Presentation on theme: "1 Water Quality Standards for CSD A look at Australian, UK, ISO/EN, AAMI and WFHSS standards and guidelines QLD SRACA August 2014."— Presentation transcript:
1 Water Quality Standards for CSD A look at Australian, UK, ISO/EN, AAMI and WFHSS standards and guidelines QLD SRACA August 2014
Current AS 2.1 WATER QUALITY FOR CLEANING “Tests should be conducted weekly on the hardness of the water, and records kept.” “High water hardness will leave a white-grey coloured residue on all types of surfaces, which in the case of instruments will shorten their life span. Water hardness also affects the activity of the detergent”
Current AS 2.1 WATER QUALITY FOR CLEANING “Consideration should be given to the use of softened, filtered, demineralized, or even distilled water in at least the final rinse stage of the washing process and preferably all washing stages. Water treatment, reverse osmosis or softening units should be selected having regard to the total demand, volume and rate of treated/softened water required in the instrument washing area. Water with high mineral content is unsuitable for the rinsing of instruments due to mineral deposits permanently damaging and seriously shortening the life of the instruments.”
ISO Washer-disinfectors —Part 1: General requirements, terms and definitions and tests Quality of final rinse water Tests for chemical purity Tests for chemical purity shall include tests for those determinands known to influence the efficacy of the process. NOTE This can include, but is not limited to, tests to determine the value of the following: conductivity; pH; oxidizable substances [determined by the European Pharmacopoeia (EP) method or as redox potential determined by the United States Pharmacopoeia (USP) method]; total hardness (salts of Ca2+, Mg2+, Sr2+ expressed as mmol CaCO3); total dissolved solids (TDS) determined as evaporative residue; inorganic phosphate [Pi] and inorganic silicate [SiO2], determined as the molybdate reactive species; chloride [Cl−
ISO Washer-disinfectors —Part 1: General requirements, terms and definitions and tests Quality of final rinse water Tests for bacterial endotoxins If a requirement for the level of bacterial endotoxins in the final rinse water is given in other parts of ISO 15883, determine the level by the limulus amoebocyte Iysate (LAL) test with a sensitivity of 0,25 EU/ml, or better, using the method given in the European Pharmacopeia (EP) or United States Pharmacopeia (USP). Tests for microbial quality Make a total viable count by membrane filtration of not less than 100 ml final rinse water sample. Place the filter on R2A-medium in accordance with Annex D, or other suitable low nutrient medium and incubate at 28°C to 32 °C for a minimum of 5 days to determine the aerobic mesophillic viable count.
ISO Washer-disinfectors —Part 1: General requirements, terms and definitions and tests Quality of water used during testing Prior to carrying out operational qualification and performance qualification testing, determine the quality of water used at each stage of the operating cycle other than the final rinse (see also 6.4.2). Tests for chemical purity shall include tests for those determinants known to influence the efficacy of the process. NOTE This can include, but is not limited to, tests to determine the value of the following: conductivity; pH; oxidizable substances [determined by the European Pharmacopoeia (EP) method or as redox potential determined by the United States Pharmacopoeia (USP) method]; total hardness (salts of Ca2+, Mg2+, Sr2+ expressed as mmol CaCO3); total dissolved solids (TDS) determined as evaporative residue.
ISO Washer-disinfectors —Part 1: General requirements, terms and definitions and tests ISO provides a qualification for the water quality but it does not quantify limits ISO does not provide a prescriptive specification for water To a very large extent ISO remains subjective and subject to interpretation and justification. IF you are operating to ISO standard who ultimately determines the standard for water quality?
ISO Washer-disinfectors —Part 1: General requirements, terms and definitions and tests 5.23 Water supply The quality of water required for each process stage shall be specified by the WD manufacturer. When necessary, means shall be provided to monitor the attainment of this water quality either periodically or continually for each cycle. NOTE The quality of water can include consideration of chemical purity, hardness, temperature, supply pressure, microbial contamination, etc. The monitoring function can be provided by equipment external to the WD, installed on the water supply system. The WD shall be designed to operate either: a) with potable water supplied directly to the WD, or b) with potable water supplied to the water treatment equipment supplying the WD. Water treatment equipment can include, e.g. a softener, de-ionizer or reverse osmosis plant, as necessary.
