Why is ventilation in the pool necessary? In order to maintain an appropriate climate, in particular humidity and temperature, any pool should be equipped with a reliable and properly designed system of supply and exhaust ventilation. Pool ventilation is especially important for large facilities, pools at medical institutions, etc. Do not forget about ventilation when designing small swimming facilities in private homes. The ventilation system of the pool should be carried out with strict compliance with sanitary standards.
Accounting for normalized air parameters
The criterion for the correct design of the pool ventilation system is compliance with environmental standards, in which any visitor to the pool would feel quite comfortable. In addition, due attention should be paid to such parameters as the humidity level and temperature in the pool room. Pool ventilation is an essential element that must be taken into account at the design stage of construction.
The main of these parameters are:
- permissible humidity level, which should not exceed 65%;
- correspondence of water temperature to ambient temperature: such a difference is allowed no more than 2 degrees;
- The optimum temperature of the water in the pool: there are different opinions on this subject, but in general it should be within 30-320C (for pools where the water is heated);
- taking into account the comfort of the swimmers staying outside the water, the maximum permissible value of the air velocity in the pool room is set - not more than 0.2 m / s.
When installing ventilation systems, it is also necessary to take into account such an important criterion as the value of the calculated air exchange - it must be at least 80 m3 / h for each visitor. The throughput, that is, the estimated number of visitors to the pool, must be considered at the beginning of the development of the project. Thus, even at the design stage, pool ventilation should accurately set the maximum pool capacity.
As you know, decisive importance is also attached to the difference in the volumes of air supplied to the room and removed from it. Otherwise, visitors can constantly be overcome by a feeling of stuffiness (with an excess of supply air), or a draft (with an excess of removed air). Both that and another is especially inadmissible in pools at the medical and improving organizations. The allowable difference should not exceed 50% of the total air exchange.
In addition to purely hygienic indicators, ergonomic indicators, in particular noise, are of great importance in the development of a ventilation and air conditioning system. Ventilation equipment should be installed in such places so that the level of noise it produces is minimal (and without prejudice to the design capacity of the fans). The noise level in this room should not be higher than 60 dB. Ventilation and air conditioning systems must strictly comply with all sanitary norms and rules. These norms are clearly regulated by the legislation of the Russian Federation and are spelled out in the relevant Construction Norms and Regulations and GOSTs and other regulatory documents.
Features of the development of a pool ventilation system
Since we are talking about a room where a significant number of people are constantly located, the supply and exhaust ventilation should completely exclude the formation of any harmful factors during its functioning - both for people and for pool devices. In the latter case, it refers to the condensation of moisture vapor, which in the presence of a large body of water (and at slightly higher water temperatures than normal) leads to a gradual accumulation of moisture on the surfaces of ventilation shafts. Taking into account the material of these surfaces in such cases, premature failure of the ventilation ducts due to corrosion is expected. Moreover, rust particles falling into the fan coverage area (supply ventilation is especially vulnerable) can cause jamming of their work planes and an accident in production equipment.
The way out of this situation is to provide effective protection of the working surfaces of ventilation shafts without compromising their performance.
System insulation
Insulation can be done in two ways:
- creation of corrosion-resistant protective screens made of durable plastic;
- the use of inlet valves with the presence of electric heating, which would quickly work out the change in temperature and humidity conditions in ventilated rooms.
- use of steam traps.
Construction of a pool in a private house
As for public pools, ventilation of a private pool is designed taking into account all the above circumstances, but the capacity of ventilation equipment, based on the smaller area of such a pool, as well as a limited number of visitors, may be lower. In particular, it is necessary to take into account the fact that the individual use pool operates as required. Therefore, the required equipment may have lower productivity. However, during the design process, it is possible to provide for the installation of additional systems of supply and exhaust ventilation systems, which will be included in the assistance to the basic equipment with full use of the pool. This eliminates the excessive consumption of electricity, but provides the optimal value of air exchange in it. At the same time, the organization of the ventilation system and the requirements regarding the safety of its use should be maintained at the same level as for the ventilation equipment of public pools.
Indicators taken into account when calculating pool ventilation
1. The area of the room.
2. The estimated frequency of air exchange for supply and exhaust ventilation of the pool.
3. Standard values for air supply per visitor.
4. Permissible values of air temperature in the room.
At the same time, the system of supply and exhaust ventilation developed for such conditions should solve the tasks with the greatest possible compactness of the nodes included in it. For this purpose, heaters, fans, and a system of working filters that are optimal in overall dimensions and performance are selected. The developed monoblock systems of these nodes largely meet the set requirements. Moreover, when choosing a ventilation system, it is possible to provide for the recovery of excess heat generated by the fans in order to partially reduce the cost of heating the pool. The achieved energy savings of up to 25%. However, with sufficient justification of the climatic zone of the construction of the pool, as well as its volume, it is advisable to install additional sources of heating, for example, water heating. If for the purposes of such heating it is supposed to take water from the general system for supplying it to the pool, then during the design, additional water purification filters must be provided, since water for use in the pool and technical water for heating have sharply different quality requirements and are regulated by different GOSTs. Typically, private pools are rarely located in the main building - often in a special annex or in a separate building. Accordingly, the ventilation of the pool in this case should be designed independently of the main ventilation system of the building. In order to reduce the moisture capacity in the pool room, which entails damage to the ventilation shafts, the water mirror is usually closed. At the same time, the evaporation of water decreases, the overall moisture indicator decreases, the need for additional pumping of water into the pool bowl is practically eliminated.
