BS EN 15232:2012 is a Standard that is extremely important to those involved in designing, installing, operating and using building controls or building energy management systems (BEMS).

BS EN 15232 is all about energy performance of buildings – impact of building automation, controls and building management. It’s a fairly self-explanatory title, but the real beauty of BS EN 15232 is that it offers a very simple and easy-to-understand labelling system for BEMS.
We are all used to the notion of Energy Performance Certificates (EPCs) for buildings. This labelling system was born out of the Energy Performance of Buildings Directive. The BS EN 15232 Standard was created at the same time, as part of wider research on the energy performance of buildings.
Simply put, the Standard rates BEMS from A to D. A building with a controls ‘system’ in Class D has no BEMS in the sense that we would understand it. This means no automatic heating or cooling control, no control of air at room level and manual control of daylight and lighting.
For all calculations, the Standard uses Class C as the basic class of wider building control. The Class C BEMS includes: control of heating and cooling at room level using thermostatic valves, time-dependent air conditioning and ventilation controls and manually-controlled motorised blinds.
As we move up the scale, Class A includes control of heating and lighting at room level with communication between controllers. There is also on-demand control of air conditioning and ventilation at room level, with a variable set-point for outdoor temperature compensation. There are also automatic lighting and daylighting controls – and blind controls are integrated with lighting and HVAC systems.
Ultimately, what BS EN 15232 is recommending is an integrated approach to demand-led controls in buildings. In simple terms, nothing is switched on unless required and the standard setting is ‘off’. What’s more, the different systems within a building – lighting, heating, cooling, blinds, etc. – communicate and work in harmony.
For example, daylight detectors ensure that lighting is switched off and blinds go up automatically to minimise use of artificial light. However, temperature sensors will ensure that if solar gain is causing the air conditioning to switch on (using energy), the blinds will close again and lights switch on. The building keeps itself in balance, permanently ensuring both occupant comfort with optimal energy use.
The key word here is integration. The ability to make HVAC, lighting and blinds work together on a system that shares sensors is challenging for designers and controls professionals.
Use of open protocols such as BACnet and DALI (for lighting) in the controls sector have made integration easier. However, what about existing buildings that need to upgrade their controls systems? Tying in a number of legacy control systems that were not designed with ‘integration’ top of mind is very difficult.
One new approach that is gaining ground in the UK is with PC-based controls systems. These cut through the old rivalries of proprietary controls protocols, and can simply sit at the top of an existing group of controls systems, bringing them together and placing information for the facilities team on a single head-end.
Not only does this approach create integration from a disparate group of systems, it also saves significant sums of money that might otherwise have to go into removing all controls and starting from scratch with a new BEMS.
The engineering team at Gatwick Airport took this integrated approach when it upgraded lighting controls and opened the door to wider integration with the building's entire BEMS.
The Gatwick engineering team realised that its estate was operating many different lighting control solutions, each working in isolation, with little real-time condition monitoring and reporting. The team was therefore focused on finding a solution that would not only improve control of lighting, and allow the team to make alterations to the system as they required, but also work with the BMS, rather than separately to it.
Gatwick therefore decided to work with Beckhoff Automation and its delivery partner Interior Automation (IA). They deployed IA’s BuildingSight software, using the existing DALI or DSI cabling and, where possible, network infrastructure, to provide control and real-time monitoring of the connected lighting.
The system displays and records its associated energy usage directly to the airport’s BMS for analysis. Each control node throughout the estate also gives the engineering team seamless connectivity to the whole range of additional Beckhoff fieldbus components. This makes future developments in BMS quick, infinitely flexible and cost effective to deploy.
The solution is rooted in industrial PC (IPC) technology, so the control system has the capacity to be scaled from a stand-alone single application device - such as lighting - through to multi-core devices capable of full building control. The IPC is also capable of vast data processing and reporting in real time. This is the key characteristic that makes it open and adaptable to future needs.
The system can now monitor energy usage directly at the electrical panels or provide virtual metering when needed. Changes can be made when required by the in-house team, allowing them full control of their solution.
The integrated approach is the only way to ensure that building owners and managers get the full benefits of a BEMS. Selecting an open PC-based platform ensures that the integration is not only more straightforward, but also allows the building to develop into the future and to keep pace with fast-moving controls technology.
Standard BS EN 15232 is a great place to start when specifying a new BEMS or looking to upgrade an existing system, but integration must be at the heart of the solution.

* Beckhoff Automation has developed a CIBSE CPD-accredited training presentation on BS EN15232. For information and to book a seminar, please email Karl Walker (