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Copy of jimma university institute of engineering and technology

  1. 1. JIMMA UNIVERSITY JIMMA INSTITUTE OF TECHNOLOGY(JIT)MAINTENANCE METHODOLOGY TERM PROJECT BYSTUDENTS OF BIOMEDICAL ENGINEERING Students’ name: ID NO 1.Keneni Benti………………………................................00499/02 2.Birhanech Worku…………………………………………….00218/02 3.Abdulmelik Adilu………………………………………………00024/02 4.Shibre GerremeW………………………………………………00712/02 5.Zelalem YiGzAW…………………………………………………00903/03 Submission date: 02/06/2012 i
  2. 2. Abstract:The intention of this project is to have deep understanding of special biomedicalequipment called steam autoclave. It is an instrument used to sterilize microbiologicallife which exists on surgical equipment. Every company producing this device has itsown manual for installation, maintenance and operation of the device. Without readingthis manual, one cannot simply make the power ON since the device is too harmful andit has complex electric circuit which may cause shock if not properly operated. The thingthat motivates us to do this project on steam autoclave is due to such electric shock andcontamination caused by the operator’s error. Therefore it is aimed at minimizing thisand other problems concerning the device.Acknowledgement:We would like to thank our instructor AtoWondimu Fanta for his unexplainable moralsupport and encouragement towards this project. We also show our gratitude to ourfriends and all who supported in one way or the other for the completion of this project.In addition, we would like to thank jimma university for providing full internet accessfor us to complete this project. Finally, we want to say thanks for God who made all thispossible. ii
  3. 3. Table of contents: 1. Chapter one: page Introduction……………………………………………1 Back ground……………………………………………2 Problem’s statement…………………………………….2 Objectives……………………………………………….3 TheMain topics of maintenance methodology………...4 2. chapter two: Operational principles of steam autoclave………………7 Technical specifications………………………………….7 Sterilizing process………………………………………...8 Controlling parts………………………………………….9 Methods of using steam autoclave ………………………9 Schematic diagram……………………………………….10 Accessories……………………………………………….11 3. Chapter three: Installation of steam autoclave………................................11 Items for autoclaving……………………………………..12 Loading an autoclave……………………………………..12 Unloading an autoclave…………………………………...13 Quality control…………………………..............................14 General procedures……………………...............15 4. Chapter four: Maintenance and troubleshooting………………….16 Corrective maintenance…………………………….16 General preventive maintenance……………………17 Troubleshooting……………………………………..19 5. Chapter five: iii
  4. 4. Result and conclusion…………………………………………20Recommendation…………………………………………20References ……………………………………………….21Appendices ………………………………………………21Lists of figures: 1. figure1: schematic diagram of autoclave 2. figure2: maintenance cycle lists of tables: 1. table 1: autoclave’s capacity 2. table 2: troubleshooting 3. table 3:appendices iv
  5. 5. CHAPTER ONE:Introduction:The machine described in this project is a steam autoclave sterilizer that hasbeenspecially designed to sterilize most of the materials and instruments used in dentalsurgeries, doctorssurgeries and hospitals in general.This project contains general information pertaining to autoclave operation, and is to be used as ageneral reference.When performing autoclave operations, all procedures must be performed in accordance withthespecifications provided by the customer and in accordance with federal, provincial,andmunicipal safety legislation and company procedures, safety rules and regulations.The operating cycles can be monitored by means of the pressure gauge, warning lightsand by theposition of the controls.An autoclave is a specialized piece of equipment designed to deliver heat under pressureto a chamber with a goal of decontaminating or sterilizing the contents of the chamber.Decontamination is the reduction of contamination to level where it is no longer a hazardto people or environment, while sterilization is the total destruction of microorganismspresent.This is achieved because heat damages the cell’s essential structures, including thecytoplasmic membrane, rendering the cell no longer viable. This will only occurs if thematerial is heated to the specific temperature for a given period of time. Theseparameters will vary depending upon the nature of the microorganisms present and thecharacteristics of the load itself.To facilitate this transfer of heat, moisture is often added; but this does not guaranteesuccess. A number of other factors must be considered.The common types of steam sterilization cycles are gravity-displacement, whichremoves air from the chamber by gravity displacement as steam-entering chamber exertspressure on air; and the pre-vacuum cycle, which removes air by a vacuum pump whilesteam is simultaneously injected into the chamber. 1
