European Ventilation Standards EN 13779 to EN 16798

European Ventilation Standards: EN 13779 to EN 16798

European ventilation standards establish the technical framework for ventilation system design, indoor environment quality classification, energy performance assessment, and testing procedures across all EU member states. The primary standards—EN 13779 (now superseded by EN 16798), EN 15251 (replaced by EN 16798-1), EN 12599 for testing, and EN 13053 for air handling unit ratings—define ventilation rate methodologies, indoor air quality categories, air cleanliness classifications, energy efficiency metrics, and commissioning protocols that differ substantively from North American approaches codified in ASHRAE Standards 62.1 and 62.2.

EN 16798: Energy Performance of Buildings - Ventilation

Standard Development and Structure

Transition from EN 13779 and EN 15251: EN 16798 series replaced and consolidated earlier European ventilation standards effective 2019, providing updated methodology aligned with Energy Performance of Buildings Directive (EPBD) requirements. The standard addresses energy performance calculation while maintaining ventilation design principles.

EN 16798 series structure:

• EN 16798-1: Indoor environmental input parameters for design and assessment of energy performance including air quality, thermal environment, lighting, and acoustics
• EN 16798-2: Interpretation of requirements in EN 16798-1 for commercial buildings
• EN 16798-3: Ventilation for non-residential buildings - Performance requirements for ventilation and room-conditioning systems
• EN 16798-5: Calculation methods for energy requirements of ventilation systems
• EN 16798-7: Calculation of system ventilation effectiveness
• EN 16798-9: Calculation methods for residential ventilation
• EN 16798-13: Calculation of cooling systems
• EN 16798-15: Energy performance of buildings - Ventilation for buildings - Calculation methods for energy requirements of heating systems
• EN 16798-17: Ventilation for buildings - Guidelines for inspection of ventilation systems

Indoor Air Quality Categories (EN 16798-1)

Classification system: EN 16798-1 establishes four indoor air quality (IAQ) categories based on occupant expectations and building type, fundamentally different from ASHRAE 62.1’s prescriptive approach.

Design principle: Select IAQ category during design phase based on building purpose, occupant expectations, energy performance targets, and economic constraints. Higher categories require increased ventilation rates but provide superior occupant satisfaction and productivity.

Ventilation Rate Determination

Two complementary methods:

Method A: Ventilation rate based on perceived air quality:

The required ventilation rate accounts for emissions from both occupants and building materials:

$$q_{tot} = n \cdot q_p + A \cdot q_B$$

Where:

• $q_{tot}$ = Total required ventilation rate (L/s)
• $n$ = Number of occupants (persons)
• $q_p$ = Ventilation rate per person (L/s·person)
• $A$ = Floor area (m²)
• $q_B$ = Ventilation rate per floor area for building emissions (L/s·m²)

Category-specific ventilation rates (low-polluting buildings):

High-polluting buildings: For spaces with significant material emissions (new construction with low-emission materials not selected), multiply $q_B$ by correction factors 1.5-3.0 depending on emission level.

Method B: Ventilation rate based on specific contaminants:

For spaces with known dominant contaminants (CO₂ in densely occupied spaces, specific pollutants in industrial ventilation):

$$q = \frac{G}{C_i - C_o}$$

Where:

• $q$ = Required ventilation rate (m³/s)
• $G$ = Contaminant generation rate (mg/s or L/s for CO₂)
• $C_i$ = Indoor design concentration limit (mg/m³ or ppm)
• $C_o$ = Outdoor contaminant concentration (mg/m³ or ppm)

CO₂-based calculation (metabolic generation):

$$q_{CO_2} = \frac{n \cdot G_{CO_2}}{C_{i,CO_2} - C_{o,CO_2}}$$

Where:

• $G_{CO_2}$ = CO₂ generation per person ≈ 19 L/h (0.0053 L/s) for sedentary office work
• $C_{i,CO_2}$ = Indoor CO₂ concentration limit (ppm above outdoor)
• $C_{o,CO_2}$ = Outdoor CO₂ concentration (typically 400 ppm)

Category-specific CO₂ limits:

Comparison with ASHRAE 62.1

Fundamental approach differences:

Office space example comparison (100 m², 7 occupants):

EN 16798-1 Category II:

