A hard lesson

As a consequence, there was little time to go through the usual consultation process and, more importantly for building services engineers, to de-bug the software required to calculate carbon emissions - the result of which has been to foist a new and unproven piece software on the industry.

SBEM, (the Simplified Building Energy Model), was developed for the government by BRE. But BRE is not to blame for the impossible circumstances in which it has found itself. Indeed, it deserves a great deal of credit for producing the bones of a valid analysis tool in less than a year. The problem for BRE and engineers alike is that SBEM can have a huge influence on a building's design and hence cost, so it must stand up to intense technical scrutiny. It is getting there, but in the meantime it is engineers who have to deal with the fall-out. It has not been easy, as our Letters pages testify.

In an attempt to eliminate some of the bugs, the software is constantly being revised, which inevitably results in changes to a building's energy consumption. It's bad enough when software changes force engineers to spend time and money revisiting a design, but that is as nothing compared to the humiliation they face in having to explain to a client why a design will no longer comply.

Fortunately, the situation is about to get better. It was always the government's intention to have two routes to compliance with Part L: one using SBEM, the alternative through "other approved software tools". As we report in News Analysis, an alternative to SBEM is finally available: the government has approved two alternative software tools.

So, the situation may finally be improving. But the way engineers have been made to suffer for the government's shortcomings is unforgivable. If anything good is to come out of this debacle, it is that the government has learnt a lesson about foisting ill-conceived regulatory changes on an industry. It is one governments around the world would do well to heed.