Post Occupancy Evaluation: operational performance of a refurbished office building

This blog was written by Dr Michelle Agha-Hossein BEng (Hons), EngD, Sustainable Building Consultant for BSRIA's Sustainable Construction Group

This blog was written by Dr Michelle Agha-Hossein BEng (Hons), EngD,
Sustainable Building Consultant for BSRIA’s Sustainable Construction Group

My Engineering Doctorate study aimed to investigate how and to what extent office building refurbishment can help to improve occupants’ satisfaction, perceived productivity and well-being while optimising building’s operational performance.

A case study approach and a “diagnostic” post-occupancy evaluation style of framework were adopted in this study to evaluate the performance of a recently refurbished 5-storey office building in detail and find opportunities to reduce the gap, if any. The study divided the workplace’s environment into three categories: ‘physical conditions’, ‘interior use of space’ and ‘indoor facilities’. Employee surveys and interviews revealed that interior use of space was the most important aspect of the building influencing occupants’ perceived productivity, well-being and enjoyment at work (happiness) while the improvement of the indoor facilities had no significant effect.

The study also concluded that issues with the physical conditions (such as noise and temperature) causes negative effects on perceived productivity but improving this aspect to a higher level than it is required would not necessarily increase perceived productivity. In contrast, improving the interior use of space aspect of a workplace would increase employees’ perceived productivity proportionally.  These results, however, should be considered with cautious as employee’s satisfaction surveys and interviews revealed that employees’ levels of expectation might have affected their levels of satisfaction with their new work environment.  This could cause some bias in the results of buildings’ performance evaluation. A potential

Old working environment

Old working environment

solution to this issue is to measure occupants’ expectations for their future workplace at the design stage to try to fulfil these expectations as much as possible. How well the new work environment met occupants’ expectations is another factor that should be measured at the post-occupancy stage.

It was also noted that the occupants density at the building was low at the time of the study (17.7m2/person) and that the space was not fully and effectively utilised and more than 50% of the workstations were often not in use. The link between improving space utilisation and the building’s energy consumption as well as its occupants’ perceived

New working environment

New working environment

productivity and well-being merits further investigation. These results are important in the projects where increasing productivity is a key and the budget is limited.

In terms of energy performance and CO2 emission, it was revealed that the actual emission of the building was three times more than the design target. Most of the low cost opportunities identified to reduce the gap were related to the building management and control as well as occupants’ behaviour. I will be doing a webinar very soon on simple energy efficiency tips related to building management and control and occupants’ behaviour. Watch BSRIA’s website for more details about this webinar. 

Making buildings better – measuring for improved building performance

Andrew Eastwell, BSRIA CEO

Andrew Eastwell, BSRIA CEO

BSRIA has always been in the business of measuring, whether it is a physical quantity such as temperature or pressure, a market assessment such as volume of product imported to a given country or a softer, more management-orientated value such as a benchmark or satisfaction score. Measuring is a fundamental characteristic of our industry’s operations and it is in BSRIA’s DNA.

The need for accurate and more comprehensive measurement has been increasing in response to the revolution that is the low carbon agenda. Revolution is no idle description either. In just over a decade, carbon signatures of new buildings have been required to fall to “nearly zero” – yet few owners were even aware of their building’s operational carbon use at the start. In looking backwards over the past few years, I think BSRIA can be proud of its role in promoting the increased use of through-life measurement embedded in processes such as Soft Landings and the associated building performance evaluations.

There is another BSRIA process that is associated with the collection of measurements. This is the process that turns detailed, often randomly accumulated and frequently disconnected data and information into documents that can be used by our members to guide them in their work. A couple of decades ago this process was greatly enhanced by the availability of a managed construction research programme that not only contributed funds from central government but much more importantly brought focus and long term stability to the accumulation of knowledge. This stability was crucial since it enabled individuals to establish research skills and careers with enduring value to the sector they served. Loss of this programme has also resulted in a loss of cohesion between frontline companies willing to collaborate within the longer term research process.

There is a however a new kid on the block that may be about to revolutionise the traditional measure/analyse/publish process that has dominated research and guidance in our sector.

As disruptive technologies go, Big Data has managed to remain under the public radar quite well until the recent disclosures of the USA “Prism” project. Under Prism, colossal quantities of data harvested from both open and private sources are analysed to identify supposed threats to homeland security. It is the use of automatic analytics software combined with large arrays of sophisticated new sensing technologies that makes Big Data techniques so intriguing for the built environment sector.

By way of example, consider the problem of maintaining comfortable temperatures in a space. Traditionally we have used lab research on volunteers to establish what “comfort” requires. Ole Fanger took years to generate his widely used algorithms but they still do not cover all the possible variables that affect perceived comfort. We now use a thermostat, with a setpoint guided by Fanger, and assume that all is well with our occupants. In the new paradigm, cameras utilising facial recognition software will be capable of spotting yawning (too hot, too much CO?) or sluggish activity (too cold). This data is available for every worker in a given space and a “voting” system used to optimise comfort over the group.

