This reference provides the available dimensions, weight, stud bolt information, and CAD resource for a Weld Neck Flange 16 Inch Class 900. Use the listed values for preliminary drafting and component identification, then verify the flange, pipe, gasket, and bolting details against the project specification before fabrication or installation.
The page is especially useful when coordinating a flange with pipe schedules, raised-face flange details, stud bolt requirements, and a piping layout. The bore is not a single universal dimension because it must correspond to the connected pipe wall thickness and schedule.
Weld Neck Flange 16″ Class 900
Weld Neck Flange 16″ Class 900 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 16″ Class 900 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS):16″
- DN Size: DN400
- Outside Diameter:705mm
- Flange Thickness:88.9mm
- Hub Diameter:508mm
- Bore Diameter: varies depending on pipe schedule and pipe wall thickness
- Raised Face Diameter:469.9mm
- Weight: 273kg
- Number of Bolts:20
- Stud Bolt Size: 1 5/8″ UNC (or M42) x 285 Long
- Hole Diameter: 1 3/4″ (44.45mm)
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 16″ Class 900 is commonly used for:
- Process piping systems
- Oil and gas lines
- Refinery and petrochemical piping
- Very 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 16″ Class 900, which can be used for drafting, detailing, piping layout coordination, and fabrication reference.
Available Weld Neck Flange Class 900 Sizes
This size is part of the Weld Neck Flange Class 900 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 Use This Weld Neck Flange Reference
The existing dimension list is the primary lookup section for this flange size and pressure class. It identifies the nominal pipe size, DN designation, outside diameter, thickness, hub diameter, raised face diameter, weight, bolt count, stud bolt specification, and hole diameter. These values should be read together rather than treated as independent fabrication instructions.
- For drafting: use the flange outline and the accompanying DWG download to coordinate flange placement, bolt-circle representation, and connected piping.
- For pipe matching: check the pipe schedule and wall thickness before selecting or confirming the flange bore.
- For bolting: confirm the listed stud bolt size, length, thread form, hole diameter, gasket requirements, and assembly specification as one coordinated set.
- For procurement: verify material grade, facing, pressure-temperature requirements, inspection requirements, and the project piping class before ordering.
Weld Neck Flange Design Context
A weld neck flange transfers load through its tapered hub and welded pipe connection. Compared with a flange form that does not use an extended tapered hub, this geometry is intended to support a more gradual transition between the flange and pipe. The actual suitability of the connection depends on the applicable design conditions, material, welding procedure, pipe geometry, gasket, bolting, and installation controls.
Related Piping References
For broader design and drafting work, connect this reference with related resources covering pipe dimensions and schedules, flange facing types, stud bolts and nuts, gasket selection, and piping CAD blocks. These topics help explain why the flange bore, mating components, and bolting details must be checked as a complete connection.
Frequently Asked Questions
What does the Class 900 designation identify?
The Class 900 designation identifies the flange pressure-class category used for selection and rating review. It should not be treated as a standalone operating-pressure value; the permitted service condition depends on the applicable material, temperature, design rules, and project requirements.
Why does the flange bore vary?
The bore is selected to suit the connected pipe’s schedule and wall thickness. Confirm the pipe dimensions before using the flange for fabrication, modeling, or procurement.
What is the purpose of the tapered hub?
The tapered hub provides a gradual transition between the flange and pipe and helps distribute stresses near the welded connection. Final design suitability still requires engineering verification for the intended service.
Can the DWG file be used for fabrication?
The DWG file is useful for drafting, layout coordination, detailing, and reference. Before fabrication, verify all dimensions, bore details, facing requirements, materials, tolerances, and project-specific notes against the governing documentation.
What should be checked before ordering this flange?
Confirm the nominal size, pressure class, flange type, material specification, facing, bore, pipe schedule, gasket, stud bolts, length, and applicable pressure-temperature requirements. The purchase description should match the project piping specification.