Ventilation in a private house made of plastic pipes: specifications and installation rules

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Dur­ing the con­struc­tion of a pri­vate house, max­i­mum atten­tion is paid to the qual­i­ty of enclos­ing struc­tures, as well as ensur­ing pro­tec­tion from the neg­a­tive effects of the envi­ron­ment. At the same time, over time, dur­ing the oper­a­tion of the build­ing, the own­ers begin to notice that in order for the air in the room not to be heavy, they often have to ven­ti­late the premis­es, which caus­es some dis­com­fort (espe­cial­ly dur­ing the cold sea­son).

In the last cen­tu­ry, win­dows and doors were not as tight as mod­ern ones, so min­i­mal ven­ti­la­tion was pro­vid­ed. Now, in order to orga­nize suf­fi­cient air exchange with ven­ti­la­tion in all rooms of a pri­vate house, it is nec­es­sary to take care of the design of the ven­ti­la­tion sys­tem at the design stage of the house.

Lack of ade­quate ven­ti­la­tion is the main cause of mold in rooms.

Why is it necessary to install a ventilation system

In the last few decades, the need for orga­niz­ing a ven­ti­la­tion sys­tem has increased for the fol­low­ing rea­sons:

  • All ameni­ties are locat­ed inside the build­ing;
  • Fire­places or heat­ing stoves are installed that require a con­stant sup­ply of air to func­tion prop­er­ly;
  • In the base­ment, pools and saunas are often built, to remove mois­ture from which not only pow­er­ful ven­ti­la­tion is nec­es­sary, but also a prop­er­ly select­ed air dry­er;
  • When con­struct­ing build­ing envelopes, mate­ri­als with min­i­mal air per­me­abil­i­ty are used to ensure max­i­mum ther­mal insu­la­tion of the build­ing.

A prop­er­ly designed and installed ven­ti­la­tion sys­tem will avoid the fol­low­ing prob­lems:

  • The appear­ance of mold due to high humid­i­ty (the accu­mu­lat­ed con­den­sate from mois­ture is an excel­lent envi­ron­ment for the devel­op­ment of microor­gan­isms);
  • Incor­rect oper­a­tion of the fire­place due to lack of sup­ply air to main­tain the flame and the release of com­bus­tion prod­ucts out­side the build­ing through the chim­ney;
  • Dizzi­ness and loss of strength due to the high con­cen­tra­tion of car­bon diox­ide in the air;
  • The spread of odors from the kitchen and bath­rooms through­out the house;
  • Accu­mu­la­tion of grease on walls and fur­ni­ture due to the absence of an exhaust hood over the hob.

Many own­ers of pri­vate hous­es think about the orga­ni­za­tion of ven­ti­la­tion only after the occur­rence of the prob­lems described above. How­ev­er, in this case, its instal­la­tion will take much more time and effort. It is nec­es­sary to get acquaint­ed with the prin­ci­ple of oper­a­tion of the sys­tem before the start of con­struc­tion work at the design stage of the facil­i­ty.

Types of ventilation systems

The task of the ven­ti­la­tion sys­tem is to replace pol­lut­ed indoor air with clean out­door air. This can be done both nat­u­ral­ly by build­ing exhaust ducts and com­plet­ing plas­tic win­dows with ele­ments for micro-ven­ti­la­tion, or mechan­i­cal­ly using spe­cial equip­ment. The first method is not rec­om­mend­ed, espe­cial­ly for hous­es with a large area, for the fol­low­ing rea­sons:

  • Nat­ur­al ven­ti­la­tion oper­ates due to the dif­fer­ence in pres­sure between sup­ply and exhaust air, which is removed using ver­ti­cal ducts. In sum­mer, the para­me­ters of indoor and out­door air are almost equal, so the sys­tem will not be effec­tive;
  • In win­ter, cold sup­ply air will cause incon­ve­nience.
To increase the effi­cien­cy of nat­ur­al ven­ti­la­tion, ven­ti­la­tion shafts can be com­plet­ed with deflec­tors that increase draft.

