When should we use wireless technology in the construction industry?

When we build our new smart buildings, there is one thing I think is not very smart: we are still cabling all temperature sensors, CO2 sensors, VAV units, heating valves or radiators. This involves kilometres of cable and is not very flexible.

"Lease contracts are changing from 8–11 years to 3–5 years, which means the technical delivery must survive several tenants – so it needs to be flexible!"

Control of our buildings has over decades become very good at autonomy, meaning the control should function locally and information should not leave the building. In the image on the left I have taken a topology diagram from Sandnes municipality. But by doing it this way, you can see that a lot of cabling is required since all field components need a cable. You can also question the vulnerability of the system if the PLC goes down.

Let's say we had gone for wireless technology instead – we would have saved kilometres of cabling, avoided the interface between Electrical/BMS/Pipework, and could more easily take responsibility for one's own contract package. In addition, you can easily change the solutions afterwards, because you don't need to account for a communication cable.

Stability is often an argument for continuing with cable. I would gladly put that discussion to rest. We work on wireless networks all day long – the wireless network is the most important thing for most people in an office job, and we trust it. Even when it comes to large amounts of data. Our sensor technology uses a thousandth of this, and any downtime on Wi-Fi is critical – just a few seconds of delay is unacceptable. But if our temperature sensor has a 5-minute delay, does that matter? Does the temperature in a room change that much? What is the worst that happens? We get 21 degrees instead of 22.

Costs and accessibility are perhaps the most important reason why we can't wait any longer. The challenge is that there is a jungle of components with varying battery life and range. Choosing the right components for the right projects is very important. Ten years ago, Tridium launched both Zwave and Enocean support in perhaps the most widely used BMS chip, JACE, but it never really got off the ground. This has perhaps led to many other companies emerging on the sideline to disrupt this market.

Learning by trying wireless technology is an important lesson – we must be willing to try!

Security is a somewhat surprising criticism of wireless technology and cloud solutions. Especially when you think back to 2013, when Dagbladet "hacked" 290 traditional systems because there were so many vulnerabilities in them. When talking about wireless protocols today, security is taken for granted. Every day we send millions of wireless signals/data to the cloud via our online banks, but here we ask no questions. Downtime on internet banking or BankID happens occasionally, but we survive it, and it is always resolved in a reasonable time.

When data goes through the cloud we gain enormous advantages in terms of scaling, backup, downtime, hardware upgrades and much more. The disadvantage is of course that data leaves the building and there can be downtime. In the same way that the PLC in the Sandnes municipality topology diagram goes down, the cloud or the gateway connecting to the cloud can go down. It is important to be aware of this so that you create a good control strategy.

The control strategy must include a plan for what happens if the cloud goes down. If we control a ventilation system based on wireless temperature and CO2 sensors, the strategy will typically be to control based on the exhaust air sensor (which is the average of all rooms) with a minimum/maximum limit on the supply air – essentially how we do it today. So the worst that happens if something goes down is that control defaults to what we have today.

–Always have a good control strategy, then wireless technology with clouds isn't so scary!

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