• Ventilation of the metallurgical shop
• Forge shop ventilation
• Thermal shop ventilation
• Machine shop ventilation
• Welding room ventilation
• Paint shop ventilation
• Ventilation of the electroplating shop
• Woodworking shop ventilation
• Knitting shop ventilation
• Car service ventilation

Ventilation design

Industrial ventilation, regardless of the type of production process, faces the main task - to cope with the hazards that are released during production.

The hazards include:

1. Heat dissipation;
2. Moisture release;
3. Steam and gas emissions, including toxic substances;
4. Dust emissions;
5. Smoke emission (aerosols) - the release of the smallest solid particles freely floating in the air, etc.

Industrial ventilation

In this regard, several main tasks arise:

1. Correctly calculate the performance of the ventilation system, sufficient to achieve the necessary conditions in the room.
2. Develop suitable air supply and exhaust methods to make the system as efficient as possible. This includes the development of an aspiration system. Aspiration in industry - suction of air from the place of dust formation (during production processes) in order to prevent its spread throughout the room.
3. Design, if necessary, an air filtration system.

And the most important thing, which is especially important in our conditions, is to develop a system that will be as reasonable as possible from an economic point of view. This demonstrates the skill of the ventilation company - to develop a system with the highest price-quality criterion.

Proper umbrellas, shelters, air showers, natural exhaust, proper suction, humidification - these and many other points can reduce the air flow in the ventilation system, which means the cost of equipment, air network, work, etc. At the same time, the efficiency of the system will remain at the desired level.

General rules ventilation of workshops and industrial ventilation

There are two types industrial ventilation- general exchange and local (local suction, etc.). General ventilation copes well only with heat release, i.e. when there is no entry of significant hazards into the atmosphere of the workshop.
If gases, vapors and dust are released during production, mixed ventilation is used - general exchange plus local suction.
However, there are cases when general ventilation is practically abandoned. This happens at enterprises with significant dust emissions and in the case of the release of particularly harmful substances. In both cases, powerful general ventilation can spread dust or hazards throughout the workshop.

In general, the general concept of building ventilation industrial facilities- remove the maximum harmfulness with the help of sweeping suction, and dilute the remaining harmfulness in the room with fresh air in order to bring the concentration of harmfulness to the maximum permissible concentrations. If you understand this idea, you will understand the essence of design.

Since the release of hazards is most often accompanied by heat release, therefore, particles of pollution (which did not fall into the local suction) go up, under the ceiling. That is why under the ceiling of the workshops there is a zone with maximum pollution, and below - with minimal ones. In this regard, ventilation is most often arranged as follows - the inflow is fed down into the working area, and the general exchange hood is under the roof. However, when heavy dust is released, it settles immediately, creating maximum pollution at the bottom.

There is a main rule for the ventilation of workshops: “Supply air to a clean area and extract it from a dirty one”

To remove gas hazards, vapors, aerosols, it is most effective to use shelters (local suction, which completely or partially covers the source of pollution). Often there is a need to install an air shower - a device that directs a stream of clean fresh air to the face of a person working at a workplace. Often it is impossible to create acceptable conditions for a person in any other way. Usually one shower delivers 1700 - 2000 m3/h of air.

Determining the air flow rate of local suction:

When designing local suctions, one should be guided by the most important rule- the suction must have such a shape and must be located so that the drawn out flow of harmful substances does not pass through the area of ​​the person's face.
Calculation of the ventilation system in general case is done like this:
1. The amount of air required for effective work suction.
2. The air drawn out through the suctions is compensated by the same inflow.
3. In addition to this, general ventilation is designed with a multiplicity of 2-3.

The calculation of the air flow through the local suction is carried out (with a simplified calculation) according to a simple formula:
L=3600 x F x v, where L is the air flow through the umbrella (what we want to Determine), 3600 is the conversion of the flow in m3 / h, F is the area of ​​​​the cut of the umbrella (i.e. the area through which air is drawn in), V - air speed at the edge of the umbrella (there is a table of required speeds).

For example, an umbrella over the stove, the area of ​​​​the umbrella at the place of air intake is 2 sq.m. The required speed for the effective removal of the heat of a conventional umbrella without overhangs is 1-1.2 m / s. L = 3600 x 2 x 1.1 = 7920 m3/h. The calculation of air through shelters is carried out in the same way (only for each type of production, its own air velocities in the openings of shelters and types of shelters, usually within 0.7-1.5 m / s).
As for the suction funnels for harmful gases and vapors, the air speed in them should be at least 10-15 m / s.
On slot suctions, the speed should be 4-6 m/sec. The slot width is often 50 mm.

