How do we test the carbon monoxide detectors and exhaust fans in our HOA parking garage?

By OurHOA · General information · Revised October 26, 2026

How an HOA board tests parking garage carbon monoxide detectors and exhaust fans: what the mechanical code asks, a testing log, alarm response and wording to copy.

Part of the HOA board handbook: vendors, projects and upkeep.

The short answer

An enclosed parking garage fills with car exhaust every morning and every evening, and the only thing moving it out is a set of exhaust fans controlled by gas detectors on the walls. If a detector drifts or a fan belt snaps, nobody notices until someone gets a headache in the elevator lobby. The board's job is to know what the system is supposed to do, prove that it does it on a schedule, and keep the paper. In practice that means four things. Find the design: how many detectors, what they sense, the setpoints and the fan rates. Hire a qualified mechanical or controls contractor to test the detectors with calibration gas and confirm the fans ramp up. Walk the garage monthly to check that the fans are running and the panel shows no faults. And have a written plan for the day an alarm sounds. The rules come from the mechanical code your city or county adopted, your declaration and your contracts, and they vary by state and by edition. Treat this guide as education, not legal or engineering advice.

What the mechanical code expects

Many cities and states base their mechanical code on the International Mechanical Code. In its August 2026 Code Corner article on the 2024 edition, the International Code Council explains section 404.1: ventilation in an enclosed parking garage must run continuously or be controlled automatically by carbon monoxide detectors used together with nitrogen dioxide detectors, listed to UL 2075. Under automatic control the fans run full-on at no less than 0.75 cubic feet per minute per square foot of floor area, or at a standby rate of no less than 0.05. The article says the exhaust rate can never go to zero. A 20,000 square foot garage level, then, needs at least 15,000 cfm at full-on and 1,000 cfm on standby. Older editions read differently, and states amend the text. Minnesota's rule 1346.0404, for example, requires both a CO and an NO2 detector and has the fans start at 25 parts per million of CO or 3 ppm of NO2. So the first call goes to your building department: which edition applied when the garage was permitted, and has the system been altered since? Florida is the simplest case. Florida Statutes section 553.73 creates one statewide Florida Building Code covering mechanical systems, and subsection (7)(a) names the International Mechanical Code as one of the model codes the Florida Building Commission reviews for each update. In Texas and Colorado, ask the city or county building department which code and edition it enforces where the garage sits.

Find out what you have and who maintains it

Before testing anything, pull the paperwork. Look for the mechanical drawings from the original permit, the controls submittal from the installer, and any service reports. If none of that survives, have the controls contractor build an inventory on the first visit. It should list: - Each detector by location and the gas it senses (CO, NO2 or both) - The make and model, and the date each sensor was installed or last replaced - The setpoints that switch the fans from standby to full-on - Each exhaust and supply fan, its rated airflow and what it serves - Where the control panel is and what it does on a fault or power loss The statutes put most of this on the association. Texas Property Code section 82.107(a) makes a condominium association responsible for maintaining, repairing and replacing the common elements. Florida Statutes section 718.113(1) does the same, apart from limited common elements the declaration assigns to owners. Colorado's section 38-33.3-307(1) applies to every common interest community, subject to the declaration. A garage under a mixed-use building may belong to a separate parking association or a commercial owner, so read the declaration and any shared facilities agreement before signing a service contract.

A testing routine a small board can keep

Monthly, a board member or the building's maintenance person walks each garage level. Listen and feel for airflow at the exhaust grilles, because a standby fan should never be off under the 2024 code. Check the control panel for trouble lights or fault messages. Look for detectors that are missing, painted over, wrapped in plastic from a painting job, or knocked loose by a tall van. Write the date and what you found in a log. On the schedule the detector maker sets, the controls contractor exposes each detector to calibration gas and confirms three things: the detector reads the right concentration, the fans switch to full-on at the setpoint, and the panel returns to standby once the gas clears. Sensors wear out, and the manufacturer's manual gives the calibration interval and the sensor replacement life. Get both in writing in the service contract instead of guessing. Once a year, have the mechanical contractor service the fans: belts, bearings, motor amperage, dampers that open and close, and intake and exhaust louvers clear of leaves, bird nests and stored items. Ask for measured airflow on each fan compared with its rating. Keep every report with the garage's other records. Our guide on building an HOA preventive maintenance schedule shows how to fold these dates into the community's calendar.

