The indoor microclimate has a significant impact on the people using the building. Temperatures that are too low or too high affect the well-being of employees and their productivity in a negative way. This article will explain:
- What thermal comfort is and what elements shape it.
- What the optimal workplace temperature is, and what happens when it rises or drops significantly.
- What the legal conditions regarding office temperatures are.
- How rising air temperature inside buildings can be prevented and how the employees’ thermal comfort can be increased.
The influence of indoor microclimates on thermal comfort
There is a continuous heat exchange between people and the environment, which is impacted by the temperature and speed of air particles, water vapor pressure, and the average temperature of radiation. The human body functions properly if its temperature is kept constant. This is why there are mechanisms that regulate its temperature – to generate heat which is necessary to live or to remove excess heat. Thermal loads from the environment weaken those mechanisms. This leads to thermal imbalance of the body which decreases the thermal comfort.
Thermal comfort influences human well-being, and different factors add to it, such as: type of clothing, physical activity and other environmental parameters. When these are applied to room conditions – the temperature and relative humidity of the air have a key impact on the well-being of people.
When building facilities, designing interiors, ventilation and air conditioning systems, these factors should be taken into account, making sure that employees will be comfortable. Failure to provide proper working conditions may result in serious consequences.
Room temperature and decreasing performance
The Polish Ecological Building Association in its “Healthy Office” report indicates that thermal comfort influences mood, efficiency, productivity and work satisfaction. If the temperature in the room is too high, employees feel tired, while temperatures that are too low make it difficult to maintain concentration. The research they refer to shows that in cool interiors, work efficiency drops by 4%, and in hot ones by as much as 10%. These results are confirmed by studies conducted at the Technical University of Helsinki and the Lawrence Berkeley National Laboratory. Scientists have found that the productivity of employees is highest at 21-22°C, and each increase of 1°C causes a decrease in productivity by 2 percentage points.
Influence of temperature on work efficiency
Occupational health and safety regulations usually regulate the minimum temperature value in a facility – the highest temperature margin often remains undefined. High air temperature in a room significantly affects the well-being of people staying in it – physical and mental efficiency decreases, heart rate increases and blood pressure drops, breathing accelerates and sweating increases. It is worth knowing that, in line with the idea of ensuring thermal comfort and the health and safety of people in the building, the prevailing conditions in the workplace may cause increasing body temperature by 1°C (up to 38°C).
Workplace temperature standards are defined differently depending on the country. Below you can find some examples of countries from different continents. In places where high outdoor temperatures prevail, appropriate regulations were established as early as the 20th century. In Poland, extreme temperature values at the workplace were defined in the regulation on general health and safety regulations in 2003. In regard to the extreme weather phenomena occurring nowadays (including heat waves) and the progressive changes in Poland’s climate zone, the established regulations are considered insufficient. There are still no clear guidelines on the upper temperature limit inside buildings, which have been defined and adopted only by agreement.
Standards for temperature in the workplace in individual countries
Appropriate conditions in rooms intended for constant use (more than 4 hours) should be met not only for the people working there, but also for economic reasons. The employees’ decreased productivity causes financial losses for the company (more frequent breaks, lower productivity, production downtime, etc.). Followed by increased operating costs of ventilation and air-conditioning devices and high energy bills on top of that.
What causes rising temperatures in buildings?
To answer this question, you have to start with the building’s heat balance. This is the difference between heat gain and loss, which is influenced by the location and shape of the building, the method of heating and ventilation, the presence of machines, heat given off by people and animals, the type of lighting or insulation, among others.
In summer, when the temperature outside is higher than inside the building, one of the main factors that influences the increasing temperature indoors is the increased heat gain in rooms caused by heat conducted through partitions of the building. The heat transmission depends on 3 factors: the temperature of external and internal surfaces and the thermal resistance of the partitions, which is described by the ratio of the materia’s thickness to the value of the thermal conductivity. The flow vector depends on the temperature distribution inside and outside, and the greater the temperature difference, the more heat (in a given time unit) penetrates the partition.
One of the largest surfaces in large-area single-storey buildings is the roof. Solar radiation causes it to heat up and generate thermal energy. The heat is emitted inside and increases the air temperature, which results in a decrease in the comfort of employees, losses in stored assortment or an increased cost of air conditioning maintenance in the summer.
The effects of inadequate temperature in the workplace
The most popular way to lower the indoor temperature is through the use of air conditioning systems. Using AC in some buildings is impossible due to technical limitations or high investment costs. On the other hand, constructing the installation in a facility with high “temperature stringency” is often insufficient to maintain proper temperature, even if the roof is properly insulated. The ongoing climate changes, provoking heat waves, reduce the efficiency of air conditioning equipment, so building owners often fail to meet temperature requirements. The solution may be to build an advanced cooling and ventilating system, e.g. use a precision air-conditioning system, which will help to maintain a constant temperature in a given room. Server rooms can serve as an example, where it is necessary to maintain certain conditions, and where if the air temperature is increased by only 1°C, the performance of the devices will deteriorate, which will immediately increase the demand for energy. In this case, the use of a modern and energy-optimized precision air-conditioning system ensures that the proper temperature indoors is maintained at all times. However, even the most energy-efficient installations can consume several million kWh annually, which translates into hundreds of thousands or even millions in electricity bills. *
What can you do to lower the temperature in a building?
The solution to the problems above is to use reflective materials on the roof to regulate solar radiation. As a result, the roof will not heat up and won’t accumulate heat, and consequently won’t transfer it inside.
The COOL-R liquid waterproof coating is defined by high emissivity and reflectivity – it effectively reflects sun rays, prevents overheating of a given surface and prevents the production of thermal energy. COOL-R lowers the roof temperature and minimizes heat transmission into the building. The temperature of the sheathing, compared to other coatings, may be up to 70% lower . This has been confirmed by readings from pyrometers and thermal imaging cameras during tests carried out on reference objects.
COOL-R roof, Medical laboratories, Madrid, Spain
The COOL-R coating significantly reduces external heat gain, minimizing the roof surface heat. As a result, by reducing the temperature inside a facility, COOL-R improves the thermal comfort of employees and significantly reduces the demand for air conditioning – and thus – reduces the overall consumption of electricity. COOL-R therefore helps to achieve higher energy efficiency and lower CO2 emissions.
- extends the life of the roof by up to 10 years, by reducing the temperature-caused damage of the roof,
- is a durable coating which protects the roof against UV radiation and weather conditions,
- creates a seamless waterproof layer that eliminates leakages.
As a result of using the COOL-R system, thermal comfort is improved, which not only improves your employees working conditions, but also improves their efficiency as they’ll need fewer breaks and downtime, which will translate into higher production efficiency and a reduction of warehouse losses.
* Conclusion based on data presented in the case study “Components of an effective and safe precision air conditioning system in a data processing center” by Piotr Kowalski, Director of the Engineering Department of Emerson Network Power Sp. z o.o. for the website Klimatyzacja.pl.