1. Evacuation
2. Description of an evacuation system
3. Aspects to take into account when carrying out an installation
4. Calculation of sanitary pipes’ diameter
5. Dilatations during the installation
6. Internal quality control of the manufacturer according to the UNE-EN 1329-1 regulation
7. Recommendations for transport, storage and placement on site of PVC accessories
8. Conditions to be accomplished by the evacuation internal network
9. Preventive maintenance recommendations for a evacuation network

Using PVC as a material for a fluid piping installation carries out implicit economic, safety and versatility advantages regarding a lacking in maintenance.

We avoid calcareous incrustations in piping, so that we maintain the section where the fluid runs constantly and we decrease the risk of obstruction.

Moreover, this material’s accessories have a very smooth inner surface, what decreases significantly the loss of energy charge and consumption of the tapering facilities.

1. Evacuation

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EVACUATION accessories made by IBIDE FITTING PLASTIC S.L. are regulated by the UNE-EN 1329–1 regulation about CHANNELING SYSTEMS IN PLASTIC MATERIALS FOR SEWAGE EVACUATION (AT A LOW AND HIGH TEMPERATURE) INSIDE THE BUILDINGS’ STRUCTURE NON PLASTICIZIED (PVC-U) POLI(VINYL CHLORIDE).

This European regulation specifies the requirements for pipes and accessories in poli(vinyl-chloride) channeling systems, intended to be used inside the buildings as well as buried inside the buildings structures (marked with “BD”).

The test parameters to which this regulation is referred are also specified.

This range of accessories is designed to evacuate any kind of waste and rain water in buildings, except water coming from facilities with long duration drains at a high temperature, for example, industrial laundries PVC-U accessories are not recommended.

2. Description of an evacuation system

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An evacuation net must be able to transport rain water coming from natural rains outside of a building without polluting as well as sewage coming from the use of sanitary devices (washing machines, showers, sinks, toilets, etc…)

For the evacuation of this water, net internal pipes can be designed in three different ways which lead to the three internal distribution systems.

Unitarian system

This system is designed for the common collection of waste and rain water in the same down pipes or sewer pipes.

Its simplicity and economy can be highlighted as advantages, but presenting as a disadvantage that its measuring must foresee atmospheric precipitations.

Due to this disadvantage, when these precipitations are not produced, sewer pipes are over measured so the risk of producing deposits and sediments increases.

The danger of syphonage also increases when precipitations are significant and down pipes substantially increase their flow, since there can appear hydraulic cylinders that need a more energetic ventilation. This system is not recommended for buildings with more than 6 floors.

Separative system

In this system, the evacuation is made through two independent channeling, so diversions, down pipes and sewer pipes are different for waste water and rain water.

This system requires a double net in most of the street as well as double connection in every land.

From the technical point of view, this system is the most appropriate. Nevertheless it is not used too much because of its expensive cost and, a lot of times, due to the fact that separative sewage systems do not exist.

Mixed system

It is the most used system in which derivations and down pipes are independent for waste and rain water. Both nets are unified in common sewer pipes gathering them together in one channeling.

This system is the simplest one regarding installation, since just one sewage channeling is needed in every street and just one connection in every land.

It is an intermediate solution between the unitarian and separative system that partially reduces the disadvantages of every pure system.

We can take into account the following classification for accessories and pipes in a sanitary installation:

3. Aspects to take into account when carrying out an installation

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Ventilation of the installation

Ventilation is a key factor for the proper functioning of the evacuation net. If it is not enough, there causes the communication between the pipes inner air and the local sanitary air, therefore this air is polluted.

The cause of this effect is the formation of hydraulic cylinders due to the accumulation of discharges.
This phenomenon consists of the appearance of a hydraulic piston that compresses the air of the lower part of the installation, generating an overpressure.

At the same time, on the top of the installation there will appear a depression which creates a suction effect in the installation. The smaller diameter of the downpipe is and the biggest flow wastes that it collects; the hydraulic cylinders’ formation is intensified.

As a suction consequence, traps get empty, so they break the hydraulic closing letting bad smells go through.

This effect is intensified when it rains, since the risk of hydraulic cylinders’ formation is greater, as the normal discharge flows are added to the rain flows.

Bad smells can also be perceived during summer, through terraces and courtyard drains, due to the lack of hydraulic closing of the traps because of the water evaporation, thus, in this case, it is convenient to frequently fill them with water.

