Design of ventilation, air conditioning and heating systems is regulated by SNiP 2.04.05-91. In accordance with the principles of construction, design decisions should not:
- violate the purity of the air;
- create excessive noise or vibration in rooms, in particular, at the installation site, the noise level should not exceed 110 dBA;
- be a fire hazard.
In addition, the design of ventilation and heating systems should provide for the maintainability of equipment. This may surprise homeowners, but typical project documentation includes a calculation of the number of personnel who must operate the equipment. Otherwise, everything is pretty obvious: the presence of aggressive media in air ducts requires corrosion resistance from pipelines and air ducts, and hot surfaces are invariably isolated, which implements the idea of fire safety already mentioned above. If insulation does not help reduce the temperature of some areasof the designed system to a safe one, it is strictly forbidden to place them in rooms where the presence of flammable aerosols or gases is possible. And such premises should be taken into account separately when designing ventilation systems. Any non-standard elements of the system must be made of materials approved for use in construction.
General calculation for premises where people work is underway:
- In summer - based on the maximum allowable temperature in the premises with the formation of excess heat. In the absence of such, an economically feasible temperature is selected from the allowed range. The calculated data are indicated in the applications, and not everything is so obvious here. The temperature cannot exceed 28 ° C, but at lower rates, the ambient temperature begins to vary accordingly. The design of air conditioning and ventilation systems is aimed at fulfilling the above requirements.
- In winter - based on the economic feasibility of maintaining a certain temperature in the room, which is within the allowable range. With a minimum temperature is easier, it should not be lower than 14 ° C.
In this case, the flow velocity and relative humidity are also selected from a number of acceptable values.
For fully automated rooms where people are not permanently present, the rules prescribe a slightly different approach:
- To warmfor a while, operation is allowed at an air temperature equal to the outside temperature, and if an excess of heat is formed in the room, then the design of ventilation systems should aim to force the temperature difference to be brought up to 4 degrees. At the same time, the temperature in the room should not be lower than 29 ° C, otherwise you can ignore the temperature difference between inside and outside. These conditions are valid if additional air heating is not required.
- In the cold period, if there is no excess heat, it is necessary to maintain a temperature of 10 ° C, but if there is excess heat, the design of ventilation systems should be aimed at maintaining an economically feasible temperature.
Climatic operating conditions should be taken in accordance with the annexes of SNiP II-3-79.
