Egg Breaking Operations

Egg breaking operations present unique HVAC challenges requiring precise environmental control to maintain food safety while supporting high-volume automated processing. The breaking room environment directly impacts bacterial control, product quality, worker safety, and sanitation effectiveness.

Environmental Design Criteria

Temperature Requirements

Breaking room temperature control serves multiple critical functions:

Primary Temperature Zones:

Breaking room temperature must balance bacterial inhibition with worker productivity. USDA 9 CFR 590.570 requires liquid eggs be maintained below 7°C (45°F) during processing, but the breaking environment operates slightly warmer to support human workers.

Temperature Control Strategy:

Q_total = Q_product + Q_equipment + Q_lighting + Q_workers + Q_ventilation + Q_infiltration

Where:

• Q_product = Sensible heat from incoming eggs and containers
• Q_equipment = Heat from breaking machines, conveyors, pumps
• Q_lighting = Heat from required illumination (minimum 540 lux)
• Q_workers = Metabolic heat (300-400 W per worker at moderate activity)
• Q_ventilation = Load from outdoor air for IAQ
• Q_infiltration = Leakage through doors and penetrations

Humidity Management

Relative humidity control prevents condensation while maintaining sanitation effectiveness:

Target Parameters:

• Operating RH: 50-60% at 10-13°C
• Maximum RH: 65% (condensation prevention)
• Minimum RH: 45% (dust control, worker comfort)

Dewpoint depression must be maintained above all surface temperatures:

ΔT_dp = T_surface - T_dewpoint ≥ 2.8°C (5°F)

Condensation Risk Surfaces:

• Stainless steel breaking machine frames
• Cold water piping for egg washing
• Refrigerated product collection tanks
• Exterior walls and columns
• Air distribution ductwork

Dehumidification load calculation:

m_water = (W_outdoor - W_indoor) × ṁ_air

Where:
W = Humidity ratio (kg water / kg dry air)
ṁ_air = Mass flow rate of ventilation air (kg/s)

Air Quality and Ventilation

Outdoor Air Requirements

ASHRAE 62.1 does not specifically address egg breaking facilities. Design values based on food processing industry standards:

Air Distribution Design

Supply Air Strategy:

Laminar downward airflow patterns minimize airborne contamination:

• Supply Velocity: 0.25-0.38 m/s (50-75 fpm) at diffuser face
• Distribution: Ceiling-mounted perforated panels or high-induction diffusers
• Throw: Short throw to occupied zone (1.5-2.5 m / 5-8 ft)
• Temperature Differential: 6-8°C (10-15°F) supply below space temperature

Exhaust Air Strategy:

Low-level exhaust removes heavier-than-air contaminants and floor-level moisture:

• Exhaust Location: 300-450 mm (12-18 in) above floor
• Placement: Near shell waste conveyors, floor drains, equipment cleaning stations
• Exhaust Rate: 70-80% of supply air (maintain positive pressure)

Pressurization Requirements

Positive pressure relative to adjacent spaces prevents contamination infiltration:

Pressure monitoring and control loops maintain differentials during door operation and equipment cycling.

Equipment Heat Loads

Breaking Machine Heat Generation

Automated breaking machines produce significant sensible heat:

Inline Breaking Equipment:

Motor and Drive Loads:

Q_motor = (HP × 0.746 kW/HP) / η_motor × η_drive

Where:
η_motor = Motor efficiency (0.90-0.95 for premium efficiency)
η_drive = Drive efficiency if VFD used (0.95-0.97)

Pumping and Transfer Equipment

Liquid egg transfer pumps and circulation systems:

Conveyor Systems

Shell egg infeed and shell waste removal conveyors:

• Infeed Conveyors: 3-10 kW depending on length and capacity
• Shell Waste Conveyors: 5-15 kW (material handling load)
• Product Transfer: 2-5 kW per system

Total equipment load for medium facility (200,000 eggs/hr capacity):

Q_equipment_total = 80-120 kW (273,000-410,000 BTU/hr)

Sanitation and Washdown Design

HVAC System Considerations

Corrosion-Resistant Construction

All HVAC components in breaking rooms require sanitation-grade materials:

