Class 150 Flange Dimensions in mm

Table of Content
- Class 150 Flange Dimensions in mm
- Key Class 150 Flange Dimensions Descriptions
- Does Class 150 mean 150 PSI?
- Class 150 Flange Pressure Rating
- Flange Pressure Class Examples
- What Is The Difference Between PN16 and Class 150 Flange
- Common ASME Flange Classes Used in Petrochemical
- 150 LB Flange Thickness
- Class 150 Flange Weight In KG
- AISI 150 Flange Material
- How to Choose Between Class 150 Flange and Class 600 Flanges?
- Class 150 Flange Bolt Pattern
- Class 150 Steel Flange Equivalent
- ANSI 150 Flange Types
- ASA 150 Flange Standard
- Class 150 Flange Gasket Dimensions in mm
- Class 150 Flange Hydrotest Pressure
- 150# Flange Bolt Holes
- Class 150 Flange Vs Class 125
Class 150 flange can handle ~285 psi at 100°F. 150 LB flange designed to connect pipe as per ASME B16.5. 150# flange cover bolt circle, dimensions, pressure rating, weoght, pipe size and bolt hole. Class 150 steel flange made from materials like carbon or stainless steel, alloy steel, duplex and super duplex, nickel alloy for low to high pressure applications. AISI 150 lb flange available in various types like SORF, WNRF, BLRF, THRF, LJRF, LWNRF, plate, spectacle blind, orifice and socket weld flanges with FF, RF and RTJ face. Flange rating is often followed by a “Lb”, “#” or “lbs”. Pressure class of a ANSI B16.5 class 150 forged flanges indicates the MAWP (maximum allowable working pressure) in psi (pounds per square inch). Everything you need to know about class 150 flange dimensions in mm.
Class 150 Flange Dimensions in mm

