Proving the future – how to keep up with Building Regulations

"From a standing start in 2006 to today, the builders have grasped the importance of air tightness testing as a proxy for quality of construction and the contribution good airtightness makes to energy efficiency" Mike Smith, Engineering Director

“From a standing start in 2006 to today, the builders have grasped the importance of air tightness testing as a proxy for quality of construction and the contribution good airtightness makes to energy efficiency” Mike Smith, Engineering Director

The rapid adoption of airtightness testing and the ability of the industry to achieve the right result first time in 89% of tests is one of the success stories of the UK construction industry over the past decade. The BSRIA Compliance team tested over 10,000 dwellings and 720 non-dwellings in 2012 and found the average dwelling airtightness value was 4.89 m3/(hr.m2) envelope area at 50 Pa (against a maximum regulatory value of 10 m3/(hr.m2)).

From a standing start in 2006 to today, the builders have grasped the importance of airtightness testing as a proxy for quality of construction and the contribution good airtightness makes to energy efficiency. The testing itself is rigorous, robust and, arguably, now at a very low economic price. It has respectability provided by UKAS accreditation for non-dwellings testing, the training of testers and, in the case of dwelling testing, registered testers through the Airtightness Testing and Measurement Association (part of the British Institute for Non-Destructive Testing).

The mantra should be “Build tight, ventilate right”. As fabric standards improve, driven on further by the 2013 Building Regulations, the role of passive and mechanical ventilation systems increases in importance. Unfortunately in the world of unintended consequences, we are seeing dwellings achieving better airtightness values than the designer intended which of course means less air leakage (and associated energy waste), but this is only useful if the designed-in ventilation systems can cope with these outcomes. In a nutshell the infrastructure supporting domestic ventilation engineering has not developed at the same pace as the improvement in building airtightness.

There is of course significant current activity to help remedy this problem but, as is so often the case, we are now on the back foot with increasing numbers of examples of poor installations and the inevitable questioning of the value of mechanical ventilation solutions.

The systems we are talking about are not complex but they are sensitive to errors. What is missing is not so much the technology or science but the widespread creation and adoption of proper codes of practice. Mechanical ventilation (MV) systems and the more complex MV heat recovery (MVHR) systems have to be site tested to ensure they are extracting and supplying appropriate amounts of ventilation. In the course of its compliance testing BSRIA is seeing two main kinds of problems.

The first is the performance of the specified equipment in a given situation, i.e. that the fan is correctly selected to match both the actual application and the inherent system losses that the system components will introduce. In simple terms this comes down to understanding the resistance characteristics of ductwork and its routing and the resistance of terminal units both inside and out. There is a widespread misunderstanding that ventilation fan outputs are usually quoted with outputs measured in “free air”. In reality they have to overcome backpressures from fittings. Even where kits are bought we see alternative terminal units used, usually to meet architects demands for aesthetics.

The second is the actual installation of the associated ductwork where there is a very poor understanding of the dramatic effect on performance that can arise from bad workmanship.

In a recent case BSRIA found approximately one metre of flexible ductwork that had been stuffed into the cavity wall for a straight through the wall installation that is approximately 300 mm thick. An additional 100 mm dogleg had been introduced on site to match the actual positioning of a porch structure. The result was a lot of fan noise with almost zero movement. The fan, when bench tested with zero back pressure, had a performance of 22 l/s, the designed performance including the ducting was 20 l/s however the actual performance was 5 l/s.

As part of the “catch up” in dealing with the rapid rise in the use of domestic ventilation we have identified that the act of measuring MVHR performance using published guidelines will give false results if the correct equipment or correction factors are not used. There is an easy remedy but not widely used at present. The automatic volume flow meter with pressure compensation – more commonly known as a “powered diff” will provide an instantaneous and accurate value. A more common hooded anemometer will impose a back pressure on the terminal, ducting and fan under test and the readings must be corrected (post use) specifically for both the anemometer model and the actual fan under test. More detail on this can be found in BSRIA’s “Domestic Ventilation Systems – a guide to measuring airflow rates – BG46/2013”.

And all of this is compounded by a lack of thinking regarding operational needs, limited controls, and poor instructions to the user, especially on what maintenance is required to keep performance at its peak.

