“In one sense, there’s nothing new about the 2006 Part L of the Building Regulations,” says Ant Wilson of Faber Maunsell. His words will offer some comfort to a construction industry which is struggling to get to grips with this far-reaching legislation on the conservation of energy in buildings.

Wilson has spent the last few years speaking on Part L, and working with government to help educate and train the construction industry on its application. At the core of Part L 2006, says Wilson, is a straightforward principle: “The 2006 Part L uses the same carbon emissions calculation method which was the route to compliance under the 2002 Part L. Now as well as meeting a set of design limits, which aren’t a lot different from the previous elemental standards, you must demonstrate a reduction in CO2 dependant on building type. It is more of a belt-and-braces situation.”

So the principles of Part L do seem uncomplicated. However, you shouldn’t relax too soon. The key issue as far as Wilson sees it is that far too few people understood the 2002 Part L. “The problem is that in the past very few people really did use the carbon emissions calculation. The majority of engineers are not familiar with this method.”

Others agree that in spite of extensive press coverage, government-backed training programmes and CPD seminars, the industry still has a lot to learn. BRE’s Anthony Slater comments: “I think there is a lot of interest out there, but many people still don’t really understand what they are legally obliged to do now, until someone from Building Control turns up and asks for an air tightness certificate.”

The government has tried to disseminate as much information on the new Part L as possible, and this has been one of the most extensive campaigns ever run to introduce new construction legislation. That said, it is difficult to control the quality of training offered across such a large industry. Wilson says: “Most of the training has been pointing out how the 2006 Part L differs from the 2002 version. The problem is that people just don’t understand about Part L. There’s no point telling people how it’s different from before when they haven’t looked at the previous legislation. My advice is that people need to sit down and read the new Part L.”

One of the main reasons that anyone involved in construction needs to fully understand Part L 2006 is that it introduces legal requirements which were previously only voluntary. Wilson says: “Air tightness testing was only in the Approved Documents last time so it wasn’t a legal requirement. You should have been doing it, but there was no enforcement. Now it is part of the legal framework. You also have a legal obligation to commission your M&E and to provide the target and building’s CO2 emission ratings. It is now clearly in black and white that you must do these things.”

Also, achieving compliance with Part L will now involve use of new modelling software. EDSL has recently become the one of the first companies to have its TAS Building Designer software accredited by the Government. This means that it can be used to show compliance.

EDSL’s Alan Jones explains: “The modelling concept is simple really. You are taking a copy of your design – the shape, the location. You then put in a building services system as described by CIBSE’s TM32, which outlines the efficiencies of various components. You then have a good practice building which complies with Part L 2002. That sets the standard, and then you have to reduce that building’s carbon emissions by 28%”.

But Jones warns that the software is not designed to be an alternative to understanding Part L. “People are looking for software to give them all the answers which is understandable, because compliance is a complex procedure and people are very busy. There is also a shortage of good engineers which is why people are looking to packaged solutions to give them guidance.”

Jones points out that there is no substitute for experience when it comes to using the new software: forensic skills are needed to look behind the numbers and understand what’s happening to the building.

Modelling software consultancy SouthFacing is also developing software to help with Part L compliance. Their Carbon Checker SBEM interface has recently passed the DCLG accreditation tests. SouthFacing’s Ben Cartmell agrees that experience of building modelling is a must: “Engineers have used modelling for some time for high profile buildings, but the quality of modelling has varied dramatically. There is an unwritten issue that when people use software they trust it. They press ‘go’ and get a number and that’s what they use. But the quality of engineers using the software is very important. They need to be able to look at the numbers and know if they are sensible or not.”

Ant Wilson concurs that putting too much faith in the output of software causes problems. “Using the National Calculation Methodology Software, you have to use specified information to a large extent, and that is a worry. If people see performance levels coming out of the software, they are going to think that’s what they’re going to get when they run their building. We have to get people away from thinking like that.”

All agree that modelling skills will need to become included more in university courses if future engineers are going to be dealing with this increased use of the technique. Jones adds that any training for today’s engineers has to be more than one day: “You can spend time training someone in the classroom but when they go out on a project they will meet all sorts of twists that they weren’t expecting to see. How do you solve those problems? It’s not just about using the software, it’s about technical know-how.”

Modelling will take place at the early stages of a project. The acid test for buildings of appropriate size and type will be at the completion of the project, with the now-obligatory air tightness test. Those experienced in this field believe that this is likely to be the toughest challenge posed by the new Part L.

David Pickavance heads BSRIA’s air tightness testing division and says that the industry is in for a shock. “Many buildings fail the air tightness test first time. The problem is that very few people test again. Building Control hasn’t done anything to enforce remedial works because it hasn’t been a legal requirement. It worries me that now air tightness testing is obligatory, designers may set themselves high standards for air permeability without realising the implications – or how difficult it is to achieve.”

It seems that very little learning has been done by the industry to improve its ability to create air tight buildings. Pickavance says: “I once asked a contractor what he did differently to achieve a 5 rather than a 10 air tightness rating. He said ‘We hope harder’!”

He adds that BSRIA can offer advice on achieving air tightness, but it’s not always followed. “We were asked by a contractor to take a look at a project they were building. They were half way through construction and asked for some tips on passing an air tightness test. So we gave them advice, for which they paid. Once it was completed, we tested it and the building failed abysmally. We started taking out ceiling panels to see what had gone wrong and found that they hadn’t followed any of our advice.”

Anthony Slater of BRE says that learning from mistakes is a valuable step that the construction industry should be taking. “We have worked with teams that have completed one building which has failed its first air tightness test. But they have learned from that and gone on to build others which have achieved a better score.

