This reference page provides dimensional and drafting information for a Blind Flange 2 1/2 Inch Class 900 connection. Use the data below when reviewing piping layouts, flange details, maintenance isolation points, and CAD coordination.
The dimension list identifies the nominal size, equivalent DN designation, flange thickness, weight, stud bolt information, bolt-hole details, and bolt count. Treat these values as a coordinated set: changing the flange class, nominal size, facing arrangement, or bolting specification can affect connection compatibility.
Blind Flange 2 1/2″ Class 900
Blind Flange 2 1/2″ Class 900 is used to seal the end of a piping system or close off a flange connection in Class 900 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 900 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS): 2 1/2″
- DN Size: DN65
- Flange Thickness: 41.1mm
- Weight: 16kg
- Stud Bolt Size: 1″ UNC (or M27) x 160 Long
- Number of Bolts: 8
- Hole Diameter: 1 1/8″ (28.575mm)
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 900 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 900, which can be used for drafting, detailing, and piping layout coordination.
Available Blind Flange Class 900 Sizes
This size is part of the Blind 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, gasket type, bolt length, and applicable pressure-temperature rating.
How to Use This Blind Flange Reference
A blind flange has no center opening, so it closes a flanged connection rather than providing a passage for fluid. It may be removed later for inspection, maintenance, equipment isolation, or a planned line extension. Because the flange closes a pressure boundary, selection and installation should be reviewed against the complete piping specification and the applicable pressure-temperature requirements.
Reading the dimensional data
The existing reference identifies both NPS and DN terminology. NPS is commonly used in North American piping documentation, while DN provides a metric nominal designation. These labels describe the nominal connection size; they should not be treated as a substitute for checking the complete flange geometry.
The bolt information should be reviewed with the mating flange, gasket, washers, nuts, and installation procedure. Confirm that the bolt arrangement, hole diameter, bolt length, and thread form are compatible with the complete assembly. Actual bolt engagement can also depend on mating-component thicknesses and gasket selection.
Drafting and CAD coordination
Use the downloadable DWG as a drafting reference for layout and detailing. Before issuing a fabrication or construction drawing, compare the CAD geometry with the project flange specification, mating component, gasket seating arrangement, and required clearances. A drawing file is a coordination aid and does not replace engineering review or fabrication verification.
Related piping references
This page can be used alongside references for flange dimensions, pipe schedules, flange terminology, gasket selection, stud bolts, and CAD piping details. Reviewing those topics together helps distinguish nominal size, connection geometry, and installation requirements.
Verification before use
- Confirm the applicable project and piping specification.
- Verify flange material, facing, gasket, and bolting requirements.
- Check pressure-temperature suitability through the responsible engineer or governing specification.
- Confirm the mating flange and bolt-hole alignment before fabrication or installation.
- Review the latest approved drawing and procurement requirements.
Blind Flange Class 900 FAQ
What is a blind flange used for?
A blind flange closes the end of a pipe, vessel nozzle, valve connection, or other flanged opening. It can provide a removable closure for isolation, maintenance, inspection, or future modification.
Does a blind flange have a center bore?
No. A blind flange is a solid flange without a center bore. Its purpose is to block the connected opening rather than allow flow through the flange.
Why should the mating flange be checked?
The blind flange must align with the mating connection and use compatible geometry, bolting, gasket, and facing requirements. Matching only the nominal size is not sufficient for a complete installation review.
Can the DWG file be used for fabrication?
The DWG file is useful for drafting, layout, and coordination. Fabrication should proceed only after the geometry, material, tolerances, project specification, and approved engineering documents have been verified.
Is Class 900 alone enough to select the flange?
No. The class designation should be considered with the applicable standard, material specification, temperature conditions, flange facing, gasket, bolting, and project design requirements.
What should be confirmed before installation?
Confirm the latest project requirements, mating-flange compatibility, gasket and bolt specification, bolt length, material requirements, and applicable pressure-temperature rating before installation.