9.25.3.3.(1)

Intent 1:

To limit the probability of inadequate airtightness, which could lead to:

• excessive heat loss or gain due to air mass transfer,
• excessive air infiltration and exfiltration,
• excessive airborne vapour transfer from interior above ground and exterior below ground, or
• precipitation ingress due to air pressure differences.

This is to limit the probability of deterioration, which could lead to compromised structural integrity of assemblies acting as or protected by environmental separators, which could lead to harm to persons.