This reference page provides the dimensional and connection details for a Blind Flange 1 Inch Class 400. Use the published values when checking piping layouts, preparing fabrication drawings, or coordinating a flange connection with valves, equipment, and pipework.
The page also explains the purpose of a blind flange, identifies common uses, and provides access to a CAD drawing for drafting and design coordination. For related information, see the site’s flange dimensions, pipe schedules, gasket, stud bolt, and piping terminology references.
Blind Flange 1″ Class 400
Blind Flange 1″ Class 400 is used to seal the end of a piping system or close off a flange connection in Class 400 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 1″ Class 400 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS): 1″
- DN Size: DN25
- Flange Thickness: 17.5mm
- Weight: 1.8kg
- 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 1″ Class 400 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 1″ Class 400, which can be used for drafting, detailing, and piping layout coordination.
Available Blind Flange Class 400 Sizes
This size is part of the Blind Flange Class 400 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 dimensions section separates the main identification and connection data into practical drafting fields. NPS identifies the nominal pipe size, while DN provides the corresponding metric designation used in many piping documents. Thickness, weight, bolt-hole information, and stud bolt details support preliminary layout and material coordination.
A blind flange has no center bore. Unlike a flange intended to pass fluid through a connected pipe, it forms a removable closure at a flanged connection. Removal can provide access for inspection, maintenance, isolation, or a future connection, subject to the requirements of the piping system.
Connection and Installation Checks
- Confirm that the blind flange matches the mating flange, including the flange class, facing arrangement, bolt-hole alignment, and gasket selection.
- Check the project material specification and verify that the fasteners, gasket, and flange materials are compatible with the service.
- Confirm the required bolt engagement and tightening procedure rather than relying on nominal bolt length alone.
- Review the applicable pressure-temperature requirements for the selected materials and service conditions.
- Use the CAD file as a drafting reference, then verify the final fabrication and installation details against the project documents.
Useful Related References
Readers comparing this component with other connection types may also want to review blind flange dimensions by size, flange facing terminology, pipe outside-diameter references, gasket selection guidance, and stud bolt terminology. These related references help connect the flange data with the surrounding piping design.
Frequently Asked Questions
What is a Blind Flange 1 Inch Class 400 used for?
It is used to close the end of a piping system or blank a flanged connection. Common uses include equipment isolation, valve and nozzle blanking, maintenance shutdown work, and future piping modifications.
Does a blind flange have a center opening?
No. A blind flange is a solid flange without a center bore, so it closes the connected line rather than allowing the pipe contents to pass through.
What bolt information is listed for this flange?
The source data lists 5/8 inch UNC, or M16, stud bolts with a listed length of 90, and four bolts. Confirm the project specification and mating flange requirements before procurement or installation.
Can the CAD drawing be used for fabrication?
The CAD file is provided for drafting, detailing, and piping layout coordination. Final fabrication should be based on verified project documents, material requirements, connection details, and the applicable flange standard.
What should be checked before installation?
Confirm the flange material, gasket type, bolt requirements, mating connection, and applicable pressure-temperature rating. Installation and tightening should follow the project’s approved procedures.