  6. 6. Background :Sterilization means the use of physical or chemical procedure to destroy all microbiallife, including highly resistant bacterial endospores . Bacterial endospores are the mostresistant of all living organisms because of their capability to withstand destructiveagents.Although the physical or chemical process used to destroy all pathogenic micro-organisms including spores is not absolute , when all parameters of the sterilizationprocess have been met,instruments,supplies and equipment are thought to be sterile.  Sterilization falls into the following three categories: 1. High temperature/pressure sterilization.Eg steam autoclave. 2. Chemical sterilization. Eg, Ethylene Oxide(EtO). 3. Radiation sterilization. Eg, Gamma, Electron Beam, X-Ray.Using microbiological monitor is the only way to ensure that sterilization has beenachieved. Although thermally sensitive tapes and bag markers indicate exposure tosterilization conditions, they do not verify that sterilization has been achieved. Results ofstudies of the effectiveness of dental office sterilization have been variable, with 2% to20% failure rates in monitored sterilization attempts. The majority of sterilizationfailures have been found to be due to human error, rather than equipment’s failure.From the above three categories of sterilization, High temperature/pressure sterilizationwhich is performed by steam autoclave is the only sterilization technique that is going tobe discussed throughout the end of this project.Steam autoclave is the oldest, safest and the most cost effective method of sterilizationinthe medical equipment industry. It is an instrument used for sterilization of surgicallyused equipment by using steam form of distilled water.Problem statementIt is a statement form of a device’s problem. Whenever a certain device fails to work, itmust be repaired to be reused. For its correction or maintenance, there should be properproblem statements concerning the device’s failure. For instance, in steam autoclave,there may be many problems that make it non-functional. Examples of these problemsare briefly shown in this project under the topic of troubleshooting in chapter four. 2
  7. 7. Objectives:General objectives: the general objectives of this project is to let students tooutstandingly understand what maintenance is, how it is done, when it should be doneand what procedures are needed to do. Besides, it is also used to understand installing,operating, troubleshooting and maintaining general medical instruments. Theseinstruments differ in a way how to operate, maintain, install, and etc. Therefore, everyequipment has its own operational and maintenance manual. So, by looking through thatmanual, one can achieve the intended performance or action of equipment.Specific objectives:specifically, this project briefly explains special medicalequipment, steam autoclave. It is an instrument used for sterilization of surgicalequipment to kill out all microbial life. These text clearly talks about the equipment’soperational principles, installation, purpose, building blocks, troubleshooting andmaintenance. Afterreading this project paper one can confidentially install, troubleshoot,operate and brilliantly maintain every types of steam autoclave used in hospitals. 3
  8. 8. The basic topics of maintenance methodology: 1. maintenance activitiesThis methodology refers to the action taken by technicians for maintaining aninstrument. The maintenance activity should be done by experienced technician. Even ifthe availability of qualified technicians to accomplish maintenance and repair is readilyavailable, the tasks of the maintenance man are extremely difficult for the everincreasing usage of modern equipment. some of the modern day equipment are often toocomplex, too costly, inappropriate and difficult to maintain in developing society. Themain definitions and types are briefly explained in chapter four of this project. 2. FaultsFaults are the failure that one equipment exhibits. It is the state of abnormality of theequipment. Such failures may be caused by the operator or by the equipment itself.Unless faults are corrected properly by the qualified technicians,, it will leads to theautomatic expiration of the equipment. To diagnosis this problem, maintenanceprocedures should be taken. In an autoclave, there may be many faults which are causedby different problems such as: The timer fails to operate, The pressure gaugeremainsat a standstill even during thesterilizing cycle, Water remains in thechamber, The machine fails to pressurizeduring the cycle, The pressure increasesveryslowly and etc. 3. Reparability Before disassembling certain equipment for maintenance, one should identify whether it is repairable or not. After its reparability is identified, the technician can simply apply the maintenance to repair the equipment. Reparability is a capacity of equipment to be maintained. 4. Elements of maintenance methodology There are different elements of maintenance methodology which are the techniquesapplied to correct the failed equipment.The purpose of maintenance is to ensure that health care equipment is safe and in good condition and that all resources are used economicallyAll of them are in detail explained in chapter four of this project. 4
