Most serious accidents occur about three years after people have started working as hvacr technicians. At that point, they seem to think they know everything and start taking risks.

They take shortcuts, such as leaving safety glasses in the vehicle.

Another example is carrying a toolbox, refrigerant drums, and other material up a 20-ft ladder using one hand. This is dangerous, and has caused serious injury.

•  Always use a rope to pull up this material.

•  Any job requiring moving heavy machinery requires at least two people.

•  Also, working alone on a roof or in an empty building should be avoided. If you must work under these conditions, have someone check on you, in person or by roam phone, every hour. Don’t take chances.

•  Another tip is to wear nonskid shoes (not leather soles), particularly where oil or plastic granules could be on the floor. Steel-tipped shoes also are recommended.

•  Avoid loose clothing, such as unbuttoned sleeves or shirt tails out. Any moving machinery (fans, compressor shafts, pulleys, etc.) can and has caused serious injury.

•  Long-sleeved shirts will protect you from hot compressor discharge lines and pipes. Earrings, bracelets, and loose neck chains also can be hazardous. If you have long hair, cover it with a cap for your own protection.

•  Most don’t think about this, but from the moment a technician starts his vehicle, he is sitting on a potential time bomb due to the cylinders of refrigerant and acetylene he is carrying. Secure these tanks from rolling around and make sure all valves are tightly closed.

•  Don’t rely on the refrigerant drum rupture disc. An over-charged refrigerant drum could explode if left in a hot vehicle.

Some service companies purchase large cylinders of refrigerant and recharge this refrigerant into smaller drums to save money. This is not only illegal, it is dangerous.

Refrigerant drum

This service call reveals a system that is undercharged, requiring leak repair and recharging. The leak is found and corrected.

You have other calls and decide to quicken the recharging by heating the refrigerant drum with a turbo torch. Since you have inverted the drum, you are driving raw refrigerant into the compressor low side with the compressor running.

Wow! Goodbye crankcase oil. It is possible to drive the crankcase oil into the compression chambers, which could cause broken valve reeds or worse. (Always charge a system into the low side as a gaseous vapor with the compressor running. Even then, watch for oil turbulence or low oil level in the crankcase sight glass.)

Since you are heating the drum on the gaseous side, a black spot appears on the surface of the drum. You shut off the torch and feel the drum.

A blister forms on your palm. Go get your burn ointment. Another 10 sec and the drum would have exploded. A turbo torch will create heat to 2,500°F and allow metal fatigue to the point of destruction in 60 sec.

The disposable drums now in use have a wall thickness one-quarter of the returnable type years ago. Even then, you could not return these drums if they had burn marks. The safest way to warm the drum is to place it in a tub of warm water (90°), assuming the system pressure is lower than the drum pressure.