1. OS2
  2. OP2
  3. OS3
  4. OH1
  5. OS1
  6. OH4


OH1 Indoor Conditions


[F21,F80-OH1.1,OH1.2,OH1.3]Applies to elements that support or are part of an environmental separator.


Intent 1:

To limit the probability of the entrapment of moisture inside closed building envelopes, which could lead to:

  • excessive post-installation shrinkage and warping,
  • wood decay, which could lead to a loss of lumber strength, or
  • the exposure of other materials that are moisture-sensitive and susceptible to decay to high moisture levels and decay fungi.

Where lumber supports or is used in an environmental separator, this is to limit the probability of compromised performance of the building envelope, which could lead to:

  • condensation,
  • precipitation ingress, or
  • compromised thermal performance of components intended to provide resistance to heat transfer.

This is to limit the probability of:

  • an inadequate control of indoor air and surface temperatures, drafts, relative humidity, or water accumulation,
  • the generation of pollutants from biological growth or from materials that become unstable upon wetting, or
  • deterioration, which could lead to further compromised integrity of environmental separators.

This is to limit the probability of:

  • negative effects on the air quality of indoor spaces,
  • the inadequate thermal comfort of persons, and
  • contact with moisture.

This is to limit the probability of harm to persons.

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