The Problem Solver: Understanding Gas Cylinders

As I was strolling through the electronic mail last year I saved (what I thought to be) a very valuable posting at www.balloonHQ.com. Questions had been raised about helium cylinders, their ratings, sizes, safety issues, etc. A reply from Lorinda Ferrell of Continental Sales in Sacramento, California had a most interesting and informative reply. It is printed below for your own information and protection.

All the information you need is on the shoulder of your cylinder. First find the pressure that the tank is rated for, this usually follows DOT3A and then 4 numbers. Those four numbers tell you the pressure rating of your tank. Next find the last hydro test date and note if there is a “plus” and/or a “star” after the date. The “plus” tells you the tank is rated for a 10 percent overfill. The star means the tank is good for 10 years instead of 5 years before it needs hydro testing again. The first size you described is called and S and comes in two pressure ratings.

An S tank, 1800 PSI (pounds per square inch) rating and a plus is 120 cubic feet, no plus is 108 cubic feet.

An S tank, 2015 PSI rating and a plus is 135 cubic feet; no plus is 123 cubic feet.

The next size up comes in two pressure ratings, but one is a K and one is a KH.

A K tank, 2015 PSI rating and a plus is 217 cubic feet; no plus is 200 cubic feet.

A KH tank, 2265 PSI rating and a plus is 244 cubic feet; no plus is 219 cubic feet.

A T tank, 2400 PSI rating and a plus is 291 cubic feet; no plus is 265 cubic feet.

Your next problem is that just because a tank is rated for a 10 percent overfill, that does not mean that they are filling it that way, that is the maximum they can fill it. When you get your K/KH tank back, check the PSI (at 70 degrees F), or better yet have them check it for you. If your PSI is:

2015 - 200 cubic feet
2215 - 217 cubic feet
2265 - 219 cubic feet
2490 - 244 cubic feet

Also remember that gauges get out of adjustment easily, so you might want to check it on something you know first to make sure it is reading correctly. We keep the ones we use for gauging tanks bolted to the wall, it only takes a couple of times dropping them before they aren’t very accurate. We no longer deliver helium tanks, so I am no longer really current on the transportation of cylinders. The DOT (Department of Transportation) requires placarding when hauling 1000 pounds or more. Tank weights are as follows:

 "S"        135   70 pounds
 "K/KH" 219/244  140 pounds
 "T"        291  160 pounds
 40 cf aluminum   19 pounds
 55 cf aluminum   25 pounds
 88 cf aluminum   32 pounds

I am sure the state regulations vary. In California, to haul more than 1000 pounds you need a different Class driver’s license and a permit from the California Highway Patrol. And who knows what other requirements they have now.

The only other thing I can add is that everybody seems to want a manifest in the vehicle, even if you are hauling less than 1000 pounds, it is strongly recommended. If your vehicle is in a crash and cylinders get loose, they want to know how many were on the vehicle at the time. They also want the DOT designation for what you are hauling which is “Helium, Nonflammable Gas UN1046”. We just incorporated the cylinder information as part of the mileage log in the vehicle, so even when we weren’t placarded, there was always a current count of the cylinders in the vehicle.

As far as discovering the specifics of the regulations for your state, I found the Highway Patrol very informative and helpful.

Hope this helps.

Lorinda Ferrell, CBA

Continental Sales, Sacramento, CA USA

Wholesale Distributor for the Professional Balloon Artist

For customer service: 800-350-4386, Sales@ContSales.com