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KS17: Indoor Air Quality & Ventilation
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KS17: Indoor Air Quality & Ventilation

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This guide presents an overview of indoor air quality (IAQ) in buildings, and outlines how IAQ impacts on occupants’ health and performance. Ideally the surrounding environment and facilities in a particular space should provide healthy conditions in terms of sufficient fresh air, low pollution concentrations, adequate lighting and heating, access to drinking water and catering areas, and satisfactory sanitary installations. Cooling and/or air conditioning may also be needed depending on climate conditions and internal heat gains. The building should also have security and fire/smoke protection systems to protect the occupants and the building fabric in the event of unwanted intrusion and the outbreak of a fire or other undesirable high risk event (e.g. flooding).

Section 2 gives an overview of IAQ, regulations and standards, types of pollutants and allowable exposure limits, their impact on health, and the relationship between thermal comfort and IAQ.

Section 3 provides information on ventilation systems, and on the calculation of required flowrates to ensure good IAQ.

Section 4 explains how control of IAQ might be achieved.


1 Introduction

2 Indoor air quality (IAQ)

2.1 Definition and importance of IAQ
2.2 Why ventilation is required
2.3 Requirements for good IAQ
2.4 Regulations and standards
2.5 Common pollutants, pollutant sources and related health issues
2.5.1 Pollutant types

Gaseous pollutants
Volatile organic compounds (VOCs)
Water vapour

2.5.2 Pollutants and exposure limits (short/long term)
2.6 Occupant comfort and IAQ
2.7 Sick building syndrome (SBS)
2.8 External (outdoor) air pollution

3 Ventilation systems

3.1 Types of ventilation system
3.1.1 Natural ventilation
3.1.2 Mechanical ventilation
3.1.3 Mixed mode ventilation
3.2 Required ventilation flowrates for good IAQ
3.2.1 Fresh air Prescribed flow rates
3.2.2 Flows required for thermal comfort (heating)
3.2.3 Flows required for thermal comfort (cooling)
3.2.4 Flows between spaces and pressurisation
3.2.5 Pollutant removal
3.3 Measuring ventilation and IAQ
3.3.1 Measurement of flowrates

Tracer gas methods
Direct measurement methods

3.3.2 Measuring IAQ

4 Achieving optimum IAQ

4.1 Reducing the risk of poor IAQ
4.1.1 Fresh air supply rates
4.1.2 Well designed air distribution systems
4.1.3 Filtration
4.1.4 Regular maintenance of ventilation plant
4.1.5 Selection of materials to minimize pollutant emissions


Author: Eoin Clancy

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