The ventilation net needs lower pipes diameters than the ones used in the evacuation net. A relationship of approximately 3/5 can be established. The material used can be the same as the one used in the small evacuation net.

4. Calculation of sanitary pipes’ diameter

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In order to choose the diameter of the splits from which the installation is formed, we must carry out the necessary calculations in order to find the balance between functionality and economy of our installation.

In the determination of sanitary pipes diameters, the usual hydraulic formulas cannot be used, since, if we tried to do it in a rigorous mathematical way, we would have an excessively complex hydropneumatic problem due to the fact that these pipes do not work with the complete section.

For all these reasons, a base unit called discharge unit has been fixed. It encompasses in its concept the flow and the simultaneity or frequency of use, so the diameters are stablished based on the experience of existing sanitary installations.

The discharge unit (DU) is defined as the quantity of water that a simple device as a private-use sink with a pipe exit of Ø30mm can evacuate and has a value of 0,47 L/s.

Therefore, it is equivalent to a sink capacity and it allows us to express according to this unit which we can look up in Table 1.

Likewise, we can also see the minimum diameter for the recommended drain of each device: Occasionally, this diameter is oversized in order to prevent blockages due to solid objects’ falls.

As discharges can vary according to the use of the installation, two kinds of installations are stablished based on its use:

• Private use: home installations
• Public use: Installations where there is no limit of persons, nor uses times.

Each pipe of the installation must have a diameter whose drainage capacity in discharge units is equal or higher than the total of devices that flow into.

In the Table 2 we can see the drainage capacity of the tubes according to its nominal diameter:

If there is a joint, the pipe exit must have, at least, as drainage capacity as the total amount of discharge units coming from the entry pipes.

The down pipes’ diameter to be used is obtained by taking the highest value of the ones obtained, taking into account the maximum quantity of DU in the downpipe and the maximum quantity of DU in each pipe based on the number of floors.

The Table 3 indicates the necessary diameter for the downpipes according to the exposed conditions:

Horizontal sewer pipes of waste waterare measured in order to work midsection up to a maximum ¾ section, under uniform flow conditions. The sewer pipe diameter based on the maximum number of DU and the gradient can be extracted from Table 4.

5. Dilatations during the installation

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PVC suffers changes in its physic properties as it is exposed to temperature changes. When temperature increases, it reduces its viscosity, thus its length increases. The lineal expansion coefficient of this material goes from 0,07 to 0,08 mm/m ºC, this means that when temperature increases 1ºC, a 1m pipe will measure 1,00007m. This value does not represent significant changes on the size, but when there are longer sections as well as higher temperature variations, these changes start to be relevant, so we need to take precautions.

On one hand, we can use unions with an elastic joint as the ones used in the sliding coupling with an expansion joint, which can absorb length changes. They must be installed, at least:

1. In downpipes that cross concrete slabs, one on the accessory that collects water in every floor.
2. In downpipes with fixed points, one on each fixed point.
3. In downpipes without fixed points, at least, one every 4 meters.
4. In horizontal assemblies, at least, one every 4 meters.

We can also make normal changes in the pipes direction, which provide us an appropriate means to compensate the expansion if the temperature variation is too big.

The situation of a fixed point FP can be calculated through the minimal length of the bending side L_MIN.

6. Internal quality control of the manufacturer according to the UNE-EN 1329-1 regulation

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The accessories made by IBIDE FITTING PLASTIC S.L. are subjected to a quality control during the manufacturing process and once the final product is finished, in which the controlled characteristics are monitored with some tests and at a frequency established in the next chart:

A. Visual analysis

In the visual test, as the test is carried out without increases, inner and outer surfaces of the accessories must be smooth, clean and without grates, ampoules, impurities, holes and any other surface imperfection that may prevent accessories from satisfying the regulation.

 

B. Dimensional analysis

In the dimensional analysis, average diameters, densities and lengths are measured, so they must be in accordance with the tolerances given by the following table:

C. Heat behavior

This test is carried out according to the UNE-EN 763 PLASTICS PIPING AND DUCTING SYSTEMS. INJECTION-MOULDED THERMOPLASTICS FITTINGS. TEST METHOD FOR VISUALLY ASSESSING EFFECTS OF HEATING.

