This reference page provides the published dimensions and bolt information for a Blind Flange 12 Inch Class 300. Use the source values for preliminary drafting, flange identification, procurement review, and piping layout coordination.
A blind flange has no center bore, so it closes a flanged connection rather than passing fluid through the flange. It may be installed at a pipe end, equipment connection, valve connection, or planned future branch. Before purchase or installation, compare the flange details with the connected flange, gasket, fasteners, facing, material specification, and project requirements.
Blind Flange 12″ Class 300
Blind Flange 12″ Class 300 is used to seal the end of a piping system or close off a flange connection in Class 300 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 12″ Class 300 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS): 12″
- DN Size: DN300
- Flange Thickness: 49.3mm
- Weight: 84kg
- Stud Bolt Size: 1 1/8″ UNC (or M30) x 170 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 12″ Class 300 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 12″ Class 300, which can be used for drafting, detailing, and piping layout coordination.
Available Blind Flange Class 300 Sizes
This size is part of the Blind Flange Class 300 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, reference weight, stud bolt details, bolt count, and hole diameter. These values are useful when checking a piping arrangement, preparing a detail, or coordinating the flange with a matching component. The listed CAD/DWG file can support drafting and layout work, but the drawing should still be checked against the project specification before fabrication.
NPS, DN, and flange identification
NPS 12 and DN300 are nominal designations used to identify the connected piping size. They should not be treated as a substitute for checking the complete flange geometry. For a reliable connection review, confirm the mating flange type, facing arrangement, gasket dimensions, bolt-hole pattern, fastener specification, and available clearance.
Understanding the Class 300 designation
The Class 300 designation identifies the flange pressure class within the applicable flange system. It is not, by itself, a universal allowable working pressure for every service condition. Pressure-temperature limits depend on factors such as material, temperature, design code, gasket selection, and the piping system specification. Use the applicable engineering requirements rather than selecting a flange from the class label alone.
Bolt and installation checks
- Confirm that the stud bolt size and length match the mating flange, gasket arrangement, washers, and joint configuration.
- Verify that the specified UNC fastener and the alternative metric designation are acceptable for the project; do not mix systems without engineering or procurement approval.
- Check the hole diameter and bolt count against the mating flange before ordering or drilling any component.
- Use the project tightening procedure and verify that the joint is suitable for the intended service and isolation duty.
Related piping references
For broader design and drafting work, pair this page with the site’s references for flange dimensions, pipe schedules, flange types, piping terminology, and CAD/DWG resources. These related topics help connect the blind flange dimensions with the pipe, fittings, valves, and equipment shown in the same assembly.
Frequently Asked Questions
What is the listed thickness of the Blind Flange 12 Inch Class 300?
The source data lists a flange thickness of 49.3mm.
How much does the Blind Flange 12 Inch Class 300 weigh?
The listed reference weight is 84kg. Confirm the final supplied component against the manufacturer’s documentation and material specification.
What bolt size is specified?
The source lists 1 1/8" UNC (or M30) x 170 Long stud bolts, with 16 bolts and a listed hole diameter of 1 1/4" (31.75mm).
Does a blind flange have a center opening?
No. A blind flange is solid across its face and is used to close a flanged connection or piping end.
Is a Class 300 blind flange suitable for every Class 300 service?
No. Confirm the material, temperature, pressure-temperature rating, gasket, facing, fasteners, and project design requirements before use. The class designation alone does not complete the engineering selection.
Is a CAD file available for this flange?
Yes. The page includes a DWG download identified for the Blind Flange 12 Inch Class 300. Review the drawing and coordinate its geometry with the project’s approved dimensional information before fabrication.