This reference page brings together the key identification, dimensional, bolting, and CAD information for a Blind Flange 4 Inch Class 400. Use the data below when checking a piping layout, reviewing a fabrication drawing, or locating a matching flange for an isolation or closure point.
For a complete connection review, compare this flange with the related pipe dimensions and schedules, flange facing, gasket selection, and stud bolt references used elsewhere in the piping design.
Blind Flange 4″ Class 400
Blind Flange 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 4″ Class 400 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS): 4″
- DN Size: DN100
- Flange Thickness: 35.1mm
- Weight: 15kg
- Stud Bolt Size: 7/8″ UNC (or M24) x 140 Long
- Number of Bolts: 8
- Hole Diameter: 1″ (25.4mm)
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 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 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
A blind flange has no center opening, so it closes a flanged connection rather than providing a passage for fluid. That makes it useful where a line, nozzle, or equipment connection must be isolated, temporarily closed, or retained for possible future work.
The dimensional list identifies the nominal size, metric designation, flange thickness, mass, bolt arrangement, and hole information for this specific Class 400 entry. These details should be read together: the bolt count and hole diameter affect mating compatibility, while the listed stud bolt information supports preliminary connection and drafting checks.
Connection and Installation Checks
- Confirm that the mating flange has the same nominal size, pressure class, facing arrangement, and bolt pattern.
- Check the project material specification and the applicable pressure-temperature requirements before selection.
- Verify gasket type, sealing surface condition, tightening procedure, and stud bolt requirements with the responsible engineer or project specification.
- Account for access and clearance when the blind flange will be removed during maintenance or inspection.
- Use the downloadable DWG as a drafting aid, then confirm final fabrication information against the approved project documents.
Related Piping References
Readers comparing this item with other components may also need references for pipe schedules, raised-face and other flange facings, flange dimensions, bolt and nut terminology, and CAD piping details. These related topics help distinguish a dimensional match from a complete, approved piping connection.
Frequently Asked Questions
What is the purpose of a Blind Flange 4 Inch Class 400?
It closes a flanged piping, vessel, valve, or equipment connection where no flow passage is required. It can support isolation, maintenance shutdown work, or a future connection point.
Does a blind flange have a center bore?
No. A blind flange is solid across its center and is designed to seal the end of a piping connection.
Can this flange be matched with any 4-inch flange?
No. Nominal size alone is not sufficient. Confirm the Class 400 designation, facing, bolt arrangement, hole information, gasket requirements, and project material specification before mating components.
What should be checked before installation?
Review the approved pressure-temperature requirements, flange and gasket specifications, stud bolt details, tightening method, and access for future removal. Final selection and installation should follow the project specification and engineering approval.
What is the CAD file used for?
The supplied DWG can assist with drafting, piping layout coordination, and detailing. It should not replace the approved fabrication drawing or project-specific dimensional verification.