Blind Flange 3 Inch Class 900 is a compact reference for checking the listed flange dimensions, bolt details, weight, and CAD resource before drafting or coordinating a piping connection. Because a blind flange has no center bore, it closes a flanged connection rather than allowing the pipe to continue through the flange.
Use the dimensional values on this page as the controlling local reference, then verify the project specification, flange facing, gasket arrangement, material, bolting, and pressure-temperature requirements before fabrication or installation. Related resources on this site can help with pipe dimensions and schedules, flange terminology, gasket selection, and CAD/DWG piping details.
Blind Flange 3″ Class 900
Blind Flange 3″ 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 3″ Class 900 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS): 3″
- DN Size: DN80
- Flange Thickness: 38.1mm
- Weight: 13kg
- Stud Bolt Size: 7/8″ UNC (or M24) x 145 Long
- Number of Bolts: 8
- Hole Diameter: 1″ (25.4mm)
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 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 3″ 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 Read This Blind Flange Reference
The reference data identifies the flange by nominal pipe size and pressure class. NPS and DN are designation systems used to identify the nominal connection size; they are not a substitute for checking the actual flange geometry listed in the project documentation.
The flange thickness, stated weight, bolt quantity, stud bolt description, and hole diameter should be reviewed together. The bolt size and hole diameter describe different features: the bolt specification identifies the fastener arrangement, while the hole diameter describes the clearance opening through the flange. Confirm that the selected studs, nuts, washers where specified, gasket, and tightening procedure are compatible with the complete joint assembly.
Drafting and Installation Checks
- Use the downloadable DWG to support layout, detailing, and coordination, but confirm drawing units and insertion scale before using it in a CAD model.
- Check the flange facing and gasket arrangement against the mating flange and piping specification.
- Confirm that the bolt pattern aligns with the mating component and that the available bolt length accounts for the full joint stack-up.
- Review material, inspection, corrosion, and service requirements before releasing the component for fabrication.
- Do not infer a project pressure limit from the class designation alone; verify the applicable pressure-temperature requirements and governing specification.
For broader design work, link this page to references covering flange classes, pipe schedules, stud bolt dimensions, gasket types, and piping isometric symbols. These related topics help readers move from a dimensional lookup to a complete, checked flange connection.
Blind Flange 3 Inch Class 900 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. It can provide an isolation point and can also support future inspection, maintenance, or line extension work.
Does a blind flange have a pipe bore?
No. A blind flange is a solid blank flange without a center bore. The mating face, gasket, and bolting form the sealed connection at the opening being closed.
What bolt information is listed for this flange?
The source data lists the stud bolt size, length, and number of bolts. These details should be checked against the mating flange, gasket thickness, nut engagement, material specification, and approved tightening procedure.
Can the DWG be used directly for fabrication?
The DWG is intended to support drafting, detailing, and piping layout coordination. It should be checked for units, scale, revision status, facing details, and project-specific requirements before fabrication or construction use.
What should be verified before installation?
Confirm the flange material, facing, gasket, bolting, joint assembly, pressure-temperature requirements, and compatibility with the mating component. Project specifications and the latest applicable engineering requirements take precedence over a general reference page.