Maintaining proper airflow, pressure, and temperature control is critical in food processing facilities to ensure product consistency, worker safety, and regulatory compliance. A well-functioning ventilation system helps control airborne contaminants, maintain comfortable working conditions, and prevent cross-contamination — all of which are essential in the food industry.
One of the most effective ways to optimize a ventilation system’s performance is through TABB — Testing, Adjusting, and Balancing. TABB is a structured process used to measure, fine-tune, and stabilize airflow and pressure levels to match design specifications. When done correctly, it ensures that a facility’s ventilation system operates at peak efficiency while meeting health, safety, and food industry standards.
This guide covers the technical details of the TABB process, common issues, and best practices specific to food processing environments.
Why TABB Matters in Food Processing Facilities
Food processing environments present unique ventilation challenges due to the materials, processes, and strict sanitary requirements involved. Without proper ventilation, facilities face issues such as:
- Airborne Particles – Flour, sugar, spices, and other fine ingredients can become airborne, creating dust hazards and contamination risks.
- Humidity and Temperature Control – Cooking, baking, and cleaning processes generate heat and moisture that need to be controlled to prevent mold and bacterial growth.
- Odor and Grease Management – Frying and roasting processes produce odors and grease-laden vapors that must be efficiently extracted.
- Cross-Contamination Risks – Maintaining proper pressure differentials between clean zones and processing zones is essential to prevent contamination.
- Compliance and Safety – Regulatory bodies like OSHA, FDA, and NFPA have strict guidelines for air quality, fire safety, and worker health that require proper ventilation and dust control.
TABB ensures that all parts of the ventilation system are working together to meet these challenges, improving energy efficiency, air quality, and operational safety.
Key Steps to Perform TABB in Food Processing Facilities
1. Pre-TABB Inspection and Planning
Effective TABB starts with a thorough understanding of the facility’s ventilation design and operational goals. Before beginning the process, collect and review:
HVAC and ventilation system design specifications
Floor plans and zoning details
Equipment types and capacities (e.g., fans, dampers, dust collectors)
Regulatory and safety requirements (OSHA, FDA, NFPA)
What to Inspect:
- Confirm proper installation of fans, ducts, dampers, and collectors.
- Check for blockages, leaks, or corrosion in the ductwork.
- Ensure that dampers and louvers are positioned correctly.
- Inspect filters and dust collection units for clogging or wear.
- Ensure that baghouse or cyclone dust collectors are installed according to the manufacturer’s recommendations.
Technical Insight:
- Verify that fan curves align with system specifications to prevent overloading or underperformance.
- Cross-check duct sizing and material specifications with ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) guidelines.
- Ensure that exhaust hoods meet the NFPA 96 standard for grease-laden vapor extraction.
2. Testing Phase
Testing involves measuring actual airflow, pressure, and temperature levels to compare them with design values.
Airflow Testing
Equipment Used:
- Anemometer (for velocity)
- Balometer (for volumetric flow)
- Pitot tube (for differential pressure)
Key Metrics:
- Air Changes per Hour (ACH): Ensures that fresh air is being supplied at the correct rate.
- Face Velocity: Test at fume hoods and exhaust vents to confirm proper containment of vapors and particulates.
- Return vs. Supply Air: Ensure balanced rates to prevent pressurization or negative pressure issues.
Formula for Volumetric Flow Rate:
Q=V×AQ = V \times AQ=V×A
where:
- QQQ = Airflow rate (CFM)
- VVV = Velocity (FPM)
- AAA = Cross-sectional area of the duct (sq. ft.)
Target Values:
- Clean rooms – 20–40 ACH
- Cooking zones – Face velocity of 100–150 FPM at exhaust hoods
- Packaging areas – Positive pressure of +0.02” to +0.05” WC
Temperature and Humidity Testing
Equipment Used:
- Thermohygrometer
- Infrared temperature gun
Key Metrics:
- Temperature Setpoints: Confirm that HVAC units are holding setpoints within ±2°F.
- Humidity Levels: Keep relative humidity (RH) between 40%–60% to prevent mold growth and ensure ingredient stability.
Pressure Testing
Equipment Used:
- Manometer (static pressure)
- Inclined tube manometer (low-pressure areas)
Key Metrics:
- Static Pressure: Confirm that pressure drops across fans and filters are within system tolerances.
- Room Pressure Differential:
- Clean zones should be +0.02” to +0.05” WC.
- Odor or dust-producing zones should maintain negative pressure of -0.02” to -0.05” WC.
- Exhaust Flow: Ensure that exhaust systems are moving 90%–110% of design flow rate.
3. Adjusting Phase
Adjusting involves modifying system settings based on test results to bring the system into alignment with design specifications.
Fan Speed and Damper Adjustment
- Adjust fan speed using the variable frequency drive (VFD) or manual controls.
- Fine-tune damper positions to achieve equal airflow distribution.
Technical Insight:
- Adjusting centrifugal and axial fan speeds should not exceed motor load capacity.
- Use a pitot traverse to calculate actual velocity pressure and adjust fan output accordingly.
Dust Collector and Air Filtration Adjustments
- Clean or replace filters in baghouse or cyclone collectors.
- Adjust dust collector pulse-cleaning cycles for higher efficiency.
- Check air-to-cloth ratio in baghouse collectors — maintain a ratio of 3:1 to 5:1 for fine dusts.
Temperature and Humidity Adjustments
- Adjust HVAC dampers for better temperature distribution.
- Increase or decrease dehumidifier settings based on humidity tests.
4. Balancing Phase
Balancing ensures that airflow, temperature, and pressure levels are consistent throughout the system.
Airflow Balancing
- Adjust terminal dampers until supply and return airflows match design specs.
- Confirm that airflow rates are within 5% of design values.
Pressure Balancing
- Fine-tune louver positions to maintain positive or negative pressure where needed.
- Confirm that total exhaust rate equals total supply rate ±10%.
5. Post-TABB Verification and Documentation
✅ Measure and record final system performance.
✅ Ensure all pressure and flow setpoints are met.
✅ Prepare a comprehensive report with:
- Final airflow and pressure values
- Equipment settings
- Recommendations for future maintenance
Common Issues and Troubleshooting
| Problem | Cause | Solution |
| Uneven airflow | Obstructed ducts or misaligned dampers | Adjust dampers and remove obstructions |
| High humidity levels | Inadequate dehumidification | Increase dehumidifier capacity |
| Dust escaping collection systems | Worn seals or overloaded baghouse | Replace seals and adjust pulse-cleaning cycles |
| Odor carryover | Exhaust system imbalance | Adjust fan speeds and exhaust volume |
Best Practices for Effective TABB
✔️ Use aluminum impellers for lightweight, high-speed applications.
✔️ Keep fan speeds at 80%–90% of full load for energy efficiency.
✔️ Clean baghouse collectors every 1,000–2,000 hours of operation.
✔️ Use stainless steel fans for high-moisture zones to prevent corrosion.
✔️ Conduct TABB annually to maintain performance.
Final Thoughts
TABB is not a one-time event — it’s an ongoing process that ensures your food processing facility operates at peak performance. Effective ventilation protects product integrity, maintains worker comfort, and helps meet strict regulatory standards.