Laboratory Airflow Testing and HVAC Balancing

HVAC Challenges in Laboratory Facilities

Laboratory HVAC systems face a set of challenges that are fundamentally different from general commercial HVAC. The primary purpose of laboratory ventilation is not comfort. It is contaminant control. The HVAC system must reliably dilute and exhaust airborne chemicals, biological agents, and particulates generated by laboratory operations. This imposes specific airflow requirements that cannot be compromised without creating safety hazards.

Fume hoods are the most critical ventilation safety device in most laboratories. A fume hood that does not achieve the specified face velocity, typically 80 to 100 feet per minute, does not provide adequate containment of the chemicals being used inside it. This is a measurable, verifiable condition, not a judgment call. Similarly, laboratory spaces must be maintained at negative pressure relative to adjacent corridors and support spaces to prevent chemical vapors from migrating to uncontrolled areas.

• Achieving and documenting specified fume hood face velocities across the full range of sash positions
• Maintaining laboratory spaces at negative pressure relative to adjacent corridors and offices
• Providing sufficient general exhaust to dilute contaminants to acceptable concentrations
• Coordinating variable air volume supply and exhaust systems to maintain room pressure as fume hood sash positions change
• Verifying HEPA filtration and biosafety cabinet performance in BSL-2 and BSL-3 environments
• Managing significant exhaust volumes while controlling facility energy costs

Testing and Balancing Services for Laboratory Facilities

Laboratory TAB begins with a comprehensive review of the mechanical design documents and the laboratory ventilation classification for each space. General chemistry labs, biology labs, tissue culture rooms, cold rooms, and instrument rooms each have specific ventilation requirements that must be identified and verified individually.

Fume hood testing is a core element of laboratory airflow testing. Face velocity measurements are taken across the full face of each hood at the specified sash height. On VAV fume hood systems, testing is performed at both minimum and maximum sash positions to verify that the control system correctly modulates exhaust airflow while maintaining the specified face velocity. Test results are compared to the design specification and to ASHRAE 110 acceptance criteria.

General laboratory air balancing verifies supply and exhaust airflows in each space. Room pressure relationships are confirmed using differential pressure gauges. For facilities with hydronic heating or cooling, hydronic balancing ensures that coils and terminal units receive design flow rates.

Industry Standards and Compliance

Laboratory ventilation is governed by several overlapping standards and guidelines. ASHRAE Standard 62.1 provides minimum ventilation requirements for occupied spaces, but laboratory ventilation typically must exceed these minimums significantly. ANSI/AIHA Standard Z9.5, Laboratory Ventilation, provides guidance on laboratory airflow design and performance criteria. ASHRAE Laboratory Design Guide offers detailed technical guidance on laboratory HVAC system design and verification.

Fume hood performance is assessed against ASHRAE Standard 110, Method of Testing Performance of Laboratory Fume Hoods, which defines face velocity measurement methodology and acceptance criteria. For pharmaceutical facilities, FDA guidelines and current Good Manufacturing Practice (cGMP) requirements impose additional documentation and change control requirements on HVAC systems that affect product quality.

Biosafety Level 2 and 3 laboratories must meet the requirements of the CDC/NIH Biosafety in Microbiological and Biomedical Laboratories (BMBL) guidelines, which specify directional airflow, minimum air change rates, and HEPA filtration requirements. These requirements must be verified by testing and documented before the facility receives approval for use with the relevant biological agents.

Our Testing and Balancing Process

1. System Evaluation. We review mechanical drawings, laboratory ventilation schedules, fume hood specifications, and applicable standards to understand design intent and testing requirements for each space and device.
2. Airflow Measurement. Supply and exhaust airflows are measured at every terminal device. General exhaust, fume hood exhaust, and biosafety cabinet exhaust are measured separately and compared to design values.
3. Fume Hood Face Velocity Testing. Face velocity is measured at multiple points across the hood face at the design sash position. For VAV hoods, testing is performed across the full sash range. Results are compared to specification and ASHRAE 110 criteria.
4. Room Pressurization Verification. Differential pressure between each laboratory space and adjacent corridors or support spaces is measured and documented. Door undercut airflow is assessed in spaces requiring maintained negative pressure with doors open.
5. System Adjustment. Dampers, VAV controllers, and balancing devices are adjusted to achieve design airflows and room pressure relationships. Coordination with the controls contractor ensures correct tracking between supply and exhaust on VAV systems.
6. Final Verification and Reporting. Final measurements are recorded for all spaces and devices. A certified TAB report documents design values, measured values, and final conditions for use in the commissioning record and facility documentation package.

Serving Laboratory Facilities Across the Tennessee Valley

MGM Associates provides lab ventilation testing and HVAC balancing for university research buildings, government research facilities, pharmaceutical laboratories, and commercial research spaces throughout North Alabama and the Tennessee Valley. We work with mechanical engineers, laboratory planners, general contractors, and commissioning agents on projects of all sizes.

• Huntsville and Madison County, Alabama
• Guntersville and Marshall County, Alabama
• Decatur and the Tennessee Valley corridor
• Birmingham and North-Central Alabama
• Chattanooga, Tennessee
• Nashville and Middle Tennessee

Related HVAC Testing and Balancing Services

Laboratory airflow testing is a specialized application within our full range of commercial HVAC testing and balancing services. Related services for laboratory projects include:

• Air balancing: supply, exhaust, and transfer air verification for all laboratory spaces
• Hydronic balancing: heating and cooling coil flow verification