>>2907356
They're not hooked to cylinders, they're hooked to 20-80ft tall pressure vessels. It's part of a sampling system, after the regulator they connect a small cylinder the size of a beer can and then send that to a lab to make sure the product is in spec. This is a place that makes gases among other things. But I've been to other facilities with similar setups that will have seperate valves(usually 2 in a row) with a gauge on the inlet and outlet. It's not like they wandered around their fab shop and realized they can save a few hundred bucks per station by repurposing a non standard valve.