CO2 Monitoring for Breweries, Bars and Beverage Systems

Does a brewery or a bar with a bulk CO2 tank need a gas detector?

Over 100 pounds of carbon dioxide, you need either mechanical ventilation or a gas detection system. The code gives you the choice, and detection is almost always the cheaper of the two.

Section 5307.3 of the 2018 IFC covers insulated liquid carbon dioxide systems used in beverage dispensing, where the quantity exceeds 100 pounds. Section 5307.3.1 requires mechanical ventilation that maintains the room at negative pressure, with an exception: a gas detection system complying with section 5307.3.2 is permitted in lieu of mechanical ventilation.

That exception is why most operators install detection. Continuously ventilating a walk in cooler or a tap room storage closet costs money every hour of every day, and it fights the refrigeration you are paying for in the same space.

Verify the edition your jurisdiction has adopted. Local amendments are common and the fire marshal has the final word.

What alarm levels does the fire code require for a bulk CO2 room?

A supervisory alarm at 5,000 ppm and a second alarm at 30,000 ppm, with the sensors mounted within 12 inches of the floor.

Section 5307.3.2 states the numbers directly. It requires carbon dioxide sensors within 12 inches of the floor in the area where the gas is expected to accumulate, an audible and visible supervisory alarm on detection of 5,000 ppm, and an audible and visible alarm on detection of 30,000 ppm.

5,000 ppm is the OSHA permissible exposure limit for carbon dioxide as an eight hour time weighted average under 29 CFR 1910.1000 Table Z-1. 30,000 ppm is the NIOSH short term exposure limit. The NIOSH value immediately dangerous to life or health is 40,000 ppm.

Where does the CO2 actually collect in a brewery?

Low, and in the places people crouch. Carbon dioxide is about one and a half times as dense as air.

The predictable accumulation points are the floor of the bulk tank room, walk in coolers and keg rooms, cellar floors, trench drains, pits under tanks, and the bottom of any stairwell down into a below grade space. Fermentation adds a second source that a detector in the tank room will not see, because the CO2 comes out of the blowoff at the tank and settles on the cellar floor near it.

A sensor at switch height will not see any of this. Mount low.

Is a confined space entry permit needed to go inside a fermentation tank?

Almost always yes, and the atmosphere has to be tested before anyone enters.

A fermentation vessel is the textbook permit required confined space: large enough to enter, limited means of entry and exit, not designed for continuous occupancy, and containing an atmosphere capable of causing death. Under 29 CFR 1910.146(d)(5)(i) the space has to be tested to determine whether acceptable entry conditions exist before entry is authorized.

Before entry means before a head crosses the manway. That cannot be done with a monitor clipped to a belt, because a diffusion instrument only reports the air it is sitting in. Testing a vessel from outside requires a pumped instrument and a probe long enough to reach the bottom of the tank, which is where the carbon dioxide will be.

The confined space entry guidance sets out the full testing sequence.

What is the difference between the brewery rule and the grow room rule?

Beverage dispensing gets a choice between ventilation and detection. Carbon dioxide enrichment does not, and needs both.

Section 5307.3, which covers insulated liquid CO2 for beverage dispensing, permits a gas detection system in lieu of mechanical ventilation. Section 5307.4, which covers carbon dioxide enrichment systems of the kind used in indoor agriculture, requires a gas detection system under 5307.4.3 and separately requires mechanical exhaust ventilation under 5307.4.4.

The alarm concentrations are the same in both: 5,000 ppm and 30,000 ppm. What differs is whether detection is a substitute or an addition. If you run both a taproom and a grow operation, do not assume the looser rule covers the other side of the building. See CO2 monitoring for indoor grows and greenhouses.

Primary sources

M Squared Safety Solutions, Inc., 981 Calle Negocio Suite 200, San Clemente, CA 92673, 949-954-6581. Every code and regulatory statement on this page was read against the cited source on 18 September 2026. Model code section numbers are cited to the 2018 International Fire Code and International Mechanical Code. Jurisdictions adopt and amend these codes separately, so confirm the edition in force where the work is. This page describes what the regulations say. Whether a given provision is satisfied at a particular facility is a determination for that employer and the code official.