Choosing pipes for heating a private house

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When buy­ing pipes for a heat­ing sys­tem, you should first of all focus on their dura­bil­i­ty, the abil­i­ty to with­stand water ham­mer and tem­per­a­ture extremes. Ease of instal­la­tion is also impor­tant. So which pipes are bet­ter to choose for heat­ing a pri­vate house? Let’s talk about this in detail.

Requirements for heating pipelines

Accord­ing to the norms of SNiP, the equip­ment used for the instal­la­tion of heat sup­ply sys­tems must meet cer­tain require­ments:

  • with­stand a work­ing pres­sure of 0.7–1.5 atm dur­ing the entire peri­od of oper­a­tion;
  • main­tain integri­ty dur­ing short-term water ham­mer at a pres­sure 1.5 times high­er than the nom­i­nal (work­ing);
  • remain sealed at a coolant tem­per­a­ture of 90°C;
  • have suf­fi­cient chem­i­cal resis­tance and UV resis­tance;
  • be easy to install and main­tain;
  • have a ser­vice life of 25 years; and for pipelines laid in hid­den struc­tures (walls, con­crete floors) — at least 40 years;
  • the mate­r­i­al used for their man­u­fac­ture must not con­tain impu­ri­ties harm­ful to human health;
  • to pro­tect against rapid clog­ging of the sys­tem, the inner sur­face of the pipelines must have an ide­al smooth sur­face, for exam­ple, for steel prod­ucts, the equiv­a­lent rough­ness can be 0.2 mm;
  • the diam­e­ter of the pipeline must be suf­fi­cient to pro­vide heat to each of the heat­ed rooms.

Addi­tion­al require­ments are imposed on the pipelines used for the instal­la­tion of under­floor heat­ing sys­tems. Such prod­ucts should be suf­fi­cient­ly flex­i­ble and elas­tic, eas­i­ly fit into loops with­out the for­ma­tion of creas­es, and keep a giv­en shape well.

Pipelines of heat­ing sys­tems must meet a num­ber of require­ments

Advice! For heat­ing sys­tems, pipes and fit­tings should be pur­chased from the same man­u­fac­tur­er. The prop­er­ties of the mate­ri­als used for their man­u­fac­ture, in this case, will be iden­ti­cal. This will ensure bet­ter seal­ing of the joints.

Steel

Which is bet­ter, steel pipes for heat­ing a pri­vate house or plas­tic? The advan­tages of met­al prod­ucts include high ther­mal con­duc­tiv­i­ty and the abil­i­ty to eas­i­ly give off heat to the envi­ron­ment. Anoth­er indis­putable advan­tage of met­al pipes is increased strength, reli­a­bil­i­ty, the abil­i­ty to with­stand even sig­nif­i­cant water ham­mer, mechan­i­cal stress and tem­per­a­ture changes.

When heat­ed, the ther­mal expan­sion of the met­al is neg­li­gi­ble, so the like­li­hood of leak­age at the junc­tion of the pipes is min­i­mal. In the event of their freez­ing, pro­cess­ing with a blow­torch or oth­er source of open flame is allowed.

But there are many dis­ad­van­tages of steel prod­ucts. The first is sus­cep­ti­bil­i­ty to cor­ro­sion. Even gal­va­nized pipes will last no more than 25 years. In the first years of oper­a­tion, there are no com­plaints about them. How­ev­er, in the process of met­al oxi­da­tion and the appear­ance of rust growths, the pipes begin to become clogged. As a result, their through­put is sharply reduced. A sim­i­lar prob­lem is a real scourge of steel prod­ucts.

The ser­vice life of black steel prod­ucts is short

They are also quite com­pli­cat­ed in instal­la­tion — it is pos­si­ble to bend met­al only on spe­cial equip­ment when heat­ed. Anoth­er dis­ad­van­tage is high ther­mal con­duc­tiv­i­ty. For this rea­son, it is not rec­om­mend­ed to install met­al pipes when installing an elec­tric boil­er.

Steel pipes stand slight­ly high­er than sim­i­lar plas­tic prod­ucts. How­ev­er, when choos­ing them, the cost and instal­la­tion work should be tak­en into account. After all, met­al weld­ing requires con­sid­er­able skills and expen­sive equip­ment.

An ide­al option for installing heat­ing and heat­ing sys­tems would be stain­less steel pipes that can last almost for­ev­er. How­ev­er, their use is lim­it­ed due to the high price and com­plex­i­ty of instal­la­tion.