Fighting heat

It is very rare for industry when only heat is released in the room, without additional hazards.
They cope with heat releases with the help of local exhausts and with the help of general ventilation.
When determining heat release from mechanisms, it is considered that up to 35 to 45% of the installed power is converted into heat.

Moisture control

In many industries, a huge amount of moisture is released. It can be removed in two ways - with the help of general ventilation or with the help of local suction. In the case of general ventilation, the air flow rate is 130-150 m3/h to remove 1 kg of moisture per hour, and with proper local suction, the same result can be achieved with 50 m3/h, and in the case of a casing - 20 m3/h. But you need to keep in mind that if the source of moisture is in the casing, then 15-20% of moisture enters the room. If an umbrella is installed, then up to 30-35% of moisture enters the room. This tells us that even the best umbrella has an efficiency of 70%.

Dust control

Most effective method dust control is a joint effort of technologists and ventilation specialists. For example, humidification of dust or the use of covers increases the effectiveness of dust control at times.
The aspiration system is a dust extraction ventilation that removes air with a dust content of more than 1 kg per 1 m3. Aspiration occurs in crushing, grinding, foundry, chemical and metallurgical shops. Distinctive feature the suction system are strongly inclined air ducts. In less dusty industries, dust-removing ventilation is used (it is distinguished by the absence of inclined air ducts).
The inflow to dusty rooms is supplied at very low speeds to avoid dusting. Perforated ducts and panels are often used. Air is removed by small funnels that are connected to casings, shelters, etc.

Important data on the suction system:

1. All air ducts should be as short as possible and should be laid over the shortest distance;
2. The system should not have horizontal sections - all air ducts are vertical or at an angle of 45-60 degrees to the horizon;
3. One aspiration system should serve from one to six local suctions.
In dust extraction ventilation (as opposed to an aspiration system), it is permissible to lay horizontal sections. Suction air ducts are made of 0.7 mm thick steel for diameters up to 200 mm and 1 mm steel for large air ducts. For highly abrasive steel bends are made of 1.5-2 mm.
The air velocities in the suction ducts are very significant (so that dust does not settle on the ducts):

Aspiration systems extract a very significant amount of dust. Typically, the air flow through a suction funnel connected to a solid casing or shelter is in the range of 1000-1700 m3 / h.
If it is impossible to install the casing, then the air flow through the onboard, upper-side and other suctions is 6000-9000 m3/h per 1 sq.m. However, you must understand that this is not the final settlement. Each device can have several funnels and suctions. Let's say the suction system of one shelter on a conveyor can be 10,000 m3/h, and the system for a crusher can be 30,000 m3/h or more.

Foundries - up to 2.5 kg per 1 m3 of air.
Crushing production - up to 8 kg.
Grinding production - up to 20 kg.!
Sandblasting production - up to 8 kg.

Of course, such an amount of dust cannot be emitted into the atmosphere. Therefore, devices for dust retention are used.
Cyclone type devices can capture 60 to 85% of dust.
Fabric filters - up to 95-99%.

Fight against chemical compounds (gas)
Air supply in chemical industries is carried out directly to the working area. Sometimes air showers are used for this - directing jets of clean air into the chest and face of the worker.
The multiplicity of general ventilation (in addition to local exhausts!) In the chemical industry, approximately, are as follows:
Chlorine production - 6-10 times
Aluminum fluoride - 3-5
Calcium chloride - 4-5
Barium chloride - 3-5
Phosphoric - 10-12
Fluoride salts - 8-10
Plasticizers - 8-10
Hydrochloric acid - 6-8
Hydrochloric acid (storage) - 3-4
Sulfuric acid (storage) - 1-2
Dyes - 4-5
Nitric acid - 7-9
Synthesis of rubber - 10-12

Shelters and zonal suctions are installed at all places of possible leakage of equipment. At the same time, one suction draws out approximately 200-1000 m3 / h. In chemical industries, where there is a risk of release of toxic substances, an emergency hood is installed. It does not turn on in the event of a failure of the main unit (in this case, the backup fan turns on), but when toxic substances are released, and the main hood cannot cope with them. Only by working together do they solve the "emergency" problem.
The emergency exhaust ratio (depending on the toxicity of substances) ranges from 8 to 16.

Emission cleaning

- Dust settling chambers (catch coarse dust) Due to stringent environmental requirements, it is often necessary to install an air filtration system on the hood. Now this industry has taken a big step forward, so this issue is solved quite simply (but not cheap). Air purification from dust is carried out in dust collectors. They can be different type:

– Cyclones (using the principle of inertia)

– Fabric and fibrous filters (cell, self-cleaning, roll, bag, mesh filters)

– Electrical

General issues

The spacing of the air intake and exhaust grilles of the ventilation systems of industrial enterprises should be carried out both in height and in width - in height - 3 meters (minimum), in width - 12 m.