  9. 9. 5. Nuances of preventive/break down and reparability centered maintenance. The time and way of performing preventive maintenance and repairing an instrument differs. Reparability is the act of repairing equipment may be after the equipment fails while preventive maintenance is the act of maintaining equipment before its failure. For instance, if the pressure gauge of steam autoclave fails to work, it must be repaired to return back to its former normal functionality. Therefore, the reparability of an instrument is extremely essential. 5.1 Preventive/break down maintenance Preventive maintenance is a type of maintenance, where equipment is maintained before break down occurs. This type of maintenance has many different variations and is subject of various researches to determine best and most efficient way to maintain equipment. Recent studies have shown that Preventive maintenance is effective in preventing age related failures of the equipment. For random failure patterns which amount to 80% of the failure patterns, condition monitoring proves to be effective. 5.2 Reparability centered maintenance Reliability centered maintenance is an engineering framework that enables the definition of a complete maintenance regime. It regards maintenance as the means to maintain the functions a user may require of machinery in a defined operating context. As a discipline it enables machinery stakeholders to monitor, assess, predict and generally understand the working of their physical assets. This is embodied in the initial part of the RCM process which is to identify the operating context of the machinery, and write a Failure Mode Effects and Criticality Analysis (FMECA). The second part of the analysis is to apply the "RCM logic", which helps determine the appropriate maintenance tasks for the identified failure modes in the FMECA. Once the logic is complete for all elements in the FMECA, the resulting list of maintenance is "packaged", so that the periodicities of the tasks are rationalized to be called up in work packages; it is important not to destroy the applicability of maintenance in this phase. Lastly, RCM is kept live throughout the "in-service" life of machinery, where the effectiveness of the maintenance is kept under constant review and adjusted in light of the experience gained.6. Maintenance planning, scheduling and organization Every maintenance activities should be planned, scheduled and organized before its performance regardless of its difficulty. But there may be unforeseen situations when equipment fails to work suddenly. To correct such equipment, there may not be enough time to plan; so we may be enforced to maintain 5
  10. 10. without plan. But the probability for maintenance to be done without plan is very low. 7. Reliability, maintainability, and availability Every medical devices used in hospitals should always be reliable and maintainable. Reliability is the ability of an instrument to function for a long period of time without any failure while maintainability is to mean equipment’s ability to be maintained. Besides, a medical device should also be available. It means the equipment should be found at every hospital or other health centers. 8. Spares provisioning It is the act of providing spare parts of a medical device. Every medical equipment posses their own building blocks from which it has been made. These blocks should be complete to achieve the desired performance of equipment. The absence of single part may cause non-functionality of the device. For instance, in steam autoclave, the absence of knocks causes the steam to be uncontrollable. 9. Networking and maintainability database This networking and maintainability database is very important manual type of database to let the users of the device to understand its operation nicely. 10.Reconditioning processIt is the act of checking the correct performance of equipment. This process is verycrucial for the safety of the equipment. Unless reconditioning process carried out, somedevices may be non-functional.11. Computerized maintenance management system formedical equipment.The appropriate program is required to control the cure cycle of the autoclave. Each cycle has adesignated rise in temperature and pressure, a precise cure period, and a specific decrease intemperature and pressure. Such processes are commonly termed the up ramp, the cure cycle, andthe down ramp.The operation of the autoclave requires the operator to select the controller or computer programspecified in the work order for each cure cycle. Any initial operation of the autoclave under anew computer program must be carefully monitored, to ensure the program is within autoclaveparameters and accurate in meeting operational requirements. Only authorized personnel may setor make changes to the autoclave program. 6
  11. 11. CHAPTER TWOOperational principles:Application:Steam autoclave is used mostly for surgical instruments. This method is not well suitedfor heat sensitive materials and instruments.Many surgical instruments are not designed to withstand prolonged heat and moisture ofthe steam sterilization process. This leads to alternative sterilization categories: chemicalsterilization and radiation sterilization, which allow heat and moisture sensitive materialsto be sterilized.Steam by itself is not sufficient for sterilization, and pressure that is greater thanatmospheric is needed to increase the temperature of steam for thermal destruction ofmicrobial life. Steam, for a specified time at required temperature, must penetrate everyfiber and reach every surface of items to be sterilized. When steam enters thesterilization chamber under pressure;• It condenses upon contact with cold items.This condensation frees heat, simultaneously heating and wetting all items in the load,thus providing heat and moisture.Any living thing will be killed when exposed to saturated steam at 120°C (250° F)longer than 15 minutes. As temperature is increased, time may be decreased. Aminimum temperature-time relationship must be maintained throughout all portions ofload to obtain effective sterilization. At the end of the cycle, re-evaporation of watercondensate must effectively dry contents of the load to maintain sterility. 1. technical specification for operation of steam autoclaveThis autoclave as been designed and built in compliance with the operators need forfunctionality, practical use and safety.This autoclave has functional characteristics that make it unique, i.e: - Main switch to power the machine. - 60 minute cycle program. - Five minutes final drying phase. - Switch to select the 121° or 134° cycle. 7
