Rubber materials in contact with potable waterConsequences of Current and Future Legislations January 2007 DSM Elastomers Michael Koch Contents Introduction Standards worldwide Main changes in standards and consequences Compounding Issues DSM Elastomers Introduction Rubber coming into contact with potable water has to meet special sanitary regulations and mechanical standards • Why these regulations/standards: Mechanical - functional aspects Sanitary - to avoid adverse effects on water quality - to prohibit risks from consumers health caused by: - discharge of undesirable substances - release of metabolic by-products leading to unpleasant tastes, odours and slime - pathogenic bacteria DSM Elastomers • Rubber products involved: - Reservoir linings - Diaphragms, o-rings in heater appliances - Washers and taps - Hoses, tubes - Seals in coupling / fitting systems Examples of surfaces with bio-film deposit Source: DVGW DSM Elastomers . drainage and sewerage pipe lines • Applicable to joint seals for all pipeline materials. Plastics and Glass-Reinforced Plastics Focus on pipe seals in contact with cold-drinking water supplies (up to 50 °C) DSM Elastomers .Rubber Product Seals: • Joint Rings for water supply. Fiber Cement. Steel. including: Iron. Clay. Concrete. Reinforced Concrete. Cast Polyurethane (waste) • DIN 4060 (?) • DVGW Arbeitsblätter VP 546 (ductile iron socket joints)).sewerage and rain water up to 95 °C) 2. Vulcanized rubber (application cold water up to 50 °C. VP547(ductile iron flange joints) • KIWA BRL 2013/04 DSM Elastomers .Main standards mechanical characteristics (Europe) • EN 681 Part 1 till 4 (since 1996) 1. TPE (waste) 3. hot water up to 110° C. Cellular Rubber (waste) 4. drainage. PVC.11 (AINSI standard for rubber gasket joints for ductile iron pressure pipe and fittings) UL 107 (UL standard for safety for asbestos-cement pipe and couplings) UL 1285 (Standard for safety for pipe and couplings. glass fiber reinforced. for underground fire service) UL 1713 (Standard for safety for pressure pipe and couplings. using rubber gaskets) ASTM C 361 / 361M (Reinforced Concrete low head pressure pipe) AWWA C111/A21.Standards mechanical characteristics (USA) • ASTM F477 (low head / high head) • • • • • • (Elastomeric seals / gaskets for joining plastic pipes) ASTM C443 / 443M (Joints for Circular Concrete Sewer and Culvert Pipe. for underground fire service) DSM Elastomers . Standards mechanical characteristics (Main Others) • ISO 4633 (International) • K 6353 (Japan) • AS 1646 (Australia) DSM Elastomers . –10 C Hot air ageing 168 h 70 C 96 h.70 C 70 h.Comparison Mechanical Characteristics Physical Property Europe Australia Japan USA Hardness IRHD Tensile strength Mpa Elongation at break % Compression set % 72 h.9 100-400 36-85 9-12 125-450 45-85 12-18 280-400 40-60 8.3-13.100 C Stress Relaxation Water resistance Ozone Resistance Optional tests 40-90 Min. 70 C 72 h.8 325-400 12-15 20 40-60 15 20 12-20 20-30 20-25 DSM Elastomers . 23 C 22 h. 13 / W270 KIWA BRL 2013/04 + ATA ACS (Arrêté ’94 /’97) EAS (under preparation) • • • • AS4020 (Australia) NSF 61(USA) K 6353 (Japan) ISO 10221(International) DSM Elastomers .Standards sanitary characteristics • • • • • BS 6920 KTW 1.3. Sanitary test types • Microbiological Growth • Chemical Migration Total Organic Carbon (TOC) • Hygienic Flavour and Odour Colour Appearance Foaming tendency Chlorine demand DSM Elastomers Specific determinations Identification of unknowns Cytotoxicity • Genotoxicity . Overview Sanitary Requirements Hygienic Microbial Europe: France Germany Netherlands UK “” Australia Japan USA DSM Elastomers Chemical Genotoxicity . non-metallic materials Organic Leachate Microbial Growth Potential Chlorine Demand DSM Elastomers Australia Japan USA “” . Rest of World Test Europe Flavour/Odour Colour/Turbidity Metals Leachate .Sanitary Requirements Europe vs.metallic materials . Microbial Growth Tests Characteristic MDOD W270 BFP/BPP Mode batch basin batch Volume (l) Water Period (weeks) Temperature (°C) 1 (refreshed) tap 7 30 0.6 (stagnant) SSF 16 25 Parameter O2 ±100 (±22 L/h.) tap 26 AMBIENT (6 –15 °C) SLIME Cost (Euro) ± 400 ± 800 ± 1000 DSM Elastomers ATP . Main Changes and Developments in Standards / Recommendations • BS 6920(UK) • KTW / W270 (Germany) • KIWA BRL 2013/04 + ATA (The Netherlands) • ACS (France) • EAS(Europe) • NSF 61(USA) DSM Elastomers . most European countries are updating their current national standards in preparation of the EAS To-days problem is the postponement of the introduction of the EAS.Main changes and developments in European standards / recommendations Awaiting the new to come EAS. which leads to further application of national standards DSM Elastomers . 