3.—(1) Subject to the following provisions of these Regulations, where—
(a)an existing provision authorises or requires a measurement to be made, or an indication of quantity to be expressed, in a relevant imperial unit,
(b)the provision has effect for economic, public health, public safety or administrative purposes, and
(c)the provision has legal effect on or after the commencement date,
the provision shall, unless the context otherwise requires, be construed on or after that date as authorising or requiring the measurement to be made, or the indication of quantity to be expressed, in the corresponding metric unit.
(2) Subject to the following provisions of these Regulations, where—
(a)an existing provision contains a reference to an indication of quantity expressed in a relevant imperial unit,
(b)the provision has effect for economic, public health, public safety or administrative purposes, and
(c)the provision has legal effect on or after the commencement date,
the provision shall, unless the context otherwise requires, be construed on or after that date as if the indication of quantity concerned were expressed in the corresponding metric unit.
(3) Subject to paragraph (4) below, any conversion of an indication of quantity expressed in a relevant imperial unit which is required to be made by virtue of paragraph (2) above shall be made by using the metric equivalent specified in relation to the relevant imperial unit in the third column of the Schedule to these Regulations.
(4) Any conversion of an indication of quantity expressed in degrees Fahrenheit which is required to be made by virtue of paragraph (2) above shall be made by subtracting thirty-two and multiplying the result by five-ninths.