What is the durability of the plumbing of a building? What is the best material for hydraulic lines?
Author:cleber
Who lives in an old apartment building knows how common are the apportionments to exchange extra pipe. Nothing more normal because the pipes have a life span which may be greater or smaller depending on the type of material and conditions of use. But how long? What materials to use? See this analysis of various types of materials, with its pros and cons.
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What is the durability of the plumbing of a building?[/caption]
The durability of pipes in use in buildings depends on a number of factors, whose estimation is difficult to be done accurately. Among these factors are:
• Nature of material of pipe and fittings - PVC, PPT, copper, galvanized steel or cast iron,
• Type of joint - solder, with thread sealant, heat fusion, fusion adhesive solvent, elastic rubber ring,
• Exposure conditions - embedded in masonry, mortar underlayment within the slab, installation with and without apparent incidence of solar radiation, subjection to thermal shock, entry drives and accommodations structural, cyclical swings subjection to internal pressure,
• Chemical nature and temperature of the fluid transported by the pipeline - chlorinated drinking water, hot water, wastewater, stormwater and other.
The drinking water provided by the urban network in certain locations may have dissolved mineral salts that show aggressive to certain materials pipes, contributing to the reduction of life. This is the case for high concentrations of carbonates and bicarbonates of calcium and magnesium, and also occur when chlorides, oxygen and chlorine free, present in small concentrations.
These components are shown aggressive over time, for example, carbon steel galvanized pipes. Two tubes of this material, of the same brand and same manufacturing batch, durability may have lead to different saline water with different natures, for example, 18 years of life in the mountain region of Rio de Janeiro and only 8 years in Curitiba and metropolitan area.
However, there is galvanized carbon steel pipes whose use in Curitiba is already 25 years old and still perform well. This was the case of Residential Condominium Iguacu, object of a technical report of my own, Eng Sergio Frederick Gnipper whose pipes of cold water, originally galvanized steel, were in satisfactory use for almost 40 years and only recently have shown obsolescence, requiring complete replacement.
The explanation for this particular case is in good quality and thickness of the protective layer of zinc applied hot (so-called galvanic) in these pipes, and the natural formation of an outer layer of protective and insulating zinc oxide, whitish appearance, which isolated the external surfaces of the pipe from direct contact with the masonry mortar or plaster of aggressive chemical nature.
One factor that dramatically accelerates the degradation of carbon steel pipes and galvanized malleable iron galvanized connections is called 'galvanic couple' or 'galvanic cell'. When these materials are placed in direct contact with another metal tube of very diverse in nature electrochemical presence of water (such as copper, for example), there arises a weak electric current of low voltage in the region of contact of dissimilar metals, as occurs with a cell or battery electric. This process causes chemical reactions of degradation of less noble metal, causing premature corrosion and accelerated the galvanized pipe.
When possible, a resource to prevent galvanic corrosion in metallic tubes is bringing an insulating layer of nonconductive material between different metals. This is the case of a strip of flexible rubber placed on the support of a copper tube support in galvanized carbon steel.
Due to the extreme variability of materials and exposure conditions, it is also difficult to assess the economic period of useful life of the pipes of a building, the words, the maximum time recommended for use in staying in the building. This is because, from a certain age at operation, uncomfortable with spending leaks and repairs off a pass pipe be significant, offsetting being replaced by a new one. Under conditions very favorable exposure over the lifetime is estimated as follows economic periods for different pipe materials:
• About 20 to 25 years for PVC pipes (reaching up to 45 years);
• About 12 to 18 years for galvanized steel pipe with fittings of malleable iron galvanized (but currently only about 8 to 10 years in certain locations);
• Over 80 years for copper pipes with copper connections / bronze when exposed to water not aggressive.
Pipes with materials more recent production technology, such as CPVC (chlorinated polyvinyl chloride), crosslinked polyethylene (PEX) and random polypropylene (RPP) have not yet reached age sufficient for use in the economic evaluation of the shelf life, per hour for them estimating durability similar to that of PVC.
In old buildings can be exchanged with all the advantages plumbing?Generally widespread replacement of pipes of a building is more difficult passages embedded in masonry and within channels and recesses of floors in buildings equipped with recessed slabs, construction technology peculiar constructions performed until the mid 70s.
That's because this substitution, in most cases, involves breaking tiles, ceramic floor tiles and hydraulic, whose replacement is very difficult to do satisfactorily, given the scarcity of identical parts in so-called 'tiles museums.' Moreover, the cost of implementation is high and therefore generally run embedded in walls and floors of bathrooms, kitchens and laundries.
There are more favorable situations, where much of the horizontal lodges inside false ceilings of gypsum, which is easy access for replacement and repair is fast and inexpensive. Another favorable situation is one in which vertical tubes run inside ducts appropriate, technically known as shafts, simply remove the lid to have full access to the pipeline.
You can not just replace the pipe obsolete, damaged or corroded by another of the same or different material, considered more durable. It is crucial to understand the causes of degradation and especially whether the new replacement pipe material have adequate durability under local conditions. This one only accredited professional and expert can determine, from the elaboration of a specific technical advice or a full technical report.
You must also comply with the technical characteristics of the installation and peculiar to each type of piping material such as maximum hydraulic pressure that will be placed and the hydraulic resistance of each material to the liquid flow.
