They can be of various shapes made of various materials. Usually they try to hide them, but having created a little, you can turn them into an art object. On them, as through blood vessels, invisible and intangible flows run. Not a single modern building is complete without them.
These are ventilation ducts. What are they, how to make them noiseless, efficient and is it possible to assemble a ventilation duct with your own hands?
The main characteristics of ventilation ducts
The main indicator by which the ventilation duct is selected: throughput.
Ventilation ducts are also characterized by:
- sectional shape;
- material;
- diameter of section.
The dimensions of the ventilation ducts are calculated according to special tables that take into account the speed of air movement through the pipe and its throughput.
The form
The shape of the cross section of the box can be:
- round;
- square or rectangular.
Boxes with a round cross section have several advantages:
- Smooth inner walls of boxes with a circular cross section do not create obstacles to the passage of air flow;
- They are easy to clean, as dirt has nowhere to linger;
- Create a little noise;
- You can use fans of lower power.
The main disadvantage of round ducts: they are difficult to hide in the interior.
With equal throughput, the cross-sectional area of a round box is 12% less than a rectangular one.
The largest and most powerful ventilation systems are equipped with rectangular steel ducts.
Ventilation ducts with a flat rectangular or square section allow more rational use of the space of the room.
The disadvantages of boxes with a rectangular cross section:
- Internal corners create resistance to air;
- To cover the pressure loss it is necessary to install more powerful and energy-intensive equipment;
- Greater aerodynamic drone.
Despite the shortcomings, the rectangular section is also popular in cottage construction. The flat ventilation duct is easier to hide behind a suspended ceiling.
Material
Ventilation ducts are made of:
- steel (stainless or black galvanized);
- plastic.
With your own hands, the ventilation duct in the garage or barn can be built from other materials at hand, for example, boards or drywall. But the design should be tight!
Plastic ducts for ventilation do not deform over time, do not change color.
Other advantages of plastic ventilation ducts:
- simply mounted;
- inexpensive
- resistant to corrosion;
- if necessary, they can be further processed (for example, rolled);
- It is easy to pick up finished fittings.
The main disadvantage of plastic ventilation ducts is flammability. Therefore, they are installed mainly in domestic premises, where contact with hot air or steam is excluded.
Ventilation ducts are made of ABS plastic of various sizes, with round and rectangular cross-section.
Section Dimensions:
- plastic: 11x5.5 cm, 12x6 cm, 20.4x6 cm;
- round diameter: 10 cm, 12.5 cm, 15 cm.
Steel ventilation ducts are made of stainless steel or black galvanized steel. Galvanized ventilation ducts are installed in residential and industrial buildings. Galvanized ventilation ducts are manufactured in standard sizes, and also made to order especially large diameters.Shaped parts are also made to order.
Pros:
- do not rust;
- simply mounted;
- convenient in operation;
- comply with sanitary standards, since microorganisms do not take root on galvanized and stainless surfaces;
- any equipment can be mounted directly on the network.
A serious drawback of galvanized ventilation ducts is expensive shaped products. Since they are usually carried out to order, their cost often exceeds the price of air ducts.
Fire protection boxes
All large public and industrial buildings have smoke protection systems. They are a network of fireproof ventilation ducts, separated by gates, valves and dampers. Through the channels, smoke is removed from the burning places outside the building, preventing it from spreading to nearby premises. Through paired ducts, fresh air enters the room from the street. Fire-resistant ducts and ducts are made only from sheet steel with a thickness of 0.8 mm or more.
Fire protection measures protect the ducts from melting.
2 methods of fire protection of ventilation ducts are widely used:
- Surface treatment of pipes with special water-based mastics (KRAUZ-vent) or paints;
- Wrapping boxes with non-combustible materials made of basalt fiber (Tizol, SOSH) or mats (KRAUZMAT).
| Kind of fireproof. material | Temper. installation. | Operation duration | Will continue. protect | Consumption in gr. on sq.m. | Layer thickness |
| Water based pastes and mastics | From +1 | Not less than 25 years | 0.5 hours
1 hour |
1600
2260 |
1mm
1.4mm |
| Mats and nonwovens for wrapping | Irrelevant | Not less than 30 years | 1,5 hour
3 hours |
–
– |
50 mm
70 mm |
Table 1. Comparative characteristics of various types of flame retardant materials
Soundproofing ventilation ducts
Steel or plastic ventilation ducts carry air currents causing aerodynamic noise. Corrugated air ducts and rattling metal ones, parts of which can slightly vibrate, are considered particularly “noisy”. The less rigid and tight the system, the more noise it will reproduce.
Causes of noise in ventilation:
- lack of air ducts in the circuit;
- illiterate installation of ducts;
- neglect of vibration isolation mechanisms;
- maximum flow speed.
Sometimes the cause of noise is improper system design.
