This blind flange reference provides the dimensional and bolting information needed to identify a 6-inch Class 300 flange for piping layouts, fabrication details, and connection coordination. Use the listed values together with the project’s piping specifications rather than treating a nominal size or pressure class as a complete design basis.
The page also explains how to review the flange data, check the mating connection, and use the associated CAD file. For related design work, compare this reference with the applicable pipe dimensions and schedules, flange types, gasket references, and piping terminology pages on this site.
Blind Flange 6″ Class 300
Blind Flange 6″ 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 6″ Class 300 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS): 6″
- DN Size: DN150
- Flange Thickness: 35.1mm
- Weight: 22.7kg
- Stud Bolt Size: 3/4″ UNC (or M20) x 120 Long
- Number of Bolts: 12
- Hole Diameter: 7/8″ (22.225mm)
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 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 6″ 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 Use This Blind Flange Reference
A blind flange has no center bore, so its main function is to close a flanged connection. In a drawing or model, it may represent a permanent end closure, an equipment blank, or an access point that can be opened during maintenance. The flange must still be checked against the mating flange, gasket arrangement, fasteners, and the project specification.
Reviewing the Dimension Data
The source data identifies the nominal pipe size, DN designation, flange thickness, weight, bolt-hole information, and stud-bolt details. These fields are useful for piping arrangement, material takeoff, support coordination, and checking whether the selected flange matches the intended connection. Nominal size identifies the piping size designation; it does not by itself define the outside diameter of every connected component.
When checking a connection, verify the flange-facing arrangement and gasket requirements in the project documents. Also confirm that the bolt size, bolt count, hole diameter, and bolt length correspond to the mating flange and the specified assembly method. Bolt tightening should follow the project or manufacturer’s procedure, with engineering review where required.
Pressure Class and Project Verification
Class 300 identifies the flange pressure-class designation; it is not a universal pressure value for every material and operating condition. The allowable rating depends on the applicable standard, material specification, temperature, service conditions, and project requirements. Confirm the pressure-temperature basis before fabrication or installation.
Using the CAD Drawing
The downloadable DWG can support piping layout, drafting, detailing, and coordination. Before using it as a fabrication or construction deliverable, confirm the drawing units, layer conventions, flange orientation, facing details, and revision status against the source data and project standards. Related CAD resources for flange types, fittings, and pipe components can help maintain consistent detailing across a piping model.
Frequently Asked Questions
What is a 6-inch Class 300 blind flange used for?
It is used to close a flanged piping, equipment, valve, or nozzle connection. Typical uses include isolation, maintenance shutdown work, and closing a connection reserved for future work, subject to project engineering verification.
Does a blind flange have a center opening?
No. A blind flange is a solid flange without a center bore. Its purpose is to block the connected line or opening rather than allow fluid to pass through.
What bolt information is listed for this flange?
The source data lists the stud-bolt designation, bolt length, number of bolts, and hole diameter. Confirm these details against the mating flange, gasket, material specification, and bolting procedure before installation.
Can the DWG be used directly for fabrication?
The DWG is provided for drafting, detailing, and piping layout coordination. Review its units and geometry against the listed reference data and the project’s approved drawings before using it for fabrication.
Is Class 300 enough information to select the flange?
No. Selection also requires review of material, service, temperature, pressure-temperature rating, facing, gasket, fasteners, and applicable project requirements. The notes on this page should be checked before procurement or installation.