For example, to replace an old galvanized steel pipe with a new copper, it is possible that many passages can run with diameters smaller than the original pipe, with equivalent performance, and sensible economy. This is because the plastic tubes and copper pipes offer less resistance to flow than the steel pipes.
For this it is necessary to elaborate a simplified design reform of hydraulic building because it involves calculations technical expertise that only a trained professional is able to do, with legal guarantee its liability CREA, according to current legislation, through issuing an ART - Technical Responsibility.
Therefore, the decision of replacing a hydraulic pipe obsolete should be taken only with the advice of a professional. This is because other factors must be evaluated at this time in favor of the building, as the possibility of changing the system discharge toilets.
Replacing the old flush valves for sanitary bowls with dump boxes embedded or coupled, which require tubes with diameters much smaller than the existing one can obtain economy running of pipes and further reduction in the monthly consumption of water in building up to 40 which will help amortize the costs over time.
Also in this opportunity should be evaluated technical and economic feasibility of installing individual meters of potable water consumption for the apartments (individual water meters), for the assessment of internal monthly expenses of the condominium with water in proportion to consumption effectively checked each unit condominium.
What kind of material should be used for the replacement pipe of the building?The building does not require the same type of material for all hydraulic and sanitary. The choice, in addition to life expectancy, must take into account the purpose of the pipe, the nature, pressure and temperature of the liquid drained (hot water, sewer, ...), the best type of joint (thread, solder ring rubber, ...) and exposure conditions (apparent pipe, embedded, ....), among other factors.
The metal tubes historically were first produced on an industrial scale and, therefore, have performance well known. There are more employees in the building installations carbon steel pipe with threaded connections of malleable cast iron, both usually hot dip galvanized (galvanized), and copper pipes soldered connections with copper and / or threaded bronze / brass. Were recently introduced in the market semi-flexible tubes of aluminum coated internally and externally consists of a plastic layer.
The metal tubes generally have the following advantages:
• High resistance to internal pressure;
• Low thermal expansion feature;
• Dimensional stability;
• High heat resistance;
• High mechanical strength;
• Highly resistant to the effects of mechanical and thermal fatigue;
• Resistant to prolonged exposure to ultraviolet radiation and the ravages of time;
• Eliminate low smoke and toxic gases when under combustion;
• Increased reliability performance information under prolonged use;
• Are non-combustible at temperatures typically reached in fires in buildings.
However, metal tubes have the following disadvantages or inconveniences:
• High thermal conductivity;
• Greater weight comparison;
• Less easy handling,
• Greater difficulty implementing threaded or welded joints;
• Increased hydraulic resistance to flow;
• Low flexibility and elasticity;
• Less safe in the joints;
• High acoustic transmission (noise);
• Higher relative cost of acquisition;
• susceptibility to corrosion;
• Easier to accumulation of corrosion deposits, suspensions and precipitation;
• Possible contamination of water by corrosion debris and lead present in welds;
• Greater ease of transmission of the effects of water hammer.
The metal tubes are especially suitable for use in functions which are subjected to high pressures, such as the network pipe of fire hydrants and discharge piping, leading drinking water from the hydraulic pump to the reservoir tank of the high building. They are also used in high buildings to take drinking water from the reservoir to the high pressure reducing valves.
Copper pipes are especially suited for driving in hot water because of its chemical stability and dimensional. Galvanized pipe and fittings are very susceptible to corrosion when the water temperature inside exceeds 50 ° C. Already have brown PVC pipes sharp drop in pressure resistance and lead to huge thermal expansion hot water, and in consequence contraindicated in these cases.
Copper tubes also have an advantage over steel pipes in the building networks for distribution of fuel gas, since the welded joints permit higher sealing while avoiding the hazardous spills, and are not subject to chemical attack constituent material of mortar in the presence of moisture, where embedded in slabs of subfloors. This gives very high copper tube life, despite its cost is nearly twice the cost of steel and up to four times the cost of plastic tubes.
Moreover, the plastic pipes comprise a variety of components manufactured from synthetic organic polymers, obtained mainly from petrochemical derivatives.
The most commonly used plastic materials are PVC (or polyvinyl chloride), the PPR (polypropylene or random), CPVC (chlorinated polyvinyl chloride or) and PEX (cross linked polyethylene or crosslinked). Plastic tubes generally have the following advantages:
• High resistance to corrosion or oxidation;
• Good durability when sheltered from the ravages of time;
• Low thermal and electrical conductivity;
• Low weight comparison;
• Ease of handling;
• Fast and easy implementation of the joints (joints require hot termofusor);
• Low flow resistance;
• Little accumulation of debris;
• Good flexibility and elasticity;
• Increased security in the performance of gaskets (exempt employment torch);
• Low acoustic transmission;
• Low relative cost of acquisition.
However, plastic tubes also have the following disadvantages or inconveniences:
• Low resistance to heat;
• Low mechanical strength;
• Low resistance to the effects of mechanical and thermal fatigue;
• degradation due to prolonged exposure to ultraviolet radiation;
• High thermal expansion unit;
• Elimination of smoke and toxic gases when under combustion;
• Poor performance information under prolonged use (not more than 40 years of use in the domestic market).
PVC pipes have been widely used in building distribution networks for drinking water, and building facilities for sewage and rainwater collection. In contrast, CPVC pipe and PPR are specially designed for conducting hot water.
Dedetizadora e Desentupidora Ribeira
http://www.ddribeira.com.brArticle Source:
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http://www.ddribeira.com.br
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