| NPS | Flange Outside Diameter | Flange Thickness | Raised Face Diameter | Hub Diameter at Base | Thru Hub Length | ||
| Lap Joint | Welding Neck | Slip On, Socket & Threaded | |||||
| X | R | O | Q | Y | Y | Y | |
| 24 | 26-1/8 | 27-1/4 | 32 | 1-7/8 | 4-3/8 | 6 | 3-1/4 |
| 20 | 22 | 23 | 27-1/2 | 1-11/16 | 4-1/16 | 5-11/16 | 2-7/8 |
| 18 | 19-7/8 | 21 | 25 | 1-9/16 | 3-13/16 | 5-1/2 | 2-11/16 |
| 16 | 18 | 18-1/2 | 23-1/2 | 1-7/16 | 3-7/16 | 5 | 2-1/2 |
| 14 | 15-3/4 | 16-1/4 | 21 | 1-3/8 | 3-1/8 | 5 | 2-1/4 |
| 12 | 14-3/8 | 15 | 19 | 1-1/4 | 2-3/16 | 4-1/2 | 2-3/16 |
| 10 | 12 | 12-3/4 | 16 | 1-3/16 | 1-15/16 | 4 | 1-15/16 |
| 8 | 9-11/16 | 10-5/8 | 13-1/2 | 1-1/8 | 1-3/4 | 4 | 1-3/4 |
| 6 | 7-9/16 | 8-1/2 | 11 | 1 | 1-9/16 | 3-1/2 | 1-9/16 |
| 5 | 6-7/16 | 7.5/16 | 10 | 15/16 | 1-7/16 | 3-1/2 | 1-7/16 |
| 4 | 5-5/16 | 6-3/16 | 9 | 15/16 | 1-5/16 | 3 | 1-5/16 |
| 3-1/2 | 4-13/16 | 5-1/2 | 8-1/2 | 15/16 | 1-1/4 | 2-13/16 | 1-1/4 |
| 3 | 4-1/4 | 5 | 7-1/2 | 15/16 | 1-3/16 | 2-3/4 | 1-3/16 |
| 2-1/2 | 3-9/16 | 4-1/8 | 7 | 7/8 | 1-1/8 | 2-3/4 | 1-1/8 |
| 2 | 3-1/16 | 3-5/8 | 6 | 3/4 | 1 | 2-1/2 | 1 |
| 1-1/2 | 2-9/16 | 2-7/8 | 5 | 11/16 | 7/8 | 2-7/16 | 7/8 |
| 1-1/4 | 2-5/16 | 2-1/2 | 4-5/8 | 5/8 | 13/16 | 2-1/4 | 13/16 |
| 1 | 1-15/16 | 2 | 4-1/4 | 9/16 | 11/16 | 2-3/16 | 11/16 |
| 3/4 | 1-1/2 | 1-11/16 | 3-7/8 | 1/2 | 5/8 | 2-1/16 | 5/8 |
| NPS | Bore and Diameter | Socket Depth | Hub Diameter at Bevel | Fillet Radius | ||
|---|---|---|---|---|---|---|
| Lap Joint | Socket Weld and Weld Neck | Slip-on Socket | ||||
| B | J | W | Z | H | r | |
| 24 | 24.25 | 23.25 | 24.25 | 2-1/2 | 24.00 | 1/2 |
| 20 | 20.25 | 19.25 | 20.20 | 2-1/8 | 20.00 | 1/2 |
| 18 | 18.20 | 17.25 | 18.18 | 1-15/16 | 18.00 | 1/2 |
| 16 | 16.19 | 15.25 | 16.16 | 1-3/4 | 16.00 | 1/2 |
| 14 | 14.18 | 13.25 | 14.14 | 1-5/8 | 14.00 | 1/2 |
| 12 | 12.92 | 12.00 | 12.88 | 1-9/16 | 12.75 | 1/2 |
| 10 | 10.92 | 10.02 | 10.88 | 1-5/16 | 10.75 | 1/2 |
| 8 | 8.75 | 7.98 | 8.72 | 1-1/4 | 8.63 | 1/2 |
| 6 | 6.75 | 6.07 | 6.72 | 1-1/16 | 6.63 | 1/2 |
| 5 | 5.69 | 5.05 | 5.66 | 15/16 | 5.56 | 7/16 |
| 4 | 4.60 | 4.03 | 4.57 | 15/16 | 4.50 | 7/16 |
| 3-1/2 | 4.10 | 3.55 | 4.07 | 7/8 | 4.00 | 3/8 |
| 3 | 3.60 | 3.07 | 3.57 | 13/16 | 3.50 | 3/8 |
| 2-1/2 | 2.97 | 2.47 | 2.94 | 3/4 | 2.88 | 5/16 |
| 2 | 2.46 | 2.07 | 2.44 | 11/16 | 2.38 | 5/16 |
| 1-1/2 | 1.97 | 1.61 | 1.95 | 5/8 | 1.90 | 1/4 |
| 1-1/4 | 1.72 | 1.38 | 1.70 | 9/16 | 1.66 | 3/16 |
| 1 | 1.38 | 1.05 | 1.36 | 1/2 | 1.32 | 1/8 |
| 3/4 | 1.11 | 0.82 | 1.09 | 7/16 | 1.05 | 1/8 |
| 1/2 | .90 | 0.62 | .88 | 3/8 | .84 | 1/8 |
Key Class 150 Flange Dimensions Descriptions
- Outside Diameter
- Bolt Size
- Bolt Spacing
- Diameter of Bolt Hole
- Bolts Number
- Bolt Circle
- Thickness of Flange
No. Class 150 flange does not indicate 150 psi flanges. 150# flange pressure class is defined by ASME B16.5 as per operating temperature and material type.
Guide to 150 LB Flange Pressure Temperature Rating in Bar
Class 150 Flange Pressure Rating
| Temperature | Class 150 Flange Pressure Rating |
| 475°C | 3.7 Bar |
| 450°C | 4.6 bar |
| 425°C | 5.5 bar |
| 400°C | 6.5 bar |
| 375°C | 7.4 bar |
| 350°C | 8.4 bar |
| 325°C | 9.3 bar |
| 300°C | 10.2 bar |
| 250°C | 12.1 bar |
| 200°C | 13.8 bar |
| 150°C | 15.8 bar |
| 100°C | 17.7 bar |
| 50°C | 19.2 bar |
| -29 – 38°C | 19.6 bar |
Flange Pressure Class Examples

