A Blind Flange 3 Inch Class 150 is a solid, bored-free flange used to close a piping connection. Unlike a flange intended to pass fluid through its center, a blind flange creates a removable closure at a pipe end, equipment nozzle, valve connection, or planned extension point.
This page provides the local reference dimensions, weight, stud bolt information, bolt count, and hole diameter for the 3-inch Class 150 size. Use the data below when checking a piping arrangement, reviewing a fabrication drawing, or coordinating the associated CAD file. The listed values should be checked against the project specification and the selected gasket, fastener, material, and pressure-temperature requirements before fabrication or installation.
Blind Flange 3″ Class 150
Blind Flange 3″ 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 3″ Class 150 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS): 3″
- DN Size: DN80
- Flange Thickness: 22.4mm
- Weight: 4.1kg
- 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″ 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 3″ 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 Read This Blind Flange Reference
The nominal pipe size identifies the piping connection category, while the DN designation provides the corresponding metric nominal reference. These labels describe the connection size; they are not a direct measurement of every flange feature.
Flange thickness, weight, stud bolt size, bolt count, and hole diameter serve different purposes during design and installation. Thickness and weight support drawing review and handling checks. The stud bolt entry identifies the specified fastener designation and length. The bolt count indicates how many fasteners are used around the flange, while the hole diameter describes the clearance opening in the flange.
Blind Flange Versus a Flanged Pipe Connection
A blind flange has no center bore, so it closes the connected opening rather than continuing the pipe passage. This makes it useful where a line must be isolated, an equipment connection must be blanked, or a future connection is being reserved. The closure still requires the correct mating arrangement, gasket selection, fastener installation, and engineering review for the service.
Installation and Drawing Review Considerations
- Confirm that the flange class and nominal size match the mating flange or equipment connection.
- Check the face condition and gasket specification required by the project.
- Verify the listed stud bolt designation, length, quantity, and flange-hole compatibility.
- Review material requirements and the applicable pressure-temperature rating before procurement.
- Use the downloadable DWG as a drafting reference, then verify the final design against approved project documents.
Related Reference Topics
For broader piping coordination, compare this entry with related flange dimensions, pipe schedules, flange facing terminology, gasket references, stud bolt references, and CAD or DWG resources. Reviewing the matching flange size on the connected component can help identify mismatches before fabrication.
Frequently Asked Questions
What is a Blind Flange 3 Inch Class 150 used for?
It is used to close a piping end, equipment nozzle, valve connection, or other flanged opening in the listed nominal size and class. Common purposes include isolation, maintenance blanking, and preparing for a possible future line connection.
Does a blind flange have a center opening?
No. A blind flange is solid across its central area and does not provide a flow passage. Its purpose is to close the connected opening.
What bolt information is listed for this flange?
The reference identifies the stud bolt designation as 5/8-inch UNC, or M16, with the listed length. It also gives the number of bolts and the flange hole diameter. Confirm the final fastener arrangement with the project specification and mating component.
Is Class 150 the same as a universal pressure value?
No. A flange class designation must be considered with the applicable material, temperature, service, gasket, fasteners, and governing project requirements. Do not use the class label alone as a substitute for a pressure-temperature rating review.
Can the DWG file be used directly for fabrication?
The DWG is provided as a drafting and coordination reference. Before fabrication, verify the drawing against the approved specification, the mating flange, material requirements, gasket arrangement, and the latest applicable project documents.
What should be checked before installing this blind flange?
Confirm the nominal size, flange class, mating connection, face and gasket requirements, fastener details, material specification, and service rating. Installation should follow the applicable engineering and project procedures.