Engineering systems 

Supply and exhaust ventilation in gas boiler rooms. Boiler room ventilation

Everyone knows from the course of high school physics that the combustion process is nothing but the product of the oxidation reaction. To maintain this reaction at a given level, oxygen is needed, and the more intense the combustion, the greater the need for oxygen. The method of burning gas or another type of fuel used in boiler plants requires a mandatory influx of atmospheric air to maintain an uninterrupted combustion process. In addition, it is necessary to solve the issue of smoke removal. These functions are performed by supply and exhaust ventilation.

According to the law, autonomous heat supply points must be equipped natural or forced ventilation system. Unlike industrial, in private construction this rule is sometimes not respected. Due to the lack of oxygen, with poor supply ventilation of the boiler room, complete combustion of fuel does not occur, which leads to a decrease in the efficiency of the boiler and its premature failure. In the absence of proper exhaust ventilation of the boiler room, combustion products enter the room in the form of carbon monoxide and soot, and this poses a threat to the safety of people.


During the operation of the boiler, air is drawn in from the room to the nozzles to maintain combustion. Previously, there was enough air entering the room naturally through unsealed openings. Now new construction Materials  allow isolating the premises almost hermetically. And if there is no influx of atmospheric air in the room, then the boiler’s productivity decreases and a “back draft” effect may occur in which smoke will go into the room. To prevent this, boiler room  it is necessary to equip both supply and exhaust ventilation.

Basically, for the normal operation of a small object is enough natural ventilation boiler. When using a medium-power boiler, it is enough to cut a hole in the wall with a diameter of up to 200 mm facing the street. A pipe is mounted in the hole. Outside, it must be protected from debris, for which a metal mesh is suitable. A check valve is installed on the inside of the pipe, which prevents air leakage from the room to the outside.

In the same way, the boiler exhaust duct is also equipped. The difference is that on the outside of the pipe you need to install protection from rain or snow (a metal umbrella is suitable), and install a check valve so that it prevents air from entering the room.

It is advisable to make a supply duct closer to the floor in the immediate vicinity of the boiler. Then the air enters directly into the furnace, without sucking in excess dust and debris, which can impair burner performance. The exhaust duct must be placed in the ceiling above the boiler. Then the combustion products, rising upward, will immediately be output. This boiler room ventilation system is the simplest and is used mainly in private construction. Its disadvantage is the inability to regulate air exchange. In addition, the air exchange itself depends on climatic factors.

The system does not have these shortcomings. boiler ventilation. Typically, such a system is mounted when it is impossible to ensure the flow of the required volume of air naturally, or for large production boilers. The reason may be that the heat generator is located deep in the room and the duct will be too long.


Another name for such a system is forced ventilation of the boiler room, because the air does not move through the duct in a natural way, but under duress. Forcing him to this built-in fan. In duct systems, duct fans are typically used. When calculating the supply air duct to the boiler room, it is necessary to select a fan based on the maximum air flow, taking into account a possible overrun of up to 30%. This value depends on the length of the duct and the presence of bends in it, etc.

To minimize the cost of installation of ventilation of the boiler room, the fan can be installed in only one part of the system. However, to ensure trouble-free operation, it is better to mechanize both the supply and exhaust ducts.

When installing forced ventilation in boiler houses that run on liquid fuel or gas, explosion-proof fans must be selected. The case of such a fan is made of copper or aluminum to prevent arcing, which can cause a fire. For ease of control, the system can be automated by coordinating the fan toggle switch with fuel supply.

The coercion system is the only difference between artificial ventilation of the boiler room from natural.

It should also be noted the undesirability of connecting the ventilation system of the boiler room with a common air supply system, as this can lead to the ingress of combustion products into the common system.

If the boiler room does not work in automatic mode, but requires the presence of personnel, it is necessary to control the air temperature in the room and, if necessary, preheat the supply air.

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Individual boiler houses are gradually recapturing the domestic market, previously occupied exclusively with centralized heating. According to experts, in the next 10-20 years the number of autonomous boiler houses of low power will increase approximately 1.5–2 times.

The installation of an industrial boiler room differs little from the assembly and commissioning of a boiler room, intended, for example, for heating public utilities, social or administrative buildings. It consists of several main stages.

24/11/2008 17:04:54

Every student knows that combustion is a special case of an oxidation process involving oxygen. In order for there to be fire and flame, air and the oxygen contained in it are necessary. The operation of an atmospheric boiler in this sense is no exception. When burning gas, any boiler, like a vacuum cleaner, absorbs air, which is then discharged into the chimney in the form of various oxides. For each boiler, the documentation indicates the amount of air consumed. The more powerful the boiler, the more air it consumes.

