This reference page provides the dimensional details, bolt information, weight, and CAD resource for a Weld Neck Flange 1/2 Inch Class 1500. Use the listed values for preliminary piping layout, drafting, flange selection, and fabrication coordination, then verify the connection against the project specification and applicable engineering requirements.
The most important coordination point is the flange bore. Unlike several external flange dimensions, the bore must correspond to the selected pipe schedule and wall thickness. The flange face, hub, bolt holes, and stud bolts should also be checked together when preparing a piping detail or fabrication drawing.
Weld Neck Flange 1/2″ Class 1500
Weld Neck Flange 1/2″ Class 1500 is widely used in piping systems that require strong, leak-resistant flange connections under high-pressure service. It features a long tapered hub that provides excellent stress distribution and is commonly applied in process piping, utility lines, refineries, power plants, and industrial systems where welding strength and reliability are essential.
This dimension data is based on ANSI / ASME B16.5-2020.
Weld Neck Flange 1/2″ Class 1500 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS):1/2″
- DN Size: DN15
- Outside Diameter:121mm
- Flange Thickness:22.4mm
- Hub Diameter:38mm
- Bore Diameter: varies depending on pipe schedule and pipe wall thickness
- Raised Face Diameter:34.9mm
- Weight: 1.8kg
- Number of Bolts:4
- Stud Bolt Size: 3/4″ UNC (or M20) x 110 Long
- Hole Diameter: 7/8″ (22.225mm)
What Is a Weld Neck Flange?
A weld neck flange is a type of pipe flange designed with a long tapered hub that is welded directly to the pipe. This design helps reduce stress concentration at the flange base and provides better strength under pressure, temperature fluctuation, and cyclic loading.
Common Applications
Weld Neck Flange 1/2″ Class 1500 is commonly used for:
- Process piping systems
- Oil and gas lines
- Refinery and petrochemical piping
- Extremely high-pressure service
- Pressure piping connections
- Industrial fabrication and maintenance work
CAD Drawing Download
This page includes the CAD drawing file for Weld Neck Flange 1/2″ Class 1500, which can be used for drafting, detailing, piping layout coordination, and fabrication reference.
Available Weld Neck Flange Class 1500 Sizes
This size is part of the Weld Neck Flange Class 1500 series. Check other sizes in the same category to find matching dimension data and CAD files for your project.
Notes
Before fabrication or installation, always confirm the latest project requirements, flange material specification, pipe schedule, bore size, gasket type, bolt length, and applicable pressure-temperature rating.
How to Read This Flange Reference
NPS 1/2 and DN15 identify the nominal pipe size using commonly used inch and metric designations. These labels are nominal references rather than a direct statement of every measured flange or pipe dimension. The dimensional list on this page supplies the geometry needed for drawing and coordination.
The flange’s outside diameter, thickness, hub diameter, raised face diameter, and hole diameter describe the main connection geometry. The long tapered hub is welded to the pipe and provides a gradual transition between the pipe and flange. This feature is one reason weld neck flanges are selected for demanding piping connections, particularly where alignment, welding quality, and load transfer require careful control.
Bore, Pipe Schedule, and Welding Coordination
The bore diameter is identified as variable because it depends on the pipe schedule and wall thickness. Do not assume that the flange’s nominal size alone determines the finished bore. Before issuing a fabrication drawing, match the bore to the actual pipe outside diameter, internal geometry, welding detail, and project requirements.
Bolt and Face Checks
The listed bolt count, stud bolt size, bolt length, and hole diameter should be reviewed with the selected gasket, flange facing, washer arrangement, and tightening procedure. The term 3/4" UNC (or M20) should not be treated as an automatic interchangeability statement; the project specification should establish the required fastener system and installation practice.
Using the CAD File
The downloadable DWG can support piping layout, equipment-interface coordination, detailing, and fabrication reference. Treat the drawing as a geometry aid and compare it with the dimensional list and the governing project documents before using it for manufacture. Useful related references include the Class 1500 flange series, pipe schedules, flange facing types, gasket selection, and piping isometric drafting pages.
Engineering Verification
Dimension compatibility is only one part of flange selection. Confirm material, pressure-temperature requirements, pipe schedule, bore, gasket, studs, weld procedure, and installation requirements with the responsible engineer or project specification. The class designation should not be used by itself to establish an allowable pressure for a particular service.
Frequently Asked Questions
What does NPS 1/2 mean on this flange?
NPS 1/2 is the nominal pipe size designation used for the flange connection. The page also gives the corresponding DN designation as DN15.
Why can the bore diameter vary?
The bore depends on the pipe schedule and pipe wall thickness selected for the connection. Confirm the pipe details before finalizing the flange bore or weld detail.
What is the purpose of the tapered hub?
The tapered hub creates a gradual transition from the pipe to the flange. It helps distribute stresses and supports the weld neck configuration used for demanding piping connections.
Are the listed stud bolts automatically interchangeable between inch and metric systems?
No. The reference lists 3/4" UNC and M20 as alternatives, but the project specification must determine the required fastener standard. Thread form, fit, material, length, washers, and tightening requirements should be checked together.
Can the DWG file be used for fabrication?
The DWG is provided as a drafting and fabrication reference. Verify its geometry against the page data, the selected pipe schedule, the flange specification, and the approved project documents before fabrication.
Which related references should be checked?
For a complete connection review, consult the related references for pipe schedules, flange facing, gaskets, bolting, weld details, Class 1500 flange sizes, and piping isometric drafting.