Chart 1. Joining casing pipes scheme - straight pipe sections

PUR foam - pianka PUR

Steel pipe - rura stalowa

Casing pipe - rura oslonowa

Pipe socket -kielich

Chart 2. Joining casing pipes scheme – bends

The technology that we offer in many respects surpasses pipe line insulation methods hitherto used (mineral wool, PUR coating halves with different types of protective casing).

Features which make solutions for renovation of district heating network proposed by our company optimal for you are listed below:

1. Owing to the use of polyurethane foam foamed by means of cyclopentane (Baytherm system VP.PU.27 HK04R) a very low heat conduction coefficient is obtained λ₅₀=0,0273 W/mK (as compared with CO₂ λ₅₀=0,031 W/mK), λ₄₀=0,026 W/mK

2. The foam used ensures considerable lowering of the amount of heat loss on the pipeline.

The amount of heat loss for the thickness of insulation as per PN-B 02421 standard  (July 2000) is shown in the charts below.

It is possible to adjust the thickness of insulation to meet individual customer requirements.

3. Using the potential of the preinsulated pipe production technology guarantees obtaining piping systems in which steel pipes, insulation foam and protective casings are tightly fitted. It ensures obtaining homogeneous insulation layer on the whole surface of the pipeline as well as complete filling of the spaces between casing pipes and steel pipes. Such solution prevents moisture instillation close to the steel pipe and air exchange through the spaces in the insulation layer. As a result the amount of heat loss is reduced to a minimum and the life of the insulation foam is being extended.

4. Insulation of bends (at any given angle) is carried out by means of direct injection of foam into prefabricated assembled casing bends on the building site. Special locks in the area of joining of two pipe sections guarantee leak tightness during foam application and during use.

5. Insulation prepared in this way does not absorb moisture.

6. Owing to the leak tightness of the insulation layer the pipeline is permanently protected against corrosion.

7. Owing to the close fitting of all elements, that is steel pipe, insulation and protective metal coating, all materials are effectively protected against theft. Moreover, it is possible to place special clasps on the inside of the casing pipe to additionally protect the metal casing from being dismantled. Hence, there is no possibility of uncontrolled devastation or stealing of the elements of the pipe system.

8. In the process of renovation already existing pipe propping systems (fixed and movable) are used. First, pipe segments situated between the propping are covered with specially designed and tightly fitted zinc plated metal casing. Then the same process is repeated with reference to the pipe propping elements and finally the resulting spaces between pipes/propping and metal casing are filled with polyurethane foam applied with the use of foam generator.

9. The insulation is uniform along the whole surface of the pipeline which effectively prevents the creation of thermal bridges, which in turn minimises the amount of heat loss (in case of PUR coating halves there are always free spaces in the area of joining of separate insulation segments). Uniformity of our insulation on the whole surface of the pipeline  (bends included) eliminates the problem of  butt joining of two coating halves existing in other technologies.

10. In the event of a district heating system failure, leak tightness of thermal insulation reduces the leak to a minimum and prevents the heat from spreading along the pipeline. Only a small part of polyurethane foam is dampened (the water leaks through riveted joints of the protective casing). To repair the damaged insulation it is only necessary to remove the dampened old insulation from the pipes, subsequently remove one zinc plated metal sheet (1,5 meter long) and finally cover the resulting space with new metal casing (joint) and fill the free space with insulating foam. The dismantled insulation cannot be used again.

11. Joints between the existing and new insulation are individually prepared to fit the type of old insulation. In places where the old and new insulation meet we insert protective casings, for instance leveling joints made of zinc plated metal sheet with shields providing protection against moisture.

12. To insulate the fittings we use insulation parts and zinc plated metal sheet shields, which can be assembled and dismantled repeatedly.

13. The procedure of direct foam injection to insulate the pipes can be performed on active pipelines.

14. For the first 10 years of use conservation of thermal insulation is not required.

15. Compensation of particular sections of insulation is made on the folds located at the ends of each protective casing. Insulation (PUR foam), like in the case of preinsulated pipes, shapes itself  plastically along with the steel service pipe which is being extended.

16. Our insulation meets the requirements of the PN-B-02421-2000 standard.

Compensation of extensions on the protective casing -mozliwość kompensowania wydłużeń na płaszczu osłonowym

PUR foam - pianka PUR

Steel pipe - rura stalowa

Casing pipe - rura osłonowa

folding (overlap) - zakładka

II. Description of materials

Protective casing – zinc plated metal sheet – in accordance with the following standards PN-89/H-92125, PN-EN 10142, DIN 24147, PN-EN 10111:2001, PN-EN-ISO8497:1997. Thickness of the metal sheet ranges from 0,7 to 1,21 mm depending on the pipe diameter. The metal sheet is plated with a layer of zinc 275 g/1 m² and is adapted to endure a temperature of up to 200 ^OC. The casing ensures high protection against mechanical damages and high resistance to weather conditions.

Rigid PUR foam insulation - Baytherm VP.PU.27 HK 04R. The foam’s structure is characterised by small porous closed cells. The following chemical substances are used for the production of the rigid PUR foam: polyisocyanates, chlorinated hydrocarbons and additional substances as per composition and prescription of the supplier of materials and foam ingredients. Insulation is made with the use of a special method of injection of foam components in the spaces between the service and casing pipes. Foam components are foamed with the use of pentane. Polyurethane PUR foam has a light brown/beige colour. Thermal conduction coefficient for the polyurethane foam amounts to λ₅₀=0,0273 W/mK (λ₄₀=0,026 W/mK) and is evidenced by tests conducted by ITB Warszawa, (tests number NF-0570/B/2003/LFK-17/2003). Adapted to work in temperature ranging from -20 to +150 ^OC.

III. Determining the thickness of insulation

Renovation of district heating networks should be preceded by determining the minimal required thickness of insulation. For heating factor not exceeding 150 ^OC, the minimal thickness of insulation layer adequate for particular steel pipe diameters depending on the localization of installation, temperatures of heating factor and coefficient l of insulation material are determined on the basis of standard PN-B-02421 (July 2000) charts. In our technology we use the coefficient amounting to λ₄₀=0,026 W/mK, for which minimal thickness of insulation is being established. On the basis of the aforementioned coefficient the type of casing pipe is selected. Chart IV presents values for thickness of insulation calculated in accordance with standard PN-B-02421 (July 2000).

The method of insulation of district heating networks described above can also be used to renovate pipelines situated in heating canals and inside buildings. Alternatively, protective casing made of UV resistant polyethylene can be used. Such casing does not require any additional conservation and allows for insulation of long straight segments of pipeline.

IV. Thickness of PUR foam insulation (calculated in accordance with PN-B-02421, July 2000)

For casing pipes made of zinc plated metal sheet – aboveground district heating network – minimal thickness of insulation [mm]

V. Heat losses

Thickness of insulation –as per chart IV, environment temperature* t=5,4 ^OC

(*average outdoor temperature in the city of Poznań in heating season 1999/2000)