The variations recorded by the commissioning engineer only relate to clause 39-ie variations from the recommendations on commissioning. They do not relate to variations in design.
yes Colin, I understand that is the way it might have been intended, but I maintain that many of the clauses under 39.2.C in respect of siting of equipment etc impacts on what the system designers and installers may have done.The commissioning engineer has no option but to highlight every non-compliance, no matter how small.
Furthermore 39.2.C.24) specifically relates to system design considerations, and whilst note 3 attempts to reduce the impact of highlighting design 'problems', in reality anything highlighted is taken as a personal 'slight' by the designer. .
So the Designer and installer don't take kindly to the commissioning engineer pointing out, for example, that it was impossible to achieve 7.5m spacing of smoke detectors in an area that the designer showed on his drawing as having, say, three smoke detectors, and the installer has done the best he could, but achieved a distance of 7.6m. In these circumstances the 0.1m probably is insignificant, but the BS model commissioning process leaves no leeway for it to be ignored as a 'minor infringement'.
Everybody wants a commissioning certificate that infers 'the system is absolutely perfect' and the commissioning engineer gets the aggravation because it is not!
Even a single variation mentioned on a commissioning certificate is not acceptable to the enduser/customer, they consider anything highlighted as a failure by the designer or the installer to do his job properly and they, invariably, in turn, blame the commissioner, for highlighting it!