Does thickness matter?

According to regulations set by the Polish Ministry of Labour and Social Policy, the minimum temperature in an office (including those in logistics parks) where sedentary work is performed should be 18°C. In production halls and warehouses, where physical work is done, the air temperature must not be lower than 14°C. In the best warehouses, higher standards apply, as developers guarantee thermal comfort with a minimum temperature of 16°C.

Although Poland is located in its own climatic zone, there are significant temperature differences between locations. Suwałki, for example, is considered a Polish cold spot, while Wrocław tends to be a few degrees warmer than other cities in Poland. This should be taken into account when planning the thickness of the thermal insulation of external walls and roofs, in order to reduce concerns about weather-dependent utility costs. And in Poland, this is especially necessary since the heating season lasts roughly from October to March.

Insulation or U value

The primary indicator of thermal insulation, or the ability to maintain the temperature inside a building, is the heat transfer coefficient – the so-called ‘U-value’, as defined by the current regulations. The lower the value of the coefficient, the better the insulation. Currently, with temperatures of 16°C inside Prologis’ warehouses, the U-value for the exterior walls is 0.20 W/sqm, while for the roofs it is 0.15 W/sqm. These rates are much lower than those achieved in other class A warehouse facilities, where the internal temperature tends to be set at 15°C or 14°C. It is made possible by the use of a 120 mm PIR insulation layer, which is twice as thick as a standard layer. Without this seemingly minor difference, the U-value for the walls can reach up to 0.45 instead of 0.20, and for the roof might go up to 0.30 W/sqm. In practice, twice as much heat energy escapes through the wall, and this means that savings on heating the hall of about 40 pct could be generated.

The critical place where heat loss is most difficult to control is the warehouse unloading area. This is a strategic place where the installation of additional insulation under the platforms, or installing air curtains, fast closing gates and loading houses, to reduce the influx of cold air during winter periods is required. This is where a properly calibrated heating system with radiant heaters, heat pumps or heating apparatuses is crucial.

Improving the insulation of warehouse buildings effectively reduces heat loss in the winter and limits the supply of warm air in the summer. Properly insulated walls, roofs, windows and floors prevent cold air from entering the building and minimise heat loss. As a result, the heating and cooling systems operate more efficiently, using less electricity or gas. We always talk about renewable energy sources in terms of reducing consumption and still focus on the demand for heat, but given our increasingly hot summers and long periods of oppressive heat, we need to be clear about one point – better insulation also means halls that heat up more slowly making them pleasantly cool in the middle of a sunny summer’s day.

From the floor to the roof

The top warehouse developers use high-quality thermal insulation in the walls, roofs, floors as well as in the docking platforms of their buildings, using such materials as mineral wool, polyurethane foam, sealing tape and foam adhesive. Analyses of thermal bridges – or areas where the insulation has become weak and can lead to greater heat loss – are carried out. Identifying and improving these areas can significantly improve a building’s energy efficiency.

Thicker mineral wool insulation of 24cm can be installed in the roofs. In addition, Prologis installs so-called ‘cool roofs’, which use white or reflective surfaces. With this simple measure, it is possible to reduce by up to 15 pct the energy consumption needed to power air conditioning and the cost of repairing UV and IR damage. Cool roofs have been installed on almost 50 pct of Prologis’ facilities worldwide. In this regard, the Solar Reflectance Index (SRI) is key. The facilities use mechanical diffusers, which are relatively simple and inexpensive devices for heat retention at the floor level. Their installation is possible at any time when the warehouse is in use. Developers also offer ventilation and recuperation systems, as well as an increasingly popular alternative – heat pumps, which are currently among the hottest and most discussed topics on the construction market.

Hall lighting

Light, primarily natural sunlight, has a significant impact on human well-being and health. That’s why in offices and manufacturing facilities, interior lighting is provided through skylights and wall-mounted window panels. The source of artificial lighting in Prologis warehouses in Poland is the exclusive use of advanced LED systems, which are equipped with motion and daylight sensors. LED lighting uses up to 80 pct less energy than traditional bulbs.

Well-insulated warehouse buildings should also be fitted with more sophisticated temperature and humidity control systems. That’s why such facilities are smart-metered so that tenants can monitor the energy and gas consumption in real-time. This helps to identify potential savings and optimise the performance of the energy systems. It is a tool that was under-appreciated just a few years ago, but now 80 pct of our customers use it every day. All this contributes to better protection against energy loss and reduces operating costs, which is especially important in the context of rising utility prices.

Green energy

The logistics industry as a whole is investing in renewable energy systems, such as photovoltaic panels, wind turbines and solar panels, to reduce its carbon footprint and utility consumption. For example, Prologis’ warehouses have been exclusively using EKO Premium from Tauron renewable energy since January 2022, and all the roofs in our newly built warehouses are structurally prepared for photovoltaics, meaning they provide 35kg of additional load capacity per sqm.

Confirmation of assumptions

Before providing a customer with a storage hall, we carry out two key tests on the facility. The airtightness test measures the rate of the airflow based on the pressure differences this generates. The thermal imaging test, meanwhile, covers the hall’s envelope, taking into account ambient conditions such as the temperature, the humidity and the dew point. Many new buildings in Poland are being subjected to BREEAM accreditation at the ‘Excellent’ level, and environmentally conscious developers include such certification as one of the elements in the implementation of their adopted ESG strategy.

The insulation of warehouse buildings plays a key role in reducing heat and cooling losses. Well-insulated buildings are able to maintain a stable interior temperature without the extensive use of heating, ventilation and air conditioning (HVAC) systems. This allows companies to reduce their energy and gas consumption, resulting in lower operating costs.

Investments is his middle name

Marcin Czerniewski has been working at Prologis for nine years as an expert in handling investment processes. He is responsible for the comprehensive handling of new projects and warehouse modernisation for existing customers – from the feasibility studies through the bidding process, budgeting, design and execution up to the supervision of buildings. He is a sustainable solutions specialist and a CCIM member. His industry experience spanning more than 14 years is supported by his education in the field. He holds a degree in construction from the Wrocław University of Technology, and also undertook postgraduate studies in real estate management at the University of Gdańsk and project management at the Wrocław School of Economics.