ASME B16.48 vs. B16.5 vs. B16.47: Key Differences for Flange Buyers

When sourcing ASME flanges, choosing the correct standard is essential for dimensional compatibility, pressure rating and project compliance. ASME B16.5, B16.47 and B16.48 are often mentioned together, but they cover different products and applications.

For flange distributors, stockists and project buyers, understanding these differences helps prevent specification errors, avoid mismatched components and make purchasing decisions with greater confidence.

1. ASME B16.5 vs. B16.47 vs. B16.48: Quick Comparison

These ranges summarize the published scopes of the standards. The applicable requirements for each product must be checked against the specified edition and relevant tables. ASME B16.5 Class 2500, for example, has a smaller maximum size than the other listed classes.
Sources: ASME B16.5, ASME B16.47, ASME B16.48.

2. ASME B16.5: Pipe Flanges

ASME B16.5 covers pipe flanges and flanged fittings in NPS 1/2 through NPS 24. Its scope includes pressure-temperature ratings, materials, dimensions, tolerances, marking, testing and requirements related to flange joints.

Common products supplied to applicable B16.5 requirements include:

• Weld neck flanges
• Slip-on flanges
• Blind flanges
• Socket weld and threaded flanges
• Other flange types within the standard’s scope

The standard includes Class 150, 300, 400, 600, 900 and 1500 flanges within its specified size range. Class 2500 is covered through NPS 12 for flanges.

For distributors and stockists, B16.5 is particularly relevant when building inventory for common industrial piping sizes. However, matching the nominal size and class alone is not sufficient. Material grade, facing, dimensions and the applicable pressure-temperature rating must also be confirmed.

When to specify B16.5: When purchasing standard-size pipe flanges or flanged fittings within NPS 1/2–24, subject to the particular product’s scope.

For product options and quotation support, visit the JS FITTINGS ASME B16.5 flange product range.

3. ASME B16.47: Large-Diameter Steel Flanges

ASME B16.47 covers large-diameter steel flanges from NPS 26 through NPS 60. It addresses pressure-temperature ratings, materials, dimensions, tolerances, marking and testing.

The standard covers pressure classes 75, 150, 300, 400, 600 and 900.

One important detail for buyers is that B16.47 includes Series A and Series B flange dimensions. These series can differ in flange dimensions and bolting arrangements. A Series A flange should not automatically be treated as interchangeable with a Series B flange of the same nominal size and pressure class.

Large-diameter flanges are relevant to major piping systems in oil and gas, petrochemical plants, power generation and other industrial facilities.

For distributors handling large-diameter orders, confirm the following before requesting a quotation:

• Nominal size and pressure class
• Series A or Series B
• Material grade
• Facing and connection requirements
• Applicable standard edition
• Quantity and required documentation

When to specify B16.47: When the required steel flange falls within NPS 26–60 and the project specifies this standard.

Do not select B16.47 simply because a flange is physically large. The specified standard and mating equipment requirements determine the correct product.

For product options and quotation support, visit the JS FITTINGS ASME B16.47 flange product range.

4. ASME B16.48: Line Blanks

Unlike B16.5 and B16.47, which cover pipe flanges and associated requirements, ASME B16.48 specifically covers operational line blanks installed between ASME B16.5 flanges.

ASME B16.48 spectacle blind flange

The standard addresses pressure-temperature ratings, materials, dimensions, tolerances, marking and testing for line blanks in NPS 1/2 through NPS 24, with pressure classes 150, 300, 600, 900, 1500 and 2500.

Line blanks include configurations such as paddle blinds and spacers, as well as spectacle-blind arrangements within the applicable scope.

These components are used to establish a positive physical barrier or an open flow path, depending on the selected configuration and installation. They are common in process piping where isolation arrangements must be managed during maintenance or operational changes.

When ordering line blanks, buyers should confirm:

• Whether a solid blind, spacer or spectacle blind is required
• Nominal size and pressure class
• Compatibility with the mating B16.5 flanges
• Material and facing requirements
• Dimensions and thickness specified for the application
• Marking and inspection requirements

When to specify B16.48: When purchasing operational line blanks designed for installation between compatible ASME B16.5 flanges.

A conventional blind flange and a line blank are not automatically interchangeable. Although both may close a pipeline, their configurations and applicable standards differ.

5. How to Choose the Correct ASME Standard

For stockists and distributors, the fastest way to identify the applicable standard is to begin with the product itself.

Step 1: Identify the component.

Is the requirement for a conventional pipe flange, a large-diameter steel flange or an operational line blank?

Step 2: Confirm the nominal size.

B16.5 and B16.48 cover products through NPS 24 within their respective scopes. B16.47 covers large-diameter steel flanges from NPS 26 to NPS 60.

Step 3: Check the pressure class.

Do not assume that every pressure class is available at every nominal size. Check the applicable standard and product tables.

Step 4: Confirm dimensions and compatibility.

For B16.47, identify Series A or Series B. For B16.48, confirm the line blank configuration and the mating flange requirements.

Step 5: Specify the material and documentation.

Provide the required material grade, facing, applicable standard edition, inspection requirements and quantity. These details help suppliers review the specification accurately.

6. What Flange Distributors Should Confirm Before Ordering

For inventory replenishment and project supply, a clear inquiry helps reduce repeated technical questions and quotation delays.

Prepare a size-and-quantity list wherever possible. Include the applicable standard, pressure class, material grade, facing type and any project-specific requirements.

For large-diameter flanges, state the required B16.47 series. For line blanks, specify the exact configuration rather than using “blind flange” as a general description.

If the specification is incomplete, provide the customer’s drawing or technical datasheet for review before placing the order.

7. Source Industrial Flanges from JS FITTINGS

Established in 1983, HEBEI JINSHENG PIPE FITTING MANUFACTURING CO., LTD. (JS FITTINGS) supplies industrial steel flanges and pipe fittings for overseas distributors, stockists, trading companies and engineering projects.

When sourcing flanges, send us your required sizes, pressure classes, material grades, applicable standards and quantities. Our team can review the stated requirements and clarify the technical details needed for quotation.

Need a flange quotation for stock or a project?

Visit our Blind Flange Product Page or contact our team with your size list and specifications.

Email: admin@jsfittings.com
WhatsApp: +86 180 0311 9682

Frequently Asked Questions

Is ASME B16.47 the same as ASME B16.5?

No. B16.5 covers pipe flanges and flanged fittings through NPS 24 within its scope, while B16.47 covers large-diameter steel flanges from NPS 26 through NPS 60.

Does ASME B16.48 cover blind flanges?

B16.48 covers operational line blanks installed between ASME B16.5 flanges. A conventional blind flange is covered within the relevant flange standard’s scope, rather than being treated as interchangeable with every line blank configuration.

Can B16.47 Series A and Series B flanges be interchanged?

Not automatically. Their dimensions and bolting arrangements can differ. Confirm the series specified by the project and the mating flange before ordering.

Which information is needed for an ASME flange quotation?

Provide the product type, nominal size, pressure class, material grade, facing, applicable standard, quantity and any required drawings or inspection documents.