This reference page summarizes the published dimensions and connection details for a Blind Flange 20 Inch Class 150. Use it to support piping layout, drafting, procurement review, and flange identification before checking the project specifications.
The page also explains the purpose of a blind flange, common installation contexts, and access to the related CAD drawing. For broader comparisons, connect this reference with the site’s flange dimensions, pipe schedules, gasket, bolt, and piping terminology resources.
Blind Flange 20″ Class 150
Blind Flange 20″ Class 150 is used to seal the end of a piping system or close off a flange connection in Class 150 service. It is a solid flange without a center bore and is commonly applied in industrial piping, maintenance isolation points, and future line expansion connections.
This dimension data is based on ANSI / ASME B16.5.
Blind Flange 20″ Class 150 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS): 20″
- DN Size: DN500
- Flange Thickness: 41.1mm
- Weight: 130kg
- Stud Bolt Size: 1 1/8″ UNC (or M30) x 160 Long
- Number of Bolts: 20
- 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 20″ Class 150 is commonly used for:
- Pipe end closure
- Equipment isolation
- Valve and nozzle blanking
- Maintenance shutdown work
- Process and utility piping systems
CAD Drawing Download
This page includes the CAD drawing file for Blind Flange 20″ Class 150, which can be used for drafting, detailing, and piping layout coordination.
Available Blind Flange Class 150 Sizes
This size is part of the Blind Flange Class 150 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 opening, so it closes a flanged connection rather than allowing the pipe bore to continue through the flange. This makes it useful where a line, nozzle, or equipment connection must be isolated, temporarily blanked, inspected, or reserved for a future connection.
Understanding the Listed Dimensions
The source data identifies the nominal pipe size, DN designation, flange thickness, mass, stud bolt information, bolt count, and hole diameter. These details should be read together when checking a piping arrangement or preparing a fabrication and installation package. The bolt information describes the fastener arrangement; it should not be treated as a substitute for verifying the complete bolting assembly, including washers, engagement, tightening requirements, and joint-access conditions.
Blind flange selection also requires more than matching the nominal size. Confirm the flange facing, gasket type, material specification, service conditions, and applicable pressure-temperature requirements against the project documents. The mating flange and the blind flange must be compatible, and the joint should be evaluated by the responsible piping or mechanical engineer where operating loads, thermal movement, or equipment forces are relevant.
Drafting and CAD Coordination
The downloadable DWG can support preliminary layout, detailing, and coordination. Before issuing a drawing for fabrication, compare the CAD geometry with the authoritative dimensional data on this page and with the project’s approved specifications. Related internal references for flange facing terminology, bolt patterns, pipe dimensions, and CAD blocks can help maintain consistent drafting conventions across a piping package.
Related Reference Topics
- Blind flange dimensions by nominal pipe size and pressure class
- Flange facing and gasket selection terminology
- Pipe schedules and outside-diameter references
- Stud bolts, nuts, washers, and flange-joint assembly
- Piping isometric and nozzle connection drafting
Frequently Asked Questions
What is a blind flange used for?
A blind flange closes the end of a pipeline or a flanged connection. It can support isolation, maintenance work, equipment blanking, inspection access, or a future line extension.
Does a blind flange have a center bore?
No. A blind flange is solid across its central face, unlike a welding-neck, slip-on, or socket-weld flange that provides a passage for the pipe.
How should the listed bolt size be used?
Use the listed stud bolt information as a reference for the published flange arrangement, then verify the complete bolting specification and installation requirements in the project documents. Bolt length can depend on the mating flange, gasket, washers, nuts, and required thread engagement.
Is the CAD file sufficient for fabrication?
The CAD file is useful for drafting and coordination, but it should be checked against the page’s dimensional reference, approved project specifications, material requirements, and the latest applicable engineering documents before fabrication.
What else should be checked before installation?
Confirm the mating flange, facing, gasket, material, bolt assembly, service conditions, and pressure-temperature requirements. Installation and design decisions should be reviewed by the responsible engineering team.