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Frequently Asked Questions

1. What is PVC-U and PVC-C?

2. Are cold water PVC-U and hot water PVC-C installations reliable and tested?

3. What is the advantage of NIBCO plastic installation systems over other systems?

4. Do cement joints present any health risk? Is it true that Legionella pneumophila bacteria breed in them?

5. Why do NIBCO installations require so many support points?

6. Is it easy to make a mistake during assembly of PVC-U/PVC-C installations?

7. What are the most common mistakes made during assembly of PVC-U/PVC-C installations?



1. What is PVC-U and PVC-C?


PVC-U (Polyvinyl Chloride) and PVC-C (Chlorinated Polyvinyl Chloride) are materials that have been used in sanitary installations for many years. PVC-U and PVC-C are successfully used both in small family houses and multi-story, multi-family buildings and in industrial installations.

2. Are cold water PVC and hot water PVC-C installations reliable and tested?

- PVC-U (Polyvinyl Chloride) as a material was known even before the Second World War and if works dependably in cold water installations as well as in installation for a variety of other substances.
- PVC-C (Chlorinated Polyvinyl Chloride) has been used in USA since 1968. In Poland, NIBCO systems are widely known since early 90s. We offer a limited 30-year warranty for PVC-C FlowGuardŽ pipes and fittings. Since its introduction on Polish market (and in other European countries), PVC/PVC-C installations boast minimum number of claims whose main source are assembly mistakes and deviation from manufacturer instructions and recommendations.

3. What is the advantage of NIBCO plastic installation over other installations?

PVC-U (Polyvinyl Chloride) has by far the best properties out of many other installation materials.
- thermal expansion a = 0,062 mm/m°K, which is nearly two times lower than for commonly used polypropylene.
- thermal conductivity I = 0,16 W/m°K. Very low thermal conductivity make makes it possible to substantially reduce thermal insulation or even eliminate it thereby reducing the cost of installation. PVC.s thermal coefficient is some 240 times lower than that of steel and about 2,400 times lower than that of copper.
- PVC installations do not corrode
- PVC-U / PVC-C installation does not sustain the burning process and extinguishes by itself after removing the fire source. The LOI - Limiting Oxygen Index for PVC amounts to 42, which means that the material requires of at least 42% oxygen to burn.
- PVC-U / PVC-C installations have are characterised by high mechanical strength that allows using thinner pipe walls. This advantage is exceptionally convenient when pipes are embedded in wall chases, which do not have to be deep. It is very important in buildings constructed from prefabricated elements.

4. Do cement joints present any health risk? Is it true that Legionella pneumophila bacteria breed in them?

Cements and plastic resin used for joining pipes in NIBCO installations are based on a mixture of fast-drying solvents. This is why the joining process (from the moment cement is applied to pipe and fitting until they are joined) cannot exceed one minute. Cement only facilitates the process of diffusion - mutual penetration of the walls of the pipe and fitting being connected - and then evaporates. A .bead. visible around the fitting on the pipe is the excess PVC / PVC-C and the pigment used to colour the cement. Cement acts in a very similar fashion as heat in heat.sealed joints.
Legionella pneumophila bacteria can breed on the inside walls of any installation especially in areas where flow in insufficient. The bacteria breed in temperatures ranging from 20°C to 55°C. Installations where cold water has temperature below 20°C and it is chlorinated are not at risk from breeding bacteria. In hot water installations it is recommended to periodically raise the temperature to 60°C-70°C. High temperature purges installation of the bacteria. Nonetheless periodical sanitary inspection evaluating the purity of transmitted water should be ordered.

5. Why do NIBCO installations require so many support points?

Each installation material is characterised by rigidity, which is different for steel and for plastic. PVC / PVC-C installations are divided into two groups: rigid and flexible. NIBCO installation fall into the first group, however raised temperature can make them more flexible. This feature must be taken into account during assembly. Correctly assembled, pipes operating in temperature 70°C require roller (sliding) supports distributed every 65cm. Distances between supports for vertical installations with the same operating parameters can greater by 20%.


6. Is it easy to make a mistake during assembly of PVC-U/PVC-C installations?

Ease of assembly of NIBCO installation sometimes causes the installer to lose his alertness. All installations system should be assembled in accordance with the manufacturer.s recommendations. All sales outlets have assembly instructions and an information leaflet INSTALLATION HANDBOOK containing a compendium of knowledge concerning the most common installation problems. Moreover, NIBCO Production Department provides assistance at +48 42 6775600. We also offer free training in place and time at customer.s convenience.

7. What are the most common mistakes made during assembly of PVC-U/PVC-C installations?

a. insufficient or no compensation for thermal expansion
Installations that are assembled outside walls or plaster almost never fail. In majority of cases room architecture requires frequent change of direction thereby providing self compensation. The only sensitive point is proper distribution of sliding supports, especially in the vicinity of elbows changing direction of the installation. Very important is determination of change of direction. Wrong placement of sliding support may cancel out natural self-compensation of thermal expansion. OC
Frequent assembly errors occur during assembly of installations in concrete walls in corrugated (.Peschel.) pipes or inside thermal insulation. Installers tend to forget to compensate for thermal expansion and shrinkage in pipes working within insulation. Even greater error is insulating the system before pouring concrete and leaving fittings without insulation. Such action inadvertently creates uncontrolled fixed points. There is a method of assembling installation without necessity to take thermal expansion into account. Installation in wall chases embedded in concrete or in concrete itself does not require any compensation, but it is necessary to provide for a sufficient concrete layer of 2.5 . 2.7cm for ½ and ¾ pipes. Protective insulation is required in places where pipe leaves the concrete. It protects the pipe against abrasion and the concrete against cracking.

b. wrong distribution of fixed points
Wrong distribution of fixed points occurs most often when installation branches off, for instance in horizontal passages from vertical shafts. No fixed point near a tee in vertical shaft may lead to displacement of installation branch, which is not always possible due to small holes in partitions and passages through walls.

c. installation overheating
Before flow heater is selected we must make sure that it is compatible with PVC-U / PVC-C installation. It is recommended to read the heater.s user manual wherein the manufacturer specifies how the device should be connected to the installation and what the temperature control system is. A defective or malfunctioning temperature regulating device, that is not capable of keeping the temperature at the required level, could allow the temperature to rise beyond the safety limits of the system. In doing so, it significantly and unnecessarily lowers the system.s durability and life. If water temperature reaches 100°C, steam may cause high pressure within installation and lead to leaks and cracks.

d. incorrect joints
Errors in joining the pipes and fittings are rare. They occur most often in large diameter pipe installations, above 2 inches. They are usually caused by exceeding the allowable joining time, by not pushing the pipe fully into the fitting socket, by improper chamfering of pipes and fittings, which causes scooping of cement, or by attempts to join without cement. Faults arising from improperly carried out joining process may cause leaks in properly supported pipelines.

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