With most buildings being in towns and cities, the ‘heat island effect’ can further exacerbate conditions and so the consequences of them.
High temperatures expose our buildings to conditions they are not used to - and often not designed for - which can stress infrastructure and equipment, accelerate biological growth and precipitate a need for short-term re-optimisation.
Anecdotally, recent conditions have seen more people coming into the office more regularly to benefit from the cooler conditions within, and that in today’s hybrid workplaces can cause further issues.
So, in looking at your building(s), what are some of the aspects you should be checking on and learning from?
This white paper outlines:
1. Water systems and services
- Hot and cold water systems
- Evaporative cooling systems
- Water features and decorative fountains
2. Building systems and services (not water)
- HVAC
- Electrical systems and services
- Fire/life safety systems
- IT and critical equipment
- Fire load and ignition sources
- Building fabric
1. Water systems and services
Increases in external temperature does cause an increase in mains water temperatures that can be exacerbated further within the building. The obvious risk here is your Legionella control, but general bacterial activity and biofilms could increase too.
Hot and cold water systems
Look for telltale signs in your records for areas of the premises which might ‘suffer’ more from increased temperature (Legionella will grow in systems operating between 20 °C and 45/50 °C). Systems prone to lower usage/stagnation should also be targeted (if of course you are not managing these already – which you should be).
Plant rooms can also get warm and retain heat for longer, so the condition, turnover and usage of your water is another factor here.
Areas to check/consider:
- Increase flushing frequencies as needed;
- Perform additional temperature checks and review regularly;
- Check ball valves and inflow temperatures;
- Check your insulation on tanks, pipes, and exposed pipework;
- Check cold water storage tanks are properly covered/screened and look for signs of leakage or damage;
- Keep outlets clean, particularly showers and other spray taps;
- Ensure calorifiers are operating correctly;
- Review and remove any deadlegs, blind ends etc. that may be present; and
- Consider temporary disinfection if control is lost.
Evaporative cooling systems
The chances are, most evaporative cooling systems will be operation flat out in very warm weather. Higher ambient temperatures reduce condenser efficiency, so this potentially brings both physical damage, leaks, faults, failures, and water quality issues into the mix.
Chemical usage will increase as well as the potential for corrosion and scale deposits to form, and the systems “scrub” more debris. Electronic components, especially those outside may also take issue with the heat and malfunction (bleed solenoids, etc.).
The system operation temperatures will almost certainly go up and this in turn can encourage microbial growth, putting more pressure on your treatment chemicals, using them faster and increasing the bio-load in the water.
It can also be a time where ‘creative cooling strategies’ are applied to their air-cooled cousins too. This hot period would not be the first time a garden sprinkler and hose has been popped under a bank of units to gain a little more cooling. In lengthy periods of warm weather,
a long hose on a hot roof will almost certainly put the temperature of the supplying (and spraying) water well above 20°C and that can cause serious problems.
Areas to check/consider include:
- Physical system condition for leaks and damage, drift etc.;
- Water treatment plant and associated controllers for operation;
- Water treatment plant for chemical usage;
- Changes in the physical condition of the water (colour, foaming, etc.);
- Changes in your monitoring results, (e.g. scale, microbiological, pH);
- Signs of increased scaling or debris;
- The need to increase strainer checks; and
- Any increased monitoring requirements (more regular micro water quality checks for instance).
Water features and decorative fountains
For these systems indoors where chemical treatment for microbiological control is employed, other than just monitoring the system and water temperature, there may be little else to do.
For those systems outside where a significant proportion of the water may warm and have sprays, but no chemical treatment, more of a watching brief is needed. If they do have fountains or sprays and the ‘pond’ temperature gets close to or above 20°C, turning the sprays off would be a very good idea.
For smaller systems evaporation can also be an issue, so keep a check on your operation water volumes as well as the temperature.
Also be aware, that despite any signage or prohibitions, these systems can become a focus for people to try and cool down in them, and that can compound the issue.
Areas to check/consider include:
- Operating temperatures of the systems;
- Turning off all spray outlets if temperatures exceed 20°C;
- Changes in water volume;
- Changes in water colour or condition; and
- Where relevant, water treatment plant and associated controllers for operation.
2. Building systems and services (not water)
Warmer air outside usually creates a substantially increased demand for cool air inside buildings and the two do not sit well together. Systems will often be at maximum for longer and that in itself poses issues. Plantrooms and risers can also gain and retain heat for long periods, and roof areas are rarely pleasant in very warm weather.