In industry, redundant system fans are often used. However, supply systems are usually not redundant (only if one unit serves several workshops or sections). Exhaust fans are duplicated according to the conditions of technology, when it is unacceptable to stop work even for a short time.

Now such a thing as a flare emission (from the exhaust system) is becoming rare, but we will mention it, nevertheless. In order not to make the exhaust pipes very high, the flare phenomenon is used. At the same time, air is ejected from a vertical pipe at a high speed from 10 to 40 m/s (depending on the harmfulness of the exhaust)!

Heating systems in workshops are most often combined with ventilation, i.e. made according to the air heating scheme - ventilation supplies warm air in a volume sufficient to maintain the required temperature in the workshop in winter.

Here is a multiplicity table for some production and laboratory facilities:

Physical laboratory	4-6
Preparatorskaya	5
weight	3
X-ray equipment	8-10
photo room	4-5
developing	10
Rechargeable	15 (from upper and lower zone)
Acid	10 (from upper and lower zone)
alkaline	8 (from upper and lower zone)
Assembly with soldering tin	8-20
Warehouse of chemicals	5-8 (sucking from cabinets)

Air ducts are usually made of galvanized steel. Preference is given to round air ducts. If the air in the air duct has a temperature of over 80 degrees or contains mechanical impurities, then air ducts made of black steel 1.4 mm and higher are used.

The air speeds are taken as follows:

Ventilation of the metallurgical shop

Ventilation of hot shops solves the main problem - to cope with the heat that enters the room.
For an approximate calculation of the amount of heat, you can use experimental data:
Open-hearth, converter, electric steel-smelting shop - 175-280 W/m3.
Rolling - 150-200
Steel and iron foundry - 50
Thermal - 200-250
Forging and pressing - 100-150.
Let's take a rolling shop with a room volume of 50,000 m3. We multiply 50,000 m3 by 200 W/m3 and get: 10,000 kW of heat enters the room.

Forge shop ventilation

Main hazards	Convective and radiant heat, carbon monoxide, sulfur dioxide, etc.
Heating	Together with ventilation.
General ventilation	Calculation for the removal of excess heat and dissolution of harmful substances to acceptable concentrations. Aeration is used at all times of the year (in this case, natural ventilation when hot air moves upwards from the stoves and is removed through devices on the roof).
Local showering	Local showering is applied at workplaces subject to thermal radiation.
local sucks	Local hoods above the filling holes of the furnaces, near the furnaces.

Thermal shop ventilation

Main hazards	Heat generation, radiant heat, oil and water vapor, carbon monoxide, sulfur dioxide, ammonia, etc.
Heating	Together with ventilation.
General ventilation	Supply air is supplied to the working area. Aeration is provided.
Local showering	Air showering of workplaces exposed to thermal radiation.
local sucks	Local suction above the loading openings, baths for washing, oxidation, neutralization, etching, cleaning, above electric oil baths. Umbrellas over the oven: Air speed through the umbrella -1.5 (chute for the release of cast iron, slag, loading window) -5 (section for pouring metal into molds) m / s. Electric arc furnaces: 1 ton - 4,000 m3/h, 3 tons - 5000, 6 tons - 6000, 10 tons - 10,000.

Main hazards	Heat emissions from electric motors, people, the sun, oil and emulsion aerosols, vapors from coolants, metal and emery dust
Heating
General ventilation	The calculation of air goes to the assimilation of excess heat and moisture emissions (but not less than 30 m3 / h per worker). Supply air is supplied from above.
local sucks	Above machines without cooling, above baths for washing parts, above tanks for the preparation of emulsions, above grinding, peeling machines (plus exhaust filters). Dust removal is carried out by local suction in the form of casings or suction funnels.

Welding room ventilation

Main hazards	Gases: nitrogen oxides, carbon monoxide, ozone, fluorine compounds.
Heating	Air heating combined with ventilation
General ventilation	Calculation of air for the dissolution of harmful substances from welding to the maximum permissible concentration. The calculation is based on weight welding electrodes consumed per hour. Manual welding - 1500-4500 m3/h per 1 kg of electrodes. Semi-automatic welding in carbon dioxide– 1700-2000 m3/h per 1 kg. Flux-cored wire welding - 2500-5400 m3/h. On average, one welding station consumes 5 kg of electrodes per hour. Hood - 1/3 from the upper zone, 2/3 - from the lower.
local sucks	If possible, local suctions are installed.

Paint shop ventilation

Main hazards	Vapors of solvents and thinners, paint dust.
Heating	Centralized or
General ventilation	Inflow to compensate for local exhausts, plus one fold. General exchange extract at least 1 times from the upper zone. Depending on whether it is heavier than a pair of air paint or lighter, the hood is organized accordingly -2/3 from below - 1/3 from above (or vice versa)
local sucks	Local exhaust at painting booths, tables, stands, dipping baths, jet flow systems, drying booths, degreasing units.