Rust deposits sig­nif­i­cant­ly reduce the per­me­abil­i­ty of the work­ing flu­id

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HDPE pipes and cross-linked polypropylene

The term HDPE is used for prod­ucts made from low den­si­ty poly­eth­yl­ene. Since this type of plas­tic does not tol­er­ate the effects of ele­vat­ed tem­per­a­tures (it is allowed to oper­ate only at + 40 ° C), cross-linked poly­eth­yl­ene (abbre­vi­a­tion PEX) is used for lay­ing heat­ing pipelines. To reduce the ther­mo­plas­tic­i­ty of the mate­r­i­al and give strength, its mol­e­cules are addi­tion­al­ly con­nect­ed into a three-dimen­sion­al net­work using cross-links. As a result, it eas­i­ly tol­er­ates ele­vat­ed tem­per­a­tures and is able to melt only when it exceeds 200 ° C.

In addi­tion to high tem­per­a­ture resis­tance, prod­ucts made of cross-linked poly­eth­yl­ene have the fol­low­ing advan­tages:

  • lack of cor­ro­sion, char­ac­ter­is­tic of any type of plas­tic;
  • increased strength and wear resis­tance: some man­u­fac­tur­ers pro­vide a guar­an­tee for this mate­r­i­al up to 50 years under oper­at­ing con­di­tions at 6 atm nom­i­nal pres­sure and tem­per­a­tures up to 70–90 ° C;
  • the abil­i­ty to with­stand tem­per­a­tures up to ‑50°C with­out loss of tight­ness; that is, such plas­tic pipes are not even afraid of freez­ing;
  • increased resis­tance to chem­i­cal com­pounds — such a mate­r­i­al is not able to come into con­tact with them;
  • elas­tic­i­ty: PEX pipes are quite flex­i­ble and ide­al for installing under­floor heat­ing, they can eas­i­ly fit into loops with­out creas­es;
  • envi­ron­men­tal friend­li­ness: poly­eth­yl­ene does not emit harm­ful sub­stances when heat­ed;
  • low price:
  • ease of instal­la­tion: for weld­ing poly­eth­yl­ene, the sim­plest equip­ment is used, the cost of which is min­i­mal.

Please note that the crosslink den­si­ty of mol­e­cules in poly­eth­yl­ene can be dif­fer­ent. Prod­ucts labeled PEX‑a are con­sid­ered the most expen­sive. How­ev­er, they have max­i­mum flex­i­bil­i­ty and are more suit­able for under­floor heat­ing. The crosslink­ing area of ​​PEX‑b mol­e­cules is small­er, and the price is not so high. At the same time, they are quite reli­able and per­fect­ly respond to pres­sure drops. But it’s hard to bend them. PEX‑c plas­tic is of low­er qual­i­ty. It is quite flex­i­ble, but is able to form creas­es.

Cross-linked poly­eth­yl­ene is an ide­al mate­r­i­al for lay­ing under­floor heat­ing

Copper

Of course, the best pipes for heat­ing sys­tems are cop­per. Their main dis­ad­van­tage is their con­sid­er­able cost. Oth­er­wise, there are prac­ti­cal­ly no com­plaints about this type of prod­uct. They pos­sess:

  • long ser­vice life: since such a mate­r­i­al is not afraid of cor­ro­sion, the ser­vice life of prod­ucts made from it can be 100 years or more;
  • increased ther­mal con­duc­tiv­i­ty;
  • high tight­ness of con­nec­tions;
  • the abil­i­ty to with­stand strong pres­sure drops, water ham­mer and tem­per­a­ture drops to ‑200 ° C, while its melt­ing point is + 1080 ° C;
  • almost com­plete absence of block­ages;
  • aes­thet­ic appear­ance.

Con­nect cop­per prod­ucts by cap­il­lary sol­der­ing, by means of com­pres­sion fit­tings or thread­ed con­nec­tion with rolling. Cop­per is also used to cre­ate the con­tours of under­floor heat­ing. How­ev­er, in this case, a spe­cial type of mate­r­i­al is used — annealed cop­per. It is heat­ed to a cer­tain tem­per­a­ture and then quick­ly cooled. As a result, the pipes acquire greater elas­tic­i­ty and flex­i­bil­i­ty. Such pro­cess­ing can slight­ly reduce the strength of the mate­r­i­al, but it is quite enough to cre­ate an autonomous heat­ing sys­tem for under­floor heat­ing.

Since cop­per is an excel­lent con­duc­tor of cur­rent, when installing pipelines from it, manda­to­ry ground­ing and the instal­la­tion of dielec­tric gas­kets are required. Dan­ger­ous for this mate­r­i­al are also eddy cur­rents that can destroy the tight­ness of the sys­tem. Plus, rather soft cop­per can be eas­i­ly dam­aged, so when installing it in a boil­er room, you will need to pur­chase pro­tec­tive cov­ers.

Advice! The com­bi­na­tion of cop­per and steel in the same pipeline is high­ly unde­sir­able. Steel will begin to rust. If such a con­nec­tion can­not be avoid­ed, it is worth mount­ing steel pipes in front of cop­per pipes (in the direc­tion of move­ment of the work­ing flu­id). Brass reacts less to con­tact with cop­per, there­fore, in the absence of cop­per adapters, it is bet­ter to use not steel, but brass fit­tings.

