How Can Property and Facilities Managers Tackle Complications with Lower Occupancy Rate Buildings?

At Demand Logic, we understand the challenges faced by properties and facilities managers during this time when buildings lie empty, or with minimal use. Our previous blog, ‘Support During the Covid-19 Pandemic’ outlined what you should look out for, that is, issues that may arise. In this blog, we’re offering our tips on what to do to prevent these issues from developing.

Limiting health risks

In the majority of buildings, there will be skeleton staff and, for some, more. No matter how many or how few people are occupying your building, limiting the health risks to them with effective management of building systems should be a top priority. The two key factors that will help achieve this are regular ventilation and appropriate temperatures for your domestic hot water.

1. Ventilation

The ventilation required will depend on the occupancy level of your building, as raised in our previous article recirculation should not be used, utilising fresh air supply only where possible Some Air Handling Units (AHUs) don’t provide ventilation, in which case they may not be needed. According to Representatives of European Heating and Ventilation Associations (REHVA) one of the most important things to avoid is air recirculation to limit the spread of the virus and other airborne illnesses. To ensure that air isn’t being recirculated, non-recirculating heat recovery, such as cross flow recuperators should be safe to use. However, they will need to have been recently inspected for air tightness. Run-around coils should also be safe to use in this instance. If ventilation is required, REHVA recommends, where possible, to avoid using fan coil units as they tend to recirculate a significant portion of air. This often presents a paradox, as fan coil units are usually the final delivery of fresh air into the space and, if not running, the fresh air from the AHUs may be extracted out of the ceiling plenum with no benefit to the space. If possible, it is advisable to use natural ventilation. If fan coils cannot be switched off, it is recommended that their fans are operated continuously through which virus particles will be removed with exhaust ventilation.

2. Domestic Hot Water Services

Stored domestic hot water can often present health and safety challenges, primarily from Legionella. Processes will already be in place to comply with building regulations, but these should also be considered when occupancy rates are reduced and the majority of taps and showers are not being used, presenting multiple dead-legs.

If you are able to provide point of use water heating for the remaining site staff, consider shutting down the domestic hot water. However, if you do so, it’s vital that the settled temperature of the water in storage pipework falls below the danger level for bacteria growth (20 degrees celsius) and is continually monitored.

If you do choose to keep your domestic hot water systems operational, ensure that temperatures are appropriate and that any necessary pasteurisation routines are operational and effective. Also, consider alternative means of regular secondary distribution to limit dead legs.

Protecting Plant

Exercising your plant is an important process that will ensure it’s ready for operation when things return to the new normal. Depending on your building occupancy levels and systems shut down policy you may have already significantly reduced plant operation.

In order to avoid neglecting this equipment, focus on the processes of valve exercising and anti-stagnation flushing. These two processes can often be confused, so it is important to note that exercising of valves only needs the valve to open and close to prevent it sticking. However, flushing cycles need pumps to be operational whilst valves are open to purge coils. Neither process needs boilers or chillers to be operational, or fan coil and AHU fans to be running. In worst cases, boilers, chillers and all fans run at the same time as all valves are open 100%, which results in an increase of wasted energy. Therefore, effective monitoring can reduce the potential for this occurrence.

Reducing the Risk of Building Damage

Building damage is often something that can be easily prevented through effective system management. It is important that this isn’t overlooked, as if it is neglected, this can result in costly repairs.

One of the main elements to monitor is building temperature. With the increase in warmer weather as we come into the summer months, some buildings may experience significant internal heat and solar gains, particularly on south facing facades. If this problem occurs, you may want to consider cooling systems to reduce the temperature. However, be aware that recirculation policies will need to be factored into this solution. This problem could also be solved by using night purge ventilation.

My advice for colder months is to ensure that the building temperature doesn't fall below levels that can cause damage to fabric and equipment through damp and mould growth. This is something to monitor regardless of occupancy rates.

Savings: Energy, Money, and Carbon

Having reviewed your plant operational policy in line with current circumstances, it is critical that the policy is implemented in line with your Building Management System (BMS). These systems often have anomalous demands, causing your equipment to operate unexpectedly and use energy that isn’t needed. To rectify this issue, ensure that the BMS is appropriately configured. A BMS that isn’t correctly configured can result in valve exercising routines inadvertently sending demand signals to pumps and primary systems. This is where data can help[1] . Double check that your systems are operating as they should be by comparing historical valve data to current plant operation.

Keeping Critical Business Systems Running Smoothly

In many buildings there may be business critical systems, such as server rooms. These systems may continue to be in use by staff working from home over VPNs, and will certainly need to be readily available when normal working is resumed.

The first stage of ensuring the continuity of business critical systems is identifying business critical plant and the processes that will need to be undertaken to keep them running at the level needed. For example, server rooms need cooling systems. This may include chillers (either the main building chillers or dedicated critical chillers) and their associated pumping systems, working in conjunction with Close Control Air Conditioning systems. Ensure that these systems are not inadvertently shut down when reducing other plant operations.

Once you have ascertained that the systems haven’t been shut down, keep an eye on chiller operation. Sometimes systems are unhappy working at lower loads so, if you have the option, try to get a smaller chiller on lead duty. Ensure that you monitor temperatures and, where available, other environmental conditions. Rapid alerting for system failures will help with this and raise the alarm when deviations from the norm occur.

As lockdown restrictions lift, things are unlikely to return to how they were before. Lower occupancy rates are likely to continue in the upcoming months, so it is crucial for property and facilities managers to act on their building data to avoid assets becoming a stress. Get in touch if you would like to talk to us about how data can help you manage your building more effectively.