Whether you use individual CO2 cylinders or a bulk CO2 tank system, you should be aware of CO2 tank safety. Thousands of liquid carbon dioxide cylinders and tanks are used across the country for soda or beer carbonation, for refrigeration, industrial purposes, medical and scientific facilities, fire suppression systems, and even indoor agriculture. All of these vessels are a potential safety hazard if not installed and maintained properly.
CO2 cylinder and tank safety is important. An accident can quickly hurt or even kill staff or customers.
CO2 Tank Safety Concerns
The primary safety concern is gas leakage after the cylinder or tank. While the cylinders or tanks are designed to withstand pressure and damage, the pipes, hoses, and fittings used to distribute the gas after the vessel are not.
CO2 cylinder pressure is about 860 psi at normal room temperature. Typical CO2 cylinders store about 50 lbs. of liquid CO2. Two pounds of liquid CO2 expands to about 20 cubic feet of pure CO2 at atmospheric pressure, or expands at a rate of 535:1. This means that in an enclosed room the CO2 gas can quickly fill with CO2 and either poison an individual or displace all the oxygen available for breathing. Because CO2 is heavier than air it will also fill any low areas like basements or under floor service areas first. If there is little air movement, pools of CO2 can exist for many hours.
Liquid CO2 temperature is also important. If the gas escapes quickly (like a fire extinguisher) it is discharged at sub zero temperatures and produces a mixture of CO2 gas and "snow". This “CO2 snow” is momentarily the same temperature as dry ice (about -110F or -79C) and can quickly result in frostbite or frozen skin.
CO2 Tank Installation
Bulk CO2 tanks and cylinders along with their delivery systems should be installed by a professional. In most cases the person to ask about professional installation is your CO2 supplier. Either they can install the tanks or direct you to someone they recommend. If your facility offers soda fountain drinks or draft beer, ask these suppliers too. It never hurts to have more than one quote.
CO2Meter is also delighted to partner with Chart Industries, the leading designer and manufacturer of bulk storage tanks to provide education and information about bulk storage solutions.
CO2 Tank Storage
CO2 cylinders stored indoors should be stood upright against a wall and secured with a chain to insure they cannot fall over and potentially damage or rupture the valve. Bulk CO2 tanks should be bolted to the floor to insure they do not tip over as well. The area around the tank and cylinders should be well-ventilated if possible and should be monitored by a CO2 safety alarm.
- CO2 tanks and cylinders should be stored in areas with a temperature less than 125F (51.7C).
- CO2 tanks and cylinders should always be connected to a reducing valve or regulator with a pressure safety valve.
- CO2 tanks should also be vented to the outside so that any discharge does not accumulate indoors near employees and customers.
CO2 System Repairs
Repairs to CO2 delivery systems should only be done by trained personnel. Even the smallest leak in a hose or fitting can have potentially dangerous results. While it may be tempting to wrap a leaking hose with tape as a temporary fix, it may not only be unwise, but could leave management open to a lawsuit or denial of insurance coverage in the case of an accident.
Fortunately, most CO2 delivery services include CO2 system installation, maintenance and 24/7 repair as part of their service package.
If you need recommendations for a gas distributor or service company in your area please contact CO2Meter. We will be delighted to provide a comprehensive list of partners in your area.
CO2 System Accidents
Accidental damage to CO2 delivery systems can and does happen. For example, a worker opening boxes with a utility blade might inadvertently slip and puncture a CO2 line. A cylinder tank cart might fall over while being moved over an uneven floor. It is important that employees who work with or around bulk CO2 tanks are trained to understand the dangers of leaking tanks and understand what to do when a leak happens. Proper training and signage are critical for protecting employees and customers around stored CO2.
The use of bulk storage of carbon dioxide in cylinders or outdoor tanks has grown exponentially over the last several years. Every restaurant, brewery, welding supplier, indoor grower as well as many manufacturers rely on bulk CO2 as part of their business.
Note that installing your CO2 storage vessel outside does not mitigate the potential for a safety hazard. The gas is being used inside and the people are inside creating the hazard. When CO2 storage vessels are installed outside safety monitors should still be installed inside your facility.
Because we offer CO2 storage safety alarms, we get asked questions about CO2 storage tanks and cylinders. Here are some of the most common questions with links to additional resources.
How are CO2 tanks and cylinders delivered?
Carbon dioxide has become a global commodity used by both business and industry. To ensure a constant supply of the gas, a supply chain of many different businesses are involved.
It starts off with collecting the gas. CO2 is a natural byproduct of many different chemical processes. The two most common are capturing it from the production of ethanol or ammonia. Ethanol production is used as a fuel additive and ammonia is used as plant fertilizer for the farming industry worldwide. Natural "wells/pockets" of CO2 also exist where the gas is extracted from underground like the Jackson Dome in the US. Additionally, CO2 can be captured in the exhaust streams of industrial burners or energy plants. While not as common, CO2 can also be captured during industrial fermentation, cement production or even removed from the air, although these processes are not yet scalable to meet the world demand.
Once the CO2 is collected it is scrubbed to get to the proper purity, then compressed into a liquid and transported via ocean cargo ships, rail tanker or truck to a regional or local CO2 distributor. The distributor is responsible for certifying the purity of the gas, then transporting it either by portable cylinder or by tanker truck to the end user.
What color are CO2 cylinders?