Ventilation of the electroplating shop (ventilation of the metal coating shop)

Main hazards	Hydrogen cyanide, dust, vapors of acids, alkalis, electrolytes, as well as heat and moisture
Heating	Air, combined with ventilation
General ventilation	All air ducts are made of anti-corrosion materials or covered with anti-corrosion materials (varnishes). The inflow compensates for all local hoods and general hoods. All adjacent rooms are supplied with 5% of the inflow to create backwater in them. In the departments for the preparation of solutions, storage warehouses and dilute cyanide salts, 3-fold air exchange is required.
local sucks	Onboard suction baths. Fans are explosion-proof. Exhaust systems baths with cyanide solutions and for baths with acidic solutions should be independent. Local suction baths with cyanide solutions, nitric and hydrochloric acids must have backup fans. The exhaust air must be filtered.

Woodworking shop ventilation

Main hazards	Sawdust, shavings, wood dust, heat from presses, glue fumes, solvents, etc.
Heating	Air, combined with ventilation
General ventilation	Supply air is supplied to the upper zone dispersed, most often through perforated air ducts. In the paint shop, general ventilation serves to dissolve solvent vapors not caught by local suctions to the maximum allowable concentrations.
local sucks	Local suction from machines, floor and underground suction for wood waste. The air is cleaned in cyclones or bag filters. In the paint shop - suction from painting booths, drying cabinets, paint grinders. Drying compartment - 30 m3 / h per 1 kg of steam (but not less than 5 times) - at the unloading gate of the drying chambers.

Knitting shop ventilation

Car service ventilation

Welding room ventilation

During welding, hazards are released: nitrogen oxides, carbon monoxides, ozone, fluorine compounds. Exhaust ventilation should remove hazards as efficiently as possible, and supply ventilation should compensate for exhaust, diluting hazards to maximum permissible concentrations (MACs).

The calculation is carried out taking into account the weight of the welding electrodes consumed per hour. Pay attention to the phrase "maximum efficiency". The fact is that if you take a system designed by an ordinary ventilation designer and compare it with a system created by a professional industrialist, then the air consumption of the system in the second case will be significantly lower.
After all, a real industrialist will pay maximum attention to air distribution: what type of local suction can capture the maximum of smoke, where to supply fresh air in order to increase the efficiency of the hood and increase the comfort of the worker.
In our practice, there was a case when, by optimizing a welding production project, we achieved an effect by reducing air consumption by 20,000 m3/h, which resulted in an efficiency of 30,000 euros.

– Manual welding – 1500-4500 m3/h per 1 kg of electrodes.
– Semi-automatic welding in carbon dioxide – 1700-2000 m3/h per 1 kg.
— Welding with a flux-cored wire - 2500-5400 m3/h.

On average, one welding station consumes 5 kg of electrodes per hour. Hood - 1/3 from the upper zone, 2/3 - from the lower. Heating - usually air, combined with supply ventilation.

The cost of ventilation of the welding shop largely depends on the consumption of electrodes. According to experience, the price ranges from 1000 to 2500 rubles/sq.m.

Ventilation at metallurgical enterprises

At metallurgical enterprises, it is not only the huge heat release in the shops that has to be dealt with. The basis of the whole system industrial ventilation constitutes aspiration, i.e. a system for removing harmful substances (mainly dust) from the workshop. aspiration system in without fail equipped with a powerful emission filtration system (electrostatic precipitator, bag filter). In addition, we must not forget that at metallurgical plants there are entire buildings-towers with equipment (for example, the supply of coal fuel to blast furnaces), which must be equipped with ventilation system, heating and air conditioning.

However, "correct" industrial ventilation copes with these tasks. Generally speaking, the design and installation of industrial ventilation in steel plants is an incredibly interesting, but difficult job.
- huge air consumption,
- fans with hundreds of kilowatts of power,
- very dusty air
- fire hazard of some premises,
- the need to maintain the set temperature,
- the task of providing employees with acceptable conditions,
- the need to provide economical and simple maintenance, these and many other problems constantly arise during the design and installation.

Machine shop ventilation

This group includes workshops with metal processing on planing, slotting, drilling, turning, milling, grinding and other machines, as well as sharpening and dressing of cutting tools.

Ventilation equipment "INTECH" is operated at facilities in Yekaterinburg and the Sverdlovsk region:

"Technical re-equipment of shop No. 3, building on city / square No. 90 ″ 144 armored repair plant
LLC "YURAL VAYARING SYSTEMS" (Radio Equipment Plant)
OJSC "EZOCM"
OJSC "Uralelectromed"
Confectionery shop IP Novruzov R.A.

