Organization of a ventilation system is one of the basic conditions for ensuring the safety of materials contained in a warehouse for a long time. Different groups of goods require certain microclimatic regimes with air circulation, but there are also mandatory basic norms that all designers of such objects must adhere to. The development of a warehouse ventilation system involves not only the selection of the most suitable equipment, but also the determination of air exchange schemes taking into account existing requirements.
Features of warehouse ventilation
The main feature of the warehouse is a high degree of clutter and lack of free space for air passage. The stored materials, as well as racks and equipment, interfere with the circulation of flows, which leads to the formation of stagnant zones. They stimulate harmful fumes, which, depending on the properties of a particular product, can not only worsen the characteristics of the local macroclimate and lead to spoilage of products, but also harm the health of warehouse employees.
Obviously, in such a situation, the organization of effective and at the same time safe ventilation is required. Communications are also set up in tight environments, which is why the design role is especially important. For the same reason, cramped space engineering routes are often combined into one channel. For example, the ventilation and heating lines of a warehouse can be laid in parallel in one circuit in certain areas. Another thing is that this configuration requires the use of special insulation for the ventilation shaft and for the heating pipeline.
The only fundamental limitation from the point of view of combining ventilation ducts with other communications relates to a sewer vertical riser. This ban on combining is subject to sanitary and hygienic requirements.
Standards for ventilation
Standards for the organization of ventilation infrastructure in a warehouse affect several technical and operational aspects, including fire safety, maintaining a favorable environmental background, maintaining an optimal microclimate for health, the well-being of employees, etc. Initially, we take into account the norms for designing warehouse ventilation, which are prescribed in the SNIP document 2.11.01-85. In it, for example, specific parameters of humidity, air velocity, its temperature and other characteristics of the microclimatic environment, which will inevitably be influenced by the air circulation system, are noted.
Moreover, specific indicators may vary depending on the type of warehouse and the nature of its operation. Much will depend on the products contained. For example, for general-purpose warehouses, the coefficient of air exchange ratio is 1. This means that the air environment must be completely updated within 1 hour at least 1 time.
In turn, objects that store flammable or chemically hazardous substances (medicines, paints and varnishes, etc.) will need more intensive circulation. In a complex arrangement of warehouse ventilation, it is also necessary to take into account the requirements of the following documents:
- NTP-APK 1.10.17.001-03. The document governing the standards of technological design of storage facilities, as well as enterprises engaged in resource supply.
- SNiP 23-02-03. Regulatory provisions regarding the thermal protection of bases and buildings with storage areas.
- SNiP 21-01-97. Fire Protection Document.
- SNiP 31-04-2001. Standards for the general engineering of warehouses.
- SNiP 41-01-2003. Documentation with regulations governing the design and installation of heating, air conditioning and ventilation systems.
Natural ventilation requirements
The advantages of this type of air circulation systems include structural optimization, which provides for the minimum inclusion of power functional units in the infrastructure. The only difficulty is that at the design stage a careful calculation is required, the errors in which will make the system inoperative.
For example, when drawing up a plan for channeling, it should be borne in mind that the length of horizontal shafts in a straight line should not exceed 3 m. Clogging of air can also hinder the natural circulation of flows, which is often found at storage sites. The total content of dust, gases and mechanical suspensions in the air should not exceed 30%. Otherwise, installation of cleaning filters will be required. The following ventilation requirements for warehouses with natural air circulation are also taken into account:
- If in ordinary residential and commercial premises infiltration corresponds to air exchange, then in warehouses its rate should be 1.5 times higher than the productivity of air exchange flowing through permeable walls, ceilings and partitions.
- In the summer, technological supply openings should work at a height of about 30-180 cm from the floor.
- In winter, supply apertures are organized as follows: in rooms up to 600 cm high - at a level of 300 cm from the floor, and if the warehouse height exceeds 600 cm - above 400 cm relative to the floor.
- Exhaust units are located above the roof ridge by 50 cm.
It is worth emphasizing that natural ventilation has many weaknesses that relate to low efficiency. Therefore, in technological zones where intensive ventilation is required due to the specifics of the materials contained, this method of air circulation is not applied.
Compulsory ventilation system requirements
This method of air circulation is characterized by a wide range of controls and high performance, which is provided by power drive mechanisms. Accordingly, there will be costs for energy supply and maintenance of equipment, not to mention the difficulties of installation, which will require additional space in the room.
In accordance with the regulations, forced ventilation of the warehouse should be used in the following cases:
- If microclimatic parameters cannot be provided by the aforementioned natural circulation of air flows.
- If local climatic conditions suggest the need for mechanical regulation of temperature and humidity indicators.
- If the organization of natural air exchange in principle cannot be implemented on a specific site due to technical and structural limitations.
The main requirements for the organization of forced ventilation of warehouses relate to equipment that is installed in hidden subceiling and wall constructions or in open areas:
- In rooms where explosive and flammable materials are stored, devices for smoke ventilation and special suction of explosive mixtures should be provided.
- Outdoor air receivers should be installed at least 3 m (horizontally and vertically) from each other.
- Closed-type fans must be provided with enclosures that protect against mechanical stress, dust and other contaminants.
- According to the sanitary and hygienic standards, the units included in the forced ventilation should not be sources of environmental pollution and noise.