So, airtightness demands have led to unforeseen consequences and something of a reaction against the use of mechanical ventilation. What then can be done to avoid making the same mistakes on other systems and concepts?

With fabric issues now largely dealt with in the Building Regulations it is likely that new focus will fall on the efficiency and operation of the MEP services in dwellings. If modelling and measuring the thermodynamics of a brick wall is difficult imagine how complex a multivalent heating system is going to be! And before being put into use, these complex integrated systems will need commissioning and possibly proving as well.

The Zero Carbon Hub has recognised that we will need to devise new test methods and regimes that, for example, will evaluate how the solar thermal collector performance meets expectations when linked with the ground source heat pump system that serves hot water generation, underfloor heating and thermal storage, in concert with a biomass boiler or room heater. Before regulation stimulates the market we need to have good practice guidance and proven on-site commissioning and test processes in place. This work is urgent and needs significant central support. With the next revision of Part L expected for 2016 – this time aimed at achieving zero (or nearly) carbon homes, time is not available to embark on a protracted negotiation with innumerable and varied industrial interests. Certainly industry’s support will be available but only for a properly directed and centrally funded programme.

If we fail to put into place a mechanism to improve the on-site verification of performance of new systems we will only have ourselves to blame for the next set of well publicised “failures to launch” and the consequent set back of achieving national aims.

BSRIA provides a range of Compliance Testing services for stress-free compliance to Building Regulations including airtightness (Part L), sound insulation (Part E) and ventilation testing (Part F).

How to procure Soft Landings

BG 45/2013 Soft Landings procurement Guide

BG 45/2013 Soft Landings procurement Guide

BSRIA has just launched its latest guidance on the Soft Landings graduated handover process.   How to Procure Soft Landings – guidance for clients, consultants and contractors is designed to help clients and their professional and building teams frame their Soft Landings requirements in a consistent and structured manner.

 The guide is a response to two clear trends in the use of Soft Landings. Primarily, clients aren’t sure what they are asking for when they call for it in tenders. Construction firms are seeing wide differences in client requirements. The initiated clients may spell it out, but for every expert client there are 20 who simply ask for Soft Landings without a clear idea of what it is.

 Many builders and contractors, particularly those not up with current thinking, are similarly clueless on how best to respond. That’s one of the downsides with an open-source protocol – the viral spread of Soft Landings is a good thing, but a lack of certification and control means that the uninitiated can easily catch a cold.

 Second, Soft Landings is being adopted by central government as a formal procurement policy. This is Government Soft Landings (otherwise known as GSL), a Cabinet Office-inspired interpretation of Soft Landings for government clients. While it’s not a million miles away from the official version published by BSRIA and the Usable Buildings Trust, GSL takes a more facilities management perspective of the process and focusses far more on getting guaranteed outcomes from the construction industry. GSL is slated to be mandated for central government projects in 2016, along with the adoption of Building Information Modelling (BIM), with which Soft Landings is well-suited.

 So what we have, then, are commercial clients still a little confused in their (voluntary) adoption of Soft Landings. On top of that is an incoming group of government clients, building anything from schools to prisons to aircraft hangers,  for whom Soft Landings is a huge unknown but who will be mandated to adopt it. BSRIA’s view is that it might be a good idea to lay out the best ways of expressing Soft Landings in client requirements, pre-qualification questionnaires, and invitations to tender, so that the clients and industry alike get greater consistency in Soft Landings projects from the very outset.  

 The procurement guide has benefited substantially from the Soft Landings User Group, a BSRIA-run team of clients, architects, consultants and contractors who have learnt from experience on Soft Landings projects what works well and what doesn’t. This learning has been used to create practical, generic requirements for Soft Landings activities that can be used in project documentation. 

 A body like the User Group is absolutely vital for the practical development of Soft Landings. BSRIA knows it doesn’t have all the answers, and in any case should not dictate how Soft Landings is put into operation on real projects. Each project has its own needs and objectives, and each form of procurement throws up its own set of opportunities and challenges. The trick is to find out what works in each context, and try and find ways round thorny issues like novation and cost-cutting for instance, both of which can compromise the best of intentions.

