Smart building technology: what to specify at the design stage

What 'smart building' actually means

The term gets applied to everything from a building with app-controlled lighting to a fully integrated development where HVAC, access control, energy monitoring and space management all share data. That range makes the label almost meaningless without qualification.

For practical purposes, a smart building is one where the technical systems – environmental controls, security, power and communications – are connected, monitored and controllable in ways that produce measurable operational or commercial benefit. The key word is measurable. Technology that can't demonstrate reduced energy consumption, improved occupancy data or lower maintenance cost isn't smart; it's complicated.

The systems that typically define a smart building are: a Building Management System (BMS), IoT sensors and connected devices, IP-based access control and security, lighting control, AV and space management technology, and the network infrastructure that ties all of it together. Each of those needs to be considered during the design phase – not during fit-out, and certainly not after practical completion.

Building management systems (BMS)

A Building Management System (BMS) is the central control platform for a building's mechanical and electrical systems. It monitors and controls HVAC, heating, cooling and ventilation – and in more integrated deployments, lighting and power as well. A BMS gives facilities managers a single interface for monitoring building performance, setting schedules and responding to faults.

The major platforms – Siemens Desigo, Schneider EcoStruxure, Honeywell Building Technologies and Johnson Controls Metasys – all operate on similar principles but differ in integration capability, scalability and cost. The choice of platform matters less than specifying it at the right point. A BMS needs its own dedicated network segment and typically communicates using BACnet or Modbus protocols. If that network infrastructure isn't planned from the outset, adding it later means significant additional cost and disruption.

The BMS should be specified with an eye on what it needs to integrate with: smart meters, occupancy sensors, lighting controls and access control systems all generate data that a BMS can use or needs to be aware of. Designing these integrations in from the start is considerably cheaper than retrofitting them.

IoT sensors and connected devices

IoT sensors are how a building develops awareness of how it's actually being used. The most common categories are occupancy sensors, environmental monitors and smart meters.

Occupancy sensors come in several types – passive infrared (PIR) for area-level presence detection, CO2 sensors for air quality monitoring and desk-level presence sensors for granular space utilisation data. These feed into both the BMS (so HVAC responds to actual occupancy rather than fixed schedules) and space management platforms that give facilities teams and tenants visibility of how space is being used.

Smart meters for electricity, gas and water provide granular consumption data that goes well beyond what a standard utility bill shows. This data is increasingly required for sustainability reporting – particularly for BREEAM (Building Research Establishment Environmental Assessment Method) ratings and Energy Performance Certificates (EPCs), both of which are now significant factors in commercial lettings and institutional investment decisions.

The infrastructure question for IoT is power and connectivity. Many sensors are battery-operated and connect via wireless protocols such as Zigbee or LoRaWAN. Others require wired connections. Either way, the locations of sensors need to be planned in coordination with M&E design to avoid expensive remedial work later.

Access control and security systems

Modern access control systems are IP-based – readers, controllers and management software communicate over the building's network rather than through proprietary wiring runs. Platforms such as Paxton, Lenel and Genetec offer cloud-managed and on-premise options, with varying levels of integration capability.

The decision between cloud-managed and on-premise server deployment has implications for both ongoing cost and data sovereignty. Cloud-managed systems typically have lower upfront cost and simpler remote administration. On-premise systems give the building owner more control over data and are sometimes preferred by tenants with specific security requirements.

Integration is where access control becomes genuinely useful. A system that's connected to HR or identity management platforms means access rights are automatically updated when people join or leave. Integration with CCTV platforms means events (a door held open, a failed access attempt) can be correlated with footage automatically. Visitor management systems extend the same logic to contractors and guests.

The specification point: access control readers, door controllers and IP cameras all need PoE (Power over Ethernet) connections. These need to be included in the structured cabling design – they can't be added as an afterthought without pulling additional cable.

