Chemical Resistance Of Plastic Piping Materials
CHEMICAL RESISTANCE OFPLASTIC PIPING MATERIALSTR-192020
ForewordThis technical report was developed and published with the technical help andfinancial support of the members of the Plastics Pipe Institute (PPI). Thesemembers have shown their commitment to developing and improving qualityproducts by assisting standards development organizations in the developmentof standards, and also by developing design aids and reports to help engineers,code officials, specifying groups, contractors and users.The purpose of this technical report is to provide information on the transport ofvarious chemicals using plastic piping materials.PPI has prepared this technical report as a service to the industry. Theinformation in this report is offered in good faith and believed to be accurate atthe time of its preparation, but is offered “as is” without any express or impliedwarranty, including WARRANTIES OF MERCHANTABILITY AND FITNESS FORA PARTICULAR PURPOSE. Additional information may be needed in someareas, especially with regard to unusual or special applications. Consult themanufacturer or material supplier for more detailed information. A list of membermanufacturers is available on the PPI website. PPI does not endorse theproprietary products or processes of any manufacturer and assumes noresponsibility for compliance with applicable laws and regulations.PPI intends to revise this technical report within five years, or sooner if required,from the date of its publication, in response to comments and suggestions fromusers of the document. Please send suggestions of improvements to the addressbelow. Information on other publications can be obtained by contacting PPIdirectly or visiting our website.The Plastics Pipe Institute, Inc.https://www.plasticpipe.org/This Technical Report, TR-19, was first issued in 1973 and was updated in1983, 1991, 1999, 2000, 2007, and December 2020. 2020 The Plastics Pipe Institute, Inc.ii
Table of Contents1.0Introduction .12.0Chemical Resistance in General . 23.04.05.02.1.Pipe and Fitting Materials .22.2.Product Design and Joining Systems . 32.3.Operating Conditions - Internal and External . 3Types of Chemical Attack On Plastics . 33.1.Permeation, Swelling, Plasticization, Solvation, and Extraction . 33.2.Direct Chemical Attack .43.3.Environmental Stress Cracking . 5Other Considerations .54.1.Chemical Families .54.2.Accelerating Factors (Concentration, Temperature, Stress) . 64.3.Combinations of Chemicals .64.4.Multi-Layered (Composite) Piping . 74.5.Rate of Chemical Attack .7Chemical Resistance Data for Plastic Piping in Non-Pressure Applications andData Table .7List of TablesTable 1: Plastic Materials Identification. 2Table 2: Resistance Codes .8Table 3: List of Chemical Resistances ( F) . 10iii
CHEMICAL RESISTANCE OF PLASTIC PIPING MATERIALS1.0INTRODUCTIONThis technical report has been developed as an informative guide on theresistance of plastic piping and fitting materials to chemical attack.It is divided into several sections: Section 2.0: Chemical resistance in general, and considerations for enduse applicationsSection 3.0: Types of chemical attack on plasticsSection 4.0: Other considerationsSection 5.0: Chemical Resistance Data for Plastic Piping in NonPressure Applications and Data TableListings of chemical resistance data are presented in Table 3 for commonplastic piping materials applicable to non-pressure applications.Determination of suitability for specific applications under stress (e.g.pressurized service) is beyond the scope of this report. Users should contactthe specific pipe or fitting manufacturer for recommendations on pressurizedapplications.Note 1: Drinking water, also known as potable water, is water that is safe to drink or touse for food preparation. Across North America, the majority of the drinkingwater that is provided in public water systems is treated with a disinfectant tocontrol the growth of harmful microorganisms. Potable water disinfectantsinclude chlorine, chloramines, and rarely, chlorine dioxide. Piping materialsintended for treated water must be resistant to such disinfectants at variouslevels, as described in product standards.For specific information about the resistance of crosslinked polyethylene(PEX) to disinfectants, please see PPI Technical Note-53 Guide to ChlorineResistance Ratings of PEX Pipes and Tubing for Potable WaterApplications and PPI Statement A Relative Oxidative Aggressiveness ofChloramines and Free Chlorine Disinfectants on CrosslinkedPolyethylene (PEX) Pipes used in Treated Potable Water.For specific information about the resistance of high-density polyethylene(HDPE) to disinfectants, please see PPI Technical Note-44 Long TermResistance of AWWA C906 Polyethylene (PE) Pipe to Potable WaterDisinfectants and PPI Technical Note-49 Recommendations for AWWAC901 Service Tubes in Potable Water Applications.1