Guideline Compiled by the DGKH, DGSV and AKI DGKH = German Society for Hospital Hygiene DGSV = German Society for Sterile Supply AKI = Working Group Instrument Preparation The use of salt-free or fully demineralised water for the final rinse step assures clean, spotless goods. Chapter of EN ISO – Part 1 lists the critical parameters. EN 285, Annex B, Table B1, lists values for the boiler water of a steam steriliser. This water quality can be recommended for the final rinse step for automated instrument processing. The following values are recommended as a guide: Conductivity: 5 μS/cm pH value: 5 – 7 Total hardness: 0,02 mmol CaO/l Salt content: 10 mg/l Phosphate: (as P2O5) 0,5 mg/l Silicate: (as SiO2) 1 mg/l Chloride: 2 mg/l
Guideline Compiled by the DGKH, DGSV and AKI DGKH = German Society for Hospital Hygiene DGSV = German Society for Sterile Supply AKI = Working Group Instrument Preparation It is recommended that at the time of validation of the cleaning and disinfection process the water quality used for precleaning, cleaning and intermediate steps be documented too. The following values are recommended as minimum requirements: Total hardness: < 3°dH (< 0,5 mmol CaO/l) Total salt: < 500 mg / l Chloride content: < 100 mg / l pH value: 5 – 8
Working group on Instrument Reprocessing AKI “Red Book” Recommendations for thermal rinse water quality published in AKI “red book” are based on EN 285 and ISO feed water quality for boilers “Since there is currently no specific standard regarding the use of demineralized water in automated reprocessing, we recommend the boiler feed water quality as defined in DIN EN 285”.
First Revision of AS 4187 picked up on EN285 and AKI recommendation 12
Choice Framework for local Policy and Procedures (CFPP) Management and decontamination of surgical instruments (medical devices) used in acute care Part D: Washer-disinfectors 13 Part 3 deals with all aspects of water supply. Captures and updates the information on water quality previously contained in the NHS Health Technical Memorandum (HTM) 2030
Choice Framework- Part D Washer Disinfectors 14
Latest revision of AS 4187 (DR April 2014) references the UK Dept of Health “Choice Framework” 15
Is water quality testing compulsory? Latest revision of AS 4187 (DR April 2014) 16 NOWHERE in the draft does it say water quality used for cleaning and rinsing medical devices SHALL COMPLY with the water quality guidelines contained in table 7.2. The word SHALL in reference to water quality is used in the following context Water quality ….“Softened, filtered, demineralized, reverse osmosis or distilled water shall be provided in accordance with the requirements specified by the equipment manufacturer” In this regard DR is consistent with the ISO Guideline. IT IS INCUMBENT UPON THE EQUIPEMNT MANUFACTURER TO SPECIFY THE REQUISITE WATER QUALTY FOR YOUR FACILITY. Just so there is no confusion as to which “equipment manufacturer” it means the manufacturer of the washer. Water quality falls under “Services qualification” which forms part of the Installation Qualification (IQ). The IQ specification are the responsibility of washer manufacturer.
Is water quality testing compulsory? Latest revision of AS 4187 (DR April 2014) 17 NOWHERE in the draft does it say water quality used for cleaning and rinsing medical devices SHALL COMPLY with the water quality guidelines contained in table 7.2. Compare with the unambiguous direction for steam quality……”The quality of water used for generation of steam for a sterilizing process SHALL comply with the requirements in table 7.3”
Frequency of testing the water quality Latest revision of AS 4187 (DR April 2014). 18
Compare Frequency of testing in DR with Choice Framework- Part D Washer Disinfectors Existing AS 4187(2003) test hardness (weekly). DR test water quality annually? Contains no other clear directions on frequency of testing ?? Choice Framework Part D Water hardness (weekly) Conductivity Final rinse (weekly) Chemical Purity tests (yearly) Bacterial endotoxins (yearly)
Choice Framework – The key elements The key factors are: Hardness; Temperature; Ionic contaminants (for example heavy metals, halides, phosphates and silicates); Microbial population; Bacterial Endotoxins 20
Choice Framework – Microbial Quality and Bacterial Endotoxin Bacterial Endotoxins Items intended for surgically invasive use should have suitably low levels of bacterial endotoxins. Bacterial endotoxins are thermostable compounds primarily derived from the cell wall of Gram-negative bacteria. When introduced into the human body, can cause a fever-like (pyrogenic) reactions and other adverse effects. They are not readily inactivated at the temperatures used for disinfection or sterilization. Water used for the final stages of processing in a washer-disinfector, where there is a significant risk of residual water remaining on the load items, should not contain more than 0.25 EU/ mL –1 when the washer-disinfector is being used to process surgically invasive items. 21
