To:
Subject: What does the letter "M" mean?

Question:

When I look at marking on flanges I see nominal sizes like 7-1/16" and 11" followed by 5M, 10M, etc. I assume this abbreviates 5,000 psi and 10,000 psi working pressures.

Have I guessed correctly?

What does "M" mean?

Answer:

You have guessed correctly. For a full explanation, including a definition of "M", see Equipment Pressure Rating.

Information above, and in other parts of this Web Site, may help persons who really seek to know. If you have a question, and you think WOODCO USA may have the capacity to answer it, please use our link and give us a chance to help.

WOODCO USA provides Web Site Tools for identification, estimating, and reference only. Do not use this information for manufacturing or inspection. Users of these tools should not use them as a substitute for professional engineering advice.  Anyone making use of the information presented does so at his own risk and assumes any and all liability resulting from such use.