• Person component: 7 × 7 = 49 L/s
• Building component: 100 × 0.35 = 35 L/s
• Total: 84 L/s (178 cfm, 0.84 L/s·m² or 1.67 cfm/ft²)

ASHRAE 62.1-2022 (Office, Table 6-1):

• Person component: 7 × 2.5 = 17.5 L/s
• Area component: 100 × 0.06 × 2.118 = 12.7 cfm = 6.0 L/s
• Total: 23.5 L/s (50 cfm, 0.235 L/s·m² or 0.47 cfm/ft²)

Result: EN 16798 Category II requires 3.6× the ventilation rate of ASHRAE 62.1 for typical office spaces, reflecting European emphasis on perceived air quality and material emissions.

Outdoor Air Quality Classification

EN 16798-1 outdoor air quality (ODA) categories:

Air filtration requirements: Outdoor air must be filtered to achieve supply air quality (SUP) matching or exceeding indoor air quality category requirements.

Supply air categories (after filtration):

Filter selection logic: Combine ODA category with required SUP category to determine minimum filter efficiency. Example: ODA 3 (urban) with Category II building (SUP 2 required) mandates minimum ISO ePM1 ≥ 50% filter (equivalent to MERV 13-14).

graph TD
    A[Determine Outdoor Air Quality ODA] --> B{ODA Category}
    B -->|ODA 1-2| C[SUP 2: ISO ePM1 ≥50%]
    B -->|ODA 3| D[SUP 2: ISO ePM1 ≥50% + Prefilter]
    B -->|ODA 4-5| E[SUP 2: ISO ePM1 ≥70% + Prefilter]
    C --> F[Supply Air Meets IAQ Category]
    D --> F
    E --> F
    F --> G[Distribute to Occupied Spaces]

EN 13053: Air Handling Unit Ratings and Performance

Scope and Application

EN 13053 establishes classification and rating system for air handling units (AHUs) covering thermal performance, air leakage, filter bypass, mechanical strength, and heat recovery efficiency. The standard enables comparison between manufacturers and specification of minimum performance requirements.

Classification Parameters

Thermal transmittance (insulation class):

Air leakage class (at ±400 Pa, ±700 Pa, or ±1000 Pa test pressure):

Mechanical strength:

Filter bypass class:

Heat Recovery Efficiency Classification

Temperature efficiency at design conditions:

$$\eta_t = \frac{t_{supply} - t_{outdoor}}{t_{extract} - t_{outdoor}} \times 100%$$

Where:

• $\eta_t$ = Temperature efficiency (%)
• $t_{supply}$ = Supply air temperature after heat recovery (°C)
• $t_{outdoor}$ = Outdoor air temperature (°C)
• $t_{extract}$ = Extract air temperature (°C)

EN 13053 efficiency classes:

Humidity recovery (enthalpic exchangers):

Additional classification for moisture transfer effectiveness:

$$\eta_x = \frac{x_{supply} - x_{outdoor}}{x_{extract} - x_{outdoor}} \times 100%$$

Where:

• $\eta_x$ = Moisture recovery efficiency (%)
• $x$ = Absolute humidity (g/kg)

Typical AHU specification example: Classification: EN 13053 - T2 L1 D1 F5 H1

• T2: U-value ≤ 0.5 W/m²·K
• L1: Air leakage ≤ 0.15% + 0.06 L/s·m² at 400 Pa
• D1: Panel deflection ≤ 4 mm/m at 2000 Pa
• F5: Filter bypass ≤ 0.5%
• H1: Heat recovery efficiency ≥ 90%

This specification ensures high-performance unit suitable for Category I or II buildings with energy recovery ventilation.

EN 12599: Ventilation Testing and Measurement Procedures

Standard Scope

EN 12599 establishes protocols for testing, adjusting, and balancing (TAB) of ventilation and air conditioning systems to verify compliance with design specifications. The standard defines measurement methods, instrumentation accuracy requirements, test conditions, and documentation formats.

Measurement Parameters and Methods

Air flow rate measurement:

Duct traverse method (EN 12599 Section 6.1):

$$Q = A \cdot \bar{v}$$

Where:

• $Q$ = Volume flow rate (m³/s)
• $A$ = Duct cross-sectional area (m²)
• $\bar{v}$ = Mean air velocity from traverse (m/s)

Traverse point requirements:

Measurement accuracy requirements:

Supply/extract terminal flow measurement:

Flow hood method: Preferred for ceiling diffusers and grilles where duct access unavailable. Accuracy: ±10% for flows > 50 L/s, decreases for lower flows.

