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How many of you have thought these two images would ever have a place in Process Safety?
I use them as visual aids when teaching some of my RAGAGEP courses, as they place a mental image that most can grasp into the students’ heads and provide them with a valid engineering metric they can use to ensure their HAZMAT bulk containers have adequate safeguards in their basic design. These metrics are used to QUANTIFY “connection sizes” on bulk tanks where “Shutoff Valves” and/or “Excess Flow Valves” would be required.
A lot of folks never really think about the actual size of openings/connections that require a Shutoff Valve, so many are pretty surprised when they learn just how small the opening has to be and which connections require a Shutoff Valve. One such code reads… (emphasis by me)
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ALL connections to containers, except connections for
SHALL have SHUTOFF VALVES located AS CLOSE TO THE CONTAINER AS POSSIBLE. … LIQUID LEVEL GAUGING DEVICES that REQUIRE bleeding of NH3 to the atmosphere and are so constructed that outward flow will NOT EXCEED that passed by a No. 54 (0.055”) drill size opening NEED NOT be equipped with excess flow valves … GAUGING DEVICES that require bleeding of the product to the atmosphere such as the rotary tube, fixed tube, and slip tube devices, SHALL be designed so that the maximum opening of the bleed valve is NOT LARGER than No. 54 (0.055”) drill size unless provided with an EFV |