 The guide provides specifically-worded requirements for each step in each of the five stages of Soft Landings.  The guidance is split into three sections, with requirements worded for clients appointing professional designers, clients appointing main contractors/builders, and contractors appointing sub-contractors.  Inevitably, there is some repetition, but the guide gets round that at relevant points by referring the reader to sections in the guide where a specific requirement is more logically located. 

Stage 3 - Pre-handover

Stage 3 – Pre-handover

The example shown is typical. Energy metering installations are proving to be a major problem – they are installed to satisfy Building Regulations, but are often not set up in a way that makes them useful. Although the Soft Landings Framework calls for an energy metering strategy, the procurement guide goes a step further by spelling out what should be provided, in this case at the pre-handover stage. Each requirement is supported by explanatory text that gives the main contractor, in this instance, some background context and the reasons for the requirement.

 Some Soft Landings stages may have more than one worded requirement. Some optional requirements have also been provided, for instance in the aftercare stages where it may be important to spell out precisely who should be involved and for how long.

 For example, under the core requirements for main contractors appointing sub-contractors, contractors have the option of requiring a subcontractor to be retained to assist the client and other members of the project team during handover, and afterwards to monitor the building’s performance. Some sub-contractors may be required to be based on site full-time during the initial aftercare period to assist with end-user queries and to undertake fine-tuning of systems. This would not typically apply to a ductwork sub-contractor, but it would usually apply to a controls sub-contractor. More critically, it could apply to any contractor whose systems or components come with automatic controls, particularly those with bespoke communication protocols (seemly most of them) which can only be adjusted by the supplier after payment of a fat call-out fee. If you’re nodding at this point, you know how it is. The Soft Landings procurement guide now covers this issue, and many others like it.

 An opportunity has been taken to fill gaps in the Soft Landings Framework, published back in 2009 when practical experience was a bit thin on the ground. For example, the guide contains a generic design work stage which was not included in the Framework. The procurement guide also provides more detailed advice on principles of procurement and tendering, how to include Soft Landings in tender processes and interviews, and some advice on the best way to budget for Soft Landings.

 The timing of the guidance also coincided fortuitously with the publication of the 2013 RIBA Plan of Work, which gave BSRIA the opportunity to align Soft Landings stages against the new RIBA stages, and those published by the CIC. There’s also a public sector Soft Landings decision tree included to help government and local authority clients dovetail their procurement requirements with Soft Landings requirements.

 Building performance research is identifying many critical aspects of procurement where clients and the construction industry need to tighten up their respective acts. The commissioning manager is a critical role, and the earlier they can be appointed the better. The procurement guide offers some advice on how to do this, and what their role should be in Soft Landings.

 Soft Landings is not job in itself but a set of roles and responsibilities shared among the client and project team. However, on large jobs particularly a co-ordinator may be needed to make sure the administration is carried out. Paperwork – which could include updating operational risk registers in BIM models for example – needs to be done by someone. If this isn’t covered, Soft Landings might fail ‘for want of a nail’.

 BSRIA hopes that How to Procure Soft Landings – guidance for clients, consultants and contractors will provide all that clients and project teams need to put Soft Landings into operation.  It is a practical guide to accompany the Soft Landings Framework – still the industry bible on what Soft Landings is about, and why you should adopt it.

 With all this talk about the performance gap between design and building operation, we mustn’t lose sight of the fact that the act of procuring a building and constructing it is a team enterprise. No-one goes into the process with the intention of doing a bad job.  Events, like many things in life, can conspire against it. What Soft Landings tries to do is provide toeholds for everyone involved to do a better job in the face of budgetary, time and skills pressures.  How to Procure Soft Landings – guidance for clients, consultants and contractors provides a whole load more toeholds for everyone.

 BSRIA BG45/2013 How to Procure Soft Landings – guidance for clients, consultants and contractors is available from BSRIA bookshop.

Changes to Part L – is carbon neutral possible for 2016?

282px-AD-L_Part_2A2006 was a big year for building energy efficiency, the European Energy Performance of Buildings Directive started to be implemented. This triggered a radically new Part L, requiring all new building designs to meet CO2 emissions targets. The Code for Sustainable Homes was launched that year, and the government made bold plans to require new dwellings to be carbon neutral by 2016, non-dwellings three years later.