It is not uncommon in private construction that this fact is not given any significance. But in vain. A working boiler draws air out of the house, creating a vacuum. In itself, this is not scary if there are enough cracks in the walls of the house or in the window openings through which air from the street enters. Recently, however, using hermetic plasters and modern window systems, houses have become impervious to airflow from the outside. But the laws of physics cannot be undone. During the heating period, a vacuum will be created in the house and the air outside will tend inward. In sealed houses, there is only one way of air penetration from the outside - ventilation ducts (hoods), which are usually arranged in bathrooms and kitchens. If the vacuum created by the boiler is greater than the resistance of the ventilation duct, the so-called reverse draft will appear from the hood. All the smells that seem to have to go through ventilation ducts will not only remain indoors, but will also actively spread throughout the house along with air entering from the street.

The solution to this problem is one - forced ventilation. It can be shared throughout the house or directly in the boiler room. From the point of view of ventilation science, it is extremely undesirable to make an inflow only to the boiler room, since there is a possibility in the event of an accident that gas will spread throughout the house. In the boiler room, in theory, there should only be hoods. However, gas services do not prohibit the supply of valves in boiler rooms. The general ventilation system, as a rule, is an expensive and complex system, therefore the cheapest and most effective way to ensure air intake is by the supply valve directly in the boiler room or in the immediate vicinity of it. There are special valves with a special design, but often they simply make a hole in the wall with a diameter of 100-150 mm. This is more than enough for the normal functioning of a medium-power boiler (20-30 kW). In the hole you can insert a sewer or vent pipe. Outside, close the pipe with a net from leaves and insects, and inside, put a simple check valve. The cost of such a solution is minimal, and the efficiency is very high. Practice has shown that in winter the supply valve does not freeze. Despite the low outside temperature, the air temperature in the boiler room is slightly lower than in the whole house.

Sometimes the diameter or location of the supply valve does not allow enough air to pass through to compensate for the air flow of the boiler. In this case, it is advisable to use the simplest fans, selecting the required air flow rate by 15% -30% more than the flow rate of the boiler. Partially, the fan power will be used to overcome the resistance of the valve, mesh, filter, duct (if any). Part of the air must go through a natural ventilation duct, which is mandatory in boiler rooms. Significant air intake through the supply valve in the boiler room must not be done! It also makes sense to turn on the fan automatically when the boiler is operating for the same purpose - so as not to create excess pressure in the boiler room.

2014-01-08 14:09:50 | Yuri
Now they sell special pipes for gas boilers, a pipe in a pipe. Cold air flows through one, while smoke flows through the other.


2013-11-24 09:59:57 | Andrey_B
Vladimir, if the draft has overturned, it means that there is insufficient air flow in the house, that is, in this way (reverse draft) the system balances the balance between the exhaust and the inflow.
1. If there are sources of powerful outflow of air, for example, a boiler, ensure a sufficient amount of air flow. Typically, boiler air consumption rates are indicated in the documentation for it.
2. Calculate the debit for ventilation channels. And if it is very large, but there is no influx, then either cover / close ventilation ducts, or provide an additional inflow.
3. After the imbalance has been eliminated, where backward thrust has formed, it may be necessary to warm up the ventilation duct so that it starts working on the hood again.


2013-11-23 10:42:36 | Vladimir
my draft in the bathroom overturned. impossible to wash, the bathroom is cold. what to do?


2011-11-27 11:16:56 | Andrey_B
Alexander, do you mean forced ventilation?
The easiest way is a hole in the wall. For natural influx, the hole must be larger in diameter than the diameter of the chimney. When installing a fan, the hole diameter can be made smaller. I also recommend installing a filter.


2011-11-26 22:46:49 | Alexander
boiler with a turbo hood, how to make ventilation easier if vent. no channels?


2011-08-16 08:51:41 | Andrey_B
Tim, the simplest supply valve is located only in the boiler room.
At the moment, a centralized ventilation system at home is not running. If you supply air to living quarters, of course, it will be necessary to provide for heating.


2011-08-15 21:35:49 | Tim
"The stronger the frosts, the higher the coolant temperature, the hotter in the boiler room."

Andrei, I understood correctly - you have one inlet for both the boiler room and the living quarters? Consequently, cold air is supplied to the living quarters? In severe frosts there is no discomfort?


2011-08-11 23:38:46 | Andrey_B
Tim, there is currently no heating for the supply air. In winter, the boiler room does not fall below +26 +28. The stronger the frosts, the higher the coolant temperature, the hotter in the boiler room. Supply air heating is obtained automatically. What you really need is a filter. The boiler room is dusty. The most amazing thing is that in winter there is a lot of dust, or rather suspension like fine sand. This is hardly a problem for the boiler, but on all pipes and fittings it lies in a thick layer.


