Seasonal commissioning – a misnomer?
Keith Barker, Chairman of the Commissioning Specialists Association, tackles some of the confusion surrounding seasonal commissioning.
Oh no! It is in the Clause 13.2.1: The commissioning specialist shall carry out seasonal commissioning of HVAC systems. Forgive me for the feeling of dread that creeps over me. Why should that be the case? Perhaps it is because seasonal commissioning is possibly the most misunderstood subject in the commissioning world. And that misunderstanding is spread far and wide. Even worse, it is my experience that a significant proportion of the mechanical engineers that include the subject in their specification do not fully understand what it means.
So, everyone is sitting in the first project team commissioning meeting. The client’s Project Manager says that the project is due to complete in 18 months’ time. That will be at the end of February. They then ask what plans are in place for the commissioning specialist to return in the summer to adjust the HVAC systems for design day operation as per the above mentioned clause. And so, it starts.
It is explained that the HVAC systems have been designed to deal with both summer and winter design days. In theory, they will not need adjustment. It is also explained that, despite this, the results when the building is in use may suggest that some adjustments may be required. However, there is just as much chance that there will be no such requirement.
The next question is, of course, why the specification calls for seasonal commissioning if it may not be required. That is hard to explain without suggesting that the person who put the clause in the specification did not understand it! That is followed by an explanation about the amount of evidence required and the 12-month minimum timespan to collect it to be able to present a reasonable picture of the building’s operation across the seasons.
Quantitative and qualitative evidence
The next hurdle is explaining about the difference between quantitative and qualitative evidence when it comes to reviewing building performance. Yes, the figures may say that the systems are doing what they are supposed to. The occupants, however, may not feel comfortable. It may be hot or cold spots, it may be drafts, or pretty much anything else.
If only getting everyone on board with the above explanations was the end of it. The next problem to be faced is that the services installation (designed by the engineer that specified ‘seasonal commissioning’?) does not have sufficient data gathering provisions to meet the expectation for monitoring of system performance or space conditions. Not every building is a ‘smart’ one as yet. Enter lots of data logging temperature/humidity sensors strewn around the building and the discussion about who is going to place them, monitor them, produce the data and make recommendations on any action required.
So, what is the solution? Firstly, don’t talk about seasonal commissioning. What you really mean is fine-tuning as described in CIBSE’s Code M. Secondly, include a proper scope and make sure what you are asking for is relevant to the building and its specification/complexity – what is required in a non-perishable goods warehouse is likely to be a bit different to what is required in a high-end office block. Thirdly, make sure the building design includes the necessary data gathering provisions for your needs.
A different ball game
Of course, all of the above is only relevant if the building is completed and handed over all at once. If it’s a sectional completion project, then it’s a completely different ball game. You are then into at least partial recommissioning at each stage completion. Any fine-tuning requirements can only really be specified for the final completion point.
The other thing to consider is the way the client intends to operate the building. Will they maintain the status quo once in occupation? Or do they have the sort of operation where they are constantly reorganising/shifting people and even whole departments? If it is the latter, then won’t they be ‘adjusting’ the MEP systems to suit? From plant operating times extended or shortened to suit business demands to the facilities management team reducing the operating temperatures of the heating circuit to match monthly budgets. The building is now way past the fine-tuning stage and is firmly into continuous commissioning territory.
It really comes down to the MEP engineer understanding the client, the intended use for the building and the way the client is likely to operate in it. Only then can they make sure that the correct clauses are in the specification to get the most effective results from the commissioning exercise.
One final thought: In an ideal world the Commissioning Manager leads this exercise. However, due to the timeframe required after a building enters its fully occupational phase to start this process, they are likely unavailable for this task, therefore the project team should plan who will lead this process at the design stage!