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To max­i­mize the cost of the sys­tem, you can put the fan only on the sup­ply or only on the exhaust. So the effi­cien­cy will increase, but the dis­com­fort from drafts will remain. In addi­tion, nat­ur­al ven­ti­la­tion ducts are impos­si­ble or very dif­fi­cult to install if the house is already built. In this case, ful­ly mechan­i­cal ven­ti­la­tion is bet­ter, which can be of the fol­low­ing types:

  1. Sup­ply and exhaust.
Scheme of sup­ply and exhaust ven­ti­la­tion using a roof fan.
  1. Ven­ti­la­tion with recu­per­a­tor.
The prin­ci­ple of oper­a­tion of the recu­per­a­tor

In the first case, fans are installed for exhaust and inflow. To ensure max­i­mum com­fort, the sup­ply sys­tem includes: a fil­ter (to trap dust from the street), a heater, a dehu­mid­i­fi­er or an air humid­i­fi­er, if nec­es­sary. The heat­ing ele­ment can be elec­tric or water. In severe frosts, the ener­gy con­sump­tion for heat­ing a suf­fi­cient amount of air is quite sig­nif­i­cant, so it is rec­om­mend­ed to use a heat exchang­er that heats the sup­ply air at the expense of the exhaust air. The cost of such equip­ment is high­er, but oper­at­ing costs are sig­nif­i­cant­ly reduced. Depend­ing on the vol­ume of the house and the type of recu­per­a­tor, its pay­back peri­od is from 5 to 10 years.

Calculation of the ventilation system

The cal­cu­la­tion of the ven­ti­la­tion sys­tem is the deter­mi­na­tion of the amount of air required. For indus­tri­al build­ings, it is nec­es­sary to car­ry out a com­plex cal­cu­la­tion, tak­ing into account heat inputs and emit­ted pol­lu­tion by all installed equip­ment. In the case of res­i­den­tial premis­es, every­thing is some­what sim­pler. It is suf­fi­cient to use the stan­dard val­ues ​​spec­i­fied in the rel­e­vant stan­dards and reg­u­la­tions. Each room is cal­cu­lat­ed sep­a­rate­ly depend­ing on its pur­pose and indi­vid­ual char­ac­ter­is­tics using one of the fol­low­ing meth­ods:

  • By mul­ti­plic­i­ty. In some rooms, the nec­es­sary air exchange does not depend on the num­ber of peo­ple or the equip­ment locat­ed in them. The mul­ti­plic­i­ty is a para­me­ter indi­cat­ing how many times per hour the pol­lut­ed air should be replaced by fresh air from the street. For exam­ple, in dress­ing rooms — 1.5 times, in show­ers — 5 times;
  • By the num­ber of peo­ple. In this way, air exchange is cal­cu­lat­ed for res­i­den­tial premis­es (liv­ing room, bed­rooms). The opti­mal val­ue is at least 30m3/h per per­son;
  • Accord­ing to the rules. For exam­ple, in the bath­room or toi­let, you need to remove 25m3/h of air, in a kitchen with a 4‑burner stove — 90 m3/h Don’t for­get that in most cas­es we call the kitchen, includ­ing the din­ing room, so for the eat­ing room you need to add at least 1 times the fresh air.

You can find a com­plete list of rules for orga­niz­ing air exchange in res­i­den­tial build­ings in MGSN 3.01–01. After deter­min­ing the amount of air to be removed and sup­plied for each room, it is nec­es­sary to make a table of the air bal­ance of the build­ing, in which the total val­ues ​​of sup­ply and exhaust must be equal.

To min­i­mize oper­at­ing costs, it is allowed to oper­ate the ven­ti­la­tion sys­tem not at full strength (in stand­by mode) in rooms where peo­ple are rarely (for exam­ple, in guest rooms, bil­liard rooms, libraries). To do this, the sys­tem must be equipped with spe­cial automa­tion and throt­tle valves that reg­u­late the air sup­ply to indi­vid­ual rooms.

Plastic as a material for the ventilation system: advantages and disadvantages

The most com­mon mate­r­i­al for air ducts is gal­va­nized steel, but in recent years, plas­tic is gain­ing more and more pop­u­lar­i­ty, as it has the fol­low­ing advan­tages:

  • Light weight. For trans­porta­tion, lift­ing to the floor and instal­la­tion of plas­tic pipes, spe­cial devices and hir­ing work­ers are not required, it is quite easy to han­dle every­thing on your own;
  • Cor­ro­sion resis­tance. This prop­er­ty is espe­cial­ly impor­tant for rooms with high humid­i­ty (bath­room, toi­let, laun­dry room, and so on);
  • Sur­face smooth­ness. Air moves through the pipes with min­i­mal pres­sure loss, more­over, over time, the inner walls are less pol­lut­ed com­pared to gal­va­nized steel pipes;
  • Ease of instal­la­tion. For the instal­la­tion of plas­tic air ducts, much less fix­tures are required.