When the alarm sounds or someone reports fumes

Carbon monoxide has no color or smell. The CDC lists headache, dizziness, weakness, upset stomach, vomiting, chest pain and confusion as the common symptoms and notes that people often describe them as flu-like. It counts more than 400 deaths a year from unintentional CO poisoning not linked to fires, and more than 100,000 emergency department visits. Write the response down before you need it: 1. Anyone with symptoms leaves the garage for fresh air, and someone calls 911. 2. If nobody is sick, call the fire department's non-emergency line or the controls contractor, depending on the reading and what your plan says. 3. Confirm the fans went to full-on. If they did not, the problem is the fans or the controls, not the cars. 4. Do not reset or silence the panel until the contractor finds the cause. 5. Log the date, time, reading, who responded and what was fixed. If the association has employees who work in the garage, such as a porter or a parking attendant, federal rules add a layer. OSHA's Table Z-1 in 29 CFR 1910.1000 sets a permissible exposure limit for carbon monoxide of 50 ppm averaged over an eight-hour shift.

The homes above and beside the garage

Garage detectors protect the garage, not the bedrooms. Unit alarms are a separate requirement, and most of the time the owner supplies them. Florida Statutes section 553.885(1) requires an operational CO alarm within 10 feet of each sleeping room in buildings and additions permitted for new construction on or after July 1, 2008 that have an attached garage, a fireplace or a fossil-fuel appliance. In Colorado, section 38-45-103(1)(a) requires the seller of a unit in an existing multi-family building with an attached garage, a fireplace or a fuel-fired appliance to make sure an operational alarm is installed within 15 feet of the entrance to each sleeping room, and section 38-45-101(5) says a multi-family dwelling includes a condominium. The board can help without taking over the owners' job. Send a reminder each fall, and when a resident reports fumes in a unit, check whether the garage panel logged anything at that hour.

A sample timeline and wording to copy

Week 1: the board asks the building department which code edition applied and pulls the controls submittal. Week 3: the controls contractor visits, builds the inventory and tests every detector with calibration gas. Two detectors read high and one sensor is past its replacement date. Week 5: the contractor replaces the sensor and recalibrates the other two. Next board meeting: the treasurer reports the cost and the board approves an annual service agreement. After that, monthly walks go in the log and the contractor returns on the manufacturer's interval. A notice to residents: 'On Tuesday, March 10, between 9:00 a.m. and noon, a contractor will test the carbon monoxide detectors and exhaust fans in the garage. You may hear the fans run at full speed and see the alarm panel light up. This is a test. If you feel unwell in the garage at any other time, leave and call 911.' A motion: 'I move that the board approve the service agreement with [contractor] for [amount] per year, covering detector calibration on the manufacturer's schedule, sensor replacement at end of life, annual fan service with measured airflow, and a written report after each visit, and authorize the president to sign.'

Mistakes to avoid

Turning the fans off to save electricity, when the current code says the exhaust rate never drops to zero. Assuming the detectors work because the panel is quiet, when only a gas test proves a detector responds. Letting a painting or sealing contractor bag the detectors and never take the bags off. Resetting an alarm without finding out why it went off. Storing bikes, tires or furniture in front of louvers. Paying for a service visit without a written report. And forgetting the garage during a concrete repair project: our guide on repairing an HOA parking garage concrete deck covers that work, and the contractor should protect or remove detectors before grinding or coating starts.

Sources

These guides are general education for HOA boards and residents, not legal, tax, or financial advice. Rules vary by state and by your community's governing documents - check with a professional for your situation.

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