9.32.3.4.(8)

Objective

OH1 Indoor Conditions

Attribution

(a),(b)[F81-OH1.1]
(c)[F53-OH1.1]

Intent

Intent 1:

[Clauses (a) and (b)] To limit the probability of the premature failure of outdoor air supply fans, which could lead to the inadequate replacement of indoor air with outdoor air.

This is to limit the probability of the inadequate control of:

  • airborne pollutants,
  • oxygen and other components necessary for breathable air, or
  • relative humidity, which could lead to condensation, which could lead to the generation of pollutants from biological growth or from materials that become unstable on wetting.

This is to limit the probability of negative effects on the air quality of indoor spaces, which could lead to harm to persons.

Intent 2:

[Clause (c)] To limit the probability that the outdoor air supply flow will not be equal to the normal operating exhaust capacity of the principal ventilation fan, which could lead to:

  • excessive negative pressure, or
  • excessive positive pressure.

This is to limit the probability of:

  • the inadequate control of airborne pollutants, or oxygen and other components necessary for breathable air,
  • the inadequate control of relative humidity, which could lead to condensation on interior surfaces,
  • where there is excessive negative pressure:
    • the ingress of soil gases (such as methane and radon),
    • the spillage of combustion products from fuel-burning appliances that are susceptible to spillage, or
    • moisture ingress from the ground, or
  • where there is excessive positive pressure, condensation within assemblies.

This is to limit the probability of negative effects on the air quality of indoor spaces, which could lead to harm to persons.

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