Abstract:
Pathology laboratories generate hazardous gases, aerosols, and other pollutants during daily operations. Therefore, a well-designed and properly constructed ventilation and exhaust system plays a critical role in protecting staff health, ensuring laboratory biosafety, and meeting environmental emission standards. This article explains the key design principles, essential construction practices, and complete service workflow of such systems.
1. Overview of Pathology Laboratory Ventilation and Exhaust Systems
A ventilation and exhaust system forms the foundation of safe laboratory operation. It fulfills two essential functions.
First, it controls airflow direction and pressure gradients to prevent the spread of harmful substances. Second, it purifies contaminated exhaust air so all emissions meet national and local environmental regulations.
To achieve this, the system typically includes supply air units, exhaust fans, airflow organization strategies, differential pressure control, and exhaust purification devices.
2. Core Design Principles
2.1 Airflow Organization and Pressure Gradient
Pathology laboratories rely on directional airflow to guide clean air toward areas with contamination risks. Consequently, critical rooms—such as grossing rooms and tissue processing rooms—must maintain stable negative pressure. This prevents hazardous gases and aerosols from leaking into adjacent spaces.
Engineers must also position supply and exhaust outlets carefully. This avoids airflow dead zones and short-circuiting, ensuring pollutants move efficiently toward the exhaust system.
2.2 Air Change Rate and Airflow Balance
To comply with biosafety construction standards, the ventilation system must provide sufficient air change rates to dilute and remove pollutants. In addition, it must maintain strict airflow balance.
The exhaust airflow must consistently exceed supply airflow so the designed negative pressure remains stable during all operating conditions.
2.3 Variable Air Volume (VAV) Control Strategy
In large or functionally complex pathology laboratories, designers often adopt a Variable Air Volume (VAV) system. This system adjusts airflow automatically based on:
- The operating status of biosafety cabinets
- Door opening and closing
- Changes in room pressure
As a result, VAV technology enhances biosafety while significantly reducing energy consumption.
2.4 Exhaust Purification Solutions
Pathology laboratories frequently release volatile organic compounds (VOCs), such as formaldehyde, xylene, and ethanol. To ensure these pollutants meet emission standards, Guangzhou Kunling Environment designs customized purification solutions. These may include:
- Activated carbon adsorption
- Photocatalytic oxidation
- Hybrid purification systems
By selecting the right purification technology according to pollutant type and concentration, the system ensures compliant and environmentally safe discharge.
3. Key Construction and Installation Requirements
3.1 Duct Fabrication and Installation
Engineers must use duct materials that resist corrosion and ensure high airtightness. During construction, Guangzhou Kunling Environment follows strict installation standards. The team seals duct joints thoroughly, arranges support brackets properly, minimizes vibration and noise, and eliminates any risk of air leakage.
As a result, the system achieves long-term stability and reliable performance.
3.2 Fan Selection and Installation
The design team selects fans based on calculated airflow and system pressure loss. High-efficiency, low-noise centrifugal fans are typically preferred. Furthermore, vibration isolation must be incorporated into the fan base. Adequate space for inspection and maintenance must also be reserved. These measures ensure the system runs smoothly and safely over long periods.
3.3 Installation of Exhaust Purification Equipment
Technicians must install purification equipment—such as activated carbon adsorption boxes—in locations that allow easy maintenance. They also add sampling ports at both the inlet and outlet ducts.
Meanwhile, all equipment bases must be firmly secured. Duct connections must remain smooth and airtight, and sufficient space must be left for filter replacement and future servicing.
Guangzhou Kunling Environment ensures the purification system integrates seamlessly with the overall exhaust design.
4. Commissioning, Testing, and Final Acceptance
After construction, the team conducts comprehensive commissioning and testing to verify system performance.
- Airflow Balancing
Engineers measure and adjust the airflow at supply and exhaust terminals to meet the design values. - Pressure Gradient Verification
They confirm that each room maintains the required differential pressure and directional airflow. - Emission Testing
A certified third-party laboratory samples and analyzes exhaust emissions to confirm compliance with environmental standards. - Final Acceptance
Once all data meet the requirements, the team submits complete commissioning records, test reports, and as-built documentation for final handover.
5. Conclusion
The design and construction of a pathology laboratory ventilation and exhaust system require a comprehensive engineering approach involving airflow organization, biosafety protection, and environmental compliance. Success depends on rigorous design, standardized construction, and accurate system commissioning.
Guangzhou Kunling Environment specializes in laboratory environmental control engineering. The company offers end-to-end services—including technical consulting, system design, equipment supply, construction, commissioning, and project delivery—to help laboratories build safe, compliant, and reliable ventilation and exhaust systems.