2011-08-11 17:14:45 | Tim
Question on ventilation of premises. Andrei, do you turn on the outboard air heating in severe frosts? Or just simply significantly reduce air exchange?

Page 1


Boiler room ventilation is most often done natural with the influx of clean air through the louvres located in the walls of the rooms behind the boilers, and with exhaust through the exhaust shafts or pipes located above the boilers in the boiler room ceiling. If it is not possible to install natural ventilation, an artificial ventilation system is created by using a fan. Exhaust fans and their electric motors installed in rooms are used for explosion-proof execution in order to avoid explosion from a spark in case of gas-air mixture formation. Explosion protection of the fan is achieved by coating the inner walls of the casing (stator) of the fan with aluminum or copper sheets or by copper plating them in another way. In this case, sparks cannot form in the fan.

Boiler room ventilation is most often done natural with the influx of clean air through the louvres located in the walls of the rooms behind the boilers, and with exhaust through the exhaust shafts or pipes located above the boilers in the boiler room ceiling. If it is not possible to install natural ventilation, an artificial ventilation system is constructed using a fan. Exhaust fans and their electric motors installed in rooms are used for explosion-proof execution in order to avoid explosion from a spark in case of gas-air mixture formation. Explosion-proof fan is achieved by coating the inner walls of the casing (stator) of the fan with aluminum or copper sheets or by copper plating them in another way. In this case, sparks cannot form in the fan.

Boiler room ventilation is most often made natural with the influx of clean air through the louvres located in the walls of the rooms behind the boilers, and with exhaust through the exhaust shafts or pipes located above the boilers in the boiler room ceiling. If it is not possible to install natural ventilation, an artificial ventilation system is constructed using a fan. Exhaust fans and their electric motors installed in rooms are explosion-proof in order to avoid explosion from a spark in the event of the formation of a gas-air mixture.

Ventilation of boiler rooms must provide at least three times air exchange without taking into account the air required for gas combustion. Air is supplied behind the boilers, and the hood is drawn from the upper zone. Gas burners of boilers and furnaces manufactured in accordance with current standards must ensure combustion stability within the limits of regulation of the allowable heat load of the unit. On the front panel or doors of the furnace furnaces, inspection openings are provided through which the burners are ignited and their operation is monitored. Explosive gas-air mixture may accumulate in fire chambers, hogs and flues; to prevent the accumulation of this mixture in the boiler gates, special openings with a diameter of at least 50 mm are arranged.

A feature of the ventilation of boiler houses built into buildings is the need to provide at least three times air exchange per hour. The volume of air entering the furnaces of the boilers for gas combustion is taken into account additionally. When determining the multiplicity, the volume of the room is taken minus the volume occupied by the equipment. The air inflow in these boiler rooms should be carried out, as a rule, behind the boilers, and the removal from the upper zone of the room. This allows you to supply cold-supply air to an area where there is no service personnel, and to remove the gas collected in the upper parts of the room as a result of possible leaks.


The method of ventilation of the boiler room with mechanical induction is carried out by installing 4 - 5 axial fans of type МЦ № 8 in special supply air cabins at the level of 6 - 1 m from the floor level. Supply air, as a rule, does not heat up. However, with large quantities of exhaust air, excess heat in the boiler room may not be enough to heat the supply air supplied from the outside.

The layout of the boiler room ventilation system is very simple. During the operation of the boilers, the air from the room is removed through the furnace devices, and the supply air is supplied in the cold season through openings with fixed shutters or window transoms of the upper tier. Deflectors are installed on the floor of the boiler room, the performance of which is calculated for at least three times the air exchange in the boiler room. In the transitional and warm seasons, when the amount of air removed through the furnace devices is not enough to ensure proper exhaust ventilation, aeration is used: air exhaust through the transoms of the upper tier and the inflow through the transoms of the lower tier. At an outdoor temperature of 10 ° C and above, through ventilation is allowed using lower tier windows for air inflow. Aeration and ventilation should be organized in such a way that the possibility of drafts in the workplace is excluded.

Fans of exhaust ventilation systems of boiler rooms must be explosion-proof. The requirements for the electric motors and starting equipment of these fans depend on their location: the motors installed in the boiler room themselves must be explosion-proof, and when installed in an adjacent room isolated from the boiler room, they must be of normal design.

The peculiarities of the ventilation device of boiler houses, and first of all gasified ones, include the fact that the air flow of the blowing units should be introduced into the general air balance of the room, ensuring its supply for combustion. The main room requiring a reliable ventilation device is the boiler room, where the boilers and the units directly serving them are installed.

When designing heating and ventilation of boiler rooms, building codes and rules for the design of heating, ventilation and air conditioning and the instructions in this section should be observed.