  12. 12. - Fully visible water filling from the top. - Built in drying cycle with evaporation system. - Continuous venting of the air in the chamber to encourage the maximum steam saturation. - Approved safety valves to prevent over-pressures. - Safety valve to protect the heating element. - Safety thermostat to monitor the drying operation. - 121° - 134° operating pressure switches. - Chamber in seamless press-molded 18/10 STAINLESS STEEL. - 7 liter chamber capacity able to hold up to 3 trays. - Condensation radiator to drain off the water at the end of the cycle. - Used water can - Filling with the 250 cc dispenser. 2. Arranging the steam autoclave to sterilizing process:2.1. Standard sterilizing:Before being sterilized, the instruments must be cleaned to remove blood residues,incrustations,foreign bodies, etc. These impurities can damage the items being sterilized,the autoclave componentsand prevent the sterilizing process from being correctlycarried out.These instruments must be made of NON-ferrous material since they could damage theotherinstruments or the autoclave itself.To achieve perfect sterilizing, it is therefore important to proceed in the following way:1. Rinse and brush the instruments under running water immediately after use to removeall deposits.2. Place the instruments in the ultrasound machine with distilled water and detergentsolution ifpossible.3. Thoroughly rinse the instruments in demineralized water to prevent scaling stains.4. Dry the instruments to eliminate all water residues which could lead to oxidation.5. Wash, rinse and dry the supplied trays and make sure that they are perfectly clean.6. To ensure that packaged instruments are perfectly dried, we recommend use ofsupport art. M9050supplied as an optional.7. If loose instruments must be sterilized, it is advisable to cover the trays with a paper orfabricnapkin to prevent direct contact with the tray surface: do not place the instrumentsstraight on to thetrays.8. Scissors and forceps should be slightly opened. Mirrors and containers should beplaced upsidedown for the sterilizing process.9. It is advisable to keep the instruments separated from each other to achieve a bettersterilizingaction. Overloading will impair the sterilizing process.10. If packaged instruments must be sterilized on the trays, place the packets with theirtransparent sidedownwards and do not overlap. The packets should not be too large.Drying will be difficult if theiredges overlap.11. The machine can operate with a maximum 3 Kg load.2.2.Sterilizing hand-pieces:1. Carefully read the hand-piece operation manual with particular attention to the partabout sterilizing. 8
  13. 13. 2. Wrap the hand-piece in the special sterilizing cloth.3. Place the wrapped hand-piece on a NON-perforated tray to prevent spilt lubricatingoil frompolluting the pipes of the autoclave.4. Proceed with a short cycle 121°C sterilizing program.5. Remember to immediately remove the hand-piece from the autoclave at the end of thesterilizingprocess.6. It is inadvisable to sterilize hand-pieces using the night cycle.It is essential to place a chemical indicator in the autoclave on each cycle, to ensure thatthe sterilizingprocess has taken place correctly.3. Controlling parts:- 1 –warning light to indicate drying cycle in progress .- 2 - 134°C cycle indicator light.- 3 - 121°C cycle indicator light.- 4 - display- 5 –cycle programmer timer.- 6 –pressure gauge.- 7 –main switch.- 8 –cycle start/stop.- 9 – chamber.- 10 –door opening device.- 11 –reset heat.4. Method of use:a) Open the door by means of the device.b) Turn on the main switch.c) Arrange the instruments on the supplied Trays without overlapping the packets. Themaximum load allowed is 1 kg.d) Fill the chamber with distilled water using the supplied dispenser, which holds 250 ccwhen full.e) Shut the door using its handle.f) Select the required sterilizing time using the timer. This time can vary depending onthe loadof instruments and the type of material.g) Activate the selected sterilizing cycle with specified buttons.h) If very delicate materials are sterilized, it is advisable to remove them as soon as thecycle ends or even during the dry phase, after making sure that the pressure gaugesetting is Ø.i) Each time that a cycle is carried out, place an indicator (the TERMALOG or VAPORLINE EXTENDER) in the sterilizing chamber to confirm the sterilizing process.j) When the display reaches Ø, sterilizing will have terminated. The door can then beopened with caution, always after having made sure that the pressure gauge is on the Øsetting.k) The machine switches off automatically at the end of the cycle and issues an acousticsignal. 9