Among the dis­ad­van­tages of plas­tic pipes, it is worth not­ing poor resis­tance to high tem­per­a­tures (there­fore, it is high­ly rec­om­mend­ed not to install them in a sauna) and a small selec­tion of sizes com­pared to steel pipes, which can be made to order. How­ev­er, for a small pri­vate house, the line is quite enough, because ven­ti­la­tion from sew­er pipes can be installed.

Selection of air ducts and equipment

After cal­cu­lat­ing the air exchange and select­ing the mate­r­i­al for the sys­tem, it is nec­es­sary to select ven­ti­la­tion equip­ment and pipeline diam­e­ters for air dis­tri­b­u­tion through­out the premis­es. The main para­me­ter at this stage is the pres­sure loss in the duct. That is, the longer the line, the nar­row­er the pipes and the greater the air speed, the greater the pres­sure loss, which means that the fan will pro­duce less pow­er. The aero­dy­nam­ic cal­cu­la­tion is rather com­pli­cat­ed, how­ev­er, for small runs, the table below can be used to select the diam­e­ter of the vent pipe.

Scheme for select­ing the diam­e­ter of the duct.

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The opti­mal val­ue of the air veloc­i­ty in the duct is 3–4 m / s, more — you will hear noise from the sys­tem, less — you will need a more pow­er­ful fan. After select­ing the sec­tions, using anoth­er table, the pres­sure loss­es along the length are deter­mined, sum­ming up the obtained val­ues, we get a fig­ure, depend­ing on which we select a fan for the sys­tem.

Scheme for cal­cu­lat­ing pres­sure loss­es in straight sec­tions of the duct.
Scheme for cal­cu­lat­ing pres­sure loss­es on the main fit­tings.

It is only nec­es­sary to sum up the val­ues ​​along the route to the most remote switchgear, the loss­es on the branch­es do not play a role. Please note that each ele­ment of the sys­tem (dis­tri­b­u­tion grill, silencer, heater) also los­es pres­sure, the spe­cif­ic val­ue is indi­cat­ed in the para­me­ters of the select­ed equip­ment.

In order for the designed ven­ti­la­tion in a pri­vate house (or in a coun­try house) made of plas­tic pipes to be as effi­cient and least expen­sive as pos­si­ble, fol­low the rules below:

  • The exhaust pipe must be raised above the ridge of the build­ing to pre­vent the suc­tion of pol­lut­ed air into the win­dows of the upper floors;
  • To ven­ti­late the under-roof space, it is nec­es­sary to install an aer­a­tor;
Plas­tic ven­ti­la­tion aer­a­tor.
  • Check valves should be installed in the branch­es lead­ing to the kitchen and bath­rooms so that extra­ne­ous odors do not spread around the house when the sys­tem is not func­tion­ing;
  • The num­ber of turns must be kept to a min­i­mum to reduce drag;
  • Use round pipes when­ev­er pos­si­ble.

When plan­ning the loca­tion of the inlet, the height of the chim­neys must be tak­en into account. The ide­al option is the loca­tion of the sup­ply equip­ment on the first floor of the build­ing, but that the sup­ply open­ing is at least a meter away from the ground.

Installation of plastic pipes

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Pipes for the ven­ti­la­tion sys­tem of a pri­vate house are mount­ed accord­ing to the fol­low­ing scheme:

  1. Drilling holes for pipes to pass through walls and floor slabs.
  2. Cut­ting the ducts to the required length.
  3. Remove uneven edges with sand­pa­per.
  4. Thread­ing pipes into con­nect­ing ele­ments (tran­si­tions from one sec­tion to anoth­er, bends, tees, and so on) using sealant.
Com­plex branch­es are best col­lect­ed on the floor first, and only then attached to the wall.
  1. Attach­ing air ducts to walls and ceil­ings with clamps and brack­ets.
  2. Instal­la­tion of equip­ment and dis­tri­b­u­tion devices.
There are grat­ings that can be insert­ed into the sta­sis in the duct with­out the use of addi­tion­al con­nect­ing ele­ments.
  1. Leak test by con­nect­ing a fan.

Impor­tant! A throt­tle valve must be installed on the sup­ply branch of the sys­tem to pre­vent drafts when the sys­tem is turned off.

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