Balancing tolerance:

System Performance Testing

Air handling unit verification (EN 12599 Section 7):

Parameters tested:

1. Total supply and extract air flow rates
2. Outdoor, supply, return, and exhaust air temperatures
3. Filter pressure drops
4. Heat recovery efficiency (temperature and enthalpy)
5. Fan power consumption
6. Supply and extract static pressures
7. Sound levels at unit and in occupied spaces

Heat recovery efficiency field test:

Measure temperatures at four points simultaneously under steady-state conditions:

$$\eta_{field} = \frac{t_2 - t_1}{t_3 - t_1} \times 100%$$

Where:

• $t_1$ = Outdoor air temperature before heat recovery (°C)
• $t_2$ = Supply air temperature after heat recovery (°C)
• $t_3$ = Extract air temperature before heat recovery (°C)

Acceptance criteria: Measured efficiency ≥ 90% of manufacturer rating (e.g., 85% rated requires ≥ 76.5% field measurement).

Specific fan power (SFP) verification:

$$SFP = \frac{P_{fan}}{Q}$$

Where:

• $SFP$ = Specific fan power (W/(m³/s) or kW/(m³/s))
• $P_{fan}$ = Total electrical power of all fans (supply + extract) (W)
• $Q$ = Air flow rate (m³/s)

Convert to common European unit W/(L/s): Divide by 1000.

EN 16798-3 SFP limits (supply + extract combined):

Room air quality verification:

Minimum testing duration: 48 hours of normal occupancy after system balancing complete.

Monitored parameters:

• CO₂ concentration (continuous or periodic sampling)
• Temperature and relative humidity
• Air velocity at workstations (< 0.15-0.25 m/s depending on category)
• Acoustic noise level (< 30-45 dB(A) depending on category)

Documentation Requirements

Test report contents (EN 12599 Annex C):

1. System description and design specifications
2. Test conditions (outdoor temperature, occupancy level, system operating mode)
3. Measurement instruments used (model, serial number, calibration date)
4. Measured data with location identifications
5. Comparison of measured vs. design values
6. Deviations and corrective actions taken
7. System balancing calculations and adjustments
8. Final verification of compliance
9. Commissioning sign-off

Energy Performance Calculation (EN 16798-5)

Ventilation System Energy Calculation Methodology

EN 16798-5 provides standardized calculation method for annual energy consumption of ventilation systems, supporting EPBD compliance and energy performance certificate (EPC) calculations.

Total ventilation energy:

$$E_{vent,tot} = E_{fans} + E_{heat} - E_{rec} + E_{cool} + E_{hum}$$

Where:

• $E_{vent,tot}$ = Total annual ventilation system energy (kWh/year)
• $E_{fans}$ = Fan electrical energy (kWh/year)
• $E_{heat}$ = Heating energy for supply air (kWh/year)
• $E_{rec}$ = Energy recovered by heat recovery (kWh/year)
• $E_{cool}$ = Cooling energy for supply air (kWh/year)
• $E_{hum}$ = Humidification energy (kWh/year)

Fan energy calculation:

$$E_{fans} = SFP \cdot Q \cdot t_{op} \cdot f_{ctrl}$$

Where:

• $SFP$ = Specific fan power (kW/(m³/s))
• $Q$ = Air flow rate (m³/s)
• $t_{op}$ = Annual operating hours (hours/year)
• $f_{ctrl}$ = Control factor (0.4-1.0, accounting for VAV, scheduling, etc.)

Heating energy without heat recovery:

$$E_{heat,no-rec} = \rho \cdot c_p \cdot Q \cdot (t_{supply} - t_{outdoor,avg}) \cdot t_{op}$$

Where:

• $\rho$ = Air density (1.2 kg/m³)
• $c_p$ = Specific heat of air (1.005 kJ/kg·K)
• $t_{supply}$ = Supply air temperature setpoint (°C)
• $t_{outdoor,avg}$ = Average outdoor temperature during heating season (°C)

Energy saved by heat recovery:

$$E_{rec} = \eta_{HR} \cdot E_{heat,no-rec}$$

Where:

• $\eta_{HR}$ = Seasonal heat recovery efficiency (accounting for bypass, defrost, etc.)

