FAQs On CO2 Cylinder & CO2 Tank Safety and Handling

Hundreds of industries rely on bulk storage amounts of carbon dioxide. Restaurants, catering companies, breweries, paintball courses, welding supply stores, and indoor plant growers all use CO2 as an integral part of their daily operations.

Because CO2 is a regulated gas with strict rules attached, hundreds of questions arise daily from regular and potential users of CO2 tanks and the organizations who provide them, complete or otherwise. Naturally, as an organization that focuses heavily on CO2 safety and measurement, we get many questions.

Typically, the questions consist of the same subjects or gravitate heavily toward the same core material. To better serve our customers, we’ve compiled a detailed set of our most frequently asked questions, all accessible from a central location for you to get immediate answers.

How are CO2 tanks and cylinders delivered?

CO2 is carried in sizeable pressurized steel cylinders. Delivery happens for use in compressed gas applications via specially designed transportable transporter-receivers and CO2 transporters.

According to the EPA, CO2 ships in a unique 'CO2 cylinder' (200, 300, or 440-pound cylinder). The cylinder and valves are brass and contain special rubber seals that form an airtight seal.

These cylinders have a safety valve at 75-100 psi that prevents the cylinder from exploding if pressure exceeds this set level. Many filling stations install a regulator on the tank that’s filled for customer pickup or distribution. Only people with proper certification/credentials can handle/fill CO2 tanks and evacuate or fill to customer standards.

Can CO2 be shipped by air?

Yes, CO2 can be delivered by air. It is a standard method used to ship gas and other hazardous materials. However, they must be appropriately labeled and are typically carried on a plane solely designated for HAZMAT transportation.

What color are CO2 cylinders?

Carbon dioxide cylinders are typically grey. However, the color of the tank is insignificant by law and is simply a suggestion. What counts the most, and is regulated by federal law, is the label and nozzle used for a tank. Stainless steel is the most commonly used metal used for CO2 cylinders. CO2 use might play a role in the color of the cylinder, depending on the organization you're dealing with.

What is the gas cylinder color code?

The suggested gas cylinder color code is as follows:

  • Carbon Dioxide – Grey
  • He-O2 – Brown, and Green
  • Instrument Air – Red
  • Medical Air – Yellow
  • Nitrogen – Black
  • Nitrous Oxide – Blue
  • O2-He – Green, and Brown
  • Oxygen – Green
  • Vacuum – White

Is CO2 dangerous?

CO2 isn't a dangerous gas or material, but it can be dangerous if it reaches high concentrations or mixes with other chemicals, such as chlorine or fluorine. For example, CO2 released in close quarters with little to no ventilation or oxygen concentration makes CO2 potentially deadly.

What level of CO2 is toxic to humans?

Different levels of toxicity exist regarding CO2 in the human body. The Occupational Safety and Health Administration (OSHA) has set the permissible exposure limit (PEL) at 5,000 ppm of carbon dioxide. The National Institute for Occupational Safety and Health (NIOSH) recommends that workers not be exposed to concentrations of CO greater than 5,000 ppm for more than 15 minutes at a time. 6,000 ppm for 35 minutes will cause unconsciousness, and 14,000 for 110 minutes will cause death. A resting human being has about 300 ppm of carbon dioxide in his body, just to put things in perspective.

What’s the difference between CO2 at the welding store and CO2 in a restaurant?

The difference between the two is small, and there’s no difference in some cases. However, welding CO2 is typically 99.5% pure and processed from ethanol production. CO2 for restaurant use is captured as a byproduct of fresh air and is always 99.9% pure. One of the most significant differences is that CO2 tanks for welding aren’t purged before refilling, and food-grade tanks are.

Can you weld with food-grade CO2?

Yes. The gas in a CO2 tank is the same as in a CO2 welding tank for beverage dispensing.

Does the quality of CO2 in the cylinder affect the taste of beer?

Yes. Even in CO2, that’s 99.9% pure, which still leaves 0.1% of additional gases that could remain in the tank if it’s not appropriately purged. Our company exists to monitor the gas quality in a tank, and we measure in parts-per-million. Even the slightest nuances can impact the final product of any beverage, especially beer.

Does beverage grade CO2 matter?