For specific information about the resistance of chlorinated polyvinyl chloride(CPVC) to disinfectants, please see Section 4: Effects of Potable WaterDisinfectants on CPVC of PPI Technical Note-62 Suitability and Fitness ofCPVC Piping Systems for Commercial Building Applications.2.0CHEMICAL RESISTANCE IN GENERALPlastic pipe and fitting materials are generally resistant to attack from manychemicals. This inherent property makes them suitable for use in numerousfluid and gas transport applications.However, there are certain chemicals that may damage plastic pipes, eitherthrough exposure on the outside of the pipe to chemicals, on the internalsurface of the pipe during the transport of such chemicals, or with exposure toinert fluids containing chemicals in various concentrations.Each material has unique resistance to chemicals in various situations. Thesuitability of a pipe or fitting system for use in a particular fluid or gasapplication is a function of several factors, described below:2.1.Pipe and Fitting MaterialsThe specific plastic material used in pipe and fittings impacts itschemical resistance. This report includes the materials listed inTable 1 Plastic Materials Identification.Table 1: Plastic Materials IdentificationABSCPVCPPPP-R 1PP-RCT 1acrylonitrile-butadiene-styrenechlorinated polyvinyl chloridepolypropylenepolypropylene random copolymerpolypropylene random copolymer with modified crystallinity andtemperature resistancePVCpolyvinyl chloridePEpolyethylene (representative of medium density polyethylene [MDPE]and high density polyethylene [HDPE]; not representative of low densitypolyethylene [LDPE])PE-RT 2polyethylene of raised temperature resistancePBPolybutylenePVDFpolyvinylidene fluoridePEXcrosslinked polyethylenePA11/ PA12 polyamide 11 / polyamide 12PSUPolysulfonePPSUPolyphenylsulfone1PP-R and PP-RCT are chemically similar to PP and are grouped together in Table 3; they maybe assumed to have similar chemical resistance2PE-RT is chemically similar to MDPE and HDPE and are grouped together in Table 3; they maybe assumed to have similar chemical resistance2
2.2.Product Design and Joining SystemsPiping dimensions, including wall thickness, construction, andcomposition (layers, fillers, etc.), can affect chemical resistance.The type of joining system can also affect the performance of thesystem in chemical handling applications. Heat fusion and solventcementing do not introduce different materials into the system. Theresistance of solvent cement to certain chemicals can vary fromgrade to grade.Other components and appurtenances in the piping system canhave different chemical resistances. Certain types of mechanicaljoints include gaskets using elastomers with their own uniqueresistances. Some piping systems include other plastic or nonplastic materials used as mechanical fitting components which canhave different chemical resistance.2.3.Operating Conditions - Internal and Externalo Chemicals or mixtures of chemicals, and their concentrations.o Operating temperature — maximum, minimum, and cyclicalvariations.o Operating pressure or applied stress — maximum, minimum andcyclical variations.3.0TYPES OF CHEMICAL ATTACK ON PLASTICSIn general, chemicals that affect plastics do so in several ways, includingsolvation, chemical attack, and environmental stress cracking.3.1.Permeation, Swelling, Plasticization, Solvation, and ExtractionPermeation is the transport of chemicals through the pipe wall viadiffusion through the free volume of the polymer matrix withoutsignificant change in the material properties. Permeability may be ofinterest in situations where the pipe is to function as a liner pipe for aless resistant material (e.g., fiberglass or steel), where the pipe istransporting particularly hazardous substances, or where the pipe isinstalled in contaminated soil.Permeability of specific plastic piping materials is not addressed inthis document. PPI Statement N Barrier Properties of PlasticPipe Used for Potable Water Service, states “In areas of known orsuspected contamination, the design of the distribution systemshould be based on a careful analysis of the situation.3
Appropriate technical data and individual manufacturers’recommendations should be consulted on the overall design of apipe system for these systems.”Note 2: See also PPI Comments on Permeation of Water Pipes and on the AWWARF Report on Hydrocarbons at hydrocarbons.pdfAbsorption occurs when a chemical diffuses into the free volume ofthe polymer matrix and accumulates there. This may result in one ormore of the following effects: swelling, plasticization, or solvation. Inthe case of absorption, physical properties may be affected, but thepolymer molecule itself is not chemically changed, degraded ordestroyed.Swelling is an increase in the bulk volume of a material caused bythe absorption of liquids or vapors from the environment. It may ormay not be accompanied by plasticization, which results in softeningand loss of strength in the material.In extreme cases, the solvating compound can fully dissolve theplastic material.Sometimes the polymer itself may not be soluble, but it may containa soluble formulary ingredient that may be extracted from thepolymer compound. This is more common in plasticized materialswhere loss of plasticizer may result in embrittlement. It is notcommon in plastic materials used for pipes and fittings and is notaddressed in this document.In gas or vapor transmission service, there may be a very slight lossof contents through the pipe wall.Lastly, a solvating or permeating chemical entrained in the materialmay be released when heat fusion or solvent cement joining isperformed. Thus, heat fusion (e.g. welding) or solvent cementjoining may be unreliable if performed on permeated pipes. Cautionshould be used in performing these processes if solvation orpermeation are suspected.3.2.Direct Chemical AttackDirect chemical attack occurs when exposure to a chemical causesa chemical alteration of the polymer molecules by chain scission,crosslinking, oxidation, or substitution reactions.4
