This reference page provides the listed dimensions and connection details for a Blind Flange 4 Inch Class 900. Use it when checking piping layouts, comparing flange components, or coordinating a CAD drawing with related pipe and fitting information.
The flange data below is presented as a dimensional reference. Before procurement, fabrication, or installation, compare the listed information with the project specification, material requirements, gasket selection, bolting requirements, and applicable pressure-temperature criteria.
Blind Flange 4″ Class 900
Blind Flange 4″ Class 900 is used to seal the end of a piping system or close off a flange connection in Class 900 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 900 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS): 4″
- DN Size: DN100
- Flange Thickness: 44.5mm
- Weight: 24.5kg
- Stud Bolt Size: 1 1/8″ UNC (or M30) x 170 Long
- Number of Bolts: 8
- 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 4″ Class 900 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 900, which can be used for drafting, detailing, and piping layout coordination.
Available Blind Flange Class 900 Sizes
This size is part of the Blind Flange Class 900 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 closes a flanged connection without providing a passage through the flange. In a piping layout, it can identify a permanent end closure, an equipment connection that may need isolation, or a location reserved for future work. The correct application still depends on the complete piping specification and the engineering requirements for the service.
Understanding the Listed Dimensions
- NPS and DN: These are nominal size designations used to identify the flange size in customary and metric terminology. They are reference designations rather than a statement of the flange’s actual measured outside dimensions.
- Flange thickness: This is useful when checking face-to-face space, clearances, and the connection envelope in a model or fabrication drawing.
- Stud bolt size and number of bolts: These entries help coordinate the bolted joint with the mating flange. Confirm the complete bolting specification, thread requirements, material, and installation procedure before assembly.
- Hole diameter: Use this value when reviewing bolt-hole clearance and alignment with the mating flange. It should be checked against the project’s flange and bolting requirements.
- Weight: The listed weight can support handling and layout coordination, but actual shipment or installed weight may depend on the final material, coating, and configuration.
Coordination With Related Pipe References
For a complete piping check, compare this flange reference with the mating flange, pipe schedule, gasket, valve or nozzle connection, and any applicable fitting dimensions. The downloadable CAD file can help with drafting and layout coordination, but it should be reviewed against the approved project data before fabrication.
Related internal references may include pipe schedules, flange dimensions, flange facing terminology, stud bolt references, gasket types, and CAD resources for other Class 900 flange sizes.
Frequently Asked Questions
What is a Blind Flange 4 Inch Class 900 used for?
It is used to close a flanged piping, equipment, valve, or nozzle connection. Typical project uses include isolation, maintenance access, end closure, and connection points reserved for future work.
Does a blind flange have a center bore?
No. A blind flange is a solid flange without a center bore, so it blocks the connected opening when installed with the appropriate gasket and bolting arrangement.
Can the listed bolt information be used directly for installation?
The listed stud bolt information is a dimensional reference. Confirm the mating flange, gasket, material specification, thread requirements, tightening procedure, and project installation requirements before ordering or assembly.
Is the listed Class 900 designation the complete pressure approval?
No. A flange class designation should be evaluated with the applicable material, temperature, service conditions, facing, gasket, bolting, and project requirements. The source notes should be reviewed before fabrication or installation.
Where can the CAD file be used?
The available DWG file can support drafting, piping layout, detailing, and coordination. Verify the drawing against approved project information before using it for fabrication.