Cop­per pipes are almost eter­nal, they are not afraid of either strong water ham­mer or cor­ro­sion.

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Polypropylene

Eco-friend­ly prod­ucts made from this type of plas­tic are used both for lay­ing drink­ing pipelines and pipelines for heat­ing sys­tems in pri­vate hous­es and apart­ments. We list the main advan­tages of this mate­r­i­al:

  • polypropy­lene has a fair­ly long ser­vice life (some man­u­fac­tur­ers pro­vide a guar­an­tee of up to 50 years), so it can be laid in walls or immured in con­crete floors;
  • high chem­i­cal resis­tance: this mate­r­i­al is not afraid of cor­ro­sion, so scale does not form in smooth pipelines;
  • suf­fi­cient mechan­i­cal strength;
  • the min­i­mum noise lev­el when pass­ing through the pipes of the work­ing flu­id (all met­al prod­ucts, unfor­tu­nate­ly, are deprived of this advan­tage);
  • strong mono­lith­ic con­nec­tions by weld­ing or fit­tings;
  • for its weld­ing, inex­pen­sive “sol­der­ing irons” are used, the work of which can be mas­tered in a short time.

Polypropy­lene costs more than ordi­nary poly­eth­yl­ene, but less than met­al-plas­tic. Anoth­er dis­ad­van­tage is the low tem­per­a­ture of the coolant — depend­ing on the type of mate­r­i­al, it can only be used at a tem­per­a­ture of + 65–95 ° C.

Pay atten­tion to the label­ing. If you do not know which of the pipes is bet­ter to choose, it is bet­ter to stop at PP‑R and PP-RCT copoly­mers, which have not only heat resis­tance (they can be oper­at­ed at tem­per­a­tures up to + 95 ° C), but frost resis­tance. They are absolute­ly not afraid of low tem­per­a­tures. Plas­tic, marked with the let­ters PP‑C, crys­tal­lizes when frozen and becomes too brit­tle. P‑N mate­r­i­al does not tol­er­ate ele­vat­ed tem­per­a­tures, so it is not suit­able for the instal­la­tion of heat­ing sys­tems. Prod­ucts marked PP‑B are used for sys­tems where the coolant is heat­ed only up to 50 ° C. PPRC mate­r­i­al with a rein­forc­ing lay­er is more resis­tant to ele­vat­ed tem­per­a­tures.

Polypropy­lene pipes

metal-plastic

If you do not know which pipes are best used for heat­ing, pur­chase met­al-plas­tic. It is con­sid­ered the best mate­r­i­al for these pur­pos­es in terms of price-qual­i­ty ratio. To give it rigid­i­ty, plas­tic is rein­forced with rein­force­ment — a lay­er of alu­minum, steel or fiber­glass. The inner pro­tec­tive lay­er is made of smooth mate­ri­als, PVC, polypropy­lene or cross-linked PEX, so lime and rust are not deposit­ed on it.

The lay­er of rein­force­ment in such pipes cre­ates a strong bar­ri­er to the pen­e­tra­tion of oxy­gen. Due to this, met­al ele­ments (con­nect­ing fit­tings, pump­ing equip­ment, etc.) are less sus­cep­ti­ble to cor­ro­sion. Plus, inserts made of alu­minum or steel sig­nif­i­cant­ly reduce the like­li­hood of ther­mal expan­sion and con­trac­tion of plas­tic dur­ing heat­ing or cool­ing. The most sta­ble are prod­ucts made of rein­forced polypropy­lene or cross-linked poly­eth­yl­ene.

The absence of cor­ro­sion and increased phys­i­cal and chem­i­cal resis­tance allows the mate­r­i­al to be used for at least 50 years. Met­al-plas­tic is sold in coils 50–500 m long. There­fore, its lay­ing can be car­ried out with a min­i­mum of con­nec­tions, fit­tings and rota­tion angle clamps.

Just like propy­lene pipes, met­al-plas­tics are con­nect­ed by weld­ing or by means of detach­able or con­di­tion­al­ly detach­able (com­pres­sion) joints. It bends eas­i­ly, so prod­ucts from it do not require spe­cial fit­ting. Such pipes can be con­nect­ed to prod­ucts from oth­er mate­ri­als using fit­tings.

Reduc­ing the ser­vice life is pos­si­ble only with large pres­sure surges in the sys­tem and long-term use when the tem­per­a­ture of the work­ing flu­id exceeds 100 ° C. When oper­at­ing in nor­mal mode, it can last up to 50 years.

The vul­ner­a­ble point of this type of prod­uct is the adhe­sive joint, which is used to bind the lay­ers of plas­tic and rein­force­ment. When the man­u­fac­tur­er uses low-qual­i­ty com­pounds, pipe delam­i­na­tion and leak­age are pos­si­ble.

Met­al-plas­tic con­sists of sev­er­al lay­ers at once

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