This reference page explains the dimensional data and practical use of a Blind Flange 3 Inch Class 2500. Use the source values for drafting, procurement, and preliminary piping coordination, then verify the complete connection against the project specification and applicable engineering requirements.
A blind flange has no center opening, so it closes a flanged connection rather than connecting one pipe bore to another. For related reference work, see the site resources for pipe dimensions and schedules, flange terminology, bolt and gasket selection, and CAD/DWG piping details.
Blind Flange 3″ Class 2500
Blind Flange 3″ Class 2500 is used to seal the end of a piping system or close off a flange connection in Class 2500 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 an extremely high pressure rating is required.
This dimension data is based on ANSI / ASME B16.5-2020.
Blind Flange 3″ Class 2500 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS): 3″
- DN Size: DN80
- Flange Thickness: 66.5mm
- Weight: 39kg
- Stud Bolt Size: 1 1/4″ UNC (or M33) x 220 Long
- Number of Bolts: 8
- Hole Diameter: 1 3/8″ (34.925mm)
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 3″ Class 2500 is commonly used for:
- Pipe end closure
- Equipment isolation
- Valve and nozzle blanking
- Maintenance shutdown work
- Process and utility piping systems
- Extremely high pressure piping applications
CAD Drawing Download
This page includes the CAD drawing file for Blind Flange 3″ Class 2500, which can be used for drafting, detailing, and piping layout coordination.
Available Blind Flange Class 2500 Sizes
This size is part of the Blind Flange Class 2500 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 Read This Blind Flange Reference
The listed NPS and DN designations identify the nominal size using U.S. customary and metric naming conventions. They are nominal identifiers, not a direct statement of the flange’s measured outside diameter or the connected pipe’s actual inside diameter. Use the dimensional entries on this page when checking a drawing or comparing the component with a matching flange connection.
The Class 2500 designation identifies the flange class specified by the reference standard. It should not be treated as a standalone allowable pressure for every service condition. The applicable pressure-temperature limit depends on factors such as material, temperature, gasket arrangement, bolting, joint design, and the governing project requirements.
Drafting and Installation Checks
- Confirm that the blind flange matches the mating flange, facing arrangement, gasket, and bolting requirements.
- Check the bolt pattern and hole information against the mating component before releasing fabrication drawings.
- Verify bolt length after accounting for flange thickness, gasket thickness, washers, and the required nut engagement.
- Review material certification, surface condition, corrosion allowance, and inspection requirements where applicable.
- Use the downloadable DWG as a drafting aid, but confirm its geometry against the approved project documents before fabrication.
Why Blind Flanges Are Used
Because the flange closes the flow path, it can support isolation, maintenance, inspection, equipment blanking, and planned future connection work. A blind flange is not a substitute for an operating isolation procedure: the line must be depressurized, drained, and made safe in accordance with the site’s approved work controls before the connection is opened or removed.
Blind Flange 3 Inch Class 2500 FAQs
What is a blind flange used for?
It closes the end of a pipe, nozzle, valve connection, or other flanged opening. It can also provide a removable closure for maintenance or future expansion.
Does a Class 2500 flange always withstand the same pressure?
No. The class designation must be evaluated with the flange material, service temperature, gasket and bolting arrangement, and the applicable pressure-temperature requirements. Do not select an allowable pressure from the class name alone.
Can the listed stud bolts be used for every installation?
Not automatically. Confirm the bolt material, thread requirements, length, washers, nut engagement, tightening method, and project specification. The required installed length can change with the mating flange, gasket, and washers.
Is the DWG file suitable for fabrication without review?
No. The DWG is a drafting and coordination resource. Compare it with the source dimensions, approved drawings, mating components, and the current project specification before fabrication.
What should be checked before ordering this flange?
Confirm the nominal size, flange class, material, facing, dimensional requirements, gasket compatibility, bolting, delivery documentation, and any inspection or certification requirements.