Industrial ventilation

Applied systems:

Central ventilation systems with necessary conditions creating normal air exchange to remove harmful impurities and replacing air exchange with clean air:

• Heat dissipation
• Steam and gas emissions
• Moisture release
• Aerosols and mists

Industrial ventilation

Clean room ventilation

Premises medical institutions, pharmacological industries, electronic industry, etc. must be kept perfectly clean. Technologies that are used in such areas require a minimum level of concentration of aerosols in the air. Initially, sterile conditions are created during the construction of such premises and the organization of their internal arrangement. In the future, cleanliness is maintained with the help of a set of special measures and special systems. One such system is the ventilation of clean rooms.

What are its features? First of all, such ventilation is distinguished by a serious level of control over the content of various kinds of particles in the air. At various points in the room, special sensors are installed that constantly take air samples and give the results of an analysis for pollution. These devices are characterized by sampling speed and sensitivity. Installation engineers choose the brand and design of the sensor, depending on the specified cleanliness class, characteristic of a particular production or medical facility.

When equipping clean rooms with ventilation, preference is given to systems with laminar air flow. Such complexes provide the supply of fresh air in straight, parallel jets, from top to bottom. That is, turbulence of air flows is not allowed, so dirty particles are not carried around the operating room or pharmacological laboratory, but are "nailed" to the floor, from where they are discharged outside by the air exhaust system.

Ventilation of metallurgical, thermal, forging, welding shops

Production related to thermal and machining metal, is always accompanied by the release of a large amount of heat and dust. We are talking about metallurgical, mechanical, welding, blacksmith shops. In order to combat these harmful factors, such enterprises use complex, combined complexes for air purification and ventilation.

One of the most demanded technologies here is aspiration systems and liquid filters. They are used to combat high levels of harmful substances and aerosols. Its main method is the installation of air ducts at a large angle of inclination. This design avoids stagnant zones inside the working casings. To combat heat, units for intensive removal of hot air and supply of new air are used. The frequency of air renewal here can reach 20 times / hour.

Combinations of local suctions with elements general ventilation provide hot shops with a reduction in internal harmful factors. In addition, managers have to take care of cleanliness environment. Therefore, special filters and cyclones are installed at various suitable sections of the ventilation complex, which prevent harmful emissions into the atmosphere.

Ventilation for electroplating

Professionals who undertake to install ventilation in electroplating shops need to have a clear understanding of the physical and chemical processes of this production. Here, a thin layer of a protective substance is applied to the surface of metal products, components and assemblies for further operation in an aggressive environment. Chrome plating, copper plating, zinc plating, nickel plating - the name of the technological process is always associated with the name of the material used for coating.

The task of the ventilation system is to minimize the concentration of harmful substances in the area of ​​​​the workplaces of galvanizers, as well as in the entire workshop. This goal is achieved by careful selection of local suction and liquid filters. Further, they are tested on this particular site. During the operation of this local protective equipment, it is necessary to measure the residual level of concentration of harmful substances at various heights, including the lowest “floor”, where people work, and the upper one, where light particles of spent compounds accumulate under the roof.

Depending on the results of this test, equipment for general ventilation is selected. Its purpose is to constantly update the air throughout the room. Mistakes in environmental calculations are unacceptable in galvanic production. People are dealing with harmful fumes, the particles of which must be removed from the air. Here are just a few examples: chromic anhydride vapors (for chromium plating), zinc oxide vapors (for zinc plating), hydrocyanic acid vapors (for gilding), sulfuric and phosphoric acid vapors (for etching). A competent approach to the development and installation of the ventilation system allows you to maintain their concentration at the maximum permissible level.

Ventilation in woodworking shops

In workshops where woodworking machines operate, the main hazard is wood dust. To reduce its concentration in the air, ventilation designers must take a comprehensive approach to the air exchange system. Units and elements must be selected strictly in accordance with the rules and regulations, the design of machines and many other factors that affect the intensity of wood dust formation and its concentration.

Local suctions are characterized by the area of ​​the working surface and the speed of air supply. Their design should provide for excellent tightness so that air with dust moving at high speed (20-35 liters per second) does not enter the area of ​​\u200b\u200bthe machine operator's workplace. The project may include the installation of dust collectors on the floor or under the floor, in the area of ​​​​the machine.

An important point is the development and installation of that part of the ventilation system, which is responsible for replacing the air in the entire woodworking shop. Here, one of the basic principles is the supply of new air from top to bottom so that dust does not rise up, but settles below, from where it is then discharged into dust collectors and removed by cleaning from the floor with aspiration systems.

