This reference page provides the source dimensions and connection details for an 18-inch Class 150 blind flange. Use it when checking piping layouts, preparing fabrication drawings, coordinating flange connections, or downloading the associated CAD file.
The technical values below are the local reference data for this page. Confirm the project specification, material requirements, gasket selection, bolting, and applicable pressure-temperature rating before fabrication or installation.
Blind Flange 18″ Class 150
Blind Flange 18″ 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 18″ Class 150 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS): 18″
- DN Size: DN450
- Flange Thickness: 38.1mm
- Weight: 100kg
- Stud Bolt Size: 1 1/8″ UNC (or M30) x 145 Long
- Number of Bolts: 16
- 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 18″ 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 18″ 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 the Blind Flange Reference
A blind flange is a solid flange with no center bore. Unlike a weld neck, slip-on, or threaded flange, it closes the end of a piping run, equipment nozzle, or flange connection. The closure can later be removed when inspection, maintenance, or a future line extension is required.
Key Dimension and Bolting Terms
- NPS and DN: The page identifies the nominal size as 18 inches and DN450. These designations describe the nominal piping size and should be checked against the connected piping and equipment documents.
- Flange thickness: This is the axial thickness of the blind flange. It affects the assembled flange envelope and should be coordinated with the mating flange and gasket arrangement.
- Stud bolt size and length: The listed bolting is 1 1/8" UNC, or M30, with the stated length. Do not substitute bolting without checking the project specification, thread system, nut arrangement, and required engagement.
- Number of bolts and hole diameter: These identify the bolting pattern information provided for this flange. The hole diameter is a bolt-hole dimension, not a pipe bore.
- Weight: The listed weight is useful for handling, lifting, support, and shipping coordination. Actual handling procedures should follow the project and site requirements.
Drafting and CAD Coordination
The downloadable DWG can support piping layout, equipment-interface coordination, and detail drafting. Before using the drawing for fabrication, compare the CAD geometry with the project specification and the dimension list on this page.
For related research, link this page with the site’s flange dimensions, pipe schedules, flange bolt size, blind flange, and CAD/DWG piping reference pages.
Frequently Asked Questions
What is an 18-inch Class 150 blind flange used for?
It is used to close a pipe end, equipment connection, valve connection, or nozzle where a removable closure is required. Typical uses include isolation, maintenance work, and future line expansion provisions.
Does a blind flange have a center bore?
No. A blind flange is a solid flange without a center bore. Its purpose is to block the connected piping or equipment opening.
What bolting is listed for this flange?
The reference data lists 1 1/8" UNC, or M30, stud bolts with the stated length and a total of 16 bolts. Confirm the required bolting against the project documents before ordering or installation.
Can the listed dimensions be used directly for fabrication?
Use the page as a piping reference, but verify the latest project requirements, flange material specification, gasket type, bolt length, and applicable pressure-temperature rating before fabrication or installation.
Is a CAD file available?
Yes. The page includes a DWG download for the Blind Flange 18 Inch Class 150 reference. The drawing should be checked against the project specification before it is used for fabrication or final detailing.