The optimal insulation must be equal to or greater than the U value calculated for the insulation of the walls and ceiling of the cell.
Isocold, calcolato lo spessore ottimale per l’isolamento, divide lo spessore in modo da posare un triplo/quadruplo strato sfalsato di lastre isolanti in poliuretano/polistirene espanso estruso a celle chiuse, con marcatura CE conformi e alla Norma UNI EN 13164, con dichiarazione ambientale EPD/LCA e Climate Declaration.
The provision of an effective vapor barrier to the outside of the insulation, finished with properly sealed joints, is of the utmost importance, since water vapor penetrating the insulation would form ice and gradually destroy the insulating material.
The air inside a cold room contains much less water vapor than the outside air. Water vapor in the air causes pressure and, together with the other gases present (such as oxygen and nitrogen), explains the atmospheric pressure we all know. The partial pressure exerted by water vapor is proportional to the amount of vapor present and the vapor in the air will tend to migrate from high partial pressure areas to low partial pressure areas. Therefore, there is a tendency for humidity in the air to pass through the insulation of a cold room in the area of low partial pressure inside. When this vapor is cooled, it condenses and at the point where the temperature is 0 ° C, it freezes to form ice. This process would continue for a long period of time and the accumulation of ice would eventually affect the insulation properties of the cold store wall and weaken
also the structure of the wall or building. Unfortunately, the external effects of this ice build-up may not manifest immediately, but long after the manufacturer's warranties have become invalid.
To prevent this type of destruction of the insulation of the cold room, it is necessary to provide a vapor barrier on the warm side of the insulation. This vapor barrier must be complete and cover the entire floor. It should be remembered that water vapor is a gas and is not sufficient only to make the external surface waterproof; overlapping joints must be sealed.
The choice of insulation is very important as it represents a large part of the total construction cost. Insulation material and thickness are also important from the energy consumption rate . In addition to a satisfactory coefficient of thermal conductivity, the insulation material should also be odor-free, anti-rot, pesticide and impermeable to water vapor.
During the reinforcement and casting of the floor, it is necessary to be very careful not to pierce the insulation protection barrier and not to place loads on the insulation in order to deform or damage the floor. In addition, it is necessary to make sure that the barrier is turned over the surface of the panel so as not to let the water from the casting pass through, all these precautions are necessary to avoid any problem of insulation or swelling of the floor.
Low-temperature deposits built directly on the ground may require special precautions to prevent the accumulation of ice under the floor of the cold store. The formation of ice causes distortions known as "Icebergs" and, in particularly serious cases, can lead to the complete destruction of the warehouse and the building structure.
The conditions that give rise to frost are quite complex, as they are related to the type and structure of the soil, the insulation properties, the availability of humidity, the size of the cell, seasonal climatic variations and other factors.
Regarding the protection against the formation of "Icebergs" we can act in two ways based on the possibility of excavation:
1. leave a space under the cold room for ventilation. The additional depth required for this structure leaves an air ventilation space under the insulation. This ventilation arrangement should be clearly free with adequate entrances and exits. The ground under the storage can be heated by a low voltage electric mat in the cold room foundation.
2. circulate a heated liquid such as glycol through a grid of pipes built into the foundation. The heat for the glycol is usually obtained from the hot gas of the compressor through a heat exchanger