Lighting and energy management

DALI – Digital Addressable Lighting Interface – is the standard protocol for intelligent lighting control in commercial buildings. Unlike simple on/off switching, DALI enables individual luminaire control and dimming, fault reporting at the fitting level, and integration with occupancy sensors and the BMS.

The commercial case for DALI is straightforward. Daylight harvesting – adjusting artificial lighting output based on available natural light – delivers measurable energy savings in buildings with significant glazing. Combined with occupancy-based control that turns lighting off in unoccupied areas, the energy reduction is material enough to affect EPC ratings and BREEAM scores.

For specification purposes, DALI requires a two-wire control bus alongside the power circuit to each fitting. This needs to be included in the electrical design. Retrofitting DALI to a building wired for conventional switching is expensive – it typically means replacing cable runs throughout the ceiling void.

Smart meters and sub-metering at circuit level give the energy management picture its granularity. Knowing that a floor's power consumption spiked at a specific time is useful; knowing which circuit or zone caused it is actionable.

AV, occupancy monitoring and space management

In commercial office and mixed-use developments, meeting room and collaboration space technology has become a significant specification consideration. Hybrid working has made the quality of meeting room AV a practical requirement rather than a luxury, and the data these systems generate is increasingly valuable for space planning.

Microsoft Teams Rooms, Crestron and Logitech Rally are the most common platforms for hybrid meeting equipment. Room booking panels outside meeting rooms provide real-time availability and integrate with calendar systems. The occupancy data from these panels – which rooms are booked, which are actually in use, which are booked but consistently empty – feeds into space planning tools such as Robin and Condeco.

The infrastructure requirement for AV is often underestimated. Each meeting room needs structured cabling to the display, the camera, the room booking panel and any room control equipment. HDMI and USB-C connectivity at the table needs conduit from the outset. Retrofitting this into a finished meeting room is disruptive and expensive.

Network infrastructure requirements

The most common failure in smart building specification is treating all of these systems as if they share the same network. They don't – and they shouldn't.

BMS, IoT devices, access control, AV and corporate IT systems all have different security profiles, different bandwidth requirements and different failure tolerances. A BMS compromise that affects HVAC control is a facilities management problem; a BMS that shares a network segment with corporate IT is a security problem. These systems need their own VLANs and, in many cases, dedicated physical network segments.

The practical specification requirements:

• Structured cabling designed to support PoE where IP cameras, access control readers, IoT devices and AV equipment will be installed
• Sufficient PoE budget in switching infrastructure – this is frequently underspecified
• Dedicated network segments for BMS and building control systems, isolated from tenant and corporate networks
• Wi-Fi coverage designed around actual occupancy patterns, not just floor area
• Comms room or IDF space planned in relation to where systems actually need to terminate

The network infrastructure design needs to be coordinated with M&E, the BMS contractor and the AV integrator before the cabling design is finalised. Changes after first fix are costly. Changes after second fix are very costly.

How to specify smart technology during the design process

The most effective approach is to appoint a technology consultant or building IT specialist at RIBA Stage 2 – concept design – so that smart building requirements can be incorporated into the employer's requirements and M&E specification from the outset.

The key decisions that need to be made during the design phase:

• Which BMS platform will be used, and what systems will it need to integrate with
• The scope and location of IoT sensors, including how they'll be powered and connected
• Cloud-managed vs. on-premise for access control and security, and the implications for server room space and network design
• Lighting control strategy – whether DALI or an alternative protocol, and the implication for electrical design
• AV and meeting room technology standards, including cabling routes to every point
• Network segmentation strategy and the physical infrastructure it requires

BREEAM assessors can advise which smart building controls contribute to credits under the relevant assessment method – this is worth understanding early if a BREEAM rating is a project requirement or a tenant demand.

The handover process matters as much as the installation. Smart building systems that facilities managers don't know how to operate revert to being dumb buildings very quickly. Operator training, system documentation and a clear support structure should be specified alongside the technology itself.