HVAC systems
These will usually bear the brunt of activity, with plant running at or beyond design capacity, which can lead to reduced cooling performance and system failures - simultaneous peak loads across the building are nobody’s friend.
Depending on occupation levels and demand for cooling from other systems and services, while most of the building may stay cool, some areas can suffer. Similarly, the temptation with high outside air temperature is to run on full recirculation (as this temperature can be significantly below that of outside). This too needs to be carefully monitored as high density areas of occupation could potentially see Carbon dioxide (CO₂) levels increase, as well as, depending on your system, dust levels. Equally you could have periods of time where you are cooling spaces with nobody in them.
Mechanically make sure the system is in good condition and well maintained. Other unintended consequences of maximum cooling can be breakdowns, water accumulation (particularly the base of chiller units) or systems leaks and valves (sticking failing/leaking).
Areas to check/consider include:
- Match the use of air handling units (AHUs) to occupation levels;
- Track recirculation rates with occupation and adjust accordingly;
- Check systems are well maintained and controllers, manometers etc. in good working condition;
- Increase inspections/preparedness for possible leaks;
- Keep an eye on your loading;
- Check filters and clean/replace as needed, on both main and any terminal units (where installed) to aid optimum performance;
- Check your Carbon dioxide (CO₂) levels regularly;
- Check compressors for short cycling and high head pressures; and
- Keep a regular dialogue with building users – keep them informed.
Electrical systems and services
High temperatures can cause a big increase in the load on circuits, leading to equipment damage and breakers tripping, not to mention the possible fire risk. With much of your electrical circuitry and services in plantrooms and risers, they can also get warm very quickly and may not be readily visible.
Demand for supply will see both building cooling systems and users (fans etc.) drawing more power and cables and transformers derate at high temperatures.
Areas to check/consider include:
- Monitor your power usage carefully;
- Keep riser cupboard and plantrooms free of extraneous materials, particularly those that may contribute to a fire of reducing air movement;
- Check for signs of overheating (smells, frequent breaker trips, noise);
- Control where possible the type of electrical equipment being used; and
- Make more frequent checks on switch rooms and lift motor rooms etc. - checking for items such as unusually warm distribution boards or equipment.
IT and critical equipment
Uptime is crucial with IT, but servers and comms units don’t like heat either. While, unless a catastrophic failure occurs, properly installed and maintained data rooms should not be affected too badly, those units tucked away in risers or other cupboards may not fare as well with potential data loss or system outages (or indeed fires).
Areas to check/consider include:
- Target localised comms and server equipment and check it is not overheating or likely to; and
- Discuss with IT better locations for these units.
Fire load and ignition sources
Touched on already in a number of sections the risk of fire will always increase with very hot weather. Materials dry out, off-gas more and equipment gets hot, which with a high ambient temperature pushes up two sides of the fire triangle (fuel and ignition).
Areas to check/consider include:
- Check all your flammable materials are properly stored;
- Keep plantrooms and other areas containing plant and equipment, free from boxes and other debris likely to increase your fire loading;
- Keep your smoking areas clean and clear; and
- Keep an eye on vegetation close to the premises which might become increasingly dry, brittle and flammable.
Building fabric
Unusually warm weather can do unusual things to our building fabric, with movement in materials, caused through, for example, thermal expansion, melting and drying.
Where occurring, the resultant movement of these materials can lead to anything from cracks, leaks and sticking doors/windows to masonry, or other materials, becoming dislodged and falling. The risks are obvious and the older the building, the longer these effects have been experienced.
While hopefully not an effect seen in many mechanically ventilated buildings, property that is south and west facing and with lots of glass can suffer temperatures increase due to trapped solar heat. This is not good for either the building or occupants.
Drainage systems can dry out during long periods of hot weather which in turn can cause damage and/or odour issues. The former may then go onto cause issues with flooding or blockage down the line, while the latter is much more a short term dissatisfier!
Areas to check/consider include:
- Check your building(s) for signs of fabric damage or movement, paying particular attention to overhangs or areas below which people access regularly;
- Consider the orientation of your building and whether during very warm, or maybe not so warm, weather conditions areas to the south and west are prone to higher or excessive heat gain; and
- Keep an eye on your drainage system(s) for signs it may be drying out.
