Construction quality could be catching up with other industries

This blog was written by Lynne Ceeney, Technical Director at BSRIA

If you order steak and chips at a restaurant, but the waiter delivers hake in strips, you would be rightly annoyed. Instinctively you blame the waiter, but it could have been a problem with the ordering software, a misreading in the kitchen or just the wrong dish being picked up.  Whatever, you would send it back – it is not what you ordered.   In new buildings, this happens all the time.  Poor communication during the briefing, design and construction process, and poor handover and operation leads to a building that doesn’t deliver the performance the client thought they had ordered in the first place.  Unlike a dinner, it’s not practical to send a building back and wait for the one you asked for to be delivered.  Instead extensive snagging lists, expensive defect resolution and defensive “best we can do” fixes by the facilities team are often used to try and get the building closer to its intended performance – and “closer” is usually the best that can be achieved. The owner and occupier end up with a disappointing building, and the designers and construction company are left with a disappointed client.  The blame chain spreads, and it’s hard to pin down the fault.

The impacts run way beyond disappointment.  Occupier discomfort impacts staff retention, and the increased societal focus on wellbeing indicates that employees will expect higher standards from their place of work.  Poor commissioning or confusing controls mean building systems that don’t work properly and need constant attention or premature replacement, as the uncomfortable working conditions impact on worker productivity.  Inefficient buildings use more energy requiring more cash and causing more carbon emissions.  In fact buildings contribute 37% of UK green house gas emissions from gas heating, and consume 67% of the electricity used in the country.  It’s no wonder that larger investors are taking much more of an interest in the sustainability and performance of buildings rather than just the upfront capital cost.  Good buildings are an asset, poor buildings become an expensive liability in terms of operating costs and void periods. Competitive property markets compound this situation.

With a typical building having a life expectancy of at least 60 years, we are building in problems for this generation and the next.  We’re not great at mass retrofitting, (and the high demand for additional building stock means a capital, skills and material shortage) so we need to get it right first time.  Effective management tools with this aim abound in other sectors, for example DRIFT, (Doing it Right First Time), Six Sigma, LEAN and Zero Defects.  We see the approach being used in food manufacture, car making, pilot training, and patient healthcare, to name but a few sectors.  So what about construction?

Soft Landings is the equivalent tool for the construction sector.  This tried and tested process was developed to help to produce better performing buildings – not necessarily exceptional in performance, but buildings that deliver in operation what they were designed to do in the first place.  Getting a building right requires a shared focus on operational performance of the building right from the start, and throughout the design, construction and commissioning process.  The use of Soft Landings delivers this shared focus, improving communication and collaboration between all parties in the building delivery chain.  It helps everyone to avoid the pitfalls that diminish operational building performance. It fits with RIBA stages, integrates into existing construction processes, and does not require a specific building procurement model.  You can download Soft Landings guidance from the BSRIA website .

However it is always helpful to find out about real world experiences, and to talk to others who are using Soft Landings to help them to produce better buildings.  With this in mind, BSRIA have organised the 2017 Soft Landings Conference (June 16th 2017 at RIBA, Portland Place, London W1B 1AD). You will hear from a range of speakers from different parts of the construction process – including clients – who will explain how they have used Soft Landings in their projects, and the value that it has delivered for their buildings.  You will also hear their hints and tips, and there will be plenty of time to ask questions and take part in discussion both in conference and over lunch.

It’s time for the construction industry to catch up with other industries in terms of quality, to produce buildings that perform as expected, through a delivery process that gets it right first time.  Soft Landings is a process that helps the delivery chain to do this.  For more information on the conference please contact our Events Manager, Tracey Tilbry.

