Why is pool ventilation needed? In order to maintain the proper climate, in particular humidity and temperature, any pool must be equipped with a reliable and properly designed supply and exhaust ventilation system. Pool ventilation is especially important for large facilities, swimming pools at medical and recreational institutions, etc. Do not forget about ventilation when designing small swimming facilities in private homes. The pool ventilation system must be carried out with strict implementation of sanitary and hygienic standards.
Accounting for normalized air parameters
The criterion for the correct design of the pool ventilation system is compliance with the environmental standards, under which any visitor to the pool would feel comfortable enough. In addition, it is necessary to pay due attention to such parameters as the level of humidity and temperature in the pool room. Pool ventilation is an essential element to consider at the construction design stage.
The main of these parameters are:
- acceptable humidity level, which should notexceed 65%;
- correspondence of water temperature to ambient temperature: such a difference is allowed no more than 2 degrees;
- optimal water temperature in the pool: there are different opinions on this matter, but in general it should be within 30-320C (for pools where the water is heated);
- taking into account the comfort of swimmers staying out of the water, the maximum allowable air velocity in the pool room is set - no more than 0.2 m/s.
When installing ventilation systems, it is 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 capacity, i.e. the estimated number of visitors to the pool, must be taken into account at the beginning of the design of the project. Thus, even at the design stage, the ventilation of the pool must accurately determine the value of the maximum throughput of the pool. As you know, the difference in the volume of air supplied to the room and removed from it is also of decisive importance. Otherwise, visitors may constantly be overcome by either a feeling of stuffiness (with an excess of supply air) or a draft (with an excess of exhaust 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 rate.
In addition to purely hygienic indicators, ergonomics are also of great importance when developing a ventilation and air conditioning system.indicators, in particular noise. Ventilation equipment must be installed in such a way and in such places that the level of noise produced by it is minimal (and without compromising the design performance of the fans). The noise level in this room should not exceed 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 spelled out in the relevant SNiPs and GOSTs and other regulatory documents.
Features of the development of the pool ventilation system
Since we are talking about a room where a significant number of people are constantly located, the supply and exhaust ventilation must completely exclude the formation of any harmful factors during its operation - both for people and for pool devices. In the latter case, we have in mind the condensation of moisture vapor, which, in the presence of a large body of water (and at slightly higher than normal water temperatures), leads to a gradual accumulation of moisture on the surfaces of ventilation shafts. Due to the material of these surfaces, premature failure of the ventilation ducts due to corrosion is expected in such cases. Moreover, rust particles, falling into the zone of action of fans (supply ventilation is especially vulnerable), can cause jamming of their working planes and an accident of production equipment. Way out of this situationis to ensure effective protection of the working surfaces of ventilation shafts without compromising their performance.
System isolation
Isolation can be done in two ways:
- creating corrosion-resistant protective screens made of durable plastic;
- using inlet valves with electric heating, which would quickly work out changes in temperature and humidity conditions in ventilated rooms.- using steam traps.
Construction of a swimming pool in a private house
As with public pools, the ventilation of a private pool is designed with all of the above in mind, but the capacity of ventilation equipment, based on the smaller area of \u200b\u200bsuch 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 pool for individual use operates as needed. Therefore, the required equipment may have a lower capacity. However, during the design process, it is possible to provide for the installation of additional supply and exhaust ventilation systems, which will be included in assistance to the main equipment with the full use of the pool. This eliminates the excessive consumption of electricity, but ensures 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 must be maintained at the same level as for the ventilation equipment of public pools.
Indicators taken into account when calculating the ventilation of the pool
1. Room size.
2. Estimated air exchange rate for supply and exhaust ventilation of the pool.
3. Normative values of air supply per visitor.4. Permissible room temperature.
At the same time, the supply and exhaust ventilation system developed for such conditions should solve the tasks set with the greatest possible compactness of its components. For this purpose, the heaters, fans, as well as the system of working filters, which are optimal in terms of overall dimensions and performance, are selected. The developed monoblock systems of these units largely meet the requirements. Moreover, when choosing a ventilation system, it is possible to provide for the recovery of excess heat generated by fans in order to partially reduce the cost of heating the pool room. The resulting energy savings are up to 25%. At the same time, 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 of its supply to the pool, then the design must necessarily provide for additional water purification filters, since water for use in the pool and technical water for heating have sharply different quality requirements and are regulated by different GOST. Usually poolsindividual use is rarely located in the main building - more 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 indicator of humidity decreases, and the need for additional pumping of water into the pool bowl is practically eliminated.
Principles for determining design performance
The above parameters can be used as a basis, but some changes are allowed for a private pool. In particular, the lower limit of relative air humidity can in some cases 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 levels 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 clarification of the actual air flow. There are experimental tables that set the temperature in the pool room and the area of its bowl. Depending on these parameters, based on the data in the table, you can easily set the required value of the average hourly air supply. Further, in a similar way, you can determine the required powerventilation installations. Let's say, with a pool area of 32 m2 and a design temperature of 340C, 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 the ventilation of the pool 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;
- the total area of the pool;
- the outside air temperature in the pool construction area (separately for the coldest and for the warmest five-day period of the year);
- minimum water temperature in the pool;
- minimum air temperature;
- estimated number of pool visitors;- estimated temperature of the air leaving the pool room (required to determine the risk of condensation).
Indicators taken into account
- Heat exchange in the pool due to solar heat in summer, from visitors actively using the pool, from water heated for the pool, from its evaporation from the surface, and from a number of other factors.
- Heat exchange due to the difference in water temperature in the pool (with an increase in the number of swimmers, the average water temperature rises). Calculated data for pool ventilation must be compared with standard air exchange values. 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 air temperatures in the warm and cold seasons. Accordingly, the total capacity of ventilation units is determined for two options for operating the pool. If necessary, the design solution includes spare areas for the installation of additional ventilation units. Additional areas must be taken into account, on which additional supply ventilation can be placed to ensure an uninterrupted supply of fresh air to the pool room. In addition, the reserve area is also taken into account, on which additional exhaust ventilation can be placed to ensure the outflow of "exhaust" air.
Ventilation design
Firstly, some reduction 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. The designed ventilation of the pool requires calculations.
Weight volume of incoming air
W=exFxPb-PL, kg/h.
In this formula:
F is the estimated water surface area in the pool, m2;
Pb is the design pressure at 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, then for the practical application of the formula it is worthrecall that 1 Bar=98.1 kPa.
E - evaporation intensity factor, kg (m2hourBar), which depends on the specific design and operating rules 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 increase sharply with an increase in the number of visitors:
- with a small number of them - 15;
- with an average amount - 20.
- with a significant amount - 28;- additionally, with water attractions - 35.
Air mass flow rate
mL=GWXB-XN, kg/h, and the air flow by its volume - according to dependence.
L=GWrxXB-XN, kg/h.
Here:
L – volume flow, m3/h.
mL – mass flow, kg/h.
GW – total volume of moisture evaporating in the pool room, g/h.
XN – mass of moisture outside the pool, g/kg.
XB – mass of moisture inside the pool, g/kg.
r – air density in the room for a given temperature regime, kg/m3. It should be noted that the moisture content in the pool varies depending on the season. 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 unacceptable 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 ceilingpool cover space. For reasons of possible short circuits and subsequent fire, it is forbidden to install air conditioners built into this system. Thus, the installation of ventilation systems is not such a complicated process as it might seem at first.
