What is the minimum fresh air required in an office?

For a standard low-pollutant office (Category II), the requirement is 7.5 l/s per person plus 0.6 l/s per m² of floor area. (Table 1)

How do I calculate total ventilation rate?

It's the sum of the rate required for occupants and the rate required for the building fabric: q_v,tot = q_v,pers + q_v,build. (Clause 5.2)

What are the building categories mentioned in the code?

Category I (low-polluting), Category II (medium-polluting, e.g., offices), Category III (high-polluting), and Category IV (very high-polluting). (Table 1, Note)

Is this code mandatory?

Its adoption is voluntary unless cited by a regulatory authority, such as in building energy codes like ECBC (Energy Conservation Building Code).

IS 9008 Part 1

: 2019

Energy Performance of Buildings - Part 1: General Requirements for HVAC Systems

CurrentSpecializedCode of PracticeBIMMEP · HVAC and Air Conditioning

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This standard specifies the minimum energy performance requirements for the design, installation, and commissioning of HVAC systems in buildings. It provides a comprehensive framework covering system design, equipment sizing, controls, and insulation to promote energy efficiency in building operations.

Specifies general requirements and methodologies for calculating and evaluating the energy performance of HVAC systems in buildings.

Quick Reference Values

Minimum office ventilation rate (Category II)7.5 l/s per person

Minimum office ventilation rate (per area)0.6 l/s per m²

Typical occupant density in office10 m² per person

Typical ACH for mechanically ventilated classroom3-4 ACH

Standard air density1.2 kg/m³

Specific heat of air1006 J/(kg·K)

Key Formulas

q_v,tot = q_v,pers + q_v,build — Total ventilation rate

P_fan_spec = Δp_tot / η_fan_tot — Specific fan power

Φ_V = ρ_a * c_a * q_v * (θ_supply - θ_outdoor) — Thermal energy for treating ventilation air

Practical Notes

This standard is aligned with international norms (ISO/EN) and is intended for detailed energy simulation and performance analysis, not just basic equipment sizing.

The total required ventilation rate is a sum of the rate for occupants (bio-effluents) and the rate for the building itself (diluting pollutants from materials). Both components must be calculated.

Pay close attention to the 'System Ventilation Efficiency' (Table A.2), a critical factor that represents how effectively fresh air is distributed to occupants.