Insulated or not?
In a cold climate, the building should be insulated if the air inside is to be temperate. The greatest amount of heat is lost through the roof; it is also lost through the walls and the floor. In addition, there are high heat losses through the windows and doors. The thickness of the insulation depends on the climate and winter temperature; lower winter temperatures mean that more insulation is required. In walls and roofs mineral wool made of glass or rock is used for insulation; expanded polystyrene (PS) is commonly used in the floor when this is of concrete. All these materials have a low k value. PS can also be used in walls or roofs providing it is covered by concrete.
This is because it can produce toxic gases if it catches fire. Taking Norway as an example, it is normal to use 15 cm mineral wool in the walls and 30 cm in the roof. The PS in the floor is 5–10 cm thick (equal to 20–25 cm of mineral wool which has a higher k value.
Whether insulation is to be used or not depends on the rooms and how they are utilized. The office, mess room and toilet are normal insulated in cold climates. Whether the production rooms are insulated or not depends on the desire to improve the working environment.
If the building is insulated, it will be of sealed construction so it will be necessary to use a ventilation system to ensure exchange of the air inside. If the walls are not insulated and airtight, the wall construction can be open so that a ventilation system is not required. Then the wall can be simply made with split panels or only a plastic grating; natural air exchange is thus ensured and there is no need for ventilation.