 

Overheating in homes

This post was written by BSRIA's Saryu Vatal

This post was written by Saryu Vatal, Senior Consultant of BSRIA’s Sustainable Construction Group

BSRIA’s Residential Network organised an event on the 22nd of July focussing on the issue of overheating in homes with an excellent line up of speakers. Nicola O’Connor started the day summarising an extensive research project by the Zero Carbon Hub that brought together input from government, industry and academic experts to understand the challenges around tackling the risk of overheating in homes (http://www.zerocarbonhub.org/current-projects/tackling-overheating-buildings). Chris Yates from Johnson and Starley made an appraisal of the assumptions and requirements within the Building Regulations and associated guidance as well as the implications for mechanical ventilation system manufacturers. Neil Witney from DECC explained the challenges around defining and regulating of overheating within homes, current policies and mechanisms that may be introduced in the future in response to the growing body of evidence highlighting the issue. Paul Ciniglio from First Wessex shared the organisation’s findings from several research projects and experience from their own developments, which resonated with issues highlighted by members of the audience. Bill Gething of Sustainability + Architecture and professor at the University of West England brought into perspective how changes in the way homes have been designed and built over the recent years has led to a shift in the performance of homes. James Ford, partner at Hoare Lea discussed some key considerations for designers to address the issue at early stages, to help minimise risk and dependence on active cooling solutions.

Extent of overheating

Evidence indicates that up to 20% of homes in England may already be overheating. Areas where additional risks have been highlighted include:

  • Common areas in apartment blocks, especially where community heating is installed – these areas are not assessed using SAP as they are outside the dwelling envelope. In reality, being unoccupied spaces these are often not modelled for their thermal performance (and energy use) at all. Community heating is being incorporated in an increasing number of projects and the supply network remains live even in the summer to meet the domestic hot water demand. Ensuring that the specification and installation of insulation for the distribution pipework is adequate is becoming increasingly important as buildings are made more airtight. Often stairwells and circulation areas have a high proportion of glazing and, with recent improvements in the general standard of construction and materials, tend to retain a large proportion of the heat gains. It is now important to incorporate a ventilation strategy for these spaces so that the accumulated heat can escape.
  • Urban areas – the average temperatures in city centres can be more than 4°C higher than rural areas. Flats are more common to city centres and these are often close to sources of noise and air pollution and have limited, if any, potential for cross ventilation. All these factors can combine to limit the effectiveness of natural ventilation in addressing the build-up of heat and not just in the summer. Building designs that incorporate large proportions of glazing in their facades, such as penthouses, if not carefully designed, can require air change rates that are unrealistic to achieve, using natural or mechanical ventilation systems.

Need for a definition

A number of sources and definitions are being referred to currently when evaluating for the risk of overheating in homes. These include CIBSE’s Environmental Design Guide A (2006) which sets standards for comfort, although it is not mandatory to use this to demonstrate compliance with the Building Regulations. Dynamic modelling through tools such as TAS and IES offer the opportunity of making a more comprehensive evaluation than SAP, but this option is skill, time and cost intensive. Building Regulations do not relate to limiting overheating for thermal comfort, just limiting the use of fuel and power for air-conditioning. The minimum evaluation for demonstrating compliance with Criterion 3 of Approved Document Part L of the Building Regulations needs to be carried out using SAP. While SAP is not intended to be a design tool, it is accepted that it is the default tool the industry uses widely.

Research projects have highlighted that dwellings can demonstrate a risk of overheating when evaluated against the CIBSE standard but not when modelled in SAP. Surveys from the Zero Carbon Hub study showed that nearly 60% of the housing providers surveyed had checks in place to assess the risk of overheating. However, only 30% of these housing providers explicitly included the requirement for considering the risk of overheating as part of their employees’ requirements to architects and designers. This suggests a missed opportunity for the issue to be addressed early on in the process, when cost and energy efficient measures may be effectively incorporated.

There are several challenges around the definition of conditions under which overheating can be said to occur as several factors contribute to this, including but not limited to air and radiant temperatures, humidity, air velocity, level of activity the adaptability of the individual. There are several checks that can be built into the design process which can help identify the risk at an early stage and allow for a method for mitigating these to be set up and followed through.

Contributing factors
The energy efficiency of homes in the UK has improved significantly in terms of reduction of space heating loads. This has come about in new homes through Approved Document Part L 1A of the Building Regulations and in existing homes through schemes such as the Green Deal. Homes are now less leaky and better insulated to keep warmth in but attention and emphasis is needed on measures to facilitate the expelling excess heat adequately when temperatures rise.

