This 18 inch Class 300 blind flange reference brings together the published dimensional data, bolt information, weight, and CAD resource for a closed-end flange connection. Use it as a drafting and coordination reference when checking piping layouts, equipment connections, and maintenance isolation details.
The page also explains how to interpret the flange information without treating nominal size, pressure class, bolting, gasket selection, or material specification as interchangeable design decisions. Confirm the project requirements before fabrication or installation.
Blind Flange 18″ Class 300
Blind Flange 18″ 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 18″ Class 300 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS): 18″
- DN Size: DN450
- Flange Thickness: 58.7mm
- Weight: 181kg
- Stud Bolt Size: 1 1/4″ UNC (or M33) x 195 Long
- Number of Bolts: 24
- Hole Diameter: 1 3/8″ (34.925mm)
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 18″ 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 18″ 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
A blind flange has no center opening, so its primary function is to close a flanged piping or equipment connection. Unlike a flange intended to connect directly to an open pipe bore, the blind pattern forms a solid termination that can be removed when access, inspection, maintenance, or future modification is required.
Key Information to Check
- Nominal size: Use the stated NPS and DN designations to coordinate the flange with the piping system and related components.
- Class: Treat the Class 300 designation as part of the flange selection and rating context. The applicable pressure-temperature limits still depend on the project specification, material, service, and governing requirements.
- Bolting: Check the listed stud bolt size, length, bolt quantity, and hole diameter against the mating flange, gasket arrangement, and installation requirements.
- Thickness and weight: These values are useful for drawing review, material handling, support coordination, and checking whether the selected component matches the intended reference.
- Standard basis: The source identifies ANSI / ASME B16.5 as the reference standard. Confirm that the project specification calls for the same standard basis before using the data for procurement.
Related Reference Topics
For broader piping coordination, link this page to the site’s blind flange dimensions, Class 300 flange references, flange types and terminology, stud bolt size guides, and piping CAD and DWG resources. These related references help users compare connection types and locate matching components without confusing a blind flange with a weld neck, slip-on, or threaded flange.
Drafting and Installation Considerations
Use the downloadable DWG for layout and detailing support, then verify the mating flange face, gasket, bolt assembly, material specification, and access requirements against the project documents. A drawing reference should not replace an engineering review of pressure-temperature rating, loads, corrosion allowance, fabrication requirements, or safe isolation procedures.
Frequently Asked Questions
What is an 18 inch Class 300 blind flange?
It is a solid, no-bore flange used to close the end of a piping system or blank a flanged connection. The page provides the source-listed dimensions, weight, bolting information, and CAD file for this configuration.
Does a blind flange have a center bore?
No. A blind flange is solid across the center. It closes the connection rather than providing a passage for fluid through the flange.
Can this blind flange be used for any Class 300 piping system?
Not automatically. Confirm the applicable material, gasket, bolting, pressure-temperature requirements, mating flange details, and project specifications before selection or installation.
What information should be checked before ordering?
Check the nominal size, flange class, thickness, weight, stud bolt details, bolt quantity, hole diameter, reference standard, material specification, gasket requirements, and required CAD or fabrication documentation.
Is a CAD file available for this flange?
Yes. The source content includes a DWG download for the 18 inch Class 300 blind flange. Use it for drafting and coordination, and verify critical dimensions against the approved project documentation.