Code-compliant fresh air and comfort — ventilation, exhaust, and indoor-air-quality systems engineered for the space.
What We Provide
Outside air, exhaust, pressurization, and filtration — here is how we get code-required ventilation and clean air into commercial buildings.
Where It Applies
Ventilation work from our Tucson base covers offices, restaurants and commercial kitchens, and industrial buildings with real exhaust loads.
The Design-Build Advantage
Fans need power, and economizers and exhaust interlocks need controls. We install all of it, so the ventilation on the drawings is the ventilation that actually runs at occupancy.
Back to HVACDesert Filtration
Tucson air is not neutral. From mid-June through September, monsoon outflow can push a wall of dust across the valley in minutes, and every intake, louver, and door sweep on the building is on the receiving end. Filtration here has to be designed for that — not copied from a spec written for a milder climate.
MERV ratings describe how much fine particulate a filter actually captures. MERV 8 is the working floor for most commercial spaces; MERV 11–13 is the upgrade path, and MERV 13 is where a filter starts meaningfully catching the fine dust and wildfire smoke that irritate occupants and coat coils. The trade-off is static pressure: a tighter filter resists airflow, and an older air handler with no blower headroom can lose real CFM trying to push through it — the building ends up with cleaner air and not enough of it.
That is why we look at the air handler or rooftop unit before we specify the filter. Often a deeper pleated filter — more media area in the same frame — delivers the higher MERV rating at a pressure drop the existing blower can live with. Where it cannot, the honest answer is a fan or equipment conversation, not a filter that quietly starves the system.
Outside Air, By the Numbers
ASHRAE 62.1 is the national ventilation standard behind the mechanical code enforced in Tucson and Pima County. It sets a minimum outside-air rate for every occupancy — and plan review expects to see the math.
The ventilation-rate procedure adds two components for each space: a per-person rate driven by how many people the space is designed to hold, and a per-square-foot rate driven by floor area and use. An office, a classroom, a dining room, and a gym all land in different places. We run those calculations space by space, then size the outside-air intakes, dampers, and duct paths to deliver the total — with system effects and filter losses accounted for, not ignored.
A ventilation schedule on the drawings is a promise; the balance report is the proof. We commission and balance the outside air so each zone actually receives the airflow the calculation promised at occupancy — because an intake damper that never opens past ten percent serves nobody. Design, installation, and balancing under one contract means the number on the permit set and the number at the grille are the same number.
Demand-Controlled Ventilation
Outside air is not free in the desert. Every CFM a building brings in on a 108°F afternoon has to be cooled more than thirty degrees before it does anything useful, so ventilating a conference room sized for forty people when three are present is pure waste — on the hottest days of the year, at the moment the cooling plant can least afford it.
Demand-controlled ventilation fixes that. CO2 sensors read how many people are actually in the space, and the controls modulate the outside-air damper in proportion — full design airflow when the room is full, the code minimum when it is not. IECC-based energy code already requires it in some densely occupied spaces, and in Tucson's climate it is one of the highest-return controls upgrades a building can make.
Exhaust & Make-Up Air
Every CFM an exhaust fan removes has to come from somewhere. Get the replacement air wrong and the hood loses capture, doors slam, and the building drafts — get it right and nobody notices, which is the point.
The International Mechanical Code requires make-up air for kitchen hoods, interlocked so hood and make-up air run together. The desert question is what condition that air arrives in: untempered summer air dumped near the cook line satisfies the code and fails the cooks. We design make-up air with evaporative cooling or partial conditioning where the kitchen needs it, route the grease exhaust and supply ductwork to code, and balance the hood so capture holds when every appliance is running.
Fume hoods, dust collection, and process exhaust move serious air, and they usually have to keep the room negative to its neighbors while doing it — contaminated air should leave through the fan, not the corridor door. We install the exhaust, the make-up air path, and the controls interlocks that keep those relationships true when hoods open, fans stage, and the space actually operates.
Building Pressurization
A building that exhausts more air than it brings in runs at negative pressure, and a negative building makes up the difference on its own terms — pulling unfiltered outdoor air through every door, crack, and pipe penetration it can find. In Tucson that infiltration arrives hot and carrying dust, which is why some buildings grow a film of grit at every entrance no matter how often the floors are cleaned.
The fix is measurement, not guesswork. We total the exhaust, total the outside air, measure pressure at the envelope, and rebalance until the building sits slightly positive — so the only air that enters is air that came through a filter first.
FAQ
The questions building owners and facility managers ask us most about fresh air, filtration, and dust in Tucson.
For most commercial spaces, MERV 8 is the working floor and MERV 11–13 is the upgrade path — MERV 13 is where a filter starts meaningfully capturing the fine particulate that monsoon dust storms and wildfire smoke push into a building. The catch is static pressure: a MERV 13 filter resists airflow more than the filter the unit was designed around, and an older rooftop unit with no blower headroom can lose real airflow trying to push through it. We check what the existing equipment can handle first — often a deeper pleated filter delivers the higher rating without starving the unit.
On condition, not on a calendar. During monsoon season — roughly mid-June through September — a single dust storm can load a filter that would otherwise last months, so we check monthly and change when the pressure drop across the filter bank says so. The rest of the year, quarterly checks are usually enough. Our service and maintenance crews build that dust-season cadence into planned maintenance.
ASHRAE 62.1 is the national standard for how much outside air a commercial building must bring in, based on occupancy type, people count, and floor area. The mechanical code enforced in Tucson and Pima County builds its ventilation requirements on the same model, so plan review expects ventilation calculations for each space. We run those numbers, size the intakes and dampers, and balance the delivered airflow so the building passes inspection and actually breathes the way the calculation promised.
Demand-controlled ventilation uses CO2 sensors to bring in outside air in proportion to how many people are actually present instead of the worst-case design count. In Tucson that matters more than almost anywhere: every CFM of outside air on a 108°F afternoon has to be cooled more than thirty degrees before it does anything useful. Matching outside air to real occupancy in conference rooms, dining areas, and classrooms is one of the highest-return controls upgrades in the desert, and IECC-based energy code requires it in some densely occupied spaces.
That is a building running at negative pressure — the exhaust fans are moving more air out than the HVAC system brings in, so the building makes up the difference by pulling unfiltered outdoor air through every door, crack, and penetration. In the desert, that make-up air arrives hot and dusty. We measure building pressure, compare total exhaust against outside air, and rebalance so the building sits slightly positive and the only air that enters is air that went through a filter.
Yes. The International Mechanical Code requires make-up air for commercial kitchen hoods, interlocked so hood and make-up air run together. Without it the hood fights the building — capture suffers and doors slam. In Tucson the real design question is the condition that air arrives in: untempered 105°F air dumped near the line answers the code and fails the cooks, so we look hard at evaporative cooling or partial conditioning for make-up air in restaurant work.
For more of the year than most people expect. Tucson's dry air and cool desert nights give an economizer real hours — shoulder seasons, mornings, and nights when outside air is cooler than return air and can do the cooling for free. The desert caveats are dust and calibration: intakes need filtration that keeps monsoon dust out, and a stuck economizer damper quietly loads the cooling plant all summer. We test them at commissioning and keep testing them on maintenance.
Tell us about the space and what it's used for. We'll come back with the airflow numbers and a way to hit them.
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