Choice Framework – Treatment processes to remove Microbial Contaminants and Bacterial Endotoxin Bacterial Endotoxins RO treatment plants remove almost all dissolved inorganic contaminants by passing the water, under pressure, through a semi-permeable membrane against an osmotic gradient. The process will also remove a high proportion of organic material, bacterial endotoxins and microorganisms. Some RO units are fitted with a final 0.2 μm filter to control bacterial numbers. An RO system removes bacteria, endotoxins and approximately 95% of chemical contaminants. Water softeners, “base-exchange” softeners, de-ionisers do not remove non- ionic contaminants such as organic materials, microbial contaminants, bacterial endotoxins. Moreover ion exchange columns can become fouled and colonised with microbial contaminant and cause a significant increase in the microbial content of the water. Deionised water should not be used for the final rinse of products intended for invasive use without further decontamination processing by heating,f iltration etc. 22
Choice Framework – Testing for Microbial Contaminants and Bacterial Endotoxin Bacterial Endotoxins The sampling containers used should be specific for the determinands of interest. This should include, as appropriate: 250 mL sterile pyrogen-free single-use containers (for determination of bacterial endotoxin levels and/or total viable count); Samples should be stored at 2–5°C and tested within 4 h (previously 48 Hours) of collection. HTM 2030 section Samples should be tested within four hours of collection or stored at 2ºC to 5ºC and tested within 48 hours of collection. 23
Choice Framework – Ionic contaminants and associated metrics Hardness final rinse (both Choice and 4187 revision) <50mg/L. 4187 Revision other stages < 60mg/L Choice other stages > 125mg/L should employ softening Choice other stages >210mg/L not suitable for use EN285 2mmol/L = 2ppm
Choice Framework – Salts & mineral contaminants and associated metrics Chloride <10mg/L in final rinse and <120mg/L other stages (chromomorphic salt - #1 suspect for pitting and crevice corrosion) Heavy Metals (determined as lead) Final Rinse <10mg/L Causes staining and corrosion of steels Iron Final Rinse < 2mg/L Causes corrosion of steels and staining Phosphate Final Rinse < 0.2mg/L Contributes to scaling an blackening of steels Silicate & Silica (SiO 2 ) Final Rinse < 0.2mg/L Other stages <2mg/L
Choice Framework – Treatment processes to remove mineral and ionic contaminants Mineral contaminants will exist predominantly as dissolved ions. Ions responsible for water hardness Ca, Mg together with other metals ions responsible for staining can be removed by ion exchange systems such as water softeners; water deionisers and RO treatment plants. Ion exchange systems to not remove non-ionic species such as dissolved Silica Dioxide. Silica Slip If ion exchangers are used in the production of fully demineralized water, glaze- like discolorations may occur as a result of silicon dioxide passage. Quality monitoring of the fully demineralized water by way of monitoring of electrical conductivity is not adequate for identification, as the silicon dioxide does not imbue the water with conductivity. Practical experience has shown that silicon dioxide passage may occur even at electrical conductivity of approximately 1 μS/cm. 26
Typical silica discoloration in the rinsing chamber and on the surface of the instrument caused by cleaning agent containing silicate, or excessive levels of silica in the water. Silica
Choice Framework – Ionic contaminants and associated metrics Conductivity & Total Dissolved solids Conductivity Choice framework <30µs/cm Choice framework tested weekly (Final Rinse) revised draft DR <30µs/cm EN285 and AKI Redbook <5µs/cm (boiler feedwater) The most telling parameter, captures the most information It readily identifies changes in water quality and alerts you to when more detailed analysis is required. Total dissolved solids (TDS) Choice framework 4mg/100mL = 40mg/1000ml = 40ppm (mg/L) revised draft DR <0.4mg/L??? TDS is measured as conductivity with a conversion factor applied. TDS mg/L = electrical conductivity mS m –1 × 1.6.
Conductivity Toowoomba Hospital
A Checklist of what a water quality standard should include 30 A water quality standard should provide a specification. A clear unambiguous statement that Water used for final rinse and/or cleaning SHALL comply with the requisite specification. Not left to other 3 rd parties. Water quality specification checklist Current revision of AS4187 adapted form “CHOICE FRAMEWORK” Qualifies what to test forYES Quantitative limitsYES Suitable methodologiesNO (contained in Choice Framework) Testing frequencyNO (annual??) Binding – SHALL COMPLY with spec.NO (Not prescriptive. Defers to WD manufacturer)
Water Quality Standards for CSD A look at Australian, UK, ISO/EN, AAMI and WFHSS standards and guidelines QLD SRACA August 2014.