G R E E N T E C H

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Clinic ventilation and air changes per hour (ACH) verification

Description Of The Service

Medical, dental and surgical clinics, endoscopy and procedure rooms, sterilization/reprocessing areas and compounding pharmacies must be able to show how their ventilation actually performs: supply and exhaust airflow in every room, air changes per hour (ACH) and the pressure relationship between rooms (positive or negative). GreenTech Air Balancing measures each room on site, calculates ACH from the measured supply airflow and the room volume, observes pressure relationships and documents every deficiency, with reference to CSA Z317.2 healthcare HVAC principles and the design intent of the project engineer.

Typical situations: a new clinic fit-out or tenant improvement, a renovation or HVAC modification, preparation for an Out-of-Hospital Premises (OHP) inspection in Ontario, a landlord or engineer requesting verification, or comfort and odour complaints in treatment rooms. Most clinics are measured in a single site visit; the report follows shortly after. Final design and code compliance remains the responsibility of the design professional, owner and/or regulatory authority — our role is to provide accurate, independent field measurements and clear documentation.

Room-by-Room Airflow Measurement
Supply, return and exhaust airflow measured at every diffuser and grille in CFM and L/s, with room dimensions and volume recorded for each treatment, procedure, waiting and support room.
ACH Calculation & Pressure Relationships
Air changes per hour calculated from measured supply airflow (ACH = CFM × 60 ÷ room volume in ft³). Pressure relationships observed for procedure rooms, sterilization and soiled utility rooms, washrooms and isolation spaces.
Equipment & Fan Performance Verification
AHU, RTU, HRV/ERV and exhaust fan performance recorded (RPM, Hz, ESP/TSP, amperage, airflow), HEPA filter pressure drop when applicable, and balancing to design values where adjustment is possible.
CSA Z317.2 — HVAC in Health Care Facilities
Our measurements and report are prepared with reference to CSA Z317.2 principles (ventilation rates, pressure relationships, filtration) so that engineers and inspectors can compare measured values with the applicable requirements.
ASHRAE 170 & Project Design Criteria
Where the project specifies ASHRAE 170 or engineer-defined design values, measured results are reported against those criteria with the percentage of design for each room and terminal.
Independent TAB Procedures (AABC / NEBB)
Measurements follow recognized TAB procedures using calibrated instruments. GreenTech Air Balancing is an independent TAB firm: we do not install or repair HVAC equipment, so our results stay impartial.
A Report Inspectors Can Read
Room dimensions, volume, supply and exhaust airflow, ACH, pressure relationship observations, equipment data, deficiency notes and limitations — structured so that an inspector, engineer or landlord finds what they need on one page per room.
Deficiencies Clearly Identified
Rooms below design airflow, missing exhaust, wrong pressure direction or non-operating equipment are listed with measured values so the mechanical contractor or engineer can correct them efficiently.
Re-Testing After Corrections
Once corrective work is completed by the mechanical contractor, we re-measure the affected rooms and issue the updated report.

Frequently Asked Questions — Clinic Ventilation

ACH (air changes per hour) is the number of times the air volume of a room is replaced in one hour. We calculate it from the measured supply airflow: ACH = (CFM × 60) ÷ room volume in ft³. For example, 200 CFM in a 1,000 ft³ room gives 12 ACH.

The requirement depends on the room type and on the applicable criteria: CSA Z317.2 tables, ASHRAE 170, provincial guidance and the design engineer's values. We measure the actual ACH and pressure relationship and report them against the criteria provided; determining the applicable requirement remains with the design professional and the regulatory authority.

Yes. We provide the measured ventilation documentation typically requested — airflow per room, ACH, pressure relationships and equipment performance — in a clear report. The compliance determination itself is made by the inspecting body and the design professional.

We document the deficiency with the measured values. Corrective work (fan speed, damper or duct modifications, equipment repairs) is performed by the mechanical contractor or specified by the engineer; we then re-test the affected rooms and update the report.

Yes. We serve Ottawa, Gatineau, the Outaouais, Eastern Ontario and Western Québec, and we deliver reports in English or French.

Opening or renovating a clinic?

Send us the floor plan and the mechanical drawings or the room list and we will prepare a quotation for the ventilation verification, usually within one business day.

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About GreenTech Air Balancing - Our Process and Expertise
How We Work

How To Work With
GreenTech Air Balancing

Professional HVAC Balancing Service 1
System Assessment & Technical Review

We begin with a detailed review of the HVAC systems to understand design intent, current operating conditions, and performance gaps. Our team evaluates airflow, waterflow, static pressure, and control sequences to establish an accurate baseline before any adjustments are made.

Professional HVAC Balancing Service 2
Precision Testing & Field Measurements

Using industry-standard TAB instruments, we perform precise field measurements across the entire system — diffusers, grilles, VAV boxes, terminal units, hydronic loops, and mechanical equipment. Each measurement follows recognized balancing procedures to ensure repeatable and reliable results.

Professional HVAC Balancing Service 3
Final Balancing, Compliance & Documentation

Once optimal performance is achieved, we compile a comprehensive report including measured data, compliance verification, system observations, and corrective recommendations. Our documentation is structured for engineers, consultants, and facility managers to support long-term building efficiency.