What Is The Difference Between PN16 and Class 150 Flange
- PN16 flange rated for 232 psi (16 bar) at a reference temperature
- PN16 flange is compared to a low Class 300 flange.
- Class 150 flange rated for about 285 psi at room temperature (38°C)
- Class 150 flange is closer to PN20 flange
Common ASME Flange Classes Used in Petrochemical
| Pressure Class | Casing Material | ASME Standard | Optional Classes |
| Class 150 | Stainless Steel | ASME B16.5 | Class 300, Class 600 |
| Class 150 | Carbon Steel | ASME B16.5 | Class 300, Class 600 |
| Class 150 | Ductile Iron | ASME B16.42 | Class 300 |
| Class 125 | Cast Iron | ASME B16.1 | Class 250 |
Everything You Need to Know About 150# Flange Thickness and Weight Chart in KG
| Size | Thickness | Outer Diameter |
| 24 | 1.880 | 32.00 |
| 20 | 1.690 | 27.50 |
| 18 | 1.563 | 25.00 |
| 16 | 1.440 | 23.50 |
| 14 | 1.380 | 21.00 |
| 12 | 1.250 | 19.00 |
| 10 | 1.190 | 16.00 |
| 8 | 1.130 | 13.50 |
| 6 | 1.000 | 11.00 |
| 5 | 0.940 | 10.00 |
| 4 | 0.940 | 9.00 |
| 3 | 0.940 | 7.50 |
| 2.5 | 0.880 | 7.00 |
| 2 | 0.750 | 6.00 |
| 1.5 | 0.690 | 5.00 |
| 1.25 | 0.630 | 4.63 |
| 1 | 0.563 | 4.25 |
| 0.75 | 0.500 | 3.88 |
| 0.5 | 0.440 | 3.50 |
| NPS | Class 150 Weld Neck Flange | Class 150 Blind Flange | Class 150 Socket Weld Flange | Class 150 Slip On Flanges |
| 24 | 120.6 | 193.5 | 99 | 99 |
| 22 | 101.3 | 159.8 | 83.3 | 83.3 |
| 20 | 88.7 | 128.3 | 74.3 | 74.3 |
| 18 | 74.3 | 99 | 58.5 | 58.5 |
| 16 | 63 | 81 | 44.1 | 47.7 |
| 14 | 51.3 | 63 | 40.5 | 40.5 |
| 12 | 39.6 | 55.4 | 28.8 | 28.8 |
| 10 | 24.3 | 31.5 | 19.4 | 19.4 |
| 8 | 18.9 | 21.2 | 13.5 | 13.5 |
| 6 | 11.7 | 12.2 | 8.6 | 8.6 |
| 5 | 9.5 | 9 | 6.8 | 6.8 |
| 4 | 7.4 | 7.7 | 5.9 | 5.9 |
| 3½ | 5.4 | 5.9 | 4 | 4 |
| 3 | 5.2 | 4.1 | 4.1 | 4.1 |
| 2½ | 4.5 | 3.2 | 3.6 | 3.6 |
| 2 | 2.7 | 2.3 | 2.3 | 2.3 |
| 1½ | 1.8 | 1.8 | 1.4 | 1.4 |
| 1¼ | 1.4 | 1.4 | 1.4 | 1.4 |
| 1 | 1.4 | 0.9 | 0.9 | 0.9 |
| 3/4 | 0.9 | 0.9 | 0.9 | 0.9 |
| 1/2 | 0.9 | 0.9 | 0.9 | 0.5 |
ASME B16.5 Class 150 Flange Available in Various Garde and Materials
How to Choose Between Class 150 Flange and Class 600 Flanges?