Homes are expected to provide comfortable conditions for occupants all year round and through a range of different occupancy patterns, which may in reality be considerably different to the standard assumptions made in modelling tools like SAP. It is possible that if modelling for thermal comfort is carried out assuming worst case assumptions for occupant density, external conditions and hours of occupancy, many homes would require mechanical cooling. There are, however a number of common sense measures that can be applied to ensure the impact of key contributing factors are minimised. These include controlling solar gains from south and west facing glazing and making provisions for adequate, secure ventilation especially when thermal mass has been incorporated in the structure.
The current extent of overheating in homes must be seen in the context of the anticipated changes in climate. With external temperatures expected to rise with an increased frequency of extreme weather conditions, homes built today must be fit for purpose for warmer summers.

Mechanical cooling?
There has been a rise reported in the installation of mechanical cooling systems in homes in the UK, more noticeably so in the south. While this may be an expected feature in high end homes, the cost of running these systems can be prohibitive, or at least perceived as so, for households where minimising expenditure on energy and fuel is a priority.
There is potential to develop low carbon mechanical cooling systems such as reversible heat pumps. The large scale uptake of these can however have some serious implications for energy supply and the capacity of the grid to accommodate a draw in peak summer months.

Way forward
In addition to affecting comfort, exposure to high temperatures over prolonged periods can have a significant impact on the health and well-being of residents. It is critical therefore to agree on a set of parameters that can help define overheating in homes and this should be carried out with input from bodies such as Public Health England.
Until a definition and modelling strategy is developed, designers and housing providers can refer to several good practice guides and research studies that help embed a common sense approach to design. There is significant potential to mitigate the risk of overheating in homes if early stage design decisions are taken with due consideration for the issue. The limitations of mechanical ventilation systems to help achieve comfort in homes must be acknowledged so that the final burden of an ill-considered design does not rest with the occupants.

References and further reading
http://www.zerocarbonhub.org/sites/default/files/resources/reports/ZCH-OverheatingInHomes-TheBigPicture-01.1.pdf
Design for Climate Change, Bill Gething and Katie Puckett, RIBA Publishing Feb 2013
http://www.arcc-network.org.uk/wordpress/wp-content/D4FC/01_Design-for-Future-Climate-Bill-Gething-report.pdf
http://www.zerocarbonhub.org/sites/default/files/resources/reports/Understanding_Overheating-Where_to_Start_NF44.pdf

To find out more about our Residential Network and to download the presentations from this meeting check out BSRIA’s Network pages.  To find out more about all of BSRIA’s networks contact tracey.tilbry@bsria.co.uk.

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. 

Emerging themes from Innovate UK’s BPE programme

This blog was written by Peter Tse, Principal Design Consultant for BSRIA's Sustainable Construction Group

This blog was written by Peter Tse, Principal Design Consultant for BSRIA’s Sustainable Construction Group

Back in May 2010, Innovate UK (formally TSB) embarked on four year programme, providing £8m funding to support case study investigations of domestic new build and non-domestic new build and major refurbishment projects.  In total the programme has supported 100 successful projects to provide a significant body of work, that provide insights on the performance of various design strategies, building fabric, target performances, construction methods and occupancy patterns, handover and operational practices.  This work will be shared across the industry providing evidence based information, increasing industry understanding to support closing the loop between theory and practice, ensuring the delivery of zero carbon new buildings is more readily and widely achievable.

Currently project teams are concluding their investigations and collating their findings, and dissemination of the results of the programme will begin in earnest in the first half of 2015.  However, as the programme has progressed, there are some consistent themes that are emerging.  Focussing on the non-domestic projects, I will address a couple of these emerging themes.

The first is around adopting innovative building systems to deliver low energy consumption and comfortable conditions, and unintended consequences associated with these technologies.  This covers a broad spectrum of building technologies including solar thermal, heat pumps, biomass boilers, earth tubes, rainwater harvesting, controls and natural ventilation strategies.  Innovation in its essence will have some inherent teething problems, which is often overlooked in the charge towards reaching our carbon reduction targets.  The obvious default stance is to specify proven and reliable technologies which are delivered by a team that is familiar with the technology, but our journey towards delivering true low carbon building in operation would inevitably be prolonged.