Net heating energy requirement:

$$E_{heat} = E_{heat,no-rec} - E_{rec} = (1 - \eta_{HR}) \cdot E_{heat,no-rec}$$

Seasonal Performance Adjustments

Heat recovery efficiency correction factors:

Effective seasonal efficiency:

$$\eta_{seasonal} = \eta_{rated} \cdot f_{degrad} \cdot f_{bypass} \cdot f_{defrost}$$

Example calculation (Northern Europe office building):

• Design outdoor air flow: 5000 m³/h (1.39 m³/s)
• SFP: 1.8 kW/(m³/s) (supply + extract)
• Heat recovery rated efficiency: 85%
• Operating hours: 3500 hours/year (weekdays, 10 hours/day)
• Control factor: 0.7 (VAV with night/weekend shutdown)
• Supply temperature: 18°C
• Heating season average outdoor temperature: 5°C
• Seasonal HR efficiency: 85% × 0.95 × 0.80 × 0.90 = 58%

Fan energy:

$$E_{fans} = 1.8 \times 1.39 \times 3500 \times 0.7 = 6,126 \text{ kWh/year}$$

Heating energy without recovery:

$$E_{heat,no-rec} = 1.2 \times 1.005 \times 1.39 \times (18-5) \times 3500 = 76,000 \text{ kWh/year}$$

Energy recovered:

$$E_{rec} = 0.58 \times 76,000 = 44,080 \text{ kWh/year}$$

Net heating energy:

$$E_{heat} = 76,000 - 44,080 = 31,920 \text{ kWh/year}$$

Total ventilation energy:

$$E_{vent,tot} = 6,126 + 31,920 = 38,046 \text{ kWh/year}$$

Energy savings from heat recovery: 44,080 kWh/year (58% reduction in heating energy)

Primary energy impact (electricity factor 2.0, heat factor 1.0):

• Fan primary energy: 6,126 × 2.0 = 12,252 kWh PE/year
• Heating primary energy: 31,920 × 1.0 = 31,920 kWh PE/year (assuming district heating)
• Total: 44,172 kWh PE/year

Without heat recovery, total would be 88,252 kWh PE/year (50% reduction achieved).

Residential Ventilation (EN 16798-9)

Residential Ventilation Rate Requirements

Whole-dwelling ventilation rate:

$$q_{tot,dwelling} = n_{bedrooms} \cdot q_{bedroom} + A_{living} \cdot q_{living}$$

Typical minimum rates (Category II residential):

Alternative approach: Air change rate method:

$$q_{ACH} = \frac{n \cdot V}{3600}$$

Where:

• $n$ = Air changes per hour (ACH)
• $V$ = Dwelling volume (m³)

Minimum air change rates:

Residential Ventilation System Types

System classification per EN 16798-9:

System A: Natural supply and extract:

• Windows, trickle vents, passive stacks
• No mechanical components
• Lowest energy consumption (zero electrical)
• Climate-dependent performance
• Indoor air quality: Category III-IV typically

System B: Mechanical extract only:

• Continuous or intermittent extract fans
• Natural supply through trickle vents or grilles
• Low energy consumption (50-150 W)
• Depressurizes dwelling
• Indoor air quality: Category II-III achievable

System C: Mechanical supply only:

• Mechanical supply with natural exhaust
• Pressurizes dwelling (positive pressure prevents infiltration)
• Moderate energy consumption
• Uncommon in residential (more typical in commercial)

System D: Balanced mechanical supply and extract with heat recovery:

• Supply and extract fans with heat exchanger
• Highest indoor air quality potential (Category I-II)
• Highest energy consumption for fans (200-500 W)
• Significant heating energy savings (40-70%)
• Increasingly mandated in NZEB residential construction

Energy comparison (100 m² dwelling, Northern Europe):

Conclusion: Despite higher fan energy, System D reduces total energy by 37% compared to natural ventilation through heat recovery.