Using beverage-grade CO2 makes a huge difference. When it comes to using CO2 for beverage consumption, you want 99.9% pure CO2, and even in this case, the room is left for other gases. Using a purged tank is equally important to remove significant traces of additional gas.

How big a CO2 tank can I use without a safety alarm?

According to OSHA, any establishment that houses more than 100 lbs. of compressed CO2 at one time must have a CO2 storage safety alarm. Several more regulatory matters outline CO2 safety for businesses that use it regularly. 100-lb. tanks are 62” tall and 10.5” wide and are used by companies looking to avoid the time-consuming process of switching tanks multiple times daily.

Why do CO2 tanks need to be chained?

Chains on CO2 tanks are part of regulatory compliance that requires the tanks to stand straight up to avoid any accidents or injury.

Where can I get my CO2 tank filled?

Typically, local hardware stores fill small CO2 tanks for personal use. However, welding supply stores handle any needs much bigger than a 10-20 lb. tank or multiple tanks at a time. When you consistently use large amounts of CO2, places like AirGas, Praxair, and other industrial-sized suppliers are more convenient.

Does Home Depot fill CO2 tanks?

No, Home Depot does not fill CO2 tanks. However, they carry all of the supplies needed to refill these tanks on your own, including the empty tanks themselves, regulators, and more.

What's the difference between CO2 Cylinder Price and CO2 Cylinder Refill Price?

The cost of a CO2 tank depends on whether you’re filling an old one or buying a new full tank. The quality of the tank, purity of the gas, and any additions also play a role. Use the following information as a guideline:

  • 5 lb. CO2 cylinder refill: $19.99, Brand new CO2 cylinder price: $69.99
  • 10 lb. refill: $24.99, New: $79.99
  • 15 lb. refill: $29.99, New: $89.99
  • 20 lb. refill: $34.00, New: $99.99

A lot of companies deliver CO2, allowing you to exchange your empty tanks for full ones. Personally, this comes in handy when I'm looking for a CO2 cylinder near me. When you start getting into more significant amounts of gas, the price drops considerably.

There is also a significant difference between aluminum and steel tanks and whether they have siphon tubes.

How do I know how much CO2 is in my tank?

There are two options for measuring the amount of CO2 left in a tank. The most convenient method is using a dual gauge regulator, which only requires reading a simple dial that decreases as gas dispenses. However, if you’re using a portable tank without a regulator gauge, using the remaining weight is the most accurate way to measure what’s left in your tank. The tank should contain a sticker printed with the empty weight of the cylinder. Place the tank on a scale and subtract the empty cylinder weight from the current weight, giving you the current amount left in the tank.

Can my CO2 tanks be filled with other gases besides CO2?

Filling a tank with different types of gases is never recommended. Some tanks aren’t made for flammable gases, while others are. Other gases intended for cylinders don’t mix well with others, possibly leading to an explosion if mishandled. Certain gases also damage the interior of tanks if they’re crafted from softer metals, leading to further complications. Refer to this guide for labeling tanks based on types of gases and more.

How can I prevent CO2 leaks from occurring?

A Department of Transportation DOT-3AL rated tank should hold up for years. However, a hydrostatic wall expansion test must be conducted on each tank every five years. Stamps proving this test should be on each tank's outside surface, and anyone filling them should be mindful of the updated stamp.

However, most tanks will leak if they are not filled correctly. The proper way to fill a CO2 tank is to contact a CO2 Supplier to fill the co2 tank for you. Due to the safety involved, it is quite risky to fill on your own.

Another method that works for some people is to fill the tank partially, then put the regulator on and fill it. If you do this, make sure that if there is any pressure in the tank, it will be released when you put on the regulator.

If you have an older system that uses a "D" sized tank (instead of an "E"), you may have trouble getting enough pressure out of your regulator. This tank has a much smaller volume than an "E" sized tank, requiring less force to push air through it.

Using proper hoses and regulators plays a massive role in securing your tank and preventing leaks.

You can follow as many rules and tips as you’d like, but there’s no guarantee a tank won’t leak, and you must have a way to identify a leak when it takes place. A CO2 safety alarm is the only surefire way to guarantee your safety and identify a leak when it happens.