Ventilation in knitting shops

Knitwear production has its own hazards: excessive heat generation (from knitting machines), high humidity (from dyeing equipment, steam presses), dustiness (from looms, sewing machines). Each of these harmful factors requires a special approach to the design of the ventilation system, therefore, in the weaving industry in various workshops ventilation units have different configurations.

In rooms where steam presses are used, powerful exhaust hoods are installed in the workplace area, designed to drastically reduce the level of humidity. Right wet air is replaced by dry streams with the help of injection units that act as local supply ventilation. Thus, the specialist servicing the equipment is in a safe environment that does not threaten his health. In knitting shops, exhausts are installed to remove warm air, while the normal temperature balance is maintained by fresh, cooled and moistened jets to prevent drying out and thread breakage.

Harmfulness of knitwear production can manifest itself jointly in a particular room, depending on the internal workshop structure of the enterprise. Therefore, a specialist designing ventilation here needs to have an idea of ​​the technological processes of weaving, knitting, dyeing and cutting shops.

The main task of ventilation is to clean the air in the room from pollution. They belong to the following categories: heat, moisture, steam, gases, dust, smoke, fine particles of materials. For this, two types of ventilation are used:

• General ventilation - provides the movement of air flows throughout the workshop. It is used in cases where production processes are not accompanied by the release of toxic substances or fine mechanical particles.
• Local ventilation - cleans the air in a particular workplace. It removes excess heat, ensures the permissible content of harmfulness in the workshop.

Both types of ventilation are often used. In this case, the maximum concentration of harmful gases and particles is removed by the local system, and the remaining elements are diluted with fresh air supplied by general ventilation. Here the principle applies: "take away the air masses from the contaminated area of ​​the workshop, submit it to a clean one." Equipment that uses the supply and exhaust principle of operation copes with this task.

If during the operation of the workshop it is released a large number of pollution, their proper removal is ensured by installing shelters - this is a category of ventilation, which is a local suction. They partially or completely cover the source of secretions. Such a ventilation system can save air flow, electricity.

Heat is released during the operation of units in the workshop, during certain production processes. When organizing the supply and exhaust ventilation system, special equipment is installed - a heat exchanger. It uses the generated heat to heat the air flow from outside into the building. This task is possible only if the air inside the workshop does not contain various oils.

Workshop ventilation – just-in-time installation of the system

Installation of ventilation in the room consists of the following steps:

• drawing up a layout, calculating the performance of equipment, determining the need for installation local ventilation;
• installation of pipelines, umbrellas, suctions;
• placement of fans, control units.

Work in the welding shop is a complex and hazardous occupation. This is due to the fact that in the process of welding, chemicals and hydrogen are released into the air masses. That is why to create ventilation system In the welding shop, increased demands are put forward.

Air exchange during welding work in the workshop

An effective welding shop ventilation system is a balanced supply and exhaust system, which should demonstrate high air purification results at relatively low energy costs.

According to SNiPam II-33-75:

• the speed of the air flow when installing local ventilation should be 0.8-2.1 m / s;
• when the consumption of welding materials is more than 0.21 g/h, it is necessary to install general ventilation. With lower electrode consumption rates, only a local air exchange system can be dispensed with;
• the speed of movement of air masses directly in the area of ​​welding should be 0.4-1.0 m / s;
• the flow of fresh air masses should be directed to welding;
• when using a welding machine in closed containers or at increased intensity, an influx of clean air with a temperature of more than 19 degrees should be supplied directly to the worker's mask.

The shop ventilation system should:

• eliminate harmful substances by means of local ventilation;
• provide a microclimate in the room according to sanitary standards N 1009-73;
• eliminate chemical components using general ventilation.

In the welding shop, a general exchange and local supply and exhaust ventilation system is used.

Welding shop ventilation: air supply features

When arranging the ventilation system, air exchange in the workshop can be supplied both by vertical flows and horizontal ones.

Horizontal air exchange

When supplying air flow in a horizontal direction, the ventilation system must be installed in such a way as to capture the air space of the entire room. The formation of air stagnation is unacceptable. The air exchange rate must be more than 0.1 m/s. This scheme is great for small spaces. For example, in a workshop with parameters of 30x20 m, 7 fans are installed with a total capacity of 7000 m3 / h, which create horizontal air flows. Fans are installed on one wall at a height of up to 4 m and provide a stable supply of fresh air masses. Fans with a capacity of 7000 m3 / h are installed at the same height on the wall opposite the inflow of air masses. They also remove polluted air.

The bottom scheme can be used for workshops, the distance between the inflow and exhaust of which is not more than 100 m. In the case when the distance is greater, the air masses “freeze” and harmful substances accumulate. The efficiency of the system is significantly reduced. With such a problem, it is necessary to install additional fans or jet devices that will accelerate the flow of fresh air masses.

