GF Piping Systems have undertaken extensive tests to investigate the behaviour of a large number of commercially available disinfectants when transported in pipes and fittings made of PVC, PE and PP. Our tests on PVC have been supplemented by further tests carried out by the Henkel company, Düsseldorf.
Results of earlier preliminary tests served as the basis, providing the following criteria:
- Disinfectant solutions have a strong capillary force. Pipe joints must therefore be treated with extreme care.
- The make or type of disinfectant is likely to be changed several times during the operating life of such a piping system.
- Different disinfectants have different compositions and behave differently towards plastics.
The purpose of the experiments was to compile a planning guide taking into account the above criteria. For testing the resistance of the pipe material, the specimen was filled with disinfectant instead of water and long-term internal pressure tests were carried out as stipulated in the standards. The pipe joints suited to each pipe material were tested at the same time.
Disinfectants are usually aqueous or alcoholic solutions containing special active agents against microbes. They usually also contain detergents, whose capillary force enhances the antibiotic effect. Chlorine separators may also be used, depending on the application. The pH value may vary within certain limits, from slightly acidic to slightly alkaline, but this has practically no effect on the resistance of the plastics.
The tests encompassed pipes and fittings made of PVC, PE and PP as well as the appropriate joints.
PVC-U (Polyvinyl Chloride)
The different disinfectants investigated affected PVC in different ways. The long-term durability results for PVC with water were only partly equalled. With some of the disinfectant solutions tested, the specimen failed prematurely due to stress corrosion.
All the solvent cement joints tested remained leak proof up to the failure of the test specimen.
The required test duration could only be achieved by lowering the test pressure. The resulting load corresponded to that given in the standards for dangerous media against which PVC is resistant.
It was seen from these tests that stress cracking can only be expected at relatively high circumferential stresses, or after extensive periods of under load. The effective load placed on piping components in practice results from the internal pressure and possibly from transmitted stress occurring from the installation conditions.
The nominal long-term duration of the pipes was equalled or exceeded with each of the disinfectants tested. The socket fusion joints remained leak-tight until testing was discontinued long after the nominal duration had been exceeded.
PP proved not to be resistant to any of the disinfectants tested. The test specimens failed in every case even before reaching the minimum test duration.
An Environmental Product Declaration, EPD®, is a verified document that reports environmental data of products based on life cycle assessment (LCA), Product Category Rules, and in accordance with the international standard ISO 14025 (Type III Environmental Declarations), giving them wide-spread international acceptance.
The EPD® logo type and the acronym EPD® are registered trademarks within the European Union and use of them within the EU is therefore only allowed for certified EPDs within the International EPD® System.
The Australasian EPD® Programme was established by ALCAS (Australian Life Cycle Assessment Society) and LCANZ (Life Cycle Association of New Zealand), based on the framework set up by the International EPD® System. All EPD®s in the Australasian EPD® Programme are published within the International EPD® System, for global alignment and market visibility.
What’s the Purpose and Benefits of an EPD ?
The overall goal of an EPD® is to provide relevant and verified information to meet various communication needs. An important aspect of EPD® is to provide the basis of a fair comparison of products and services by their environmental performance. The methodology includes all relevant environmental impacts starting from the production of the raw material, to production, use of the product, through to the end of life (cradle-to-grave) eg raw material extraction, transportation to converters, converting process, transport to trench, construction, use and end of life.
EPDs are increasingly recognized in international markets and being demanded within procurement processes. Green rating tools recognize EPDs, such as the Green Star tool of the Green Building Council Australia, which includes EPD Innovation Credits and LEED v4
An EPD ensures that you can effectively communicate your environmental credentials to your clients and avoids risks associated with unsubstantiated environmental claims (e.g. greenwash).
Georg Fischer has prepared five EPD’s for PE, PP, PVC, PVDF and PB plastic pipe systems in line with EN 15804 “Sustainability of construction works – environmental product declarations – Core rules for the product category of construction products”
Plastic pipes are widely used for the transportation of disinfectant solutions. Selecting the material requires great care since some types of disinfectant solutions can damage certain thermoplastics.
A series of tests were carried out in which PE proved to be suitable without reservation, whereas PP failed completely. PVC is also suitable, as long as certain rules are adhered to when making solvent cement joints and when establishing the operating conditions.
PVDF pipes are also suitable for these kinds of applications.
For several years now plastic pipes and fittings have been preferred for transporting disinfectant solutions in hospitals and clinics. Certain characteristics of disinfectants and the working conditions must be taken into account when planning the pipeline, e. g. in selecting the pipe material and the type of joints to be used.
This topic will be further examined in the next blog edition.
The COOL-FIT/iFIT calculation tool allows you to calculate all the pipe system parameters important for cooling, such as pressure loss, heat emission, contraction and temperature loss.
