top of page

Accredited Certifications, Diplomas, and Courses for over 300,000 Technicians nationwide

Safety Measures in HVAC Industry

EPA 608 Core Chapter 11

Safety Equipment

In this module, we will take a look at the different safety procedures that need to be followed in the HVAC practices. Skip to quiz!


Technicians need to take care when handling refrigerants because they can be toxic and can be potentially life threatening.

Liquid refrigerants can cause frostbite because of the low temperatures that they can reach. This is why technicians need to wear clothing that covers all parts of the body.

Safety Attire

When handling refrigerants, the following needs to be worn:

  1. Safety Glasses

  2. Safety Shoes

  3. Butyl-lined Gloves

  4. Long sleeve Shirt

However, just wearing safety attire does not guarantee safety. Technicians must also follow all necessary safety precautions for the refrigerant and the equipment.

In HVAC systems, you will often find a sight or viewing circular glass connecte

d on the liquid line. This is a tool to let the technician see if the refrigerant is in liquid or vapor phase.

If you see that the glass is clear on a system that is running, that means the refrigerant is liquid. If there are bubbles, the refrigerant is in its vapor phase.

Ice or dirt may form on this sight or viewing glass due to low temperature. If this happens, the technician should use an alcohol spray to remove the ice or dirt from the sight or viewing glass.

Do not:

  1. Chip at the glass to break the ice, and

  2. Do not use tools to get rid of the ice.

Chipping at the glass risks breaking it, which releases refrigerant. This would be considered venting under Section 608 Regulations, which we discussed earlier. If this happens, you have a much bigger problem on your hands.

Safety Data Sheets (SDS)

Each refrigerant will come with a Safety Data Sheet (SDS). This sheet contains important safety information and is provided for all solvents or chemicals, including refrigerants.

A refrigerant’s SDS provides special instructions for emergency procedures that are specific to that refrigerant. Technicians need to review this sheet before servicing.

This sheet includes specific information on:

  1. Protective equipment

  2. Toxicity

  3. First Aid

  4. Health effects

  5. Storage

  6. Disposal procedures

  7. Spill Procedures.


Safety Precautions

This module will look at the different safety precautions that need to follow in the HVAC practices. Skip to quiz!

Oxygen Deprivation

When handling refrigerants, our first priority is always safety. Wearing the correct safety attire is important in preventing frostbite from contact with the refrigerant. But it is only the first step.

Other dangers to HVAC technicians are falls and electric shocks. This is because technicians have to get on ladders to access components and have to work with electrical parts.

But did you know that the number one cause of refrigerant-related deaths is actually oxygen deprivation?

Technicians work with refrigerant gases that are odorless and invisible. So it can be hard to tell refrigerant has leaked.

What ends up happening is that because these refrigerants are denser than oxygen, they sink to the bottom of the room, pushing oxygen to the top. Imagine a lava lamp that is settled. The oxygen you need to survive is floating at the top, and you and the refrigerant are at the bottom.

Without oxygen, you will suffocate. This is why oxygen deprivation is the number one cause of death in handling refrigerants.

If refrigerants are inhaled in high concentrations, they can cause heart irregularities and/or unconsciousness. This is dangerous because if the technician is unconscious, then this can also lead to oxygen deprivation.

For all of these reasons, safety procedures need to be taken seriously.

If refrigerants are released in a contained area, you need to either:

Wear a Self-contained breathing apparatus (SCBA), or

Leave the area

If refrigerants are released in a contained area, normal protection is not sufficient. This includes safety goggles, butyl-lined gloves, and dusk masks.

Self contained breathing apparatus (SCBA) are heavy duty equipment designed to specifically prevent oxygen deprivation. If you cannot locate one, you must leave and evacuate the area.

Pressurized Substances

If you are pressurizing equipment, you need to verify the equipment’s allowable test pressure. This design pressure information will be on a nameplate located on the equipment. You should check for the low-side test pressure value.

If you find corrosion on the body of the relief valve, you must replace the valve. The purpose of the relief valve is to protect against too much pressure in the compressor.

If the relief valve is corroded, it will not be able to prevent catastrophic failure in the compressor in the case of too much pressure. That is why the relief valve needs to be replaced if corrosion is found.

When checking for leaks, technicians should never use oxygen or compressed air to pressurize appliances. This is because oxygen or compressed air can explode when mixed with compressor oil or refrigerants.

Oxygen cannot be mixed with oils for this reason. Oxygen also cannot be mixed with any grease, which act like oils.

Recall that the best way to test for leaks is with dry nitrogen. When charging a system with nitrogen, you need to charge through a pressure regulator. This means that you need a relief valve to make sure pressure is not too high.