Vertical air exchange

To arrange vertical air exchange, it will be necessary to install several fans in the basement, which will supply fresh air to the workshop through ventilation shafts. Holes for such installation are mounted in the floor and closed with special gratings with cells, the diameter of which does not exceed 50 mm. The speed of the air masses should be 4.5 m/s when leaving the fans and, accordingly, 0.1 m/s when entering the room. The performance of supply fans for a room of 30x20 m is 3400 m3/hour. Exhaust fans are installed at a height of up to 6 m, usually on the roof. Their productivity is 6800 m3/hour. Such a ventilation system is able to quickly clean the air in the workshop and reduce the concentration of harmful substances in the air to an acceptable level of 2 mg/m3.

Important! mechanical system ventilation must comply with the requirements of SNiP 2-33-75.

Work area ventilation

In accordance with GOST 12.3.003-86, the welding shop must be equipped with local ventilation with an exhaust air suction rate of more than 1.5 m/s. Local ventilation can be installed using a movable suction nozzle connected to a flexible ventilation hose.

When using the automatic type of welding, the accumulation of gases and chemicals occurs by means of slot-like suctions no more than 350 mm long, located at a height of 50 mm from the immediate welding site. If the welding machine does not allow you to install a slotted suction of the required length, then it is rational to use several local suctions.

The amount of air removed by local suction must be determined by the formula:

L = K (cube root) * a,

where K=12 for single slotted suctions and K=16 for several slotted suctions, a is the current strength supplied by the welding machine.

Important! High pressure fans are used for local suction.

Local suctions are connected to the general exchange channel using a flexible hose when the welding machine moves no more than 2 m. When the machine moves more than 2 m, mobile ventilation devices are used.

Argon and carbon dioxide welders are equipped with a local ventilation system with a lower suction of 2000 m3/hour. A control valve should also be installed.

The local ventilation system must eliminate more than 75% of harmful components from the air masses. The remaining 25% is drawn out by the general ventilation system.

Welding room ventilation design guide

The textbook "Designing ventilation of assembly and welding shops" by O. Ya. Logunov provides detailed information on the installation of the ventilation system of the welding shop, indicating all calculations and diagrams. According to instructions:

• the ventilation system of the welding shop must be autonomous;
• the use of the method of recirculation of air masses is strictly prohibited;
• supply air must be heated or cooled (depending on temperature indicators) before being supplied to the workshop;
• the air volume during manual welding should be up to 4500 m3/h, when using an automatic device - 2000 m3/h, when using flux-cored wire - 5400 m3/h.

Ventilation in the welding shop: examples of equipment

The choice of equipment for creating a ventilation system should be approached with full responsibility, because it must provide constant air purification and a normal microclimate in the room:

1. The ventilation system "Sovplim" for local use is equipped with an electrostatic filter and a flexible exhaust device. With its help, harmful substances are removed directly from the workplace, and do not spread throughout the premises. The range of the system is 6 m, which allows you to effectively clean the working area.
2. BVV air distributor system, which allows creating a zone of clean air directly at the welding site. The system is installed at a height of more than 2 m and provides high-quality displacement of air masses from working area.
3. Local FilterBox systems allow you to clean the welding place from dust and harmful components that have entered the air masses.
4. VRP brand fans equipped with an electric motor.

Important! The choice of equipment performance for creating a ventilation system for a welding shop depends on the area of ​​\u200b\u200bthe room, the number of people and the type of welding machine used.

Ventilation in the welding shop must be uninterrupted. It is mandatory to install an emergency ventilation system, which must be as effective as the main one.

The main task of indoor air exchange is to ensure optimal parameters microclimate. The main documents according to which ventilation is designed are SNIP 41-01-2003 and GOST 12.1.005-76. Ventilation of enterprises, in addition to maintaining the temperature regime, must ensure that the concentrations of dust, moisture, harmful aerosols or gases in the workplace are within acceptable limits. At the same time, the specifics of the industry and the equipment used, the parameters of the building form certain requirements for ventilation. industrial premises.

Mechanical and mechanical assembly shops

In machine shops for processing metal blanks, turning, drilling, milling, slotting, gear cutting, grinding, planing, grinding and other machines are used. When working on such equipment, the air is saturated with fine metal dust, there is additional heat radiation from the engines of machine tools and the cutting zone. The coolants and machine oil used in the machining process in the form of steam and aerosols pollute the atmosphere of the room. Therefore, ventilation of machining shops is mandatory.

Ventilation and heating of industrial premises for machine shops are often combined in single system. The ventilation of the machine shop is carried out by the influx of clean air, which is supplied from the upper part of the building, as well as by local exhausts. To ensure normal microclimate parameters, exhaust elements (local ventilation) must be installed above grinding and peeling machines. In addition, this equipment must also be equipped with dust collectors (protective cover or suction funnel). Also, hoods should be mounted above baths for washing products and tanks with emulsions for various purposes.