Ventilation requirements for warehouses with flammable liquids
On the example of rooms with flammable liquids , that is, with flammable liquids, it is worthwhile to show the option of arranging ventilation with increased regulatory requirements.
To begin with, it should be noted that this purpose of the warehouse also determines strict requirements for its layout and location in the building. For example, objects with the storage of flammable materials cannot be located in proximity to residential complexes and healthcare facilities.
In terms of communication support, conditions are created for a stable air outlet. The supply and exhaust ventilation scheme of the warehouse is used, in which automatic flow control systems and air composition analyzers are used. In other words, in addition to the main circulation function, constant monitoring of the microclimatic and chemical parameters of the indoor air should be carried out. The operation mode of the fan depends, among other things, on the indicators of sensors monitoring the condition of storages with combustible materials.
System design
The development of a design solution is the most crucial stage in the implementation of an air exchange system, which determines its basic structural and functional properties. In the process of designing warehouse ventilation, specialists take into account the following data:
- Conditions in which it will be possible to connect communications to central engineering networks.
- Type and volume of materials to be contained.
- Characteristics of the main lighting and heating system.
- Requirements for seasonal air circulation - for example, is there a need to connect cooling equipment to the supply ventilation in the warehouse in the summer.
- The number of personnel that will be present at the warehouse.
- The orientation of the room relative to the cardinal points.
- Characteristics of door and window openings, as well as their type and quantity.
- The type of roofing and the possibility of its use to bring the vent riser out.
- Possibilities of installation and connection of ventilation equipment.
Warehouse ventilation calculation
To determine the type of equipment used and the layout of the air ducts with specific parameters, it is necessary to calculate the system according to individual technical and operational indicators. One of the key values will be the aforementioned ventilation rate of the warehouse, which shows how many times the air must completely change in 1 hour. It is desirable that in a room with conditionally safe products a change should be made at least 1 time, but in the presence of the same paints and varnishes or similar materials, it is worthwhile to ensure double updating of the air environment at the same time.
Next, you can proceed with calculations by area and air replacement rate. So, for rooms with a height of about 3 m, the inflow per 1 m 2 should be 3 m 3 in 1 hour. The calculation of the ventilation of the warehouse with regard to the arrangement of the mine will also be important here: in order to ensure a stable air outlet velocity of 2-3 m / s, channels with a diameter of 100-150 mm should be used. This applies to premises with an area of about 50-70 m 2, but for large storage areas, rectangular shafts with a section of up to 300-350 mm may be required.
Applied Equipment
The natural ventilation system manages with a minimum number of functional units (usually adapters, recuperators and filters), but it also requires material for laying mines. Rectangular and round, flexible and rigid, plastic and metal ducts can be used. The main thing is that the ventilation rate of the warehouse should ensure a sufficient circulation rate with complete exhaustion of exhaust air for 1 hour. Since the natural circulation to a large extent also depends on external conditions, it is worthwhile to make an amendment to this project by adding about 10-15% to the diameter air duct.
As for forced ventilation, it provides for a whole range of functional units and assemblies that provide intensive air circulation. The main units of this equipment include:
- Ventilation unit. Industrial cooler with blades and a power drive in the form of an electric motor. Depending on the area of the warehouse and the branching scheme of the ducts, up to a dozen such devices can be provided.
- Heat pump. The unit generates the heat necessary for microclimatic balance, in which air flows will naturally rise up without mechanical support and artificially creating pressure drops.
- Fancoil Block of an industrial air conditioning and air distribution system that performs several tasks of preparing the flows passing through it.
- Chiller. A system for cooling circulating air, the purpose of which is to utilize the excess heat accumulated in the storage room.
- Condensing unit. It also acts as a kind of microclimatic and humid regulator that stimulates the evaporation of hot streams.
Installation activities
Even at the design stage of the warehouse in the building, channels for laying communications are provided, although the contours can also be made suspended in certain areas. According to them, air ducts must be laid, which are connected to the equipment at separate nodal points or are led out to separate ones in the inflow / exhaust zones. For assembly activities, you will need the following set of tools with materials:
- A screwdriver with a drill function. It is advisable to use the battery model, since it is more likely that when installing remote channels there will be no possibility of directly connecting the device to the network.
- Hammer and pliers for mounting metal duct segments.
- Marking tool - pencil, tape measure, level.
- Sealants, electrical tape and self-adhesive film.
Installation of air ducts is carried out in separate sections that are joined together. Typical installation of warehouse ventilation is carried out by means of bandage or flangeless connections. For the initial fixation, it is worthwhile to use adhesive consumables, which will temporarily ensure the fixation of the segments, and then use hardware to fix the channel to the walls. As for equipment, fans, chillers, condensing units and other units are mounted in prepared openings and niches. For their fastening, hardware, mounting brackets, metal profiles and self-tapping screws with riveted consumables from the delivery are used.
Conclusion
The circulation of air in a warehouse is extremely important not only to preserve the consumer properties of the contained products, but also from the point of view of ensuring safety. This also applies to preventing fire threats, and maintaining an optimal sanitary and hygienic level. Air renewal due to warehouse ventilation eliminates fire threats while maintaining a favorable microclimate for employees. At the same time, the system should be carefully thought out in various parameters - from power and performance to ergonomics and energy saving.
Comprehensive accounting of the full range of technical and operational indicators of the ventilation infrastructure will allow for the implementation of an economical and at the same time effective air exchange system.