An additional level of complexity can be added with innovative systems; one healthcare facility introduced solar thermal and a combined heat and power (chp) unit, to supplement natural gas fired boilers for heating and hot water requirements. With several sources of heat complexity is added to the control strategy, trying to strike a balance between changing heat demands of the building and optimisation of the system.  This complexity, coupled with a requirement for increased operator understanding often leads to system underperformance.

The practicalities, maintenance and associated costs of innovative systems is seldom fully realised by clients.  An office reported success of the rainwater harvesting system, but were surprised at the frequency of filter changes to mitigate the system being blocked.  Another office had to regulate a fan associated with earth tube ventilation system, as running at a higher speed caused too much noise for occupants.  A school had ingress of water to an underground wood chip store rendering the biomass boiler idle for significant periods.  A hotel employed automatic external blinds which retracted in windy conditions to avoid damage, thus offering no shade to occupants during sunny, windy days.

DC-Innovative-Construction-Services-Building-Maintenance1It is clear a reality checking process is required for design decisions to mitigate such matters.  BSRIA’s Pitstopping guide, which resides within the Soft Landings framework describes a process that allows construction teams to periodically reconsider critical design issues by focusing on the perspective of the end user.  This also provides an opportunity for the client to understand the full ramifications of implementing innovative building systems for a more informed decision, and to align client expectations.

The second theme involves the process in delivering innovative technologies, with a particular a focus on commissioning and handover.  The commissioning period residing at the end of the build process is often susceptible to being squeezed.  When the decision has been taken to adopt an innovative building system, there is increased pressure during commissioning to ensure the system is operating as intended.  With the additional complexity associated with innovative technologies, it is vital the commissioning time is adequate to complete comprehensive scenario based testing; how is hot water delivered if the solar thermal does not provide a contribution, how is the building operator alerted the status of the system, how can the operator diagnose the problem, how long can the system operate without the solar thermal contribution without major detrimental effects etc.  To ease the burden on the commissioning period, it is clear commissioning should not be afterthought, but an integral part of the build process.

The commissioning period also signals a time where many of the stakeholders with tacit knowledge of the innovative building systems have changing responsibilities. It is vital this knowledge is captured for users before the opportunity is lost.  Building manuals, user guides and logbooks need to be completed so users can relate to their building environment, understand control of the environment and capture major alterations.

Figure 1 - South façade showing café, street and incubator office blockMany projects reported that guidance for both users and operators was often lacking, with several BPE teams developing guidance as part of their projects to support users.  Commonly BPE teams have also struggled to find initial design intent and operational strategy associated with innovative technologies, highlighting the importance of handover documentation.  Training of users is another key element to knowledge continuity, but several projects reported changes in staff being a core reason for innovative systems underperforming, as documentation was not kept up to date.  The value of clear concise user guidance is evident; BSRIA’s Building Manual and Building User Guides helps individuals responsible for creating building logbook and user guides.

In this blog, I’ve only addressed a couple of areas in regards to emerging themes, to hear more about findings from the programme, come hear me speak at the Energy Management Exhibition (EMEX), at Excel, London on the 20th November, 2014.  Additionally, join the BPE community at connect.innovateuk.org, and search for Building Performance Evaluation.

Designing for change

Ian Harman of Marflow Hydronics (BSRIA Members)

Ian Harman of Marflow Hydronics (BSRIA Members)

With the industry moving at such a fast pace, new innovations are being introduced all of the time. Manufacturers are inventing great new products that offer many benefits; solving the problems of the present to provide a better future. The biggest problem that they face, though, is launching these products on to the market. This is where BIM could really help. 

I think it’s fair to say that people don’t really like change. We like to stick to what we know and what we feel comfortable with. This seems to be the case in our industry. Many people, from consultants to installers, are still completing jobs and planning projects in the same way they’ve been doing it for years; that is in very traditional ways. A prime example is how there is still much use of two port control systems despite Pressure Independent Control Valves having been around now for quite a while. These newer products are faster to implement and more reliable in the long term, yet there is still a reluctance with some people to adopt the new technology.

