This reference page provides the listed dimensions, weight, stud bolt information, and drawing resource for a Blind Flange 2 1/2 Inch Class 400. Use the data when reviewing piping layouts, preparing fabrication details, or coordinating a flange connection with related equipment.
A blind flange has no center bore, so it closes a flanged connection rather than providing a passage for fluid. The dimensional list below should be read together with the project piping specification, flange-facing requirements, gasket selection, and pressure-temperature conditions.
Blind Flange 2 1/2″ Class 400
Blind Flange 2 1/2″ Class 400 is used to seal the end of a piping system or close off a flange connection in Class 400 service. It is a solid flange without a center bore and is commonly used in industrial piping systems, maintenance isolation points, and future pipeline expansion connections where a higher pressure rating is required.
This dimension data is based on ANSI / ASME B16.5-2020.
Blind Flange 2 1/2″ Class 400 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS): 2 1/2″
- DN Size: DN65
- Flange Thickness: 28.4mm
- Weight: 6.8kg
- Stud Bolt Size: 3/4″ UNC (or M20) x 120 Long
- Number of Bolts: 8
- Hole Diameter: 7/8″ (22.225mm)
What Is a Blind Flange?
A blind flange is a blank flange used to close the end of a pipeline, vessel nozzle, or equipment connection. It provides a secure shutoff point and is often selected when future maintenance, inspection, or line extension may be required.
Common Applications
Blind Flange 2 1/2″ Class 400 is commonly used for:
- Pipe end closure
- Equipment isolation
- Valve and nozzle blanking
- Maintenance shutdown work
- Process and utility piping systems
- Higher pressure piping applications
CAD Drawing Download
This page includes the CAD drawing file for Blind Flange 2 1/2″ Class 400, which can be used for drafting, detailing, and piping layout coordination.
Available Blind Flange Class 400 Sizes
This size is part of the Blind Flange Class 400 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, gasket type, bolt length, and applicable pressure-temperature rating.
How to Use This Blind Flange Reference
Start with the nominal size and class designation when checking compatibility with a mating flange. Then compare the listed thickness, bolt arrangement, hole diameter, and stud bolt information with the applicable fabrication or installation documents. Matching the flange connection requires more than checking nominal pipe size alone.
Blind Flange Selection Considerations
- Connection compatibility: Confirm that the mating flange, facing, gasket, and bolting arrangement are compatible with the blind flange.
- Isolation and access: A blind flange can provide a removable closure for maintenance, inspection, equipment isolation, or a future line connection.
- Design verification: The Class 400 designation should be reviewed with the applicable material specification and pressure-temperature requirements. It should not be treated as a standalone approval for a particular service.
- Installation control: Verify bolt length, thread form, tightening procedure, gasket type, and site requirements before assembly.
- Drafting coordination: Use the downloadable DWG together with the listed dimensions and the project drawing standard. Confirm orientation, facing details, and mating components before issuing fabrication drawings.
Related Piping References
For broader design and drafting work, this page can be reviewed alongside references for blind flange dimensions, flange bolt sizes, pipe flange classes, ASME B16.5 flange dimensions, and CAD/DWG piping drawings. A comparison with weld neck, slip-on, and threaded flanges can also help clarify when a blanking flange is the appropriate connection type.
The existing dimension list is the local reference for this specific flange entry. When a project uses a different material, facing, gasket, or design basis, confirm the controlling project documents before fabrication or installation.
Blind Flange 2 1/2 Inch Class 400 FAQ
What is the purpose of a blind flange?
A blind flange closes the end of a pipeline, vessel nozzle, valve connection, or other flanged opening. Because it has no center bore, it creates a removable closure for isolation, maintenance, inspection, or future expansion.
Does this blind flange include a center bore?
No. A blind flange is a solid flange without a center bore. The mating connection and sealing arrangement still need to be checked for compatibility.
What information is provided on this page?
The page lists the reference standard, nominal size, DN designation, flange thickness, weight, stud bolt information, number of bolts, and hole diameter for this entry. It also provides access to a CAD drawing file.
Can the listed bolt information be used for every installation?
Use the listed bolt information as a reference for this flange entry, then confirm the final bolt length, material, thread requirements, gasket, tightening method, and project specification before installation.
Is the Class 400 designation enough to select the flange for service?
No. Selection also depends on material, pressure-temperature conditions, gasket and facing requirements, mating components, and the applicable project design basis. Final suitability should be verified by the responsible engineer or piping authority.