Cylinder safety

Refrigerants are packaged in both disposable and returnable cylinders; both types meet certain Department of Transportation (DOT) specifications.

Disposable cylinders are just that, disposable, and should never be refilled with anything.

Returnable cylinders have a liquid-vapor valve located on the top. A returnable cylinder should never be filled above 80% of the cylinder volume. If the cylinder is going to be exposed to temperatures higher than 130ÞF, it should not be filled above 60%.

Yet daily, we get cylinders that are filled to 100% of their capacity. Recently I had a 123-lb cylinder (commonly called a 150-lb cylinder) dropped off that weighed in at 207-plus lb. Water capacity on the cylinder was 123 lb, tare weight was 49 lb. Do the math!

The contractor brought it in on his pick-up truck, lying down on its side. There were indications that the safety relief had released some refrigerant.

Hydrostatic pressure can be a killer. While pressure relief safety devices provide some safety, they do not eliminate all risk.

Weigh cylinders on an accurate scale, and inspect them before filling. Look for dents and rust, and check the DOT certification date. If the cylinder has rust, dents, or the certification date is overdue, do not use the cylinder.

Recovery cylinders and drums must be painted gray with the shoulder portion painted yellow, per DOT regulations. Label cylinders and drums with a 4- by 4-in. green, nonflammable gas label. Label your cylinders with the type of refrigerant recovered.

Refillable cylinders must be retested and recertified every five years, with the test date stamped on the cylinder shoulder in accordance with DOT regulations. A test to see if it will hold air pressure by your local LP company does not count.

A company that has been approved by DOT to perform cylinder testing and recertification must perform a hydrostatic pressure check.

Handle cylinders with care during transport. Never lay them down on their sides, and make sure that they are firmly strapped in an upright position.

Never roll a cylinder on its base or lay it down to roll — use a wheeled device. Improper handling of cylinders can cause a sudden release of refrigerant, resulting in frostbite, blindness, or even death by oxygen depravation.

Oil, contamination

Proper care should be observed in handling oil from refrigerant equipment, which may contain hydrochloric and hydrofluoric acids, which can produce lung and skin damage.

As a refrigerant reclaimer, we see on a daily basis that some technicians and organizations are not observing some of these obvious practices.

Another area of major concern in transferring refrigerants is avoiding cross-contamination of refrigerants. Mixing of refrigerants was a big problem in 1992 through 94, then it started to get a little better. Since approximately 1997, the mixed refrigerant problem has been getting worse again.

I have talked to a lot of hvacr companies and technicians about the issue of mixed refrigerants. Under no circumstances should different refrigerants be mixed.

Some of the problems I have found are a lack of recovery cylinders on service trucks to handle all the refrigerants the technicians deal with. You should have a cylinder for every refrigerant type you deal with regularly on your vehicle. The recovery cylinder should be marked for the refrigerant type in use.

Part of the problem is improper recovery machine operation. Just because your recovery machine has an oil-less compressor with a pump-out feature, does not mean you do not have to change the drier and pull a vacuum on the recovery machine before using it on a different refrigerant type.

Proper safety and training, although required by Section 608 of the Clean Air Act, is only part of compliance. We recommend that you have a designated compliance manager. Include in your regular company meetings EPA updates and refresher courses on proper refrigerant recovery and safety.