Hot production ventilation

Automatic ventilation control is achieved by integrating a control unit and a whole set of auxiliary equipment into the air exchange system. The main element ("brain" of the automated system) is the controller.

Hot shops in industry are all production facilities where the work process is accompanied by a large release of heat into the air. Such workshops include foundry and melting (open-hearth, converter, electric steelmaking), thermal, forging and rolling.

Ventilation of a hot shop should solve two problems - the removal of radiant and convective heat that is released during the operation of the equipment, and the removal of smoke and harmful impurities (carbon monoxide, sulfur dioxide, ammonia) from the air. Since heat and smoke are emitted in huge quantities (the temperature in the workshop even in winter does not drop below +30°C, and in summer it is +45 ... +50°C), it is quite difficult to ensure sufficient ventilation efficiency. To solve this problem, practically all types of ventilation should be used in hot shops: natural, general exchange supply and exhaust, and local.

Almost all types of hot shop equipment must be provided with local exhausts. The calculation of local ventilation, as well as its installation, is carried out in such a way as to ensure the maximum removal of harmful impurities. However, local exhausts do not always fully cope with the localization of emissions, therefore, in addition to them, the shop should be provided with general exhaust ventilation with mechanical stimulation in the upper part of the shop. In addition, windows should be provided in the roof to provide natural aeration. Additionally, a supply general ventilation system is installed in the workshop, and at the same time air shower systems are used at workplaces with radiant heat emissions.

When designing ventilation of foundries or other areas of hot production, bag or electric dust filters should be provided at the outlet of exhaust systems, as well as special air purification devices that neutralize harmful gases before being released into the atmosphere.

Ventilation of welding shops

The operation of welding equipment of any type (manual, semi-automatic in a shielding gas environment, automatic using flux-cored wire) is accompanied by the release of nitrogen oxides, carbon oxides, ozone, as well as harmful fluorine compounds. Ventilation of the welding shop is realized with the help of a general exchange supply and exhaust system. If possible, installation of industrial ventilation systems of local exhaust design is also carried out. At the same time, the calculation of the ventilation of the workshop is carried out in such a way that the exhaust system catches maximum amount emitted impurities and purify them from the air before being released into the atmosphere.

The exhaust ventilation of the welding station must be installed so that 2/3 of the exhaust air is removed from the lower part of the workshop, and 1/3 from the upper one. The purpose of industrial ventilation of the supply type is to compensate for the removed air and ensure that the concentrations of harmful substances in the air do not exceed the maximum allowable standards.

According to the same principle as air exchange in welding production, plasma cutting ventilation is organized.

Paint shop ventilation

The ventilation of the paint shop should be focused on the removal of solvent vapors and air suspension of paint particles, the concentration of which in the air during paintwork is quite high. These substances pose a serious threat to human health, as they are carcinogens. In addition, they are explosive and flammable substances.

Ventilation of paint shops, as in principle, and any other production, is determined by the air flow. But the required air flow when painting products of various dimensions differs not even at times, but hundreds of times. Thus, ventilation of spray booths for small parts without the use of atomizers and sprayers should provide an air exchange rate of 5-6 times per hour. While when painting large parts from a spray gun, in order to reduce the concentration of harmful substances in the air to acceptable values, it is necessary to provide air exchange at a rate of 20 to 100 times per hour, which is economically unprofitable in large workshops. Therefore, for such workshops, ventilation during painting should reduce the concentration of impurities in the air only to the extent that it guarantees complete explosion and fire safety. At the same time, workers are provided with personal protective equipment - respirators and protective clothing.

The ventilation of the spray booth is carried out using a general exchange supply and exhaust system and local exhausts. The supply ventilation system is calculated in such a way that the volume of air masses supplied exceeds the amount of air removed from the room. The spray booth ventilation system is equipped with explosion-proof check valves on the air ducts.

Exhaust ventilation in a paint shop depends on the type of impurities emitted: if gas vapor is lighter than air, then general exchange devices should remove 2/3 of the exhaust air from the upper part of the workshop and 1/3 from the bottom, if it is heavier, air exchange is organized in reverse order.

Paint booths, tables, booths, dipping baths, spray painters, dryers and degreasers are equipped with powerful local exhaust devices. At the same time, it is forbidden to combine hoods into a single duct system. Exhaust systems are used explosion-proof design with spark-proof fans.

The organization of industrial ventilation and air conditioning is a task, the solution of which can only be entrusted to a professional designer who specializes specifically in the manufacturing sector. Efficient operation of industrial ventilation, its durability, as well as the health and even life of working personnel depend on properly designed and calculated air exchange.