About the calculations
You can select a calculation type from the menu. It is possible to make different calculations such as Pressure loss, Condensation, Heat loss, Contraction and Temperature loss. Under the menu Supports, a table with recommended support distances are available. “Data” includes different kinds of documentation e.g. formulas and specifications of materials and fluids.Find the Cooling Calculation Tool at:
If you have any questions regarding the tool or the data shown, please do not hesitate to contact us by replying to the blog or email firstname.lastname@example.org
The choice of material and the pressure rating of the pipe components are important for both operating safety and for attaining the specified minimum operational life of the system.
The decisive factors are:
- operating pressure
- operating temperature
- medium transported
- duration of service.
Separate calculations are necessary if safety factors are different or the operational lifetime is modified.
In Australia we need to deal with joining both metric and inch piping systems; so we need to convert and understand how it measures up. For those unfamiliar with the difference between metric and inch sizes the following note may be helpful. In imperial systems, the sizes of pipes, fittings and other components such as valves are identified by reference to the nominal size of the bore of the pipe expressed in inches and fractions of an inch.
In metric systems, however, sizes are identified by references to the outside diameter of the pipe expressed in millimetres. For converting metric to imperial it should be understood that metric sizes are not simply inch sizes which have been converted into millimetres and called metric; their actual dimensions are slightly different and they are with the exception of 2½ ” (75 mm) and 5″ (140 mm) not interchangeable.
Water which has been produced using → Ion exchangers, reverse osmosis or distillation, but which still contains a residue of certain ions. Purified water (“aqua purificata”) prepared according to the → DAB (and used in many pharmaceutical products) belongs to this category. Its specific conductivity at 25°C lies between 1 µS/cm and 50 µS/cm. Water for injection (“aqua ad injectabilia”) used in hypodermic syringes is categorised in the → DBA as a “cleaner” pure water. It is used as a solvent and as a fluid for diluting those medicines which can be applied by injection or by infusion. Sterility is a prerequisite.
Water which is fully salt-free (deionized). It is produced by the use of ion exchangers or by distillation. The quality of the resulting product is codified by various standards (e. g. DIN, ISO 3696). No ionogenic contents (= anions and cations) may be present. The specific conductivity at 25 °C lies between 0.1 µS/cm and 1 µS/cm
Water of the very highest purity. It is made from distilled water using supplementary ion-exchange techniques, → Active carbon and other absorbing materials. It contains only the slightest traces of organic compounds, micro-organisms and electrolytes. The specific conductivity at 25 °C is less than 0.1 µS/cm.
Water can contain very many substances and has to be processed or purified according to its proposed use. The results are a variety of degrees of purity which can be characterised according to diverse criteria. [e. g. measurements of → Conductivity (electrical); determination of the amount of specific types of ion.]
Water with different qualitative features (its suitability as → Drinking water could be included) for business, industrial and agricultural purposes
Water with medium salt content, e. g. the mixture of fresh and salt water which is found at the mouths of rivers. The specific conductivity at 25 °C lies between 0.05 S/cm and 1 S/cm.
Water of a quality which conforms to the TVO (Trinkwasserverordnung = German Drinking Water Ordinance) regarding, for example, the maximum amount of pollutants. Drinking water has to be maintained at a temperature below 25°C. Its specific conductivity at 25 °C lies between 50 μS/cm and 5000 μS/cm.
GF Piping Systems would like to wish you a safe and enjoyable Christmas, and New Year. We look forward to a busy 2015 for all.
Please note that our blog will be not be monitored during the festive season from COB Tuesday 23 December 2014, until Wednesday January 7, 2014.
Please note our offices throughout Australia will be closed at midday Wednesday December 24, 2014, and will reopen on Monday January 5, 2014. If you have any urgent inquiries during this time, please contact Simon Naef on 0418 214 037.
Water hammer, or surge pressure, is a term used to describe dynamic surges caused by pressure changes in a piping system. They occur whenever there is a deviation from the steady state, i.e. when the velocity of the fluid is increased or decreased, and may be transient or oscillating. Waves of positive or negative pressure may be generated by any of the following:
• opening or closing of a valve
• pump start-up or shutdown
• change in pump or turbine speed
• wave action in a feed tank
• entrapped air
The pressure waves travel along at speeds limited by the speed of sound in the medium, causing the pipe to expand and contract. The energy carried by the wave is dissipated and the waves are progressively damped.
The pressure excess to water hammer must be considered in addition to the hydrostatic load, and this total pressure must be sustainable by the piping system. In the case of oscillatory surge pressures extreme caution is needed as surging at the harmonic frequency of the system could lead to catastrophic damage.
The maximum positive or negative addition of pressure due to surging is a function of fluid velocity, bulk modulus of elasticity of the fluid, pipe dimensions and the modulus of elasticity of the pipe material.
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