4 Growth of aquatic micro-organisms test 2.1 Samples for testing 2.0 Specification 2. General methods of test 2.6 The extraction of metals 3. £ 9001000 material DSM Elastomers .5 The extraction of substances that may concern to public health 2.0 The GC/MS identification of water leachable organic substances Time span: 810 weeks .2.BS 6920 • • • • • • • • • • • (non-metallic products in contact with drinking water) 1.1.3.2.3 Appearance of water 2. Cost approx.2 Tastes imparted to water 2. Tastes imparted to water by hoses conveying food/drinks 2.0 High temperature tests 4.2. Reading WRc-NSF. Birmingham ITS. Medmenham Listing via WRAS Swindon DSM Elastomers . Cranleigh WQC.Revision BS 6920 • WBS / WRc WRAS • Review Parts 1 to 3 (2001) Part 1 : odour assessment re-introduced Part 2 : MDOD : optional 2 weeks test extension for borderline materials Part 3 : optional boiling water test • Accredited Laboratories (UK): Law Laboratories. and re-audit compounds often fail on new introduced odour/flavour test - MDOD test will be maintained for the time being.Revised standard BS 6920: Consequences • New . means variation in test results due to lack on reproducibility DSM Elastomers . BS 6920 Listing Procedure WRAS listing for 5 years Current DSM compounds listed: R2008. R2009: R2010 (till 2007) DSM Elastomers . Odour...13 (9-12-1986) • 5 Categories ( depending on S/V ratio) A B C D1 D2 • Pipes (S/V ratio 1:1) Liners (S/V ratio 1:4) Hoses (S/V ratio 1:6) Large diameter seals (S/V ratio 1:25) Small diameter seals (S/V ratio 1:50) Basic Requirements: Colour.3. Turbidity TOC value Chlorine consumption Bacterial content Release of Formaldehyde and Phenol to the water Release of primary/secundary N-Alkyl/Arylamines Max. A-C products W270: microbial growth test • Positive List • Cost KTW approval: Euro 1200. Testing time: 6-8 Month DSM Elastomers . Contensts of Zn. W270: Euro 800. Pb and ACN No presence of secundary aliphatic/cycloaliphatic amines in cat.KTW Recommendation Part 1.-. KTW: Status and Developments Time schedule 2007 for the preparation of the new “Leitlinie Gummi” Proposal UBA/WdK Disclosing of recipes New positive List will be based on Synoptic documents 0 till 4 and the positive lists of BfR and European standard (EFSA) 2002/72EG Revised W270 test will be proposed as new European standard for microbial growth determination instead of BFP test 13 Members(WdK Group “Trinkwasser”) will take part on Round Robin test Current W270 test versus revised one Toxicological evaluation of rubber vulcanisate via GC/MS screening 13 Members will take part on Round Robin test (according CEN TC 164 wg3 ahg7) Test Institutes TZW Karlruhe. BAM Berlin (only KTW) DSM Elastomers . Hygienic Institute Gelsenkirchen. 05 + 0.Comparison W270 (1999) versus revised W270 Shortcomings current W270 Test: • Testing time of 6 Month • Determination of slime quantity with a limiting value of 0.03 = 0.12 and 16 weeks) Requirements on deposit (bacterial growth) Revised • Large contact areas (hoses.3 ml/800 cm2 • D2 Seals: <0.23 < 0.1 ml/800 cm2 • D1 Seals: < 0.20 + 0.12+0. liners): <0.15 < 0.02= 0.03 = 0. 8.1 ml/800 cm2 Changes: • Duration of Test • Limiting Value • Determination of quantity of surface deposit (via centrifugation method) • Test-scheme (measurements after 4.5 ml/800 cm2 DSM Elastomers .07 Current < 0. KTW Consequences • Introduction of new positive list could influence current used polymers (monomers) and compounding ingredients • Introduction of revised standard W270 will lead to more constant microbial growth figures • * New classification of categories limits application of current used compounds. EPDM and IIR based hoses (category C →A)* Hoses are tested according Arbeitsblatt W543(December 2004) which involves functional tests. W270 and KTW 1.3. e.13 (odour and taste) DSM Elastomers .g. KIWA BRL 2013/04 + ATA • In 2000 revised standard BRL 2013/04 has been introduced .1994.1(exception tear. still valid • Introduction of microbial growth test under consideration . issued 01.KIWA Bio-film Formation Potential (vd Kooy) • Introduction OAS Approval Cost (including ATA/ BFP tests) about Euro 2000-3000.