- Class 150 flange is generally used in low pressure services like as HVAC, oil & gas, water lines, and petrochemical.
- Class 600 flange is typically used in high pressure services, critical piping systems.
| NPS | Class 150 Flange Number Of Holes | Diameter of Class 150 Flange Bolt Circle | Diameter of Bolts | Class 150 Flange Bolt Length | |
| Stud Bolts | Machine Bolts | ||||
| 24 | 20 | 29.50 | 1 1/4 | 6 3/4 | 6 |
| 20 | 20 | 25.00 | 1 1/8 | 6 1/4 | 5 1/2 |
| 18 | 16 | 22.75 | 1 1/8 | 5 3/4 | 5 |
| 16 | 16 | 21.25 | 1 | 5 1/4 | 4 1/2 |
| 14 | 12 | 18.75 | 1 | 5 1/4 | 4 1/2 |
| 12 | 12 | 17.00 | 7/8 | 4 3/4 | 4 |
| 10 | 12 | 14.25 | 7/8 | 4 1/2 | 4 |
| 8 | 8 | 11.75 | 3/4 | 4 1/4 | 3 1/2 |
| 6 | 8 | 9.50 | 3/4 | 4 | 3 1/4 |
| 5 | 8 | 8.50 | 3/4 | 3 3/4 | 3 1/4 |
| 4 | 8 | 7.50 | 5/8 | 3 1/2 | 3 |
| 3 1/2 | 8 | 7.00 | 5/8 | 3 1/2 | 3 |
| 3 | 4 | 6.00 | 5/8 | 3 1/2 | 3 |
| 2 1/2 | 4 | 5.50 | 5/8 | 3 1/2 | 3 |
| 2 | 4 | 4.75 | 5/8 | 3 1/2 | 2 3/4 |
| 1 1/2 | 4 | 3.88 | 1/2 | 3 1/4 | 2 1/2 |
| 1 1/4 | 4 | 3.50 | 1/2 | 2 3/4 | 2 1/4 |
| 1 | 4 | 3.12 | 1/2 | 2 3/4 | 2 1/4 |
| 3/4 | 4 | 2.75 | 1/2 | 2 1/2 | 2 |
| 1/2 | 4 | 2.38 | 1/2 | 2 1/4 | 2 |
Class 150 Steel Flange Equivalent
| Material | Castings | Flange |
|---|---|---|
| Stainless Steel 348 High Temperature Service |
– | ASTM A182 F348 ASTM A182F348H |
| Stainless Steel 347 High Temperature Service |
ASTM A351 CF8C | ASTM A182 F347 ASTM A182 F347H |
| Stainless Steel 317 Stainless Steel 321 |
– | ASTM A182 F321 ASTM A182 F321H |
| Stainless Steel 310 Stainless Steel 316 |
ASTM A351 CK20 ASTM A351 CF3M ASTM A351 CF8M |
ASTM A182 F310H ASTM A182 F316 ASTM A182 F316L ASTM A182 F316H |
| Stainless Steel 304 | ASTM A351 CF3 ASTM A351 CF8 |
ASTM A182 F304 ASTM A182 F304L ASTM A182 F304H |
| Stainless Steel 304 | ASTM A351 CF3 ASTM A351 CF8 |
ASTM A182 F304 ASTM A182 F304L ASTM A182 F304H |
| 13 Cr Alloy Steel | ASTM A217 WC6 ASTM A217 WC9 ASTM A217 C12 |
ASTM A182 F22 Class 3 ASTM A182 F5 ASTM A182 F9 ASTM A182 F6 |
| Alloy Steel | A217 Grade WC4 | ASTM A182 F12 CL2 |
| Nickel Alloy Steel | A352 LC3 | ASTM A350 LF3 |
| High Temperature Service | A217 Gr WC1 | ASTM A182 F1 |