In the calculations, when checking the operation of boiler room ventilation systems to maintain air balance, it is necessary to take into account the air flow for burning fuel.

The ventilation of the furnace compartment, combined with the boiler room, is equipped similarly to the ventilation of boiler rooms converted to gas. Bakeries operate throughout the year with a uniform load, usually in three shifts. The volumes of necessary air exchange, as well as for boiler rooms, are determined for the winter, transitional and summer periods. When summing up the heat balance, heat emissions from boiler equipment and from the oven for baking bread are taken into account.

Direct daily maintenance of boilers, gas pipelines, gas control unit, draft devices and ventilation of the boiler room is performed by the staff. In this case, the administration is obliged to provide free access to gas pipelines and gas-consuming installations for Gorgaz employees.

In boiler rooms, closed tanks with a steam cushion should be provided for collecting drainage of steam pipelines, condensate of steam-water heaters and heaters of the boiler heating and ventilation system. When the condensate collection tanks are located in or near the boiler room, all drains should be directed; into these tanks. At the same time, special drainage collecting tanks are not provided in the boiler room.

  • Purpose of the ventilation system
  • Varieties of ventilation in the boiler room: advantages and disadvantages
  • The main provisions of the arrangement of the air exchange system
  • Boiler room equipment with common house ventilation present
  • The main stages of installation

The air exchange system plays an important role in creating a healthy microclimate of any building, especially residential premises. Not a single building can do without it, regardless of whether it is residential or not.

The ventilation scheme of a private house with a boiler room.

Purpose of the ventilation system

Ventilation in the boiler room of a private house prevents the accumulation of carbon monoxide in the atmosphere and prevents back draft. As you know, such phenomena in the air pose a mortal danger, and with a slight increase of 0.2%, a person becomes unconscious and then stops breathing.

In order to create optimal working conditions, the heating boiler needs oxygen, burning which, natural combustion occurs. The high power of such equipment is associated with a significant consumption of air masses. How can I recover lost oxygen? To do this, follow the clear rules:

  1. Premises equipped with heating equipment require a threefold exchange of air.
  2. Altitude indicators of the building should correspond to 6 or more meters. If this condition is not met, the multiplicity of air masses should be multiplied, making a calculation of 25% per 1 m of decrease.
  3. If it is not possible to ventilate in a natural way, the need arises to install ventilation equipment.

The air exchange system in the boiler room requires special attention. During operation of the furnace equipment, oxygen is actively absorbed and combustion products are released.

As a result of the lack of high-quality air exchange, the following phenomena are observed:

  • unpleasant aura in the house associated with air pollution, inadequate well-being of residents, reaching serious intoxications;
  • lack of oxygen leads to poor combustion and reduced efficiency of heating equipment.

Back to the table of contents

Varieties of ventilation in the boiler room: advantages and disadvantages

  1. Natural.

In this embodiment, an exchange of air masses with the street is put on stream in a private house. The hood is located in the upper part, where the used masses are brought out, the supply aperture is at the bottom, due to which oxygen from the outside enters the room. Positive aspects of using natural ventilation:

  • installation work is associated with minimal cost;
  • the system does not require special care.

Negative points:

  • obligatory presence outer wall, the inability to place the boiler in the basement;
  • the device works if there is a difference in temperature and pressure inside and out;
  • during the cold season, the room cools noticeably as a result of the penetration of coolness from the street.
  1. Artificial.

Forced ventilation is used if the ducts have a long base and there is no natural draft. The supply system is inextricably linked with the air exchange device of the entire building, the exhaust system has one channel of interaction with the street.

Advantages of the forced system:

  • the boiler room is located anywhere in the house;
  • the operational efficiency of such devices is not determined by external conditions.

Disadvantages:

  • significant material costs;
  • if the equipment malfunctions, it is simply replaced;
  • usually the smell of burning spreads throughout the building.

If it is impossible to install a natural system in a private house, the installed equipment is used in full. You can connect this system to the boiler, then it will start at the time of starting the fuel equipment.

You can reduce material costs by installing an artificial device for blowing and blowing air.

Back to the table of contents

The main provisions of the arrangement of the air exchange system

As you know, the ventilation of a private house in a room with a gas boiler is natural and forced. Its important requirement is compliance with the correct exchange of masses and the absence of danger. To improve the operation of such a device, a number of provisions have been developed:

  1. Natural ventilation does not allow the use of horizontal sections of ducts. If this condition cannot be met, an additional fan is required. The horizontal system of such installations does not affect the compulsory system.
  2. For natural ventilation to produce results, traction is required. To ensure it, the pipe is placed in an upright position, the height indicators of which are 3 or more m.

An equally important condition for ensuring high-quality ventilation of the house will be the location of the heating equipment at the operating point: supply - at the bottom, exhaust - at the top.