Ductwork:

• Material: 316 stainless steel (preferred) or 304 SS minimum
• Joints: Continuously welded and ground smooth
• Interior Finish: 2B mill finish minimum, electropolished for critical areas
• Slope: 2% minimum toward drainage points

Air Distribution Devices:

• Diffusers: 316 SS with removable washable cores
• Grilles: Type 316 SS, no horizontal ledges for water accumulation
• Access Doors: Gasketed stainless steel frames

Drainage and Moisture Management

Condensate and washdown water management:

Condensate Drainage:

• Primary Drains: Trapped connections to sanitary sewer
• Secondary Drains: Required for all equipment above product zones
• Pipe Sizing: Oversized 50% for high-volume washdown flow
• Materials: Schedule 40 PVC or stainless steel

Washdown Protection:

Air Handling Unit Design

Breaking room AHU requirements:

Construction Features:

• Double-wall insulated panels, stainless steel exterior and interior
• Sloped drain pans, 316 SS construction
• Removable access panels on both sides for cleaning
• Cooling coils with minimum 8 fins per inch for cleanability
• Face velocity ≤2.5 m/s (500 fpm) to prevent moisture carryover

Coil Protection:

P_coil = (ρ × v²) / 2

Pressure drop increases with fouling; design for 2× clean pressure drop:
ΔP_design = 2 × ΔP_clean = 250-375 Pa (1.0-1.5 in wc)

Epoxy-coated or heresite-coated coils resist chemical cleaning agents.

Equipment Placement

Elevated Installation:

• AHUs located outside processing area or in dedicated mechanical rooms
• Supply ductwork penetrations sealed and sloped away from openings
• No horizontal ductwork runs above product zones
• Minimum clearance 2.5 m (8 ft) above floor to highest component

Access Requirements:

• Filter access from non-processing corridor
• Coil maintenance without entering breaking room during production
• Drain connections accessible for rodding and inspection

Product Temperature Maintenance

Immediate Cooling Requirements

Liquid egg temperature rises during breaking due to:

1. Ambient heat pickup in breaking room
2. Friction in pumps and piping
3. Mechanical agitation during separation

Temperature Rise Rate:

ΔT_product = (Q_total × t) / (m_product × Cp_product)

Where:
m_product = Product mass flow rate (kg/s)
Cp_product = Specific heat of liquid egg ≈ 3.6 kJ/(kg·K)
t = Residence time in processing area (s)
Q_total = Heat input rate (kW)

Cooling System Integration

Plate Heat Exchanger Cooling:

Liquid eggs cooled immediately after breaking:

Glycol System Design:

Secondary coolant for product cooling:

• Glycol Concentration: 30-35% propylene glycol
• Supply Temperature: -1 to 1°C (30-34°F)
• Return Temperature: 4-6°C (39-43°F)
• Flow Rate: Calculated for 3-5°C rise through heat exchangers

Storage Tank Environmental Control

Liquid egg holding tanks require conditioned space:

Tank Room Conditions:

• Temperature: 2-4°C (36-39°F)
• Humidity: 70-80% RH (cold space)
• Air Changes: 10-15 ACH for odor control
• Positive Pressure: +5 Pa relative to breaking room

Worker Comfort Considerations

Thermal Comfort in Cold Environments

ASHRAE Standard 55 does not directly apply to industrial cold environments. Design based on metabolic activity and clothing insulation.

Metabolic Rates for Breaking Room Workers:

Clothing Insulation (Clo Values):

• Light work clothing: 0.7-1.0 clo
• Insulated jacket and pants: 1.5-2.0 clo
• Required for 10-13°C environment: 1.2-1.5 clo

Thermal Balance:

Workers in 10°C breaking room with 1.5 clo clothing and 1.4 met activity experience:

PMV ≈ -0.5 to -1.0 (slightly cool to cool)

This is acceptable for industrial food processing environments where productivity and food safety override optimal thermal comfort.