Do-it-yourself ventilation duct insulation materials:
- mineral wool and fiberglass plates. Used for insulation of ducts;
- sound absorbing plates. Slabs made of porous polymers or rubber are convenient for soundproofing ventilation ducts;
- organic fiber materials.
Ventilation ducts are soundproofed most often with the help of multilayer sound-absorbing plates. They are easily bent, for ease of installation they are treated with a sticky layer or a self-adhesive film. Such material effectively absorbs the low-frequency hum, the most harmful to human health.
Do-it-yourself noise isolation
Tools and materials necessary for soundproofing the ventilation duct:
- sound absorbing plates;
- acrylic adhesive, foamed. Acquired at the rate of 1 kg per 3.5 - 4 square meters. m surface;
- foamed polyethylene;
- knife;
- putty knife;
- tassel.
Before sheathing the ventilation duct, it is necessary to clean its surface from dust and dirt. Foamed polyethylene is glued on all turns, corners and transitions. The material is laid with a soft layer inward, and reflecting outward.
To enhance sound insulation, distance spacers are used. If the box is not insulated, sound insulation must be overlapped, not glued. Also come if the noise insulation is not self-adhesive. Joints of sheets are glued with aluminum tape.
About ventilation ducts in the kitchen
Many owners of small apartments are wondering: “is it possible to tear down a ventilation duct that is uncomfortably sticking out of the wall?”.
The answer to the question is unequivocal: the dismantling of ventilation ducts is strictly prohibited!
Indeed, if you tear down the ventilation duct, the area of the kitchen will increase by 0.5 square meters. meter. But independent demolition of the box will entail unpleasant consequences:
- The mine is a pyramid of ventilation ducts mounted on top of each other. Dismantling any of them leaves the blocks located above practically without support;
- If the ventilation duct is demolished, all residents of the lower floors can forget about the air exchange in the kitchen and in the apartment in general.
Therefore, the Housing Inspectorate is very strict about communal utilities and will require the restoration of the ventilation duct in the apartment.
About the redevelopment of the box
Many attempts to dismantle the ventilation duct with its subsequent redevelopment ended in failure. Insufficiently competent builders recommend to demolish the box during repair and replace it with a pipe construction that partially frees up the space.
Why this cannot be done:
- House ventilation is a very gentle system, the air velocity in it drops at the slightest obstacle. Therefore, the risers should be strictly vertical, without turns and protrusions. The dimensions of all sections of the ventilation duct must be the same;
- If the arguments are not enough, see paragraph 1 of the previous paragraph.
In some cases, residents of the first floors managed to get permission to demolish their section of the box. After all, nobody lives below and redevelopment will not harm other people. It is also possible to get permission to dismantle chimneys located in the walls of old brick houses. As a rule, communications have not been operational for a long time.
However, permission is required for such work!
This is also necessary for those who plan to purchase housing in the secondary market. Pay attention to any redevelopment and require all permits. For any independent redevelopment of communications and the structures enclosing them, a fine of 2500 rubles and the subsequent restoration of the ventilation duct in the apartment is threatened.
Therefore, architects recommend thinking about how to sheathe the ventilation duct in the kitchen, turning it into a useful or effective interior detail.
DIY ventilation ducts
The simplest and most affordable version of a flat ventilation duct is plastic. But in some cases, plastic is not suitable. If it is necessary to restore the ventilation duct in the bathroom of the apartment and tile it, thin plastic walls will not support the weight of the ceramics.
In this case, you can assemble a ventilation duct from drywall. Most experts recommend using corrugation as an air duct, which is inserted into a drywall duct. This design will be airtight, which is fundamentally important for traction.
In order to make a drywall box for ventilation, you must:
- metal profiles for drywall;
- drywall;
- hammer drill;
- screwdriver (screwdriver);
- scissors for metal;
- special screws;
- dowels for attaching the profile to the ceiling or walls.
Progress:
- make markings on the ceiling and wall, taking into account the thickness of the material.
- with dowels we attach a profile of 2.7x2.8 around the perimeter of the future box.
- From the profile we cut vertical racks. Their length corresponds to the vertical size of the ventilation duct.
- we fasten them to the perimeter.
- Now we attach the lower perimeter of the box to the racks.
- We insert the corrugation into the frame and attach it to the exit from the wall.
- Now we cut out parts of the corresponding size from the drywall sheet and fasten them to the profiles using self-tapping screws.The distance between the screws is 15 cm.
Set the horizontal and vertical levels! Do not forget to insert a ventilation grill into the wall of the drywall box.
Of course, assembling such a design is more difficult than using a ready-made plastic duct for ventilation. However, in the case of drywall, you will not have a problem: how to sheathe the ventilation duct. Paint will perfectly lie on drywall, you can glue tiles or lay decorative plaster.
A very detailed video tutorial on how to assemble a box from drywall:
