This reference page covers the published dimensions and connection details for a 3/4 inch Class 150 blind flange. Use the data below when checking piping layouts, flange matching, fabrication details, or CAD drawings. The listed values are the controlling local reference for this page; project specifications and engineering approval should govern final selection.
Blind Flange 3/4″ Class 150
Blind Flange 3/4″ 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 3/4″ Class 150 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS): 3/4″
- DN Size: DN20
- Flange Thickness: 11.2mm
- Weight: 0.9kg
- Stud Bolt Size: 1/2″ UNC (or M14) x 65 Long
- Number of Bolts: 4
- Hole Diameter: 5/8″ (15.875mm)
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 3/4″ 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 3/4″ 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 for pipe flow. Instead, its solid face closes a flanged connection, allowing a line, nozzle, or equipment connection to be isolated or left ready for later access. Because the flange is installed with bolts and a gasket, the mating flange, gasket arrangement, and bolting details must be checked as one connection rather than treated as separate components.
Understanding the Listed Dimensions
The NPS and DN entries are nominal pipe-size designations used to identify the connection within piping documentation. They should not be interpreted as a direct measurement of the flange face, outside diameter, or bore. For fabrication and drafting, use the complete dimension information together with the downloadable DWG file and the applicable project drawings.
The bolt entry identifies the specified stud-bolt arrangement, while the number of bolts and hole diameter describe the flange drilling pattern. These details are important when checking alignment with a mating flange, selecting compatible hardware, and reviewing a piping assembly. Do not substitute a different bolt system or assume interchangeability without confirming the project specification.
Drafting and Procurement Checks
- Confirm that the mating flange uses a compatible Class 150 drilling arrangement.
- Check the gasket type, facing arrangement, material specification, and required bolting against the project documents.
- Use the CAD file for layout and detailing, then verify critical geometry against the authoritative dimension data before fabrication.
- Review the applicable pressure-temperature requirements and installation procedure with the responsible engineer.
For related research, compare this page with other blind flange sizes, flange dimensions, pipe schedules, and piping CAD references in the same reference library. Matching the flange class and nominal size is an essential first step, but it does not replace a complete connection review.
Frequently Asked Questions
What is a 3/4 inch Class 150 blind flange used for?
It is used to close a flanged piping, vessel, nozzle, valve, or equipment connection. Typical purposes include isolation, maintenance access, blanking, and provision for a future line connection.
Does a blind flange have a pipe bore?
No. A blind flange is a solid flange without a center bore. Its function is to block the connection rather than provide a flow passage.
Can the listed stud bolts be replaced with other hardware?
Do not assume that alternative hardware is acceptable. Confirm the bolt system, length, material, gasket requirements, and project specification before installation.
Is the CAD drawing sufficient for fabrication?
The CAD file is useful for drafting, detailing, and layout coordination, but fabrication should also be checked against the published dimension data, material requirements, applicable standard, and approved project documents.