This reference page explains how to read the listed dimensions for a Blind Flange 6 Inch Class 900 and how the component fits into common piping documentation workflows. Use the source values below when checking a flange drawing, preparing a material takeoff, or coordinating a piping layout.
For related work, compare this reference with PipeSTD resources covering flange dimensions, pipe schedules, bolt patterns, piping terminology, and CAD/DWG detailing. Those references can help connect the flange data with the adjoining pipe, equipment nozzle, valve, gasket, and bolting requirements.
Blind Flange 6″ Class 900
Blind Flange 6″ 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 6″ Class 900 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS): 6″
- DN Size: DN150
- Flange Thickness: 55.6mm
- Weight: 53kg
- Stud Bolt Size: 1 1/8″ UNC (or M30) x 190 Long
- Number of Bolts: 12
- Hole Diameter: 1 1/4″ (31.75mm)
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 6″ 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 6″ 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 listed NPS identifies the nominal pipe size, while the DN entry provides the corresponding metric designation. These labels describe the connection size; they should not be treated as a direct measurement of every flange feature.
The flange thickness and weight are useful for drawing review, handling planning, support coordination, and material documentation. The stated bolt information identifies the stud-bolt designation, length, and quantity. The bolt count should be coordinated with the bolt-hole layout shown in the CAD file and with the mating flange.
The hole diameter is a flange feature, not the same as the nominal pipe size or the stud-bolt nominal diameter. During detailing, check that the selected fasteners, washers where required, gasket, and mating component are compatible with the project specification.
Drafting and Installation Checks
- Use the downloadable DWG to coordinate the flange outline, bolt-hole arrangement, and connection location in a piping or equipment drawing.
- Confirm the mating flange and connection details before releasing fabrication or installation documents.
- Check the specified flange material, gasket type, bolting requirements, and facing details against the project documents.
- Review the applicable pressure-temperature rating rather than treating the class designation as a standalone design pressure.
- Coordinate access for bolting, removal, inspection, and future line extension where the blind flange is used as an isolation or closure point.
Related PipeSTD References
This page can be used alongside references for flange classes, pipe dimensions and schedules, flange bolt patterns, fittings, and CAD/DWG resources. Cross-checking those topics helps prevent mismatches between nominal size, connection geometry, and project-specific installation requirements.
Frequently Asked Questions
What is a blind flange used for?
A blind flange closes the end of a pipe, vessel nozzle, valve connection, or other flanged opening. Because it has no center bore, it can provide a removable closure for isolation, maintenance, inspection, or future connection work.
What does Class 900 mean on this flange?
Class 900 is the pressure-class designation identified for this flange series. The allowable service conditions still depend on the applicable standard, material, temperature, gasket, bolting, and project design requirements.
What is the difference between NPS and DN?
NPS is the nominal pipe size designation used in the reference, while DN is its corresponding metric designation. Neither label should be used as a substitute for checking the detailed flange dimensions.
Why should the bolt-hole diameter be checked separately from bolt size?
The bolt size identifies the intended stud-bolt designation, whereas the hole diameter describes the opening through the flange. Both must be coordinated with the mating flange and the project bolting specification.
Can the DWG file be used directly for fabrication?
The DWG is useful for drafting, detailing, and layout coordination. Before fabrication, verify the drawing against the project specification, approved material requirements, gasket and bolting details, mating connection, and applicable design checks.