Much has been spoken and written about the role of building management systems (BMS) in modern buildings, primarily regarding the role they have to play in improving energy efficiency. But in the era of the smart building, building owners, managers and occupiers now want more from their automation, with BMS offering the potential to make a significant contribution. Here Ian Ellis, Marketing & Sales Specialist Manager, Siemens plc, looks beyond just energy efficiency (important as it is) and discusses how BMS can contribute to well being.

Focus on four main topics

A useful place to start is to consider what is a smart building? There are many varied definitions but what they all tend to have in common is the appreciation that a smart building employs technology, not only to enable an efficient use of resources but also to create a safe and comfortable environment for its occupants. At Siemens we see four main focuses in what people want from their smart buildings: flexible space utilisation; digital transformation; a demand for health and safety; and sustainability.

The need for flexible space utilisation has grown in importance recently. Covid has reshaped the work landscape, the impact that home/hybrid working has had on the office environment being far beyond what most people anticipated. Large and small companies alike have re-evaluated their need for conventional office space. Some have relinquished it completely, requiring buildings to be changed from their original purpose; others have remodelled the structures of their working environments to reflect the different work models. This has brought a particular focus on how to react to how spaces are used.

Digital transformation is happening in all of our lives, from the technology employed in our homes to that which is driving the growth in commercial smart buildings. The IoT continues to grow exponentially, with a modern BMS usually involving significant amounts of data from potentially thousands of system devices which are constantly sending and receiving information.

Health and safety has become a greater focus for so many businesses, even more so since the Covid pandemic. Ensuring that the working environment is not only safe but is actually conducive to promoting the health and well being of a building’s occupants is now very much the goal.

Likewise with sustainability which is regularly one of the first considerations in the development and operation of a new building. When you consider the statistics relating to the de-carbonisation challenges of the built environment it is easy to see why. Some 40% of all energy is used by buildings (heating and lighting being the biggest consumers), with 39% of global energy related carbon emissions caused by buildings. This means that buildings are the biggest single source of energy usage, the other main ones being transportation and processing and manufacturing. Add to this the pressures on energy prices plus the increased introduction of green regulations and it is easy to appreciate why sustainability is high on the building and construction agenda, with companies looking to continue on a journey towards net zero.

Different levels of automation

BMS can help to address all of these issues. The level of automation dictates just how much control is available, from basic entry-level systems through which management is based on room demand right through to systems which effectively automate the whole building operation – heating, lighting, air conditioning, cooling, shade control, and door and window technology. These can all be networked to communicate with each other to enable central control through intelligent BMS.

Energy efficiency has been (and still is) a key driver for BMS. The BACS Energy Performance Classes in EN ISO 52120-1 provide a guideline for the strategies which can be adopted through a demand/control based system. It ranges from the inefficiencies of Class D through to the highest performance represented by Class A. By raising a building’s performance from Class C to Class A, energy savings of up to 30% can be achieved just by improving the design and implementation of a control system.

One of the major advances made in improving the energy efficiency of buildings has, however, actually worked against their performance in terms of occupant well being. Older buildings were typically well ventilated whereas new buildings are designed to be practically airtight. While this certainly improves energy optimisation, a consequence is that fresh air is no longer getting into buildings. The air quality in a building can therefore suffer, with more CO2, higher humidity and an increase in pollutants.

Air quality

Research suggests that the majority of people spend some 90% of their time indoors so the indoor environment is key to our health, particularly in light of the fact that pollution is typically 2-5 times higher in indoor spaces.[1] In fact, poor ventilation may account for more than 50% of all sick leave. For those that are not so adversely affected that they require time off, office work performance can still fall by over 9% as a consequence of poor indoor air quality. We have all been in buildings where poor ventilation has created a stuffy environment which directly impacts on our cognitive performance.

It is also not only short-term consequences for our health that need to be considered. Those constantly exposed to unhealthy environments can suffer a range of longer-term conditions, including high blood pressure, an increased heart rate and kidney and bone problems.

Such issues have raised the profile of how control systems can be managed, not only to improve energy efficiency but also to deliver better health for those that are using them.

There are essentially nine foundations to a healthy building: ventilation, air quality, thermal comfort, moisture/humidity, dust/pests, lighting and views, water quality, noise, and safety and security.

Returning to indoor conditions, studies suggest that 40-60% relative humidity is ideal for indoor human health and reducing virus vitality. With each person delivering approximately 8 litres of air per minute through breathing, the released air contains CO2 plus droplets and aerosols. CO2 levels should be kept below a certain level to help provide wellbeing for occupants. Attention should also be paid to VOCs (volatile organic compounds) and PM2.5 fine particulate matter which are microscopic dust particles.

Monitoring and control

Firstly, you need to be able to measure these values and then you need to be able to put controls in place. This is where effective BMS come in which are central to pursuing a green building certification (examples are Well V1, Reset, LBC, Fitwel and LEED). In its simplest form this can be just ventilation control, monitoring and adjusting temperature for example. The next stage is demand controlled ventilation (CO2 – based), which improves air quality and saves energy. Even more effective is demand controlled ventilation with active filtering which introduces more fresh air by dynamically analysing the outside air conditions, creating accurate air pressure drop control, generating the same amount of air and filtering out PM2.5s but using less energy to do so.

Research suggests that keeping CO2 levels below 1,000ppm can increase productivity by between 2-18%. As already stated, humidity levels from 40-60% are perceived as ideal, reducing virus transmission by up to 70%. By controlling the level of indoor Volatile Organic Compounds (VOCs), sick building syndrome can be avoided reducing absenteeism and improving productivity.

Connecting the dots

With the shift towards a more holistic approach to managing a building in terms of its active contribution to the well being of its users, so the need for connectivity of the sensors and control devices is becoming ever more important. Solutions are now available which allow daily building management tasks to be undertaken from one place via a cloud-based interface with no additional gateway or software. Alarm notifications for potential issues as well as graphics that visualise historical trends can provide meaningful insights into the building performance at any time, supporting the optimisation of building operations.


Intuitive online access can be available via desktop or smartphone, with installation achieved via plug and play, so system integrators, technicians and facility managers do not need engineering skills to set up, configure and operate systems. It is important that such interfaces can support a range of communication protocols to optimise connectivity (wired or wireless) – BACnet, LoRaWan, M-Bus, Modbus and KNX are all protocols used in BMS.

Optimising the potential of BMS

Digital transformation is one of the main drivers in the development of smart buildings.

The pandemic accelerated a shift in the attitude to work which has seen the needs of employees placed front and centre in the workplace. Offering an environment which is a pleasure to work in is an incentive to potential employees. Once they are employed, that environment can actively help with their productivity and health through optimised lighting, temperature, space usage and air quality. While BMS undoubtedly continue to have an important role to play in reducing energy use, by recognising their potential value in monitoring and controlling a building’s environment, they can also make a significant contribution to occupant well being.

[1] Source’ Environmental Protection Agency ‘ “Risk of Sick Leave Associated with Outdoor Air Supply Rate, Humidification, and Occupant Complaints”