Direct chemical attack frequently causes a severe reduction ofmechanical physical properties such as tensile strength, ductility,burst pressure, and impact resistance.Chemical resistance may vary greatly from one plastic material toanother (i.e., PVC, ABS, PE, etc.), and also among different cellclassifications of the same plastic type (e.g. PVC 1120 to PVC 2110,PE 3608 to PE 4710, etc.). There may also be slight variationsamong commercial products having the same cell classification,based on compound ingredients known as stabilizers or “additivepackages”.The chemical resistance of plastic piping and fittings is basically afunction of the chemical resistance of the plastic material, includingadditives and other ingredients in the final compound. In general, thefewer filler ingredients used, the better the chemical resistance.Plastic pipes with significant filler percentages may be susceptible tochemical attack whereas an unfilled material may be affected to alesser degree or not at all.3.3.Environmental Stress CrackingEnvironmental stress cracking (ESC) is defined as the “developmentof cracks in a material that is subjected to stress or strain in thepresence of specific chemicals”, as per ASTM F412 StandardTerminology for Plastic Piping Systems.Environmental stress cracking is a fundamentally differentphenomenon than chemical attack, even though they may presentsimilarly (e.g. crazing or whitening of parts, sloughing of material,minor crack formation). ESC does not result in chemical alteration ofthe polymer molecule. ESC is caused by a chemical agent incombination with inherent and applied stresses. It can often beminimized with proper installation. Direct chemical attack does notrequire any stress or strain on the material in order to occur,although it may be accelerated in conditions of high stress or strain.4.0OTHER CONSIDERATIONS4.1.Chemical FamiliesWhile the effect of each individual chemical is specific, somechemicals can be grouped into general categories based onsimilarities in chemical characteristics (acids, bases, alcohols, etc.).For example, water-based (aqueous) solutions of neutral inorganicsalts generally have the same effect on plastic piping materials aswater alone; thus, sodium chloride, potassium alum, calcium5
chloride, copper sulfate, potassium sulfate and zinc chloridesolutions have the same effect as water.However, at elevated temperatures or high concentrations, somesalt solutions may attack some plastic materials through eitheroxidation or chemical substitution when they would be benign atlower temperatures and concentrations.4.2.Accelerating factors (concentration, temperature, stress)Generally, the resistance of a particular plastic to a specific chemicalwill decrease with an increase in concentration. For example, forsome materials, dilute sulfuric acid may be acceptable, whereas95% sulfuric acid may not.The resistance of a particular plastic to a specific chemical generallydecreases as temperature increases because the rate of chemicalphenomenon (i.e. reactivity, permeation rate, solvation) tends toincrease. This rate increase is logarithmic with respect totemperature over most plastic functional temperatures and generallyfollows to the Arrhenius equation.The chemical resistance of a particular plastic generally decreaseswith increasing applied stress. This is commonly seen when thepresence of certain chemicals causes environmental stress crackingwhere unstressed parts exhibit good chemical resistance.The chemical resistance of a particular plastic generally decreaseswhere temperature or applied stress are varied or cycled. Theseeffects can be greater overall in combination. Testing should beconducted if the system is expected to perform across a wide rangeof temperatures and stresses to determine the overall combinedeffect.4.3.Combinations of ChemicalsIn some cases, combinations of chemicals may have a synergisticeffect on damaging a plastic material, and a mixture may causedamage where the individual chemicals do not. It cannot beassumed that an individual chemical’s lack of effect would apply forcombinations that include several chemicals. When the possiblecombined effect of several chemicals is unknown, the materialshould be tested in the complete chemical mixture(s) in question.6