It consists of suppressing complete molding to a certain temperature T, in a ventilated heater during a given time, depending on the wall density. Molding surfaces are tested before and after the heating, and all welding fissures, bubbles, laminations and holes are measured and expressed in percentages of wall density. The percentages obtained must be in accordance with the requirements specified in that regulation.

 

D. Vicat temperature determination

This test is carried out according to the regulation UNE-EN 727 PLASTICS PIPING AND DUCTING SYSTEMS – THERMOPLASTICS PIPES AND FITTINGS – DETERMINATION OF VICAT SOFTENING TEMPERATURE (VST).

The principle of the method consists of defining the temperature at which a normalized penetrator of a 1mm2 calibrated surface, subject to a 50 N charge, enters 1mm in a cut test tube surface of the wall of a tube or an accessory, when the temperature increases at a constant speed of 50 C/h. The temperature in centigrade degrees, when the penetration is 1 mm, is called Vicat softening temperature (VST).

7. Recommendations for transport, storage and placement on site of PVC accessories

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It is recommended, when carrying out any operation of load/unload, transport and storage of PVC accessories or tubes, to have the appropriate means and the necessary precautions in order to avoid to harm the product with the consequent quality loss.

7.1. Recommendations for transport

Accessories are supplied in their original packing, which is the best preservation place until they are used, whereas tubes are normally supplied in pallest by the manufacturer.

Load and unload operations in the vehicles for its transportation must be done without dragging, shaking or hitting the load and carrying out this operation in an ordered way.

Caution measures to be taken when transporting this product can be sum up in four points:

• Vehicles designated for this goal must be conditioned in such a way that they have a horizontal flat area without any element which may damage or hit the load.
• The placement of the load in the transportation vehicle must be carried out placing it orderly on the area aimed to it, without using any fixation elements such as cables or chains which may damage the product. The use of elastic tapes is recommended as long as the excessive crush that may deform the load is avoided.

• Unload operations must be orderly carried out, avoiding hitting or dragging the goods.
• During the transportation of the goods, placing heavy loads on them must be avoided, so that deformations do not occur. Such godos must not stand out the lorry’s platform.

7.2. Storage recommendations on site placements

• Goods shifting must be avoided at the minimum, so it must be stored the nearest as possible to the working place. The area designated to store the product must be flat and leveled in order to avoid deformations that may be permanent as well as it must be well ventilated. We cannot locate it near solvents, adhesives, fuels, paints or cutting objects that may degrade the product.
• Due to PVC fragility at low temperatures, tubes and accessories must be prevented from hits with any type of object if we are under these conditions. Moreover tubes and accessories made with this material must be protected from direct solar radiation, especially in summer. Storage near heat sources must be also avoided, preventing the temperature of the external surface of the pipe or accessories to reach 45ºC.
• Tubes must be stored by stacking them alternating the cups and letting them standing above, so that they are supported on all their length.
• It is recommended, when carrying out any operation of load/unload, transport and storage of PVC accessories or tubes, to have the appropriate means and the necessary precautions in order to avoid to harm the product with the consequent quality loss.

8. Conditions to be accomplished by the evacuation internal network

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If our evacuation net has successfully been installed by following the given recommendations, a good working quality will be guaranteed thanks to the accomplishment of the following conditions:

We will quickly achieve the evacuation of water used in different services and especially the evacuation of water proceeding from toilets.

The access of polluted air proceeding from the evacuation net in inhabited premises is avoided by means of the hydraulic closing made by traps, which will maintain at least 5 cm of water thanks to the installed ventilation system.

A total water tightness of the net will be maintained in every point, so an elastic hermetic seal in gaskets and joints, which will admit net movements without losing its impenetrability, as well as movements generated by system expansions, which will be avoided by making normal changes of pipes direction.

Thus, we will block internal retained waste that may block the piping because of the smooth inner walls offered by the PVC.

An accurate fastening of all net accessories will be achieved by avoiding possiblelandslides and vibrations which produce annoying noises due to the discharges impact.

Therefore, all materials integrating the net evacuation will have such a quality that will enhance low maintenance expenses as well as a similar duration to the one calculated for the rest of the building.

9. Preventive maintenance recommendations for a evacuation network

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IBIDE recommends a preventive maintenance of the net evacuation in order to avoid possiblewaste water or gas leaks that may endanger the building’s and its occupants’ healthiness. This maintenance and its periodicity can be sum up in this Table.