But of course there is more. This data could be available from many sources in a Prism type environment. There would now be the potential to mine the data to establish new benchmarks feeding back to the design process that can be tailored to the particular activity type. Schools, offices, homes and shops each can be analysed not just to establish a single setpoint value but to understand in great detail the envelope or distribution of responses. At last, proper large scale data sets can aid our work – and most of what we need to do this is already available through installed BEMS.

There is one further gain possible from this approach. Traditional academic research leading to refereed papers and thence to institutional guidance can take half a working lifetime to complete. Big Data results can be achieved in hugely reduced timespans. Take the case of adverts you see on Google – these are tailored specifically to you based on purchase decisions you may have only made via unconnected sites a few hours earlier. Scary but true.

Big Data is where BIM, Smart Cities, performance contracting and responsive design meet. It challenges all the preconceptions of professional codes, cuts swathes through the notion of privacy and opens up “our” market for knowledge to an entirely new set of competitive players. The next decade is going to be seriously exciting and I am sure BSRIA will remain strong to its ethos of Measuring and Managing in this startling new environment.

BSRIA provides a range of services to conduct and support BPE, from the complete evaluation to providing energy monitoring instruments and benchmarking building performance.

Soft Landings – it’s not all about the cake!

A guest post by Stuart Thompson of Morgan Sindall

Soft Landings Workshop

Soft Landings Workshop

Following on from my previous post regarding the UEA low carbon project I’d like to share our progress with the inclusion of Soft Landings.

Last week our soft landings champions met for our fifth workshop, habitually in the cafe over some cake. Rod Bunn from BSRIA joined us this time to check that we were still on track, almost a year after he helped me to introduce the soft landings framework to our UEA project stakeholders. We are in Stage 2 of the framework and we are really getting a grasp of what it’s all about, Stage 2 focuses on design development, reviews similar projects and details how the building will work. Over the last two months we held some ‘reality checking’ workshops on various topics and have gathered some great feedback on our RIBA Stage D design. This will be used to shape the detail as we move into RIBA Stage E design.

During our soft landing gatherings, the champions are challenging ourselves with thoughts like:

  • are the BREEAM Outstanding & PHPP figures really relevant to our building users? How do we demonstrate their great value to the users?
  •  ensure that our soft landings champions are empowered, to ensure that they are accommodated by the wider project team
  • can we recognise and utilise people’s talents and abilities and identify the environment in which they function most effectively?
  • has the soft landings process captured all of the creative ideas from the wider project team? 

We are also looking to create a back-casting report on Post Occupancy Evaluation and occupancy satisfaction by the

Soft landings delivery plan

Soft landings delivery plan

next meeting. We glanced through a few examples of what the client would like to see. Thinking about this report now (that will be needed in say 2 years time), is an example of how the  progressive, forward-thinking approach of soft landings will provide benefit to the client at no additional cost.

Our soft landings meetings are productive, I look forward to these, and it’s not simply about the cake!

Have you included Soft Landings in any of your projects? What are the challenges and achievements you’ve faced?

Post Occupancy Evaluation – The challenges of a ‘greener’ future

I joined BSRIA as a Graduate Engineer in January 2011. Prior to this I was studying for my PhD in the School of Civil Engineering at the University of Leeds.

An Appraisal of the performance of a ‘green’ office building

A summary of my research is given below:

The challenges of a ‘greener’ future are now a responsibility for everyone. This is particularly so for the built environment, where sustainable building design is no longer an innovative option but more of a legislative must. Unfortunately significant differences are often found between the design and measured performance of buildings, with many factors contributing towards these discrepancies.

The research work investigated, using Post Occupancy Evaluation (POE) techniques, the credibility gap between design and measured performance of a partially occupied ‘green’ office building selected as the case study. The results found that the measured energy consumption was over three times the design estimates, and the performance compared poorly against good practice benchmarks for similar buildings. The study’s POE also revealed inefficient control settings, high out-of-hours energy consumption and ineffective building management.

This study went beyond a typical POE as it also includes investigations into how the occupancy variations, and the management strategies applied under these conditions, can impact on building energy performance through the use of simulation modelling techniques (IES<VE>). This is an area where very little research had previously been carried out. At the 50% occupancy levels found at the time the research was conducted, potential annual savings of over £30,000 in utility bills and 60% in energy consumption were estimated if more effective management and control was implemented.

Social-related aspects of building performance are also investigated. Occupant satisfaction and comfort surveys were conducted and the results were compared to previous findings. The perceived comfort and satisfaction with temperature was the most disappointing finding from the survey, however overall the building was comparable to the average benchmarks, but did not perform well when compared to other ‘green’ office buildings.

The study revealed the potential for the building to be fine-tuned to perform more efficiently than was at the time of the study, however there must be suitable, skilled Facility Management to ensure this is delivered.

For more information on Post Occupancy Evaluation/ Building Performance Evaluation…..

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