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


OS1 Fire Safety


[F20,F61-OS1.2]Applies to assemblies required to provide fire resistance.


Intent 1:

To limit the probability of:

  • excessively thick mortar joints in relation to the surface area of the masonry, which could lead to water leakage through shrinkage cracks and water absorption through mortar joints, or
  • excessively thin mortar joints, which could lead to inadequate support of masonry or inadequate masonry-to-mortar bond strength, which could lead to cracking.

This is to limit the probability of precipitation or meltwater ingress, which could lead to deterioration due to freeze-thaw stresses.

Where masonry construction is required to provide fire resistance, this is to limit the probability of compromised fire resistance of the assembly, which could lead to harm to persons.

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