 0.34 0.48 0.77 1.03 1.63 2.43 3.63 5.27 12
Tee 0.13 0.2 0.38 0.56 0.92 1.49 1.76 3.27 3.53 6.99 10.19 19.13
Hex Cap 0.02 0.04 0.06 0.11 0.18 0.37 0.62 0.72 1.09 2.22 3.5 4.84
Hex Head Plug 0.01 0.03 0.05 0.07 0.14 0.22 0.44 0.59 1.03 1.8 2.6 5.2
Red Socket Please Contact Us
Hex Red Bush - 0.01 0.01 0.03 0.05 0.09 0.25 0.34 0.45 0.6 1.16 3.2
Hex Red Nipple Please Contact Us