A glide-path to zero carbon was published with interim Part L changes planned for 2010 and 2013. Come 2010, and the first round changes took place, with a 25% reduction in CO2 targets. Then the following year, the government (now a conservative-led government claiming to be the greenest ever) watered down the definition of zero carbon to exclude appliances and cooking. Fair enough, absolute zero carbon perhaps wasn’t a feasible target anyway.

Fast forward to August 2013, and the second round of changes still hasn’t happened. The government has indicated that there will be a meagre reduction of 6% in CO2 targets for dwellings, and 9% for non-dwellings, and that these will kick in in April 2014. What this says to me is that the government, at the moment, aren’t all that interested in being green. Also, that 2016 is going to be very painful for housebuilders, who will have to make a huge leap to zero carbon. This zero-carbon commitment is still in place, and was even reaffirmed in the budget announcement in March. But of course, there’s another general election before 2016….

Part L and the Green Police

It seems like just yesterday I was absorbing the 2010 incarnation of Part L. Now 2013 is creeping up on us fast, and the consultation will be closed 4 weeks from today. The plans for zero carbon homes in 2016 and non-dwellings in 2019 are ambitious, and rightly so. But what happens after 2019? It’ll be years before there are enough zero-carbon buildings to really make a dent in UK emissions. In the meantime there are thousands of inefficient buildings that won’t get touched by Part L, because no building work is being done on them. The ever-expanding list of actions that triggers consequential improvements may help – for example making works such as boiler and window replacements trigger further improvements. But there is a danger this will just discourage building owners from doing such works in the first place, or encourage them to hide their activities from the green police.

We need to come up with new ways of bringing the existing building stock up-to-scratch, that don’t involve waiting until someone decides to do some building work. Building MOTs? Mandatory follow-through of recommendations from EPCs, DECs and air conditioning inspections? Fines for excessive energy use? I don’t have all the answers, but what I am pretty sure of is that energy prices are going to keep rising as fossil fuels get scarcer and the world’s population gets bigger. Give it another few years, and businesses won’t need legislation pushing them to manage their energy use better, they’ll have to do it to survive.

Taking lighting to task

For many years the conventional method of interior lighting for workplaces was by ‘general illumination’. As lighting was not expensive to purchase, install or operate, the principle was to provide illumination over the whole floor area with a high degree of uniformity. This enabled plants or furniture to be subsequently positioned anywhere in the space and easily moved without recourse to changing the lighting array.

Council House 2 - Offices. Spot the five sources of light....

 However for the past decade UK lighting codes and standards have recommended not ‘general’ but ‘task’ lighting. The significance of this change has either been ignored or gone largely un-noticed as the illumination values were basically the same. The new concept recognised that the main critical visual task is only carried out over a small part of the total floor area. The rest of the space is used for circulation, storage, filing and similar activities all of which are less demanding in terms of illumination. Lighting the whole area to the highest illumination required can use about a third more energy than matching the illumination to the different activities.

Energy costs are continuing to rise and therefore providing the right amount of light only where it is needed is beneficial both economically and environmentally. Also variation in illumination can make the space visually more interesting than overall uniformity. Normally the reason for still providing ‘general’ illumination is because the building is a speculative development and there is no client to determine the furniture layout, or simply that the layout has not been decided yet. I think potential tenants need to be aware that for lighting to be visually efficient the equipment should be electrically efficient and the lighting design should suit the activities across the space. Providing light where and when it is not needed is inefficient regardless of lumens per watt performance of the luminaires.  

Recommended illumination levels in the past were based upon the need to determine detail in the visual task, together with the amount of contrast critical nature of the work and the importance of colour discrimination. Recently there have been massive changes to how we read the written word with print on paper largely being replaced by self-illuminated screens of computers, tablets, telephones, information signs, cash registers, etc. At the same time there has been the move towards ‘hot desking’. No longer does a space have a constant lighting need. The visual task performed at any point will depend upon the occupant at any one time. Does this mean we should revert to general illumination?

Or does the lighting of our buildings require a fundamental rethink so it is more appropriate to today’s sometimes conflicting needs of energy conservation, use of electronic media devices and flexible occupancy of spaces?   Modern lamps have long lives and therefore lighting is only infrequently changed. Installations over twenty years old are not uncommon, a time span when most other electrical equipment will have been replaced several times. 

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