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Pipe fitting standards clarified: class 150 vs 150 pound fittings

Views: 5     Author: Site Editor     Publish Time: 2021-04-21      Origin: Site

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As with most piping products, the little details matter when picking the ideal pipe fittings for your piping process.

One commonly seen issue is the difference between Class 150 (CL150) fittings and 150 Pound (150# or 150LB) fittings.

While these products will share similarities, failing to choose the right product can result in safety risks and premature product failure or cause systems to fail to meet regulatory and engineering requirements.

Not sure what the differences are? Keep reading as we look at both labels and what they mean.


Stainless steel threaded pipe fittings come in various sizes and designs suited for a particular use case, environment, and budget.

Organizations have worked hard to develop standards for pipe fittings to ensure comparable designs and specifications between manufacturers and help create a consistent, predictable, and safe experience when implementing these popular products in a range of applications.

Before we dive into the specific standards relevant to categorizing stainless steel threaded pipe fittings, let’s take a moment to look at where these standards come from.

These standards are based mainly on the work of three organizations:

  • ASTM - American Society for Testing and Materials International

  • ANSI - American National Standards Institute

  • ISO - International Organization for Standardization

These professional bodies are widely trusted across the globe for standards related to stainless steel pipe products, pipe system engineering, and a range of other topics.

Taking the standards of these three groups, the Manufacturers Standardization Society (MSS) took things further by filling out gaps in standards and further clarifying definitions and requirements.

The American Society of Mechanical Engineers (ASME) standards are also derived and compiled from the standards released by all four organizations.

The most relevant stainless steel pipe fittings standards are ANSI B1.20.1 and ASTM A351.

ANSI B1.20.1 provides the considerations when categorizing pipe fittings by dimension, while ASTM A351 defines the materials and castings used within pipe fittings.

These categorical standards ensure consistency and allow engineers to select pipe fitting products with confidence that they’ll provide long-lasting and safe performance for their intended application.

By understanding these standards and the specifications they define for different pipe fitting products, you can help to avoid miscommunications while reliably sourcing comparable products across a range of manufacturers or providers.

We are a company specialized in providing comprehensive services in all processes and activities related to the construction of buildings. We are committed to providing our clients with a solution to their needs in a dynamic, suitable, efficient and effective way, anticipating the safety and benefit of our users.



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