Intent 1:
To exempt vents from the application of Subsections 4.3.4. and 4.3.5. which would otherwise impose certain vent requirements,
if certain measures are taken [vents conform with good engineering
practice].
This is to limit the probability that:
- excessive internal tank vacuum or pressure will develop
in normal or fire conditions, which could lead to the failure of the
tank, which could lead to the escape of liquid, which could lead to
the ignition of vapour from a nearby ignition source, which could
lead to harm to persons, and
- vapour will accumulate inside or outside the building,
which could lead to the ignition of the vapour from a nearby ignition
source, which could lead to harm to persons.