This reference page provides the listed dimensions, weight, fastening details, and CAD resource for a Blind Flange 1 1/4 Inch Class 400. Use the supplied data when reviewing piping layouts, preparing drawings, or checking a flange connection against project requirements.
The page is also useful for understanding how a blind flange functions in an isolation point. Because a blind flange closes a connection rather than passing flow through a bore, fit-up, gasket selection, bolting, and access for future maintenance should be reviewed together.
Blind Flange 1 1/4″ Class 400
Blind Flange 1 1/4″ 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 1/4″ Class 400 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS): 1 1/4″
- DN Size: DN32
- Flange Thickness: 20.6mm
- Weight: 2.3kg
- Stud Bolt Size: 5/8″ UNC (or M16) x 95 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 1/4″ 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 1/4″ 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 Use This Blind Flange Reference
The dimensional list identifies the nominal pipe size, DN designation, flange thickness, weight, stud bolt information, bolt count, and hole diameter for this flange entry. These fields support preliminary drafting and component identification, while the project specification remains the controlling source for procurement and installation.
Nominal Size and Connection Identification
NPS and DN are size designations used to identify the intended piping connection. They should not be treated as a substitute for checking the mating flange, gasket, facing arrangement, fastener requirements, and applicable material specification. When coordinating a piping model or fabrication drawing, compare the flange record with the associated pipe, valve, nozzle, or equipment connection.
Bolting and Fit-Up Checks
The listed stud bolt size, bolt quantity, and hole diameter describe the fastening arrangement shown for this reference. Confirm that the selected fasteners, washers where required, thread form, usable engagement, gasket, and tightening procedure agree with the governing project documents. Bolt length should be checked against the assembled joint rather than selected from the flange entry alone.
Blind Flanges in Piping Work
A blind flange can provide a removable closure for a pipe end, equipment connection, valve location, or maintenance isolation point. It may also support a future connection, but the piping system must be safely isolated, depressurized, and verified before removal or maintenance. Do not infer allowable service conditions from the class designation alone; confirm the applicable pressure-temperature requirements and material combination.
CAD and Related Reference Work
The downloadable DWG can assist with drafting, layout coordination, and preliminary detailing. Before issuing a fabrication drawing, compare the CAD geometry with the dimension list and the project’s flange-facing, gasket, clearance, and access requirements. Related PipeSTD references for flange dimensions, pipe schedules, fittings, and piping terminology can help maintain consistent connection data across a drawing package.
Frequently Asked Questions
What is a Blind Flange 1 1/4 Inch Class 400?
It is a solid flange used to close a piping or equipment connection. Unlike a bored flange, it has no center opening for flow and can provide a removable closure for isolation, maintenance, or a planned future connection.
Does this blind flange include a center bore?
No. A blind flange is a blank closure without a center bore. The mating connection, gasket, and bolting arrangement still need to be checked before installation.
What information is included in the dimensional reference?
The source list includes the reference standard, nominal pipe size, DN designation, flange thickness, weight, stud bolt specification, bolt quantity, and hole diameter. These values should be read together rather than used as isolated selection criteria.
Can the listed bolt size be used without further checking?
No. Confirm the fastener material, thread requirements, assembled joint thickness, gasket compression needs, available thread engagement, and project tightening procedure before installation.
What is the CAD file used for?
The DWG file is intended to support drafting, detailing, and piping layout coordination. Verify the drawing against the applicable project requirements before using it for fabrication or construction.
Should the flange be selected solely from its class designation?
No. Confirm the pressure-temperature rating, material specification, gasket type, flange facing, mating component, and applicable project requirements. Final selection and installation should be verified by the responsible engineer or qualified piping professional.