Intent 1:
To limit the probability of:
- an inadequate bearing area between the staple's crown
and the shingle's surface, which could lead to excessive stress on
the staple/shingle interface, which could lead to pull-through, or
- an inadequate resistance to withdrawal from the substrate.
This is to limit the probability of
the displacement of shingles, which could lead to:
- water penetrating directly to roof decking or sheathing,
or
- compromised thermal performance of components intended
to provide resistance to heat transfer.
This is to limit the probability of:
- an inadequate control of relative humidity, temperatures
of interior spaces or water accumulation,
- the generation of pollutants from biological growth
or from materials that become unstable on wetting, or
- deterioration, which could lead to compromised integrity
of roofs or walls or of assemblies protected by roofs or walls.
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.
Intent 2:
To supersede the requirement for 4 fasteners stated
in Sentences 9.26.2.4.(2) and 9.26.7.4.(1), and increase the number of fasteners to 6 for
constructions where relatively narrow staples are used.