Intent 1:
To limit the probability of:
- an excessively high cement/aggregate ratio, which could
lead to poor workability, excessive compressive strength and attendant
high shrinkage, which could lead to tensile stresses and the cracking
of mortar or masonry units, or
- an excessively low cement/aggregate ratio, which could
lead to weak, porous mortar and inadequate bonding with masonry units.
This is to limit the probability of:
- excessive moisture transfer through masonry units, or
- deformation or cracking, which could lead to:
- where masonry units support or are part of an environmental
separator, the excessive deformation, displacement or failure of required
environmental separation elements, or
- where masonry is used in chimneys and fireplaces, compromised
integrity of chimneys or fireplaces.
This is to limit the probability of:
- condensation,
- precipitation ingress,
- moisture ingress,
- pollutant ingress, or
- compromised thermal performance of components intended
to resist heat transfer.
This is to limit the probability of:
- an inadequate control of temperatures of interior spaces,
drafts, relative humidity or water accumulation,
- the generation of pollutants from biological growth
or from materials that become unstable on wetting,
- deterioration, which could lead to further compromised
integrity of environmental separators, or
- where masonry is used in chimneys and fireplaces, the
leakage of combustion products.
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.