Prior to pressurizing a system with nitrogen, you should always install a pressure relief valve on the nitrogen cylinder. This acts as a safety measure in case the pressure is too high in the tank.

You will also need to make sure that this relief valve is installed downstream from the pressure regulator.


Handling Flammable Refrigerants

This module will look at the different techniques that need to follow while handling flammable refrigerants. Skip to quiz!

Brief Review: Flammable Classes

Recall that there are three flammability classes: 1, 2 and 3. The flam

mable classes are 2 and 3, with 2 being low flammability, and 3 being high flammability.

Examples of A3 refrigerants (low toxicity, high flammability) are hydrocarbons. This includes propane (R-290) and isobutane (R-600a).

Equipment Color Markings

If a refrigerant is flammable, there are special requirements for the equipment that it is used in. This includes refrigerants in class 2 (low flammability) and class 3 (high flammability).

If flammable refrigerant is used, the process tubes and piping that it passes through have to be marked red. Any places where there is a service connection to the flammable refrigerant also have to be marked red.

These places are marked red so that technicians can take precautions when handling those areas of equipment.

The red marking must extend at least one inch in both directions for all process tubes, pipes, and service connections with flammable refrigerants.

So as an example, all process tubes, pipes and service connections for propane (R-290) and isobutane (R-600a) will need to be marked red, with a minimum of one inch in both directions.


When recovering any flammable refrigerant, you have to make sure that your equipment is grounded.

Your equipment uses electricity and we want to minimize the possibility of any charge interacting with the flammable refrigerant. Grounding your equipment will reduce the risk of electrical fires.

Flammability Limits

With flammable refrigerants, we have to consider their

  1. Lower Flammability Limit, and

  2. Upper Flammability Limit

The Lower Flammability Limit is the lowest concentration of a refrigerant that will cause the refrigerant to sustain a flame.

This is because the refrigerant molecules are spread too thin for the fire to continue to burn through. If the amount of the refrigerant in the air is less than this limit, the refrigerant will not sustain a flame.

The Upper Flammability Limit is the highest concentration of a refrigerant that will cause the refrigerant to sustain a flame. This may be counterintuitive. How can there be too much refrigerant if it is flammable?

Recall that burning requires oxygen. If there are too many refrigerant molecules, there will not be enough oxygen for all the refrigerant molecules to burn.

But if the concentration is higher than the Lower Flammability Limit and lower than the Upper Flammability Limit, then the refrigerant can burn or explode.

If the concentration is higher than the Lower Flammability Limit and lower than the Upper Flammability Limit, then the refrigerant can burn or explode. But even so, a flame source is still needed for the refrigerant to burn or explode.

For example, we know that hydrocarbons are highly flammable. If there is a sufficient concentration of hydrocarbon refrigerant in a space, and there is an ignition source, this will likely lead to an explosion.

That is why it is important that technicians do not use flames near refrigerant cylinders.

To reiterate, if you are using flammable refrigerants, do not:

  1. Apply an open flame or steam to a refrigerant cylinder

  2. Cut or weld any refrigerant line when refrigerant is in the unit

These can provide the ignition source that the refrigerant needs to burn or explode.


Handling Cylinders

In this module, we will discuss how to use refrigerant cylinders. We will also discuss specific safety procedures for the different types of cylinders. Skip to quiz!

Cylinder Overview

Refrigerant cylinders are containers used to hold and store refrigerants. They are also known as refrigerant canisters or refrigerant drums.

We need specialized containers to hold refrigerants because refrigerants

  1. Need to be pressurized

  2. Can be highly toxic

  3. Can be highly flammable, and

  4. Can be corrosive

This is why we cannot use just any container to store refrigerant.

Because the contents of the containers are pressurized, we need to be careful with how we handle and store these cylinders.

Cylinders with flammable refrigerants will still have a red band on top of the container.

All of these requirements apply to both

  1. Disposable Cylinders, and

  2. Recovery Cylinders

We will discuss these cylinder types in greater detail in later modules.


First and foremost, we must make sure that any cylinder with refrigeran

t should never be heated with a flame. If heating is needed for servicing, you can use a heating blanket instead.

If refrigerant cylinders are exposed to flames, this can lead to:

  1. Explosions

    1. Causing serious injury

  2. Venting refrigerants

    1. Which is illegal

  3. Decomposition of the refrigerant

    1. The refrigerant inside the cylinder will become a toxic material

Cylinder Requirements

For safety reasons, we need to make sure that all refrigerant cylinders are:

  1. Free of rust and damage

  2. Clearly labeled

  3. Secured

  4. Stored properly

Before handling refrigerant cylinders, technicians need to make sure that the cylinder is not rusted or damaged in any way. If you see signs of rust or damage, the cylinder is no longer safe to use.

