Intent 1:
To limit the probability that the concrete will
not flow around the aggregate in the typically thin wall and slab
sections used in Part 9 buildings, which could lead to aggregate segregation,
which could lead to:
- reduced compressive strength,
- increased shrinkage and cracking, or
- low resistance to air and moisture transfer.
This is to limit the probability of:
- spalling,
- inadequate performance, or
- premature failure of concrete under expected environmental
or structural loads.
Where concrete supports or is used in the walls of chimneys
or fireplaces, to limit the probability of the inadequate performance
or premature failure of concrete under expected environmental or structural
loads, which could lead to the failure of these walls.
This is to limit the probability of the leakage of combustion
products, which could lead to negative effects on the air quality
of indoor spaces, which could lead to harm to persons.
Intent 2:
To limit the probability that the concrete will
not flow around the aggregate in the typically thin wall and slab
sections used in Part 9 buildings, which could lead to aggregate segregation,
which could lead to:
- reduced compressive strength,
- increased shrinkage and cracking, or
- low resistance to air and moisture transfer.
This is to limit the probability of:
- spalling,
- inadequate performance, or
- premature failure of concrete under expected environmental
or structural loads.
Where concrete supports or is used in an environmental separator,
to limit the probability of the inadequate performance or premature
failure of concrete under expected environmental or structural loads.
This is to limit the probability of:
- the compromised integrity of the environmental separator,
or
- an inadequate resistance to air and moisture transfer
through the concrete.
This is to limit the probability of:
- pollutant ingress (from the exterior or from adjacent
interior space, including soil gas, combustion products from parking
garages, and particulates),
- precipitation ingress,
- condensation,
- the ingress of moisture from the ground, or
- the compromised thermal performance of components intended
to provide resistance to heat transfer.
This is to limit the probability of:
- 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
- an inadequate control of indoor air and surface temperatures,
drafts, relative humidity, or water accumulation.
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.