1 Introduction

This report proposes a best practice approach to commissioning, completion and ongoing operation for environmentally sustainable government buildings. It is one thing to design sustainable buildings. It is another to obtain the predicted performance and benefits in practice without the follow-up that a best practice approach should provide.

For example, a 1994 US study of 60 commercial buildings found that:

more than 50% had control problems
33% had sensors that were not operating properly
25% had energy management control systems, economisers and/or variable speed drives that did not run properly
40% had problems with heating, ventilation and air-conditioning equipment
15% were missing specified equipment.

A more recent US study of the commissioning of 224 buildings for a variety of locations and building types found an average of 28 significant deficiencies in new buildings, and an average of 11 significant deficiencies in existing buildings.

Although similar studies have not been carried out in New Zealand, there is no reason to expect that the situation here is any different, and if anything it could be worse given the market constraints in terms of cost and time. These deficiencies often remain as latent defects in the building, which continue to effect a building’s performance over its life.

Better commissioning is a way of improving the outcomes and performance of sustainable building projects. Commissioning is generally only associated with the normal testing, adjusting and balancing of heating, ventilating and air-conditioning (hvac) systems. In reality it should encompass a much broader scope of activities and a more extensive range of services, including electrical, hydraulic, fire, security, communications and lifts.

The Chartered Institution of Building Services (CIBSE) defines commissioning as “the advancement of installations from the stage of static completion to full working order to specified requirements”. A fuller definition of a best practice approach to commissioning, as developed by participants and recorded in the proceedings of the first US National Conference on Building Commissioning, is as follows:

Commissioning is a systematic process, beginning in the design phase, lasting at least one year after construction, and including the preparation of operating staff. It ensures thorough documented verification that all systems perform interactively according to the documented design intent and the owner’s operational needs.

Sustainable buildings by their very nature require a high level of performance, and the New Zealand Green Building Council’s Green Star environmental rating scheme recognises the important part commissioning plays in achieving it. The management category of Green Star allocates up to six points for commissioning-related features, which could represent nearly 10% of the overall weighted score for a four-star building and 7% for a five-star building.

The proposed changes to the New Zealand Building Code (NZBC) and compliance documents include a number of new requirements on the design of HVAC systems. Although there is no specific requirement relating to commissioning, there will need to be proof of compliance that HVAC systems as “specified systems” perform to the standard. Commissioning could be used to confirm that design features comply as installed. It should be remembered, however, that the NZBC represents minimum standards, and that in this document we are concerned with best practice, which is a higher standard.

Proper commissioning has traditionally had a low profile and priority in the construction industry. However the new trend towards sustainable buildings is likely to place greater importance on better commissioning practices. As the Government is the most significant tenant of buildings in New Zealand, they have the ability to act as a catalyst for better practice in this area.

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