Air Movement Considerations

Maximum Air Velocity:

• Occupied zone velocity: 0.4 m/s (80 fpm) maximum
• Higher velocities increase convective heat loss and worker discomfort
• Use low-velocity displacement or laminar flow diffusers

Radiant Temperature Asymmetry:

Cold walls and refrigerated surfaces create radiant heat loss:

Q_radiant = ε × σ × A × (T_skin⁴ - T_surface⁴)

Where:
ε = Emissivity (0.95 for skin, 0.15 for stainless steel)
σ = Stefan-Boltzmann constant = 5.67×10⁻⁸ W/(m²·K⁴)

Minimize radiant asymmetry through:

• Insulated wall panels (R-20 minimum)
• Elevated surface temperatures on equipment
• Radiant barriers on cold surfaces

Break Areas and Temperature Transition

Staging Spaces:

• Vestibule Temperature: 16-18°C (60-65°F)
• Break Room Temperature: 21-23°C (70-74°F)
• Transition Time: 5-10 minutes recommended

Rapid temperature transitions cause worker discomfort and condensation on PPE.

Regulatory Compliance

USDA Food Safety and Inspection Service (FSIS)

9 CFR Part 590 - Egg Products Inspection:

Relevant HVAC-related requirements:

§590.502 - Facilities and Operating Procedures:

• Rooms adequately ventilated to remove odors, vapors, and noxious fumes
• Temperature maintained to prevent adulteration
• Condensation controlled to prevent dripping onto product or surfaces

§590.570 - Operating Procedures:

• Liquid eggs maintained below 7°C (45°F) during processing
• Time-temperature control from breaking through pasteurization
• Sanitary conditions maintained at all times

FDA Food Safety Modernization Act (FSMA)

Current Good Manufacturing Practices (CGMPs):

21 CFR Part 117 establishes requirements:

§117.35 - Sanitary Operations:

• Buildings maintained in sanitary condition
• Adequate ventilation to minimize contamination
• Condensate and moisture controlled

§117.37 - Sanitary Facilities:

• Adequate lighting in processing areas (minimum 540 lux / 50 fc)
• Proper ventilation in areas where airborne contamination could occur

State and Local Requirements

Additional Considerations:

• Local health department approval of HVAC plans
• Energy code compliance (IECC, ASHRAE 90.1)
• Building code requirements for food processing facilities
• Fire protection integration with HVAC controls

System Design Criteria Summary

Air Handling System Sizing

Cooling Load Breakdown (200,000 eggs/hr facility):

Air System Capacity:

CFM_supply = (Q_sensible × 60) / (1.08 × ΔT)

For 240 kW sensible at 8°C ΔT:
CFM_supply = (240 × 3412 × 60) / (1.08 × 14.4) = 31,600 cfm

Or in SI units:
L/s = (Q_sensible × 1000) / (ρ × Cp × ΔT)
L/s = (240 × 1000) / (1.2 × 1005 × 8) = 24,900 L/s

Refrigeration System Capacity

Total Refrigeration Load:

• Breaking room cooling: 240 kW (68 tons)
• Product cooling (liquid egg): 180 kW (51 tons)
• Tank room cooling: 60 kW (17 tons)
• System losses and safety factor: 20%

Total Required Capacity: 575 kW (164 tons)

Refrigeration System Type:

• Ammonia screw package for facilities >350 kW
• HFO or CO₂ cascade for smaller facilities
• Glycol secondary loop for all product contact cooling

Control System Requirements

Monitored Parameters:

• Space temperature (±0.5°C accuracy)
• Space RH (±3% accuracy)
• Differential pressure (±1 Pa accuracy)
• Product temperature (±0.2°C accuracy)
• Filter differential pressure
• Refrigeration system parameters

Control Sequences:

1. Supply air temperature reset based on space temperature
2. Humidity control through reheat or desiccant system
3. Demand-controlled ventilation based on CO₂ or occupancy
4. Pressure control through modulating exhaust dampers
5. Night setback to 7°C space temperature during non-production

Interlocks:

• Breaking equipment start = HVAC system proven on
• Low space temperature alarm at 8°C
• High humidity alarm at 70% RH
• Loss of positive pressure alarm
• Refrigeration failure alarm

The integration of these systems ensures food safety compliance, product quality maintenance, and acceptable working conditions in egg breaking operations.