There are 2 color standards for CO2 cylinders: the United States, and the rest of the world. In addition, the color standards in the US are a recommendation and not law. Therefore, you should never rely on the color of the CO2 cylinder to tell you what gas is inside. Instead, you should rely on the label on the side of the cylinder, which is required.
With all those caveats, large CO2 cylinders typically have a gray shoulder at the top of the tank and below the valve stem worldwide. CO2 tanks are typically stainless steel. Small CO2 cylinders or cartridges could be any color.
Is CO2 dangerous?
While carbon dioxide is a naturally occurring gas, too much of it in the air can cause at the least headaches, drowsiness and at the worst, poisoning or suffocation. Fresh air contains 0.04% CO2 (400 parts per million) CO2. However a leaking tank or cylinder valve, or a leaking hose or manifold can quickly raise the CO2 level in an enclosed area up to 3% or more very quickly. This is because liquid CO2 under pressure expands to 535 times its volume as a gas.
While CO2 tank or cylinder leaks are rare, leaking components in the system can and do happen. Learn more about the dangers of CO2.
What’s the difference between CO2 at the welding store and CO2 in a restaurant?
Most bulk CO2 isn’t processed from fresh air, but is collected as a byproduct of other industrial processes like ethanol production. Once the CO2 is collected it is rated according to its purity. For example the industrial CO2 in a welding shop is rated at 99.5% purse, while beverage grade CO2 used in restaurants must be at least 99.9% pure. Learn more about CO2 purity levels here.
Does the quality of CO2 in the cylinder affect the taste of beer?
Absolutely. While food grade CO2 is rated as 99.9% pure, that means there are 0.1% of other gases in the tank. At CO2Meter we like to measure gases in parts-per-million. This means there are up to 1,000ppm of other gases in the tank or cylinder that could impact the overall taste, especially in beer. For this reason, it is important to both periodically clean bulk tanks and to verify the CO2 quality with your CO2 distributor.
How big a CO2 tank can I use without a safety alarm?
The National Boiler Inspection Code and the International Fire Code recommend that any business that stores more than 100lbs. of CO2 use a CO2 Storage Safety Alarm. A 100lb. cylinder is 62” tall and 10.5” wide. This size is used in venues who want to reduce the number of tank changes each day. While the old-style cylinders are smaller, if the total combined weight of CO2 is over 100lbs. an alarm must also be used.
Where can I get my CO2 tank filled?
Small CO2 cylinders can be refilled at many local gas supply stores. Larger cylinders can be refilled or exchanged at welding supply stores. For businesses that use lots of CO2, the best solution is to contact a local, independent CO2 distributor that will schedule a truck to bring you CO2 cylinders or refill an bulk tank.
Note that transporting CO2 cylinders is dangerous. While CO2 cylinders are virtually indestructible, if the neck is broken it can become a virtual missile. This is why it is illegal to ship CO2 without proper safeguards and registration.
How do I know how much CO2 is in my tank?
You have 2 options: if your tank has a dual gauge regulator, you can read the amount of pressure on the dial. The pressure will go down as the tank empties. The downside of this method is that once the pressure begins to drop it will run out fairly quickly. For portable CO2 cylinders, the most accurate way to determine the amount of remaining CO2 is to weigh it. The empty cylinder’s weight should be printed on the side, or you can google it. Subtract the cylinder weight from the actual weight, and you know how many pounds or kilos of CO2 you have remaining.
Can my CO2 tanks be filled with other gases besides CO2?
While putting other gases in a CO2 tank or cylinder is possible it is inadvisable, dangerous, and in some situations could be illegal. Tanks are marked with the gas that is in them for safety. A grey shoulder around the nipple on a CO2 cylinder is the universal code for CO2. See a chart here (pdf). In addition, a sticker on the side of a larger cylinder or tank has hazard warning pictograms. On CO2, it is a green triangle that says “non flammable gas” If you were to fill this tank with a flammable gas, it would be dangerous to others in the future.
How can I prevent CO2 leaks from occurring?
With their sturdy Department of Transportation DOT-3AL rated design, a new CO2 tank or cylinder will not leak for decades. By law, refillable tanks must be retested using a hydrostatic (water pressure) cylinder wall expansion test or ultrasonic wall thickness test and a visual inspection every 5 years before refilling. The date of each test must be stamped on the cylinder.
The possibility of leaks is much more likely via the valves and fittings used to route the CO2 from the tank or cylinder to the place the gas is dispensed. If you’ve ever had a water leak at home, you know that they can be difficult to find and fix. The same goes with CO2 leaks.
While there is no way to prevent all leaks, you can reduce the likelihood by having a CO2 delivery system installed by a qualified technician and inspected regularly. If the CO2 valves and fittings are in an enclosed area in a business, by regulation you should also have a CO2 safety alarm to warn occupants if a leak occurs. Read more about CO2 leak training here.
CO2 Tank Safety Gas Detectors
At CO2Meter, we are proud to provide our customers with integral educational and training resources as it pertains to CO2 safety monitoring. However, as an important rule of thumb, you should always remember that when working around confined spaces and dealing with inert gases like CO2, CO2 monitors are vital.
By measuring the CO2 gas concentrations, this can help ensure employee and worker safety and minimize the risk of serious, negative health effects from occurring. Without proper CO2 monitoring, individuals can put themselves at risk and may walk into a space with high concentrations, unknowingly. This can result in experiencing negative effects such as: headaches, fatigue, dizziness, nausea, and even fatality.
We recommend individuals either use portable or wall-mounted CO2 safety devices to ensure peace of mind for yourself, your employees, or your customers.