This reference covers the listed dimensions, weight, bolting information, and CAD resource for a Blind Flange 3/4 Inch Class 400. Use it when checking a piping layout, coordinating a flange connection, or selecting a blanking component for an equipment or pipe-end connection.
The technical list below should be read together with the project specification and the mating flange details. For related research, useful internal-link topics include blind flange dimensions, ASME flange classes, flange bolt sizing, gasket selection, and piping CAD drawings.
Blind Flange 3/4″ Class 400
Blind Flange 3/4″ 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 3/4″ Class 400 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS): 3/4″
- DN Size: DN20
- Flange Thickness: 15.7mm
- Weight: 1.5kg
- Stud Bolt Size: 5/8″ UNC (or M16) x 90 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 3/4″ 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 3/4″ 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
A blind flange has no central pipe opening. Its purpose is to close a flanged connection while retaining a bolted arrangement that can be removed for inspection, maintenance, or future modification. The listed thickness and weight are useful for drafting, material takeoff, handling planning, and comparison with the project bill of materials.
Understanding the Size Designation
NPS and DN are nominal size designations used to identify compatible piping components; they should not be treated as a direct measurement of every flange feature. Confirm the mating flange, pipe, gasket, and equipment nozzle information before releasing a drawing or purchase request.
Checking the Bolting Information
The source list identifies the stud bolt designation, length, bolt quantity, and hole diameter. These details should be checked against the mating flange and the selected gasket arrangement. Actual assembly also depends on the project bolting procedure, material requirements, access for tightening, and any applicable engineering or fabrication specification.
Class Rating and Installation Review
The Class 400 designation identifies the pressure-class family, but it should not be used by itself to establish an allowable operating condition. Confirm the applicable pressure-temperature rating, flange material, facing arrangement, gasket type, and service requirements before installation.
Using the CAD File
The downloadable DWG can support piping layout, equipment-interface coordination, and detail drafting. Treat the drawing as a coordination aid and verify the final geometry against the listed reference data, the mating component, and the project’s latest design documents before fabrication.
Related Internal-Link Opportunities
- Link “blind flange dimensions” to the site’s broader blind-flange size index.
- Link “ASME flange classes” to the site’s flange-rating or pressure-class terminology guide.
- Link “flange bolt sizing” to the site’s stud-bolt and bolt-hole reference.
- Link “piping CAD drawings” to the site’s DWG download or CAD resources category.
Frequently Asked Questions
What is a Blind Flange 3/4 Inch Class 400 used for?
It is used to close a pipe end, equipment connection, valve connection, or other flanged opening where a removable blanking point is required. The exact application must be checked against the service and project design requirements.
Does a blind flange have a center bore?
No. A blind flange is a solid flange without a center bore, allowing it to close the connected opening when installed with the required gasket and bolting arrangement.
What do NPS 3/4 and DN20 identify?
They are nominal pipe-size designations for the component. Confirm the complete mating dimensions rather than assuming that the nominal designation alone defines every connection feature.
Can the listed stud bolt information be used without further checking?
Use it as the reference information provided on this page, then verify the bolt designation and length against the mating flange, gasket, material specification, access conditions, and project installation procedure.
Is the Class 400 designation sufficient for pressure selection?
No. Confirm the applicable pressure-temperature rating, material, service conditions, gasket, facing, and project requirements before selecting the flange for an operating system.
What is the DWG file used for?
The DWG supports drafting, piping layout, and coordination. Verify the drawing against the current technical data and mating components before fabrication or installation.