How can we identify equipment and infrastructure that’s failing, or at risk, because of our hotter, more humid and wetter climate? What’s the impact of extreme climate events? And, what should we look out for during routine inspections and maintenance?
This piece explores the impact our weather is having on buildings and how a seemingly isolated incident can be symptomatic of risks to essential healthcare facility systems – ones that were probably designed for a different climate to the one we live in today.
Increased rainfall
Extreme weather events are happening with greater intensity and frequency than we’ve ever seen. There’s heavier rainfall which is having a significant impact on building infrastructure; reviewing rainwater and stormwater drainage capacity and overland flow paths is key.
Overflowing gutters, downpipes and stormwater systems
When a building’s rainwater drainage system is over capacity, water leaks from gutter overflows and generally spills onto the ground below, changing the rainfall discharge pathways. While climate resilient civil and stormwater design may accommodate heavy overland rainfall, it isn’t designed for water overflowing from rainwater roof gutters on a regular basis.
Water may also leak through the exterior of a building. If this isn’t addressed, it can lead to moisture issues and mould as well as attracting rodent and insect infestation.
Most critical spaces in healthcare have strict requirements for humidity control. If there’s too much moisture in the air, for example in a perioperative department or a pharmacy, then risk mitigation procedures and remediation measures need to be enacted.
Flooded sub-ground infrastructure
Excess rain can jeopardise critical infrastructure by building inundation and flooding. This could include electrical substations, fire tanks and water pumps which tend to be located in an area prone to excess overland flow, for example lower ground or back of house areas.
Risk assessments, including an overland flow path study, may need to be carried out to review the vulnerability of critical plant areas below ground.
Unstable structures
Structural soil stability can also be impacted by extreme rain, absorbing moisture and becoming softer. Building foundations aren’t always designed for the movement of softer soil and, if soil stability isn’t addressed, this will impact the building’s structural integrity.
Underground services may also move which could lead to pipes rupturing or cables being disrupted. Older power cables are unlikely to be well insulated.
A maintenance or grounds team should visually inspect their building for cracks or engage a consultant to carry out a fabric survey. Any issues below ground need to be captured early to minimise costs and avoid disruption to healthcare services.
extreme wind and hail
Saltwater corrosion of plant or facade
Buildings impacted by marine environments are seeing an increased risk of corrosion damage from saltwater and additional rooftop plant protection may be needed.
In Australia, there are standards for buildings located in areas classed as coastal marine environments to safeguard against corrosion. However, many areas that don’t fall within this classification are still impacted by saltwater corrosion, for example Melbourne.
We anticipate the corrosive impact of saltwater on buildings will increase as extreme weather events become more frequent. The areas impacted are also likely to increase as offshore storms reach further inland.
A facilities manager may notice that during inspections, there’s degradation or rusting of the coils on their air conditioning or hot water equipment. They may also see cleaning requirements increase with more debris to remove from the coils. As these are critical for heat transfer, internal temperatures may also be impacted.
Hotter, more humid days
When it’s hotter and more humid outside, an air-conditioning plant needs to work harder to take the heat and moisture out of the air. If systems start to fail, or struggle to meet demand, the increase in internal environmental conditions (temperature and humidity) pose a significant threat to infection control.
To compound this, healthcare facilities which have traditionally flushed a building with cool outside air during a night purge may find this is less effective as the outside air won’t be as cool.
If a building doesn’t get that relief in the night to cool down, it’s going to be fighting hard against its thermal mass, built up from the previous hot day. The existing cooling plant may have some buffer but isn’t likely to have the full capacity to deal with this over a sustained period of excessive external ambient temperatures.
Power failure
On very hot and humid days, a building will drastically increase its power consumption due to the air-conditioning plant working harder. This puts pressure on both the individual building and a city’s power grid.
In some locations, we’ve seen electricity companies pay heavy industrial users and healthcare facilities to run their generators during the peak in summer in order to take pressure off citywide infrastructure. For many older facilities, this isn’t practical. Their back-up provisions may only be capable of running for a few hours. And, burning diesel fuel to power a building leads to a very poor environmental outcome.
HVAC failure
At first sight, a single system or unit that’s struggling may suggest an isolated incident. However, data analysis can uncover the true fault is that the system wasn’t designed for the weather conditions we’re experiencing now.
Polluted internal air
With increased ambient temperatures, we experience a higher risk and incidence of bushfires. The use of carbon air filtration for the management of air intakes during bushfire incidents, and low outside air quality, is becoming more prevalent in healthcare facilities.
This increases energy use of the ventilation systems due to the higher pressure of these types of filters. Combining this with the trend of providing increased outside air provisions in healthcare facilities – to improve indoor air quality and reduce the chance of airborne disease spread – produces more of a load on the ventilation systems.
Other bushfire risk mitigation measures should include regular checks of gutters and air intakes for the build-up of combustible debris such as dry leaves.
Review your infrastructure and asset lifecycle immediately
Gather local climate data
Recent peak and seasonal weather data provides you with a solid baseline for understanding your changing local climate. Qualified sustainability consultants can provide insight into the current climate and also future predictions on summer peak conditions, extended warm and humid periods, possible climate extremes and how they might impact your facilities.
Get clear on your critical and non-critical ambient design conditions
What are the critical and non-critical areas and do you have the controls’ infrastructure to separate the two? Which areas aren’t going through a clinical process? Designing for clinical conditions in areas where they aren’t required can increase unnecessary energy use.
For transient areas, low occupancy areas and non-critical areas, i.e. office spaces and consultant suites, you can consider relaxing comfort requirements to reduce the strain on the existing cooling plant.
Review your asset lifecycle
Plant selection criteria needs to consider what the output of the chiller may be at an increased design ambient.
- Are you considering like-for-like replacement?
- What additional chiller capacity is needed to cope with new climate conditions?
- Are you planning for the additional flow on needed in fan capacity and coil selections?
The usual like-for-like plant replacement no longer applies. By reviewing the conditions when your existing chillers were chosen, you’ll find that our weather, working conditions and expectations were very different.
Reconsider your internal design temperatures
Relaxing internal design conditions in non-critical and transient areas with low occupancy can help create temperature buffer zones.
Traditionally, the indoor design criteria for a large majority of air-conditioned buildings falls into a range between 21°C and 24°C with a 1°C control deadband. This can easily be widened to 21°C to 25°C with a minimum 2°C deadband, as per Building Code of Australia (BCA) requirements.
Scheduling indoor temperature set points to have a more relative condition on an excessively hot day is one way to offset the additional energy used to condition the outdoor air.
Several international design guides and reports detail how occupants of non-critical areas are generally more accepting of higher temperatures in peak conditions. This is, mainly, down to the easier transition between outdoors to indoors and the relativity of indoor and outdoor design temperatures.
Building in an adaptive set point adjustment to the building management system (BMS) enables you to adjust your internal design conditions relative to the outside temperature.
Build climate risk into your asset renewal strategy
To ensure your health facilities are resilient in our changing climate, it’s imperative you include climate risk in your strategy for asset renewal. This should support:
- adapting existing infrastructure and assets to ensure their climate resilience
- considering climate change in future infrastructure delivery, serviceability and whole of lifecycle emissions.
Climate change adaptation is an essential consideration in sustainable healthcare building design. The risks of replacing like-for-like or failing to investigate seemingly isolated incidents is too great – it risks the integrity and smooth operations of the facilities we need the most.
