This reference page provides the source dimensions and identification details for a Blind Flange 1 Inch Class 300. Use the listed data when checking flange selections, preparing piping layouts, coordinating equipment connections, or reviewing a CAD detail.
A blind flange has no center bore, so it closes a flanged connection rather than allowing pipe flow through the flange. The existing reference data below should be read together with the project specification, applicable material requirements, gasket selection, and pressure-temperature conditions.
Blind Flange 1″ Class 300
Blind Flange 1″ Class 300 is used to seal the end of a piping system or close off a flange connection in Class 300 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 1″ Class 300 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS): 1″
- DN Size: DN25
- Flange Thickness: 15.7mm
- Weight: 1.4kg
- Stud Bolt Size: 5/8″ UNC (or M16) x 75 Long
- Number of Bolts: 4
- Hole Diameter: 3/4″ (19.05mm)
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 1″ Class 300 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 1″ Class 300, which can be used for drafting, detailing, and piping layout coordination.
Available Blind Flange Class 300 Sizes
This size is part of the Blind Flange Class 300 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 the Blind Flange Reference
The dimension list identifies the nominal pipe size, DN designation, flange thickness, weight, bolt information, bolt count, and hole diameter. These values describe different aspects of the connection and should not be treated as interchangeable. For example, the stud bolt size identifies the fastener specification, while the hole diameter describes the clearance opening in the flange.
NPS and DN Designations
NPS and DN are nominal size designations used to identify the piping connection. They are reference labels rather than a complete description of every physical pipe dimension. When coordinating this flange with pipe schedules, fittings, valves, or equipment nozzles, confirm that the mating components use the required nominal size and flange standard.
Bolting and Gasket Coordination
Correct assembly requires more than matching the flange outside connection. Review the bolt count, stud dimensions, hole clearance, washer and nut requirements, gasket type, and available tightening access. The mating flange, gasket, and bolting should be checked as a complete connection under the project specification.
Using the CAD Drawing
The downloadable DWG can support drafting, piping layout coordination, and detail development. Before using it as a fabrication basis, verify the drawing units, insertion scale, layer information, mating flange orientation, gasket location, and the project’s required revision or standard.
Related Piping References
For a broader design review, compare this page with related references covering flange dimensions, pipe schedules, gasket types, stud bolts, and piping terminology. These related topics help explain how a blind flange fits into a complete piping connection without replacing the project’s engineering review.
Blind Flange 1 Inch Class 300 FAQ
What is the purpose of a blind flange?
A blind flange closes the end of a piping system, vessel nozzle, valve connection, or other flanged opening. It can provide a removable closure for isolation, maintenance, inspection, or a future connection.
Does a blind flange have a center bore?
No. A blind flange is a solid flange without a center bore. Its sealing function comes from closing the flanged opening rather than passing fluid through the flange.
What should be checked before ordering this flange?
Confirm the nominal size, flange class, applicable standard, material specification, gasket requirements, bolting, facing details, and pressure-temperature conditions. Also verify that the mating flange and equipment connection are compatible.
Can the DWG file be used directly for fabrication?
The DWG is intended to support drafting and coordination. Check its units and project requirements, then confirm all fabrication-critical information against the approved engineering documents and the authoritative dimension data on this page.
Is the listed bolt size the same as the flange hole diameter?
No. The bolt or stud size identifies the fastener, while the hole diameter identifies the opening through the flange for that fastener. Both details should be reviewed during bolting selection and connection assembly.