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The Crux of building performance

Commissioning is arguably the most cost-effective process for short-term and long-term advantages to building owners, facility managers and building occupants, says Martin Williamson. However, he adds, there are many projects in the GCC region, where commissioning is not utilised or is carried out to a low standard.

| | Mar 5, 2021 | 12:42 pm
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Buildings often do not perform in an optimal and efficient way despite significant investment during design and construction. The reasons can be wide and varied, and there is a certain inevitability that issues during construction will arise, and decisions will be made that could ultimately affect the long-term performance of the building. Building Commissioning, when utilised correctly, is a systematic quality assurance process. It increases the likelihood of buildings operating in line with their design intent, by verifying and documenting the fact that building services are designed, installed, tested and are operating in line with the Owners Project Requirements (OPR). This is primarily done with detailed planning, organisation, coordination and control of all commissioning activities.

Martin Williamson

Conversely, a building that is not operating in line with project requirements can be inefficient from an energy standpoint, financially uneconomical or suffering from poor indoor environmental quality (IEQ), of which indoor air quality (IAQ) is a significant part. This scenario is particularly prominent across the GCC region, where commissioning is largely misunderstood, under-utilised or is carried out to a low standard. A study by Lawrence Berkeley National Laboratory (LBNL), based on a database of 643 buildings across approximately 100 million square feet of floor space, found the main causes of energy inefficiency in commercial buildings to be ductwork leakage, HVAC systems running and lights left on when spaces are unoccupied, ventilation systems incorrectly balanced, dampers not working and incorrect controls set-up, with an estimated 94.6 billion kilowatt hours annually (BkWh/year) wasted across the top 13 of 100 issues identified. Ductwork leakage was responsible for the greatest energy inefficiency, accounting for 28.6 BkWh/year alone, which has been seen to be a common issue across construction projects in the GCC region.

In addition to energy savings, correcting these issues would likely improve the indoor environment, as the identified issues would have an expected impact on heating and cooling, ventilation of spaces, and potential for drafts and noise. Identifying and correcting these commonly found issues should lead to an overall increase in occupant satisfaction. Commissioning is arguably the most cost-effective process for short-term and long-term advantages to building owners, facility managers and building occupants. However, there are many projects in the GCC region, where commissioning is not utilised or is carried out to a low standard. To put this in perspective, the LBNL study found the median cost for commissioning a new building accounted for 0.4% of the total construction cost. The data received demonstrates a significant 13% energy saving in new buildings, should commissioning and management be implemented effectively. On this basis, the client’s ROI would be 4.2 years.

The purpose of commissioning in new buildings is to ensure the performance requirements of the building owners’ objectives are achieved, making sure the building is operating as efficiently as it can at the time of handover. Commissioning in existing buildings is to validate whether the building is operating efficiently and to identify performance gaps, inefficiencies and improvements needed to return it to an efficient operational condition.

There are several names for commissioning in existing buildings, namely Re-Commissioning, Retro Commissioning and Continuous Commissioning. Retro Commissioning is utilised in buildings where no commissioning was previously performed. Re-Commissioning is typically carried out every 5-10 years and completed when the building use has changed, internal fit-outs completed or equipment and components in the systems are upgraded. Continuous Commissioning is based on frequently monitoring the building use, diagnosing improvements and fine-tuning the building performance.

Re-Commissioning and Continuous Commissioning are beneficial, as they allow flexibility for changing the use of internal spaces without affecting the building’s performance. The way a building is used and operated is often different from the condition predicted during design stage, where assumptions are made for occupant density, temperature set-points, control schedules and operation of HVAC systems. A major factor is occupant behaviour, which is difficult to predict and cannot be known at the time of design. The use of the building compared to the predicted design is monitored and changes made to fine-tune the system performance. A study by Wang L, et al (Uncertainties in energy consumption introduced by building operations and weather for a medium-size office building) showed poor practice in building operation can result in an increase in energy use of 49-79%, and good practice can reduce energy consumption by 15-29%.

Commissioning as a process has become more prevalent in the GCC region in recent years, with several high-profile developers, project management companies and consultants specifying this as a requirement. As an example of implementing commissioning in the GCC region, the Dubai Green Building Regulations and Specifications (DGBR) outlines requirements for commissioning in new as well as existing buildings, highlighting the value of commissioning in securing a green future for Dubai.

To take this a step further, the regulations in the GCC region could outline the requirement of commissioning as a process by referencing publications such as CIBSE Commissioning Code M – Commissioning Management, BSRIA Model Commissioning Plan or ASHRAE Standard 202 – Commissioning Process for Buildings and Systems, which are useful publications for capturing the commissioning process throughout the lifecycle of a building.

To enhance this, it would be beneficial to specify requirements of who can complete the commissioning and management, and the level of training and experience needed. Commissioning is often completed by an independent company, whose role is to ensure compliance with the OPR; the impartial nature is part of the value of commissioning. Unless regulations specify commissioning must be independent, this allows ‘in-house’ commissioning to be completed, which is not unbiased and, citing from experience, often results in ‘covering up’ issues identified instead of resolving them.

In comparison to the UK Building Regulations, commissioning of building services is a key requirement identified, and for buildings to conform to the energy efficiency requirements, CIBSE and BSRIA methodology are to be followed, and the process should be overseen by someone suitably qualified by relevant training or experience. The regulations cite membership of the Commissioning Specialists Association (CSA), the Commissioning Group of the Building and Engineering Services Association (B&ES) and Lighting Industry Commissioning Scheme as a way of demonstrating this.

The writer is Senior Commissioning Manager, AESG, and Committee Member, Commissioning Specialists Association (GCC). He may be reached at m.williamson@aesg-me.com


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