EPA 608 Core Chapter 45 (Take full course for free)
In this module, we will discuss how recovery cylinders are used. We will also discuss specific safety procedures for the recovery cylinders.
1. Definition
Refillable cylinders are called recovery cylinders.
Recovery cylinders have a
Gray body, and
Yellow top
So if you see any cylinder that fits this description, you know that the refrigerant inside has been recovered.
Cylinders used to recover refrigerant have to be specifically designed to be refilled. This is because refrigerants are pressurized and can be flammable or corrosive.
Recovery cylinders can only be used for one refrigerant. For example, if you use a recovery cylinder for R-410a, you can only recover R-410a with that tank. This is to prevent contamination or mixing of refrigerants.
2. Hydrostatic Tests
All refillable cylinders that are under high pressure must be hydrostatically tested. During this testing, refrigerant inside will first be recovered and the cylinder will be evacuated.
The refillable cylinder will then be filled with a fluid that is dyed. This test is done to access the cylinder’s strength and for any leaks.
For example, say you have a cup that is cracked and you don’t know where. If you fill it with water, you will see where water leaking from the cup.
All refillable containers for refrigerants must be hydrostatically tested every 5 years.
3. Filling Recovery Cylinders
New or empty recovery cylinders come pre-charged with dry nitrogen. This is to prevent the cylinder from rusting.
This also means that before recovering any refrigerant in a new cylinder, you’ll need to evacuate the cylinder to get rid of the dry nitrogen. This step is important, because otherwise, you’d be mixing your refrigerant with the dry nitrogen in the cylinder.
When filling a refillable container, you must take care to not fill beyond 80% capacity. This is because the refrigerant is pressurized.
If the storage area gets too hot, the pressure inside the cylinder will increase and can cause an explosion. By leaving 20% capacity free, you are letting the refrigerant have wiggle room for that scenario.
So to reiterate, we want to fill the tank at 80% capacity to prevent explosions in the case of increased pressure in the cylinder.
Think about holding a glass of water. If the glass of water is 100% full and it reaches all the way to the rim of the cup, you’ll have a hard time moving it anywhere without spilling. But if you leave about an inch of room, you can move the cup without splashing water on yourself.
Now, when we talk about 80% capacity, we can think of this easily in terms of a liquid. But for vapor refrigerant recovery, we have specific tools that will tell us what 80% capacity is.
When recovering vapor refrigerant into the cylinder, we can control the fill level by using:
Mechanical float devices
Electronic shut-off devices, and
Gross cylinder weight
We cannot use sight glasses to determine fill capacity.
Mechanical float devices are also called float switches. They consists of a part that floats when a certain desired ratio is reached. In this case, it would be 80% capacity.
An electronic shut off device contain sensors that can tell when a certain threshold has been reached. When 80% capacity has been reached, it stops the recovery.
And finally, when recovering vapor refrigerant, we can just weigh the refrigerant cylinder to see how much has been recovered and stop at 80% capacity. The cylinder capacity should be indicated on a sticker on its body. Just multiply this number by 0.8.
Don’t forget to tare to account for the cylinder body’s weight!
When recovering refrigerant, technicians need to clearly label the:
Type of refrigerant, and
Amount of refrigerant
Recall that these are all proper record keeping requirements required under Section 608.
Properly labeled cylinders are necessary to ensure that refrigerants are not accidentally mixed. The labels will also allow recyclers to identify the contents of the cylinders.
4. DOT Regulations
As we mentioned before, it is not the EPA that decides what containers are refillable. It is the Department of Transportation (DOT) that makes this designation.
To reiterate, it is the DOT that designates which cylinders are refillable. And only refillable cylinders can be used to transport refrigerant. This is to meet the DOT’s own safety requirements on what can be transported.
If the cylinder is not designed “refillable”, it cannot used to transport refrigerant. Transporting refrigerant means just moving it from one place to another.
This can be as simple as moving it from your house to your friend’s house. For any kind of transport, the container of recovered refrigerant must be refillable, or you can be fined by the DOT.
5. Conclusion
In this module, we went over the definition of recovery cylinders. We also went over the different safety measures to take with recovery cylinders.
If recovering or transporting refrigerant, technicians need to use “refillable” cylinders, as designed by the DOT. Next we will take a look at shipping.