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    Compressed air or gas – Warning! Plastic Piping Systems designed for corrosive and/or high purity liquid service are not recommended for Compressed Air or Gas applications. There are a few specially designed thermoplastics piping systems that are suitable for selected Compress Air or Gas applications. Consult your local Harrington Office for recommendations.  Certain substances called out on the following pages reference chemicals in a gaseous state. These substances are not recommended for pressure service. They are shown to provide the chemical resistance of piping materials when coming into contact with these substances. (i.e. exposure to or immersion in these substances).   Harrington Industrial Plastics LLC, does not recommend the use of plastic piping systems for the testing, transporting or storing of compressed air or gases unless specifically designed by the manufacturer to do so.

  • When investigating the chemical compatibility of a piping system, it is important to note that all piping system components must also be investigated for compatibility. Gaskets, o-rings, valve seats, pump seals, solvent cements, tanks, and other components and materials should be evaluated for compatibility and approved by their respective manufacturers for use with the fluid medium prior to use.

  • The majority of the chemical resistance data provided in the following charts is based on chemical immersion testing run under non-pressurized conditions. Depending on the hazards of the chemical used, an additional safety and pressure de-rating factors are typically applied to the standard working pressure rating of the product (shown for water). Standard temperature de-rating factors must also be applied to pressure applications at elevated temperatures.

  • Individual chemicals that do not have an effect on the pipe material may affect the pipe if combined with certain other chemicals – the information in this guide does not address combinations of chemicals.

  • The suitability for use of a piping material in a particular process piping application is a function of: the specific pipe material itself, piping dimensions, construction, and quality, joining system, concentration of chemicals and chemical mixtures, operating temperatures (including temperature swings), operating pressure (including cyclical variations), applied stress, and life cycle information (i.e. material costs, installation costs, desired service life, maintenance, repair and replacement costs etc.).  Users must make their own assessment of the suitability of the product for the purposes required. 

  • Chlorinated and aromatic hydrocarbons, esters, or ketones are not recommended for use with PVC or CPVC thermoplastic piping materials. Although the chemical resistance of PVC and CPVC compounds is similar, they are not always the same. Caution should be used when comparing the chemical resistance properties of PVC Type I, PVC Type 11, PVC Clear, and CPVC as differences in chemical resistance exist.

  • Caution should be exercised when selecting thread paste compounds, lubricants, cleaning and wetting agents (surfactants), corrosion inhibitors and other chemical substances that come into contact with the system for compatibility as well.

  • Applications involving certain oils, surfactants, and greases and certain other  chemicals  may result in environmental stress cracking. Environmental stress cracking occurs when the piping and components are weakened by contact with these chemicals, and failures are propagated by external stress (i.e. pressure, expansion/contraction, installation. etc.) on the system.

  • Exposure of Clear PVC to certain chemicals can affect the clarity of the product over time.  Clear PVC maintains its physical properties when exposed to many substances, however, exposure to sunlight (UV) and certain nitrogen containing organics, bleaches, oxidative agents and acids will result in discoloration. Testing under actual use conditions is recommended.

Please contact Harrington Technical Services for additional technical and application information.