13. In regulation 42 (mechanical ventilation air flow rate testing)—
(a)for paragraph (1) substitute—
“(1) This regulation applies where paragraph F1(1) of Schedule 1 imposes a requirement in relation to—
(a)the creation of a new dwelling by building work; or
(b)an existing dwelling which undergoes building work for the provision or extension of any fixed building system for mechanical ventilation.
(1A) Paragraph (1)(b) excludes building work to which Schedule 4 applies.”;
(b)in paragraph (2)(b), for “.” substitute “, other than when Schedules 3 or 4 apply.”