Design Principles
The above parameters can be taken as a basis, however, some changes are allowed for the private pool. In particular, the lower limit of relative humidity in some cases can be reduced to 50%. This is due to the fact that the number of visitors to such a pool is relatively small and the discomfort from reduced humidity indicators will not be so noticeable. At the same time, the risk of condensation on the walls of the pool building is also reduced.
The design of the supply and exhaust ventilation system begins with a refinement of the actual air flow. There are experimental tables in which the temperature in the pool room and the area of its bowl are set. Depending on these parameters, based on the data in the table, you can easily set the required average hourly air supply. Further, in a similar manner, the required power of ventilation units can also be determined. For example, with a basin bowl area of 32 m2 and a design temperature of 340 ° C, the required air flow rate should be 1,100 m3 / h. The corresponding power of electrical equipment is 20 kW.
Pool ventilation calculation parameters
When making a preliminary calculation of pool ventilation in accordance with the technical requirements, the following parameters must be taken into account:
- the area of the working mirror of the pool;
- the surface area of the paths surrounding the pool;
- total area of the pool;
- the temperature of the outside air in the construction zone of the pool (separately for the coldest and for the warmest five-day days of the year);
- minimum water temperature in the pool;
- minimum air temperature;
- estimated number of pool visitors;
- estimated temperature of the air removed from the pool premises (necessary to determine the risk of condensation).
Taken into account indicators
- Heat exchange in the pool room due to the summer heat in the sun, from visitors actively using the pool, from the water heated for the pool, from its evaporation from the surface, and from a number of other factors.
- Heat transfer due to the difference in water temperature in the pool (with an increase in the number of swimmers, the average water temperature rises).
The calculated data for the ventilation of the pool must be compared with the standard values of air exchange. Based on the calculation, the supply and exhaust ventilation project is sometimes adjusted. This takes into account possible fluctuations in the initial data due to the difference in outdoor temperatures during warm and cold seasons. Accordingly, the total capacity of ventilation units is determined for two options for operating the pool. If necessary, reserve areas for the installation of additional ventilation units are laid in the design solution. Necessarily take into account additional areas on which additional forced ventilation can be placed to ensure uninterrupted flow of fresh air into the pool. In addition, the reserve area is taken into account, on which additional exhaust ventilation can be placed to ensure the outflow of "exhaust" air.
Ventilation Design
Firstly, a certain decrease in the level of permissible humidity is allowed. Secondly, the values of the actual air flow are taken into account. In this case, experimental data of indicators calculated for similar structures are often used.
Designed pool ventilation requires calculations.
Air intake
W = exFxPb-PL, kg / h.
In this formula:
F is the estimated surface area of the water in the pool, m2;
Pb - design pressure during evaporation of moisture (for conditions of high humidity and at a certain temperature of the water in the pool), Bar;
PL - water vapor pressure at standard values of temperature and humidity, Bar.
Since this dependence is used in calculations in Germany, where 1 Bar is used as the unit of pressure, for practical application of the formula it is worth recalling that 1 Bar = 98.1 kPa.
E - the coefficient of intensity during evaporation, kg (m2 * hour * Bar), which depends on the specific design and rules of operation of the pool. For pools, the water surface of which is covered with a film, this indicator is 0.5, and for an open surface - 5.
The values of this indicator sharply increase with an increase in the number of visitors:
- with a small number of them - 15;
- with an average quantity of 20.
- with a significant amount - 28;
- Additionally, in the presence of water attractions - 35.
Air mass flow
mL = GWXB-XN, kg / h,
and air consumption by its volume - by dependence.
L = GWrxXB-XN, kg / h.
Here:
L is the volumetric flow rate, m3 / h.
mL - mass flow rate, kg / h.
GW - total volume of moisture evaporating in the pool room, g / h.
XN is the mass of moisture outside the pool, g / kg.
XB is the mass of moisture inside the pool, g / kg.
r is the air density in the room for a given temperature, kg / m3.
It should be noted that the moisture content in the pool varies depending on the time of year. In winter, it is 2-3 g / kg, and in summer - 11-12 g / kg. Usually, averaged data of 8-9 g / kg are taken for calculation.
Installation and installation work
Installation of ventilation systems is carried out with careful sealing of pipelines and protection against heat loss in them. It is strictly forbidden to direct the air flow to the water surface of the pool. If the ventilation system has small overall dimensions, then it is advisable to mount it in the inter-ceiling space of the pool overlap. For reasons of possible short circuits and subsequent fire, the installation of air conditioners built into this system is prohibited. Thus, the installation of ventilation systems is not as difficult as it might seem initially.