Implementation in Practice

Design Workflow Using European Standards

flowchart TD
    A[Project Definition] --> B[Select IAQ Category EN 16798-1]
    B --> C{Building Type?}
    C -->|Residential| D[Apply EN 16798-9 Rates]
    C -->|Non-Residential| E[Calculate q_p and q_B EN 16798-1]
    D --> F[Select System Type A/B/D]
    E --> G[Determine ODA Category]
    G --> H[Select Filters for SUP Target]
    F --> I[Size Air Handling Equipment]
    H --> I
    I --> J[Specify AHU per EN 13053 T-L-D-F-H]
    J --> K[Calculate SFP EN 16798-3]
    K --> L{SFP Within Limits?}
    L -->|No| M[Optimize Ductwork/Fans]
    L -->|Yes| N[Detailed Design and Drawings]
    M --> K
    N --> O[Testing per EN 12599]
    O --> P[Energy Calc EN 16798-5]
    P --> Q[Documentation and Commissioning]

Specification Example: Office Building

Project parameters:

• Floor area: 2,000 m²
• Occupancy: 0.07 persons/m² = 140 persons
• IAQ target: Category II
• Location: Urban (ODA 3)
• Operating schedule: 10 hours/day, 250 days/year

Ventilation rate calculation (EN 16798-1 Method A):

$$q_{tot} = 140 \times 7 + 2000 \times 0.35 = 980 + 700 = 1,680 \text{ L/s} = 6,048 \text{ m³/h}$$

System selection: Balanced mechanical ventilation with heat recovery (mandatory for Category II new construction per national building codes)

AHU specification:

• Nominal flow: 6,500 m³/h (8% safety margin)
• Classification: EN 13053 T2 L1 D1 F5 H1
• Heat recovery: Counterflow plate exchanger, 85% efficiency
• Supply air filters: ISO ePM1 60% (F7 equivalent, for ODA 3 to SUP 2)
• Extract air filters: ISO Coarse 60% (G4 equivalent)
• Target SFP: 1.8 kW/(m³/s) maximum

Filter pressure drop budget:

• Outdoor air intake: ISO Coarse 60% @ 75 Pa (average)
• Supply air: ISO ePM1 60% @ 150 Pa (average)
• Extract air: ISO Coarse 60% @ 75 Pa
• Total filtration: 300 Pa

System pressure budget:

• Supply ductwork: 400 Pa

• Supply diffusers: 50 Pa

• AHU internal (coils, HX, dampers): 250 Pa

• Filters (supply side): 225 Pa

• Total supply static pressure: 925 Pa

• Extract ductwork: 350 Pa

• Extract grilles: 30 Pa

• AHU internal: 200 Pa

• Extract filter: 75 Pa

• Total extract static pressure: 655 Pa

Fan sizing:

• Supply fan: 6,500 m³/h @ 925 Pa → 1.85 kW (η = 0.60)
• Extract fan: 6,500 m³/h @ 655 Pa → 1.35 kW (η = 0.60)
• Total fan power: 3.20 kW

SFP verification:

$$SFP = \frac{3,200}{6,500/3,600} = 1.78 \text{ kW/(m³/s)} = 1.78 \text{ W/(L/s)}$$

Result: Within EN 16798-3 limit of 2.0 W/(L/s) for non-residential with heat recovery.

Summary

European ventilation standards EN 16798, EN 13053, and EN 12599 establish comprehensive technical framework encompassing indoor air quality categorization (Category I-IV based on occupant expectations), ventilation rate determination combining occupant-based and building emission components (2.5-10 L/s·person plus 0.1-0.5 L/s·m²), outdoor air quality classification requiring appropriate filtration (ODA 1-5 categories), air handling unit performance specifications (thermal transmittance, air leakage, mechanical strength, filter bypass, heat recovery efficiency classes), testing and balancing procedures with defined measurement accuracy requirements, and energy performance calculation methodologies. These standards differ fundamentally from ASHRAE 62.1 through category-based design flexibility, explicit consideration of building material emissions, typically higher ventilation rates for equivalent spaces, stringent air handling unit leakage requirements, mandatory heat recovery for higher performance categories, and integration with Energy Performance of Buildings Directive compliance calculations, collectively establishing European best practice for ventilation system design, specification, installation, testing, and energy performance verification.

Components

• EN 13779 Ventilation Non Residential
• EN 15251 Indoor Environment Criteria
• EN 16798 Energy Performance Buildings Ventilation
• EN 12599 Ventilation Testing Procedures
• EN 13053 Air Handling Units Ratings