150 lb Blind Flange

150# Weld Neck Flange

ANSI 150 lb Long Weld Neck Flange

Class 150 Slip On Flange

ASME B16.5 Class 150 Socket Weld Flange

150# Threaded Flange

150 Lbs Lap Joint Flange

class 150 Orifice Flange

class 150 Spectacle Blind Flange

Class 150 RF Flange

Class 150 FF Flange

Class 150 RTJ Flange
| Standard | Size |
|---|---|
| ASME B16.5 | 1/4″ to 24″ |
| ASME B16.36 | 1/4″ to 24″ |
| ASME B16.47 | 26″ to 60″ |
| ASME B16.48 | 1/4″ to 24″ |
| EN 1092-1/2 | 3/8″ to 80″ |
| BS 3293 | 26″ To 48″ |
| MSS SP 44 | 22″ To 48″ |
| Awwa C207 | 4″ To 144″ |
| ISO flange | 2 1/2″ To 24″ |
| Australian flange | 1/2″ To 48″ |
| Korean flange | 1/2″ To 80″ |
| Japanese standard flange | 3/8 to 60″ |
| DIN flange | 1/2″ To 48″ |
Class 150 Flange Gasket Dimensions in mm
| Nominal Bore | Bolt Holes Number | Holes Diameter | Diameter of Bolt Circle | Outer Diameter (O.D.) |
| 24 | 20 | 1 3/8 | 29 1/2 | 32 |
| 20 | 20 | 1 1/4 | 25 | 27 1/2 |
| 18 | 16 | 1 1/4 | 22 3/4 | 25 |
| 16 | 16 | 1 1/8 | 21 1/4 | 23 1/2 |
| 14 | 12 | 1 1/8 | 18 3/4 | 21 |
| 12 | 12 | 1 | 17 | 19 |
| 10 | 12 | 1 | 14 1/4 | 16 |
| 8 | 8 | 7/8 | 11 3/4 | 13 1/2 |
| 6 | 8 | 7/8 | 9 1/2 | 11 |
| 5 | 8 | 7/8 | 8 1/2 | 10 |
| 4 | 8 | 3/4 | 7 1/2 | 9 |
| 3 1/2 | 8 | 3/4 | 7 | 8 1/2 |
| 3 | 4 | 3/4 | 6 | 7 1/2 |
| 2 1/2 | 4 | 3/4 | 5 1/2 | 7 |
| 2 | 4 | 3/4 | 4 3/4 | 6 |
| 1 1/2 | 4 | 5/8 | 3 7/8 | 5 |
| 1 1/4 | 4 | 5/8 | 3 1/2 | 4 5/8 |
| 1 | 4 | 5/8 | 3 1/8 | 4 1/4 |
| 3/4 | 4 | 5/8 | 2 3/4 | 3 3/4 |
| 1/2 | 4 | 5/8 | 2 3/8 | 3 1/2 |
Class 150 Flange Hydrotest Pressure
| ASTM Specification | Class 150 Flanges Test Pressure |
| ASTM A105 ASTM A350 LF2 |
450 psig |
| ASTM A106 C ASTM A352 LC2 ASTM A352 LC3 |
450 psig |
| ASTM A203 A ASTM A203 D ASTM A516 65 ASTM A672 C65 |
400 psig |
|
ASTM A350 LF1 ASTM A515 60 ASTM A675 60 ASTM A696 Grade B |
375 psig |
| ASTM A182 F1 | 400 psig |
| ASTM A182 F2 ASTM A217 WC4 ASTM A217 WC5 |
450 psig |
| ASTM A182 F12 ASTM A182 F11 |
450 psig |
| ASTM A182 F304 ASTM A240 304H ASTM A312 TP304 ASTM A351 CF3 ASTM A479 304 |
425 psig |
| NPS | Bolts Number | Bolt Holes Diameter |
| 24 | 20 | 1 3/8 |
| 20 | 20 | 1 1/4 |
| 18 | 16 | 1 1/4 |
| 16 | 16 | 1 1/8 |
| 14 | 12 | 1 1/8 |
| 12 | 12 | 1 |
| 10 | 12 | 1 |
| 8 | 8 | 7/8 |
| 6 | 8 | 7/8 |
| 5 | 8 | 7/8 |
| 4 | 8 | 3/4 |
| 3 1/2 | 8 | 3/4 |
| 3 | 4 | 3/4 |
| 2 1/2 | 4 | 3/4 |
| 2 | 4 | 3/4 |
| 1 1/2 | 4 | 5/8 |
| 1 1/4 | 4 | 5/8 |
| 1 | 4 | 5/8 |
| 3/4 | 4 | 5/8 |
| 1/2 | 4 | 5/8 |
- Class 150 flange normally handling high pressure services suitable for steel and stainless steel (marine & petrochemical)
- Class 125 flange is generally handling for low pressure services suitable for cast iron (water & steam)