For cylinders with rust and damage, you need to:

  1. Retrieve the refrigerant inside the cylinder, then

  2. Dispose of the damaged cylinder.

You can place the retrieved refrigerant in a new cylinder to store it.

All refrigerant cylinders need to be clearly labeled with the following information:

  1. Refrigerant Type

    1. e.g. R-12

  2. Chemical Name

    1. e.g. Trichloromonofluoromethane, and

  3. UN Number

    1. eg. UN1078

A refrigerant UN Number is just like its regular ASHRAE number. The UN Number is specific for the international transport of dangerous chemicals.

Refrigerant cylinders need to be clearly labeled in order to:

  1. Avoid mixing refrigerants

  2. Identify contents for recyclers

  3. Identify the amount of refrigerant for record keeping purposes

Refrigerant cylinders need to be secured at all times to prevent tipping, falling, and rolling. This can be done by using straps that attach to a wall bracket or by using a cylinder stand.

Gas cylinders need to be stored in a place that is

  1. Dry

  2. Cool, and

  3. Well-Ventilated

The Department of Transportation (DOT) is a US federal agency. The DOT decides classifications for refrigerant cylinders that are disposable or refillable.


Disposable Cylinders

In this module, we will discuss how disposable refrigerant cylinders are used and what restrictions apply to them. Skip to quiz!


Disposable cylinders are single use containers that

  1. Are made of steel, and

  2. Cannot be refilled.

They contain up to 50 lb of refrigerant.

Disposable containers are designed so that they cannot be refilled. These cylinders use a one-way valve, also called a check valve. The one-way valve allows the refrigerant to flow only out of the container and prevents anything from going into the container.

The handle of disposable cylinders surrounds the valve of the cylinder. It’s designed this way so that if the cylinder is dropped, the handle will take the brunt of the impact, instead of the valve. This way, it protects the valve from being damaged and releasing the refrigerant.

Disposable cylinders are used only for virgin refrigerant. Recall that virgin refrigerant is refrigerant that is newly manufactured.

Virgin refrigerant is different than reclaimed refrigerant. Reclaimed refrigerant is processed to the same purity standards and is basically the same as virgin refrigerant. But reclaimed refrigerant will not be stored in disposable cylinders.

Cylinder Colors

An older industry practice was to standardize the color of disposable cylinders. This was so that technicians can easily recognize the refrigerant type by its cylinder color. As of January 2020, this is no longer the case.

Recall that AHRI stands for Air-Conditioning, Heating, and Refrigeration Institute. They are a trade organization that represents the HVAC industry. And it was AHRI who had previously set the standard colors for refrigerant cylinders.

AHRI includes refrigerant manufacturers, who produce these disposable refrigerant cylinders.

AHRI revised its Standard N to stop the use of different colors to denote different refrigerants on cylinders. This is because there are more and more refrigerants that are used in the industry and it got confusing for technicians. More than half of technicians in an AHRI survey found the colors designation confusing.

So as of January 2020, we no longer use colors to recognize different refrigerants. All cylinders now have a light green gray color. Specifically, this color is RAL 7044.

The standardized colors will still be used on printed materials including the labels that are affixed on the cylinders.

Disposal Procedure

If you are disposing of a disposal cylinder, you must:

  1. Evacuate the cylinder

  2. Reduce pressure to 0 psig

  3. Puncture the cylinder, and then finally

  4. Recycle the metal scrap

If you are disposing of a disposal cylinder, you must evacuate the refrigerant still inside by using a recovery device.

You need to make sure that the pressure of the cylinder is 0 psig before scrapping it.

After checking that the pressure is 0 psig, you need to puncture the cylinder so that it cannot be reused. You have to puncture the refrigerant with its one-way valve open.

We do this because a refrigerant cylinder is pressurized. If it is abandoned and left to deteriorate, it can explode and cause injury.

After this disposal procedure is completed, you can recycle the used cylinder with other scrap metal.


Recovery Cylinders

In this module, we will discuss how recovery cylinders are used. We will also discuss specific safety procedures for the recovery cylinders. Skip to quiz!


Refillable cylinders are called recovery cylinders.

Recovery cylinders have a

  1. Gray body, and

  2. 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.

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.

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:

  1. Mechanical float devices

  2. Electronic shut-off devices, and

  3. 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:

  1. Type of refrigerant, and

  2. 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.

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.