4.4.Multi-Layered (Composite) PipingSome piping products utilize a multi-layered (composite)construction, in which the pipe wall is constructed of layers ofdifferent materials. The layers may consist of both plastic and nonplastic.For example, PE/AL/PE and PEX/AL/PEX pipes contain mid-wallaluminum layers. Examples of all-plastic composite pipes includePVC/ABS/PVC and fiber-core PP-R or PP-RCT pipes. Layeredcomposite material pipes may have chemical resistance that differsfrom the chemical resistance of the individual materials.4.5.Rate of Chemical AttackChemicals that attack plastics do so at a certain rate, some slowlyand some more quickly. But usually, any chemical attack isincreased when temperature or stress are increased, or whentemperature or stress are varied. The particular rate of chemicalattack must be taken into consideration in the life-cycle evaluationfor a particular application. Each combination of material cost,installation cost and service life must be evaluated and judged on itsown merits.In certain cases involving a slow rate of chemical attack, particularlywhen the application will be pressurized, simple immersion data, likethat represented in Table 3, may not adequately characterizeperformance throughout the intended design life. Longer-termtesting to replicate service conditions is advisable to fully measurethe effects of these chemicals.5.0CHEMICAL RESISTANCE DATA FOR PLASTIC PIPING IN NONPRESSURE APPLICATIONS and DATA TABLEWhen plastic pipes come into contact with chemical agents it is important toknow how the pipe may be affected. For non-pressure applications, where thepipe is not subject to continuous internal pressure or stress, chemicalimmersion test data may provide suitable information. The pipe manufacturermay have additional data from similar tests, or information on previousinstallations under similar field conditions.7
The following cautions apply to Table 3 List of Chemical Resistances: Data Sources. The information in Table 3 has been obtained fromnumerous sources. The data are based primarily on plastic material testspecimens that have been immersed in the chemical and evaluated,and to a lesser degree, on field-experience. In most cases, detailedinformation on the test conditions (e.g. exposure time), and on testresults (e.g. change in weight, change in volume, and change instrength) was not available. Therefore, this information is best used onlyfor comparison of different plastic materials.Combinations of Chemicals. Chemicals that individually do not have aneffect may affect the pipe if combined with certain other chemicals. Thelist of possible combinations of chemicals is endless. Table 3 does notaddress chemical combinations.Composite Piping. Layered composite piping may have chemicalresistance that differs from that of the individual materials in the layers.Table 3 is not applicable to layered composite piping products.Applicability to fiberglass and filled materials. Table 3 is not applicableto reinforced epoxy resin (fiberglass) pipes, and to plastic pipescontaining significant percentages of filler materials.Concentrations. Where no concentrations are given (indicated as ‘P’),the commercially pure material is indicated, except in the case of solidswhere saturated aque
The chemical resistance of plastic piping and fittings is basically a function of the chemical resistance of the plastic material, including additives and other ingredients in the final compound. In general, the fewer filler ingredients used, the better the chemical resistance. Plastic pipes with significant filler percentages may be susceptible to
piping classes and the numerous piping specifications necessary to fabricate, test, insulate, and paint the piping systems, is titled either the piping material engineer or the piping spec(ification) writer. 1.2. Job Scope Whatever the title, the piping material engineer (PME) is a very important person within the Piping Design Group and .
liquid process piping systems, engineering calculations and requirements for all piping systems, basics of metal piping systems and thermoplastic piping systems. In Part 2 - the course will continue from Part 1 and review the basics of Rubber and Elastomer Piping Systems, Thermoset Piping Systems, Double Containment
Plastic bottles are responsible for 15% of total plastic consumption in Austria.13 According to the new BMK study, 300,000t of plastic - including 49,000t of plastic bottles - were put on the market in 2018. In total, 1.6 billion plastic bottles are placed on the market every year, which equals 181 plastic bottles per Austrian.14
A. ASME B31.1 - Power piping. B. ASME B31.2 - Fuel Gas Piping. C. ASME B31.3 - Process piping. D. ASME B31.4 - Pipeline Transportation system for liquid hydrocarbon & other liquid. E. ASME B31.5 - Refrigeration Piping. F. ASME B31.8 - Gas transmission & distribution piping system. G. ASME B31.9 - Buil
ASME B31.1, Power Piping ASME B31.3, Process Piping ASME B31.9, Building Services Piping AWWA Standards C200, C206, C900. 3.2.1 Piping Design Criteria Selection of inappropriate codes, standards, and requirements could add to the cost of design and construction. Thus, selection of piping standards such as ASME B31.1, B31
2.4 blast and fire strategy for piping 29 3 design of piping against explosions 35 3.1 introduction 35 3.2 interaction of piping with other design disciplines 35 3.3 loading components acting on piping due to explosions 42 3.4 types of piping and material properties 53 3.5 response of piping to blast loading 57 3.6 acceptance criteria 61
dependent on the plant design system being used to create the PCF. Most Piping Fabricators that can receive piping information in the form of PCF's will probably have the Spoolgen software from Hexagon (previously Intergraph). This software is derived from the Isogen piping isometric software that used to be the de-facto piping isometric .
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