Changes to the New Build regulation as of June 2022.
The ability to sample test has ceased, and all new builds must be tested.
Singular self-builds are no longer able to claim an exemption from testing.
The general requirement is for dwellings tested to comply with a maximum air permeability of 8m³/(h¹.m²) @ 50pa or 1.57m³/(h¹.m²) @ 4pa.
Pulse testing is an accepted method of testing at 4pa.
CIBSE TM23 has now become the new Testing Standard for APT.