The context: a routine ventilation check request in Laval
On an ordinary Tuesday morning, our team at AirGreen received a call from a residential client in Laval, concerned about insufficient air circulation in the hallways of his eight-unit building. The service request seemed straightforward: a ventilation checkup in preparation for seasonal maintenance.
What no one expected, however, was that this routine visit would uncover a potentially deadly gas leak, unnoticed for several weeks. Thanks to the alertness and professionalism of our technicians, a critical situation was avoided in a fully occupied building.
Initial findings: unbalanced ventilation and unusual warning signs
From the moment our team arrived on site, several worrisome indicators caught our attention. Technically, some exhaust vents were not operating at optimal airflow. But most notably, one of our technicians experienced a slight eye irritation upon entering the mechanical room—an immediate red flag.
We then deployed our specialized instruments to perform a deep analysis of indoor air quality. The result: abnormal levels of combustible gases, specifically methane, detected at moderate but concerning concentrations—well above acceptable limits for enclosed environments.
Pinpointing the source: a slow leak behind a gas heating appliance
After securing the area and ventilating the mechanical room, our team carried out a targeted inspection of the gas lines feeding the building’s central systems. Behind an aging natural gas boiler—installed more than 15 years ago—we found the culprit: a slow leak in a flexible connector, invisible to the naked eye but unmistakable to our detection tools.
This issue had likely gone unnoticed for several weeks, made worse by the lack of functioning mechanical ventilation in that specific area. A dangerous combination that could have escalated quickly with a single spark or pressure fluctuation.
Emergency intervention: securing, repairing, and upgrading the HVAC system
Given the seriousness of the situation, our team immediately:
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Shut off the gas supply to the boiler
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Notified Laval fire services and the building manager
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Set up temporary natural ventilation for the room
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Documented the entire intervention for public safety authorities
In the following days, we were contracted to:
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Replace the faulty connector and secure the gas supply
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Installed a new CSA-certified flexible hose
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Verified all existing gas connections
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Performed a full pressure leak test
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Modernize the mechanical room’s ventilation
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Installed an automatic gas-detecting exhaust fan
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Added a methane sensor linked to a local alarm
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Integrated an independent mechanical air renewal system
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Optimize the building’s overall common ventilation system
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Complete cleaning of horizontal ducts
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Airflow balancing using a digital anemometer
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Installed high-efficiency filters on fresh air intakes
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Results and impact: restored safety and full code compliance
Thanks to this rapid and comprehensive response, the residents’ safety was fully restored. The building now meets the highest standards in gas safety and mechanical ventilation, and the property owners have since enrolled in an annual preventive maintenance program with AirGreen.
This case clearly shows how a simple HVAC service call can reveal much deeper underlying risks. Without our presence that day, the outcome could have been drastically different.
Why this type of inspection is critical in Laval and across the North Shore
In Laval, many residential buildings constructed between 1990 and 2010 are equipped with gas heating systems paired with outdated or incomplete mechanical ventilation. These buildings are often poorly maintained due to time or budget constraints, becoming potential hazard zones without occupants even realizing it.
At AirGreen, we believe HVAC maintenance is more than comfort—it’s a collective responsibility. Our expertise allows us to intervene rapidly and rigorously across Laval, Longueuil, Montréal, the North Shore, and the South Shore.
Key takeaway: never underestimate an HVAC inspection
Here are the warning signs that should never be ignored in buildings with gas systems:
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Unusual odours (even faint) in mechanical areas
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Headaches, irritation, or drowsiness
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Absent or ineffective ventilation in enclosed rooms
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Gas appliances over 10 years old
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Unusual noises near gas lines
Our advice to avoid this kind of situation:
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Have your HVAC systems professionally inspected every year
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Replace gas flex connectors every 10 years
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Install certified gas and CO detectors in all at-risk areas
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Ensure mechanical ventilation in all technical spaces
Conclusion: a building saved thanks to one simple initiative
The story of this building in Laval is a perfect illustration of the value of true HVAC professionalism. Thanks to one simple inspection request, a major risk was identified, contained, and permanently resolved—before it could cause harm.
At AirGreen, we take every visit seriously, because every detail matters when it comes to safety. This isn’t just maintenance—it’s active prevention, in service of our local communities.
Contact AirGreen for your HVAC inspections in Laval, Longueuil, Montréal, the North Shore, and the South Shore
Are you a property owner, manager, or condo board member of a residential or commercial building? Looking to ensure the safety of your ventilation and heating systems? Call AirGreen for a professional assessment. Our mission: protecting your spaces, and the people in them.