scope:

The scope of this document is:
- to specify methods to express the quality of indoor air suitable for human occupancy;
- to allow several acceptable target levels of IAQ, depending on local requirements, constraints
and expectations.
This document applies to:
- the design of new buildings and their systems and the retrofit of existing buildings and systems;
- indoor environments where the major concern is that of human occupants;
- buildings having any combination of mechanical and natural ventilation;
- commercial and institutional buildings (residential, industrial buildings and hospitals are not
covered).
Although this document does not cover industrial buildings and hospitals, some parts of such
buildings, which are similar to commercial buildings, are covered.
The requirements of this document may not achieve acceptable IAQ for all people in all buildings, due
to one or more of the following sources of uncertainty:
- the outdoor air brought into the building may be unacceptable or may not be adequately cleaned;
- the diversity of sources and contaminants in indoor air;
- the many factors that may affect occupant perception and acceptance of IAQ, such as air
temperature, humidity, noise, odours, lighting and psychological stress;
- the range of susceptibility and preference in the population.
Furthermore, different methods may lead to different decisions in relation to, for example, ventilation
rate. It is also true that different designers may reach different decisions, even when using the same
method, where the method requires the designer to make assumptions or interpretations.
Nevertheless, following a rational and documented process is expected to (a) enhance the design and
(b) make it easier to address any problems that do arise and incorporate experience gained into
future designs.