The KNX building control system is over 25 years old, yet for many people it’s still a new idea. Here Iain Gordon explains the concepts behind the technology and considers why it is gradually gaining more ground with controls engineers and clients.
Back in 1990, a group of European manufacturers started a revolution in building control by founding the European Installation Bus Association (EIBA).
This was an example of disruptive technology. Their idea was to ensure that electrical installations with bus technology would be fit for the future and they recognised the inevitability of collaboration. The potential for intelligent control of every aspect of building management could only be fully realised if manufacturers – and their devices – talked the same language. No manufacturer could realistically do it all alone.
Their vision eventually led to the KNX global open communications standard. It has also given us a whole new approach to how we wire our buildings, because it distributes control. I also believe that it helped to accelerate development of smart devices because, with a common control protocol already established, R&D costs come right down.
Of course, changing the traditional approach to building control is like turning a containership – there’s a lot invested in the status quo. But the move away from proprietary systems and towards distributed control and the creative flexibility a truly open protocol delivers is inevitable. The Internet of Things has changed the zeitgeist; we are reaching tipping point. Not only are the old approaches becoming technically redundant, they are also financially illogical.
Open systems and flexible, scalable distributed control win hands down on both CapEx and OpEx. It’s less expensive to wire and install, and less expensive to update, maintain and manage. If a device fails, there are plenty of compatible alternatives on the market. If the building owner wants to use the space differently, reconfiguring the bus in a zone is easily accomplished, usually with no rewiring.
What Is KNX?
KNX is a bus technology focused on energy saving, optimised building performance and creating outstanding working and living environments. It brings local and zoned control to every area of the building. KNX can be integrated with any type of BMS and naturally works alongside DALI to add intelligence to light switching.
It is a global, open, standardised (EN50090, ISO/IEC14543), OSI-based network communications protocol for intelligent building control. KNX is the successor to, and a convergence of, three previousstandards: the European Home Systems Protocol(EHS), BatiBUS, and the European Installation Bus (EIB or Instabus).
The KNX standard is administered and updated by the KNX Association, based in Brussels and supported by national associations of installers, manufacturers, stockists and training providers. Worldwide, there are over 66,000 KNX engineers. In the UK, the KNX UK Association provides peer-group networking and support for forward-looking building services engineers and installers.
Back in the 1990s, twisted pair was the main transmission medium. KNX now supports all the main communications media available to engineers:
• Twisted Pair (TP - Cable)
• Radio Frequency (RF)
KNX products are made by over 400 companies. There are over 7,000 product groups to choose from, with each device independently tested for compatibility. Technically and commercially, it is a safe option.
Best kept secret?
So, why, more than 25 years down the line is KNX still one of the best kept secrets in UK construction?
It has been specified by major engineering in iconic UK buildings including the new St Pancras Station, the British Library, the O2 Arena, the Jubilee Line extension and Salford Quay’s iconic Media City. In each case, it has been seamlessly integrated with the project workflow – albeit the workflow has been updated so that different aspects of control are considered together, not separately.
Nevertheless, in the UK the main impact of KNX is in residential markets. Here custom installers have seen the opportunities not only to provide better solutions in their traditional areas of expertise but also seamlessly to extend their business. The 70/30 commercial/residential split that we see on continental Europe is pretty much reversed in the UK.
I suspect there are a number of reasons for UK inertia in the commercial sector. Change is easier in a smaller business working on smaller projects involving smaller teams. In commercial construction, we don’t really think ‘whole building’ yet. Mechanical (HVAC) and electrical engineering are separate disciplines and they often happen independently when they should be combined. Traditional workflows reflect this old way of thinking.
The life cycles of new-build and refurbishment projects are long so the separation of mechanical and electrical engineering could be a block on innovation for some time yet. Buildings going up now and in the next few years are probably already drawn and specified.
I see opportunities for progress as BIM matures in the UK, because it is causing project managers to overhaul their processes and workflows from beginning to end. We’ve also seen examples of projects adopting KNX at a late stage to gain the benefits.
Some engineers, I know, may harbour cynicism about a global standard, remembering LonWorks. However, KNX has demonstrated that it is a proven, guaranteed single standard.
Another cause of inertia may be that KNX doesn’t have an outof-the-box head-end that’s easy to sell in to developers and building users. Every KNX system will be custom built using a different mix of devices. For a KNX integrator, developing the custom front end, if needed, is the icing on the cake. The smart integration work is already done behind the scenes
I believe we are at a tipping point. Building owners’ and users’ expectations are rising in terms of connectivity and interoperability. Architects are experimenting with new materials and construction methods to meet environmental and space constraints while catering for new ways of working and using commercial space. KNX can resolve the environmental and energy control issues without curtailing their creativity.
The government is breathing down all our necks on energy efficiency: it’s not enough just to measure and visualise your consumption, you must do something about it. That calls for greater levels of controls integration.
I might also add that designing and integrating KNX controlfor a building must be the best and most exciting job in the installation industry, and I’d advise any installer to get in touch and investigate making the quantum leap now.
The industry is already crying out for KNX installers – and the demand will only get stronger.
Iain Gordon is KNX UK president