This reference provides the listed dimensions, weight, bolting information, and CAD resource for a Blind Flange 18 Inch Class 900. Use the data when checking piping layouts, flange connections, equipment isolation points, and fabrication details.
The dimensional list below is the controlling local reference for this page. Before using it for procurement or fabrication, compare the project specification with the required flange material, gasket arrangement, bolt configuration, and pressure-temperature requirements.
Blind Flange 18″ Class 900
Blind Flange 18″ 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 18″ Class 900 Dimensions
- Reference Standard: ANSI / ASME B16.5
- Nominal Pipe Size (NPS): 18″
- DN Size: DN450
- Flange Thickness: 101.6mm
- Weight: 367kg
- Stud Bolt Size: 1 7/8″ UNC (or M48) x 325 Long
- Number of Bolts: 20
- Hole Diameter: 2″ (50.8mm)
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 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 18″ 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 has no center bore, so it closes a flanged piping or equipment connection rather than allowing pipe flow through the flange. In a project model, its outside dimensions, thickness, bolt-hole pattern, and mass can affect clearance, support details, handling, and alignment with the mating flange.
The nominal pipe size identifies the associated piping size, while the flange thickness and hole information support drafting and connection checks. The stud bolt information should be reviewed together with the mating flange, gasket, washers, nut arrangement, and required engagement. Do not assume that a bolt length is interchangeable across different joint configurations.
Drafting and Installation Checks
- Confirm that the flange class, nominal size, facing arrangement, and mating component match the project drawings.
- Check the bolt-hole layout and access for installation tools before finalizing equipment or piping clearances.
- Account for the listed flange weight during handling, temporary support, and maintenance planning.
- Verify the gasket specification, bolting requirements, material designation, and pressure-temperature limits against the applicable project documents.
- Use the downloadable DWG with the site’s related flange, fitting, and piping layout references to coordinate connection details.
Related Piping References
For broader design and drafting work, connect this reference with related pages covering flange dimensions, pipe schedules, gasket terminology, stud bolts, valve connections, and CAD or DWG piping resources. Comparing nearby sizes in the Blind Flange Class 900 series can also help identify the appropriate project reference, but each size should be checked from its own dimension data.
Frequently Asked Questions
What is a Blind Flange 18 Inch Class 900 used for?
It is used to close a pipe end, equipment nozzle, valve connection, or other flanged connection where a solid closure is required. The source content also identifies maintenance isolation, shutdown work, and future expansion as common contexts.
Does a blind flange have a center bore?
No. A blind flange is a solid flange without a center bore, which allows it to seal the end of a piping system or close an equipment connection.
What information is included on this page?
The reference lists the nominal pipe size, DN designation, flange thickness, weight, stud bolt size, bolt quantity, hole diameter, reference standard, and a CAD drawing download for the specified flange.
Can the listed bolt size be used without further checking?
No. Confirm the bolt length and thread arrangement against the mating flange, gasket, washers, nuts, joint design, and project requirements before ordering or installation.
Is the Class 900 designation sufficient for service selection?
No. Class designation alone should not replace a project pressure-temperature review. Confirm material, gasket, bolting, operating conditions, and the applicable engineering specification before selecting the flange for service.