Sustainable Buildings Toolkit:
Building Management Systems 2 – Operation

BMS Advice Toolkit

Building Management Systems (BMS) offer facilities managers many advantages, including information about a building’s operational performance and energy use that can help identify root causes and correct issues in their buildings.

However, research shows that only about 20% of facility managers use 80% or more of their BMS’s capabilities. By their nature, Building Management System (BMS) can be complicated to use and appear very technical. A good system should have been designed to be simple to use, with well documented user guides to make sure knowledge of the system isn’t lost when staff leave.

Ensuring the BMS is easy to use and intuitive for day-to-day use by staff members is critical to the efficient operation of any building. An overly complicated system will be difficult to adjust and risks being left to run continuously, often with inappropriate setpoints and other settings leading to extra energy wastage.

A member of staff should be given time to look at the BMS regularly – ideally once a day – to confirm it’s working as intended. Often, a quick glance through each page can highlight an issue before it becomes known to building users. For example, you could notice the temperature output from a boiler is lower than usual, causing it to run for longer to satisfy the setpoint. This could be an early indication of a mechanical issue with the boiler.

Consider how your premises will operate in the coming weeks, and which zones in the building are planned to be used at any given time. Query whether setpoints are realistic – they may not have been reviewed for some time. For example, a high space temperature setpoint that a system is unable to reach will cause it to run continuously. If you were to set an air conditioning unit to 30degC it wouldn’t heat the room any faster than if it were set to 25degC. It will just run for longer, trying to achieve the unachievable.

Consider installing simple ‘user interfaces’ at locations around the building, allowing easy adjustment of simple settings. Locations should be easily accessible to relevant staff members. These interfaces can be programmed with any number of simple override commands to allow better use of systems and building areas.

This will require the control programming within your BMS to be updated and the options represented on your BMS PC. A modern BMS will allow access via a mobile device.

Examples of local override controls:

Stage Door / Box Office

• Open non-performance

• Performance

• Rehearsal

• Tech Set-Up

• Automatic

• All Off

Stage Manager / Lighting Control Desk

• All Off Mode

• Intermission

• Automatic

Setpoint Refinement

Review your current BMS temperature settings (known as setpoints) and modes to ensure they accommodate changing levels of occupancy at different times of the day.

It may be possible to adjust setpoints a degree or two up or down to reduce the amount of time equipment runs without sacrificing any noticeable building user comfort. You can achieve a 1% reduction in energy usage for every 1degC change of your hot water setpoint. This can save up to 5% in energy costs (always ensuring you maintain your legionella requirements).

If your ventilation plant can be speed controlled, then it may be possible to reduce the speed of your fans when occupation in the building is low using a CO2 or occupancy density sensors. The building ventilation will have been designed to cope with peak demand so a reduction in ventilation when your building is quieter will have no adverse effect on comfort.

If your building does not have individual room or zone control, consider upgrading or replacing with a system that features temperature setpoint control. In occupied areas, providing individuals control over their environment (temperature, fan speed, lighting, etc.) may help with overall satisfaction and, potentially, productivity.

Night and unoccupied setback

Reviewing current BMS setpoints for out of hours operation is another way to control energy use and costs. You could achieve 8 – 10% in energy savings while still protecting the building in extreme cold or hot weather.

Typical setbacks are 12degC, at which some plant should be started to prevent mould issues and to stay within the ASHRAE recommended range.

Free cooling

Some ventilation systems can be programmed to use the cooler night air to cool down the building without using your chiller plant. This can be especially useful in the summer months.

Optimum start/stop

An optimal start routine adjusts your equipment start times automatically based on the building’s profile and demand. Starting equipment only when necessary ensures comfort levels for building occupation, while gaining energy savings. Many modern BMS’s can provide this ‘optimal start’ function, although often the program is disabled or needs modification to work correctly.

Useful alarming

Often, a BMS that has been set-up poorly will generate hundreds of nuisance alarms. As a result, building users stop interacting with it. This is counterproductive. Alarms can be a useful tool in managing the building and its energy use. A well thought-out alarming scheme should have tiers for critical, non-critical and maintenance alarms.

Other considerations

• Check fan and pump speeds are not being operated at higher speeds than required. It may be possible to set them up to vary their speed with demand.

• Make sure heating and cooling setpoints don’t overlap. The settings of adjacent heating and cooling devices are frequently found to overlap, resulting in both heating or cooling at full capacity (which also creates discomfort). Avoid this by adjusting temperature settings to ensure there is at least a 2degC ‘gap’ in which neither heating or cooling is taking place (e.g. heat up to 21degC, cool down to 24degC, with no heating or cooling in between).

• Make sure air isn’t heated, then cooled back down again. Check that air handling units that supply air into offices are not set up so that they heat up cool outside air, only for that air to be cooled back down by cooling units in the office space. These air handling units can usually be set up so the air supply temperature responds to the heating or cooling demand of the building.

• Check over your control panels to see if any of the switches are set to the manual or “hand” symbol. If so, that item will run continuously 24/7.  If the system won’t run on “auto” there may be an issue that needs resolving. Automatic control will always save energy.

• Most modern BMS systems are capable of open communication with systems from other vendors. This means you can get competing prices for new installations from a few different vendors.

These are just a few examples. There are many options and variations that can be used to make the building easier to operate, and to reduce energy use. A conversation with a BMS contractor outlining how you use the building will allow them to create an interface that best suits your situation.

The Arts Green Book has brought together culturalorganisations and sustainability experts to create common guidance for making culture sustainable.