“The interesting thing about air tightness is that it has been regarded as a surrogate for build quality. If you look at a good quality building with decent blockwork and so on, an air tightness level of 10 is not difficult to get if there has been care in the construction. If a construction team hasn’t done it before and they don’t know what to look out for, then it can be a disaster,” says Slater.

Pickavance also believes that air tightness is about more than simply passing a test; that construction professionals should understand the full implications of poor air tightness. “If one feature has gone wrong in the construction process then it would be entirely possible in a hospital (for example) to end up with a ward where all the patients heads are cold. The effects can be drastic. I saw one building where occupants actually carried their coats with them to put on and take off as they walked from one end of a building to the other because of the temperature differences created by leakage.

“Air tightness isn’t just a compliance issue. It is an issue of liability, and that should scare people.”

It is clear that although the new Part L contains very similar elements to the 2002 version, its application and interpretation are very different. Ant Wilson points out: “You have people out there saying we don’t need to change because the worst acceptable performance values haven’t altered. In general, people have used Part L 2002 as a look-up table. If you do that now you will certainly find that the values haven’t changed. But in spite of that, the whole fundamental approach to applying it has changed. Part L 2006 is a tool which gives you a standard of building performance. People need to understand that.”

Alan Jones says that this doesn’t just impact on building services engineers: “It is a particular issue for architects because they would previously have been able to design a building to be Part L 2002 compliant. Part of the way they designed was to take that into account. Now they feel they have to have an engineer sitting next to them from the early concept stage – though this isn’t necessarily true.”

Part L 2006 will have implications far beyond the design and operation of buildings. It seems likely that main contractors will have to take responsibility for the early modelling of the building. David Pickavance comments: “If you look at a contract where the main contractor has a building to erect and the designer is working for him. You might have a building with a number of different areas, with different cladding packages – a mixture of concrete frame and slabs and steel-framed. If those areas are open to one another, who is going to see if it is compliant? The main contractor is going to put all his packages out to tender to other people who are going to design those packages. What is he going to put into his SBEM software? Who is going to take overall responsibility for that? It is increasingly important that the main contractor or agreed person must take control and communicate clearly with the various parties.”

Ant Wilson points out that contractors will be constrained in other ways. Changes to specifications will be more difficult to undertake since they will impact on what has been modelled, and therefore on the overall performance of a building. “You may think, so what if the boiler is 90% efficient instead of 92% efficient, but that could now make a difference between a pass and a fail. Those 1% figures will add up and you might only achieve a 25% improvement on CO2 emissions, not the required 28% for an air conditioned building - and that means the building doesn’t comply with Building Regulations.”

Alan Jones adds: “Contractors are saying that their flexibility is limited because whatever is on the spec is going to have to be what’s in the building and they are going to have to use that.”

For suppliers who do offer energy efficient equipment, there is clearly an advantage. Phil Ord of air conditioning specialists Mitsubishi Electric, comments: “This is a plus for us. Things like the Enhanced Capital Allowances Scheme have also helped ensure that we are specified. Part L 2006 will make it difficult for our equipment to be ‘value engineered’ out by cheaper but less energy efficient suppliers.”

Lighting suppliers have already realised that this issue of specification under Part L 2006 could be a challenge for them. Anthony Slater comments: “Lighting is specified and dealt with later on in the construction process. A lot of the energy efficiency and financial margins will already have been shaved so the lighting suppliers are concerned that they are going to be pushed to supply something very energy efficient but within tight cost constraints to make up for these issues.”

The issue of value engineering is also an important one for Ant Wilson. “When QSs talk about value engineering, they mean cost cutting! I think we need to take a different view now. Investment of capital means better performance long-term. Real value engineering should be about asking how much will it cost to save this much CO2.”

Design teams will have a lot to consider with Part L. Ben Cartmell says: “More people need to be trained in this approach to design. If they’re considering a low energy building, people tend to leap to the high cost technologies such as solar collectors, when environmental design and efficiency should be the first consideration. The message needs to go out that all options should be considered and that costs for each approach should be measured against CO2 saved over the long-term.”

There have been a number of moves in the construction industry to help ease the path to Part L 2006 compliance. Self certification is one of these. Government accredited certification schemes will give individuals the clearance to complete work to a set standard which will automatically comply with the Regulation (this approach is also being taken with other new Regulations such as Part P). CIBSE is developing a Low Carbon Consultants scheme which will enable qualified building services engineers to take on an umbrella role and take responsibility for advising on all aspects of Part L, energy efficiency and low carbon technologies.

Ant Wilson says: “The approach of self-certification will make things a lot simpler. In the case of air tightness, you just use someone who is approved and certified and as long as they have a certificate it’s just a case of handing over pieces of paper to Building Control. Long-term when these schemes are in place, it will be more effective than expecting Building Control to do all the checking.”

The construction industry likes to keep compliance processes as simple as possible. Many engineers have been asked at some time in their careers, “Get my building through Part L”. Under the previous rules that may have been possible, since checking of actual performance was voluntary and minimal. Now however, all that has changed. Main contractors, architects, engineers and facilities managers will all play a part in compliance with Part L 2006. It’s no longer a question of expecting someone else to deal with it. The whole team has to take part. From Ant Wilson’s point of view this is a big opportunity for building services engineers: “You can’t just put a building together like a kit and say it’s going to work. The building now has to work efficiently through its whole life and to me that makes this a more exciting time to be an engineer.”

It’s advisable to read the Part L document in full in order to ensure you are conversant with all its requirements. Building Regulations can now be found at www.communities.gov.uk.

These experts and others will be speaking at M&E The Building Services Event on 10 & 11 October at London Olympia. If you would like to learn more about Part L and its implications for your work, sign up for the free seminar programme at www.buildingservicesevent.com

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