Delayed start: when A1-A3 becomes B4
Delayed start is used for a building product that is not part of the building from day one, but is only installed a number of years into the study period, for example a kitchen that is replaced or an extension built later. It is specified as a number of years, not a checkbox: the building product’s production is postponed by exactly that number of years.
A1-A3 becomes B4
Section titled “A1-A3 becomes B4”Without a delayed start, a building product’s production (A1-A3) is calculated in the project’s
start year. With a delayed start of N years, production is instead moved to year start + N, and
the module simultaneously changes designation from A1-A3 to B4, because it is treated as a
replacement in the middle of the study period, in the same way as an ordinary B4 replacement.
If it lands outside the period, it goes silent
Section titled “If it lands outside the period, it goes silent”If the delayed year moves the building product outside the study period, that is, after the last year of the period, the building product does not contribute to the result at all, because the replacement falls outside. This happens without any warning in the calculation: a delayed start set too high can therefore make a building product invisible in the result, without it being clear why.
Delayed start and transport
Section titled “Delayed start and transport”If a building product is delayed or demolished, it is not transported to the construction site in the calculation (the A4 transport line contributes nothing), because it does not actually arrive at the construction site at the time an ordinary building product does.