It’s true that with any new product there’s inevitably a big learning curve to using them, and often training can be time consuming. There’s also the fear of risk. If people use a new product that they’re not so familiar with then there’s always the chance that it will go wrong. This could be because the user isn’t so experienced at using it, but also it could turn out that it wasn’t the ideal product after all and sometimes knowledge and experience can really help when making decisions. This is where BIM steps in.

Using BIM, manufacturers can create models, which I like to think of as ‘Lego blocks’, that they can send to customers to introduce them to a product. And they can do this long before any decisions have been made, at the very initial stages. The ‘Lego block’ would be a visually simplified model that not only clearly defines the spatial envelope and connection points, but also includes a wealth of ‘metadata’. This ‘metadata’ contains data fields specific to the particular products, such as flow rates for valves or electrical loads for powered devices.

BIM - Marflow Hydronics
That all means that clients can look at the products in detail and trial them in their plans from the very beginning. They will be given the time to properly analysis products and see how they will work within the system and how they will interact with other components.

By starting with the end in mind and properly understanding the system at the initial stage, it will help to future proof the project far down the line. It’s also the cheapest time to detect any issues. The easiest time to make a design or selection change is at the beginning of a project and BIM facilitates this in a much more user friendly manner than ever before. This would undoubtedly give them much more confidence in the products they’re looking to use and would, very importantly, remove that fear of risk.

BIM provides users with the time and ability to put much more thought into their projects earlier on, minimising that risk further down the line. This then increases the chance of far more successful project that works with the best products, potentially the latest and more developed ones, and there’s much more chance of it being on time and to budget.

BIM 2 - Marflow HydronicsManufacturers, like Marflow Hydronics, have been doing this to help bring new products into the limelight that otherwise customers may have been apprehensive about. More importantly, this has helped all parties get the right products specified when they may not have been otherwise. BIM may be the ideal solution to help us move more quickly into the future using more innovative products and having many of the niggling issues that have been around for so long vastly reduced, if not eliminated.

This was a guest post by Ian Harman, Technical Applications Engineer at Marflow Hydronics, BSRIA Member

If you are looking to find out more information about BIM, BSRIA runs two specific training courses:

There are also several other blog posts focused on BIM as well as a BSRIA BIM Network. 

The selection criteria of refrigerants

Salim Deramchi, Senior Building Services Engineer at BSRIA

Salim Deramchi, Senior Building Services Engineer at BSRIA

This is part two of a three part series from Salim. You can read part 1 here

There is no general rule governing the selection of refrigerants, however there are of course the five classic criteria and those are:

  • thermophysical properties
  • technological
  • economic aspects
  • safety
  • environmental factors

However, in addition to these criteria, others have to be considered such as local regulations and standards as well as maintainability and ‘cultural’ criteria associated with skills to support the units, application, and user training requirements.

The best approach when presenting evolution and trends is certainly the per-application approach. The desirable characteristics of “ideal” refrigerants are considered to be:

  1. Normal boiling point below 0°C
  2. Non-flammable
  3. Non-toxic
  4. Easily detectable in case of leakage
  5. Stable under operating conditions
  6. Easy to recycle after use
  7. Relatively large area for heat evaporation
  8. Relatively inexpensive to produce
  9. Low environmental impacts in case of accidental venting
  10. Low gas flow rate per unit of cooling at compressor

The choice of alternative refrigerants should involve a review of recycling or disposal of refrigerants. You must decide which criteria for the ideal refrigerant is of most importance to your organisation. It must be considered that the operation phase is the key factor when determining the environmental impact of the various refrigerants as there is less impact to the environment in the production and disposal stages. As an example, supermarket retailers are steadily moving away from long-established HFC refrigeration systems.

Decision making for new refrigeration plant using refrigerant alternatives such as ammonia, CO2 or hydrocarbons, which have comparatively little or no impact on global warming and zero impact on ozone layer, should consider not only the impact on the environment but the additional required skills to maintain (Ko Matsunaga).

You can  find out more information in BSRIA’s library

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