This Blind Flange 8 Inch Class 400 reference brings the key dimensional and connection information together for piping designers, detailers, fabricators, and maintenance teams. Use the source data below when checking a flange arrangement, preparing a drawing, or comparing this flange with other sizes in the same series.
A blind flange has no center opening. Instead, its solid face closes a flanged connection, allowing a pipe, nozzle, valve outlet, or equipment connection to be isolated without removing the mating flange. The flange dimensions and bolt details should always be coordinated with the mating component, gasket, facing, material specification, and project requirements.
Blind Flange 8″ Class 400
Blind Flange 8″ 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 8″ Class 400 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS): 8″
- DN Size: DN200
- Flange Thickness: 47.8mm
- Weight: 46kg
- Stud Bolt Size: 1″ UNC (or M27) x 170 Long
- Number of Bolts: 12
- 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 8″ 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 8″ 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 Read This Blind Flange Reference
The listed NPS and DN designations identify the nominal pipe size using customary and metric terminology. They are nominal size references rather than a direct description of every manufactured flange dimension. For fabrication and drafting, use the complete dimensional information supplied on this page together with the associated CAD file.
The flange thickness and listed weight are useful for layout coordination, material planning, handling discussions, and preliminary design review. Weight can also affect support, lifting, and access considerations, but final installation planning should account for the complete assembled connection and site conditions.
Bolt Details and Hole Diameter
The stud bolt size, bolt count, and hole diameter define important parts of the bolting arrangement. The bolt size identifies the intended stud or bolt thread designation and length, while the hole diameter describes the clearance opening through the flange. These are related but different values; a hole is normally larger than the nominal fastener diameter to provide assembly clearance.
Before ordering fasteners, verify the mating flange, washer arrangement, thread engagement, material compatibility, required tightening method, and project bolting specification. Bolt length can change when flange thickness, gasket construction, washers, or adjacent components differ from the reference arrangement.
Use of the CAD Drawing
The downloadable DWG can support piping layout, flange orientation checks, equipment connection coordination, and fabrication detailing. Treat the drawing as a reference for the configuration represented on this page. Confirm units, drawing scale, revision status, flange facing, and mating-part geometry before using it for fabrication or issuing construction documents.
Selection and Installation Checks
- Confirm that the nominal size matches the connected pipe, valve, nozzle, or equipment flange.
- Check the pressure-temperature requirements against the applicable rating information and project design basis.
- Verify the flange material, gasket type, facing arrangement, and bolting specification before procurement.
- Confirm bolt-hole alignment and access for installation and maintenance.
- Use the flange, gasket, and fastener combination approved for the specific service; do not select components by class designation alone.
- Coordinate this reference with related pipe dimensions, flange types, gasket references, and CAD/DWG resources available on the site.
For related research, readers may also compare other blind flange sizes in the Class 400 series and review the site’s flange terminology and pipe-dimension references. Those comparisons help identify matching connection details without substituting one flange size for another.
Blind Flange 8 Inch Class 400 FAQ
What is a blind flange used for?
A blind flange closes the end of a piping system or a flanged equipment connection. It is commonly used for isolation, maintenance access, nozzle blanking, and connections that may be extended later.
Does a blind flange have a center bore?
No. A blind flange is a solid flange without a center bore. Its face closes the connected opening when the flanged joint is assembled.
What should be checked before ordering this flange?
Confirm the nominal size, class designation, flange material, facing, gasket, stud bolt details, bolt-hole arrangement, and project pressure-temperature requirements. Also check the mating flange and the latest project documents.
Are the listed bolt size and hole diameter the same thing?
No. The bolt or stud size identifies the fastener, while the hole diameter identifies the opening through the flange. The two values must be coordinated for proper assembly clearance and bolting.
Can the DWG file be used directly for fabrication?
Use the DWG as a drafting and coordination reference, then verify its units, revision, mating geometry, material requirements, and project-specific tolerances before fabrication or construction use.