- DSM Elastomers .nearly equivalent to EN 681.and ozone test) • ATA list. KIWA Consequences New OAS will certainly lead to problems with current used SBR and EPDM compounds (introduction BFP method according NEN 1225) DSM Elastomers . residuals in material / LMS.Testing time: 2-3 Month DSM Elastomers . migration / Categories depending on application and S/V ratio) Test methods “Arrêté” (June 1997) : 1) Measurement organoleptic and physical-chemical parameters (quick screening according XP P 41-250-1) 2) Measurement organic and mineral miropollutants (end screening according XP-P41-250-2) 3) Measurement cytotoxicity (according XP P41-250-1) Test Institutes: IRH (ex LHSRP). Lille CRECEP. Vandoeuvre Cedex Institut Pasteur Service des Eaux.ACS (France) Positive list “Arrêté” (November 1994) still valid (Qm: max. limits spec. Lyon Cost: Cost total approval: about Euro 9000. Paris Carso. KIWA) • Screening and cytotoxic tests not harmonized with rest of Europe ACS is based on the study of the chemical composition and migration testing of products.ACS: current shortcomings • Approvals are very costly • Current positive list is not comparable with other lists used in Europe (KTW. France don’t determine the growth promoting properties of construction materials DSM Elastomers . organoleptic properties (odour. G.enhancement of microbial growth . F.(1999) EAS ‘on paper’: report to RG-CPDW (Feb 01) Research (4 topics) starting (2001) .affect of chlorine level • Final EAS in 2010? DSM Elastomers . flavour.hygienic properties (TOC. Cl demand) . turbidity) . NL) .EAS – Developments • • • • First initiative (1998) EAS feasibility study (UK. EAS : Assessment product data • • • • • Full information on formulation and processes Minor products? Compliance with positive lists? Degree of auditing Listing DSM Elastomers . EAS Consequences • Transition Period • Influence microbial growth test • Influence European Positive List DSM Elastomers . NSF-61 general information • Standard is product specific • No positive list available (sometimes NSF is combined with FDA) • Any ingredient can be used as long it’s not exceeding the allowable concentration level • NSF 61 is publishing the contaminant concentrations that the product is allowed to release into the water • Depends on the surface area to volume ratio of the material DSM Elastomers . NSF-61: certification process • • • • Collection of formulation information Toxicology Review of Formulation Inspection of Production Facility .annual • exposure of material/device to extractant water • analysis of leachable contaminants • Evaluation of Contaminant Levels .annual Testing of the Product .annual • Product Certification • Annual Monitoring Program DSM Elastomers . NSF-61: certification process Time for Certification: 4 months to 1 year. formulation changes may be required Cost for Certification: • Annual Audits and Listing fees: $4900 (£3200) • Testing/Toxicology: $4000 (£2700) per material Test Institutes: • NSF USA Ann Arbor (MI) • WRc-NSF UK . Brussels * * Only information about NSF procedures DSM Elastomers . Medmenham • NSF International Belgium. depends on: • submittal of product and material information • takes longer when non-certified materials are used • if products fail testing. NSF 61 Consequences • European convertors sometimes require NSF/FDA approval combined with existing KTW/WRAS/ACS approvals • Impact of chloramine resistant compounding on NSF/FDA regulations DSM Elastomers . Compounding Issues Composition of recipes will be effected by: • Transition period to EAS (no harmonization of current national standards) • New European positive list based on current food/plastics lists • Non-availability of smaller ingredients caused by REACH • Increased focus on bacterial growth and organoleptic properties • Increased use of peroxide cure because of limited presence of NA-safe accelerators on positive lists • Bad compound processing due to lack on low molecular weight additives DSM Elastomers .