The Difference Between #150, #300, and #600 Pound Flanges

Posted by Jason Welsford on Sep 28th 2016

What is the Difference Between #150, #300, and #600 Pound Flanges?

Pressure class definitions for flanged valves can be a little confusing at first, but they're actually quite simple.  Part of the confusion in this rating system stems from the interchangeability of the pound symbol--#--the abbreviation, lb or lbs, and pound or pounds.  While all of these designate the pressure rating of the flange, none of them directly indicate the amount of pressure the flange can actually handle.  For example, a #150 pound flange rating does not correlate with 150 psig, as many people mistakenly assume.

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Jason Welsford

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Jason Welsford is the third-generation owner of the FS Welsford Company and a highly regarded expert in the valve industry. Under his leadership, has grown into a leading online platform for valves and valve-related products. Leveraging his extensive knowledge of business operations and various valve systems, Jason offers tailored solutions across diverse sectors. Known for his collaborative approach and leadership skills, he consistently ensures successful project outcomes. With a commitment to innovation and excellence, Jason continues to shape the future of the valve industry.