In our last module for Core, we’ll go over considerations we have to make when shipping refrigerant cylinders. Skip to quiz!

Department of Transportation (DOT)

The Department of Transportation (DOT) is a federal agency that is in charge of regulating all modes of transport in the US.

We previously mentioned that the DOT is in charge of regulating refrigerant labels.

This is because refrigerants are considered hazardous materials. Since they are hazardous, they are a safety risk while being transported.

If not handled properly, refrigerant chemicals can explode and cause injury or worse, as we discussed in the safety modules. The DOT regulates how refrigerants can be transported in order to protect workers who handle it and the general public.

All safety information for refrigerant chemicals can be found in their Safety Data Sheets (SDS). This used to be known as the Material Safety Data Sheet (MSDS).

Refrigerant Label

The DOT requires that cylinders containing used refrigerant be properly labeled if it is

  1. Shipped, or

  2. Sent to be reclaimed

If you are sending recovery cylinders with refrigerant to be reclaimed, the DOT requires that you provide a label with the following information:

  1. Type of refrigerant (e.g. R-22)

This label is an example of one that should be put on your recovery cylinder.

The purpose of labeling is to

  1. Avoid accidentally mixing refrigerants

  2. Allow recyclers to identify cylinder contents

  3. Help technicians and owners with mandatory Section 608 record keeping requirements

Shipping Instructions

Before shipping any refrigerant cylinder, make sure that they are properly labeled.

According to safety regulations, refrigerant cylinders need to be shipped upright. Cylinders also need to be secured to ensure safe transport.

When transporting recovered pressurized refrigerant, the DOT requires the use of cylinders designated as “refillable”. If the cylinder is not designated as “refillable”, it cannot be used to transport recovered refrigerant that is pressurized.

If you are shipping cylinders that contain used refrigerant, the DOT requires that you attach DOT Classification Tags, as pictured here.

DOT classification tags are separated by class and indicate the hazard level of the substance. For example, refrigerant gases would fall under Class 2, which is gases. There are special icons on the tags that indicate whether the gas is flammable or non-flammable.

Recall that only recovery cylinders can be used to recover refrigerant. These are the cylinders with a gray body and a yellow top. Other than recovery c

ylinders, no other types of cylinders can be used to recover refrigerant.

For Hazard Class 2.2 chemicals, which are non-flammable compressed gases, the DOT requires the following information on the shipping paper:

  1. The number of cylinders of each gas

All state DOTs may also have separate requirements for shipping refrigerants. Technicians also need to check all state and local laws and regulations when shipping refrigerant chemicals.


Question #1: Where can you find any safety related information on refrigerants you’re handling?.

  1. Safety Information Sheets

  2. Safety Data Sheets

  3. Material Data Sheets

  4. All of these

Scroll down for the answer...

Answer: Safety Data Sheets

Important safety information is contained in refrigerants’ safety data sheets (SDS).

Question #2: When sending used refrigerants to be reclaimed, you must use disposable refrigerant cylinders.

  1. True

  2. False

Scroll down for the answer...

Answer: False

When transporting used refrigerants to be reclaimed, we should only use refillable recovery cylinders.

We should not use disposable refrigerant cylinders for sending used refrigerant to be reclaimed.

Question #3: What information needs to be on the label of a container sent for reclamation?

  1. Refrigerant type

  2. Date manufactured

  3. Cylinder type

  4. All of these

Scroll down for the answer...

Answer: Refrigerant type

Cylinders sent to be reclaimed must have a label indicating the type of refrigerant. For example, if we are reclaiming R-22, the label must say R-22 on it.

Question #4: When shipping refrigerant that has been used, we must use do which of the following?

  1. Attaching DOT classification tags

  2. Use recovery cylinders

  3. Properly label contents

  4. All of the above

Scroll down for the answer...

Answer: All of the above

All of the options are necessary when shipping used refrigerant.

Question #5: What position must you ship cylinders of refrigerant in?

  1. Facing the driver

  2. Upside down

  3. Upright

  4. It depends on the type of cylinder.

Scroll down for the answer...

Answer: Upright

When shipping refrigerant, we always use recovery cylinders and place them upright, securing them in place to prevent from tipping.

Question #6: When shipping refrigerants in hazard class 2.2, what information needs to be on the shipping paper?

  1. Number of molecules in the cylinder

  2. Number of times the refrigerant has been used

  3. Number of refrigerants in the cylinder

  4. Number of cylinders of each gas.

Scroll down for the answer...

Answer: Number of cylinders of each gas.

When shipping refrigerants that are classified as hazard class 2.2, the shipping papers must indicate the number of cylinders of each gas.


bottom of page