  14. 14. l) If the instruments are still wet after sterilizing, proceed as follows to complete thedryingprocess.-leave the door ajar.-select the Dry cycle.-set the required number of minutes for the drying phase.-now repeat the drying cycle, which will stop automatically.m) Use the supplied tool and wear protective gloves when removing the material fromthe chamber.n) Keep about 50 cm away from the appliance when the door is opened as residue steamcould escape from the upper side of the door and could scald the operator.o) Open the door with care, using the device and an upward movement, always aftercheckingthat the pressure gauge setting is Ø. If no resistance is opposed, the door willopen easilywhen the device is moved from the right towards the left.p) If the door is not opened immediately after the sterilizing cycle ends, condensedwatery vapor could form on its surface and drip off on opening. 5-Schematic diagramFigure1: schematic diagram of steam autoclave6. Accessories of steam autoclave- Autoclave Deodorant disc- Autoclave indicator tape- Autoclave wrap- Biological indicators, Harney- Daily autoclave performance test- Chamber brite autoclave cleaner- Glove, biohazard autoclave- Heat seal sterilization pouches- Heat sealable gusseted pouches 10
  15. 15. CHAPTER THREEInstallation and sterilization process of steam autoclave3.1. Capacityof steam autoclave that must be known by the operator beforeinstallation.Description Unit valuesPower source voltage rating v 230 ACPower source frequency Hz 50/60Machine power rating W 1000Boiler volume mm 170x270Operating pressure Bar 2.1-1.1Gross weight Kg 20Operating temperatures celsius 121 to 132Table1. steam autoclave’s capacity.3.2. Installation and preliminary inspectionsThe installer is obliged to make sure that the place in which the sterilizer is installed fitsfor that purpose.The machine is sent packed on a wooden pallet. Make sure that the packing has not beendamaged andthat everything is in a perfect condition. Handle the box by means of itshandles and place it on asurface in the immediate vicinity of the place in which themachine is to be positioned (the weight ofthe model is given in chap. 2, in the technicalspecifications).Remove the machine from its wrapping by pulling it out of the box vertically, using 2hooks (availableon the market) inserted into the two holes at the sides of the casing.Remove the polystyrene filler ballsfrom around the machine. Make sure that none of theparts has been damaged and that the machine iscomplete with all the accessoriesindicated in the consignment note. Immediately contact our reseller ifdiscrepancies arediscovered.All the packing materials must be kept for guarantee purposes. Machines returnedwithout their originalpacking will not be accepted.Install the autoclave in a well-ventilated place, well away from sinks, heat sources,grinders and fromall other machines that create vibrations and/or dust.Place the autoclave delicately on to a perfectly flat surface. Take care to leave a space ofabout 5-10 cmall around the machine to allow for aeration.Autoclave must be installed in a well-lighted place equipped with an electrical systemthat complieswith the current standards in force.Remember that cannot be built into other furniture as it is filled with water from the top.Fit the electric plug into a socket with the capacity of at least 10 amperes and equippedwith an earth connection. Make sure that the mains voltage ratingcorresponds to thevalue indicated on the label at the rear of the machine (230 Volts). It must only be filled 11
  16. 16. with distilled waterto ensure that the electrical and air-operated devicesoperateefficiently and are long lasting.Carry out a cycle of dry-run tests using one indicator (type TERMALOG or VAPORLINEEXTENDER).Keep the receipt which should be attached to the installation form and sent off alongwith the warranty.-Never connect the plug of the machine to a reduction.Do not install the machine in places at altitudes of more than 1200 m.above sealevel.If this is the case, contact the manufacturer for a special version of themachine.Use a bubble level to make sure that the surface on which the appliance isto bepositioned is perfectly horizontal.3.3 items for autoclavingAlthough autoclaving provides an economical way of sterilizing and decontaminatingitems, not all material can be autoclaved. Some materials are hazardous when they areautoclaved causing the generation of toxic /noxious gas. To identify what may or maynot be autoclaved, a general list of items has been included in this project.Items that CAN be autoclaved are:- Cultures and stocks of infectious material- Culture dishes and related devices-Discarded live and attenuated vaccines.-Contaminated solid items such as: petri dishes, pipettes, gloves, paper towel.-Items for sterilizations such as; glassware, media, aqueous solutions, equipment.Items that CAN NOT be autoclaved are:- Materials containing: solvents, volatile, chlorinated compounds (HCL, bleach) orcorrosive chemicals (such as: phenol, ether, chloroform) etc.- Material contaminated with chemotherapeutic agents- Radioactive material (without prior approval)- Some plastics.3.4 loading an autoclaveThis section will address the various steps to be undertaken when preparing andautoclaving the material to be decontaminated or sterilized.. The following factors willbe discussed: packaging (primary and secondary), identification requirements, and thefundamentals of loading an autoclave to maximize steam penetration. Each of theseplays a critical role in ensuring a successful decontamination /sterilization.Prior to Loading an Autoclave:Verification should be undertaken to ensure the autoclave has been functioning correctlyand has been meeting the validation requirements. This verification can be performedby: 12
  17. 17. 1) Reviewing the previous cycle log recordings,2) Examining the results of the daily* verification records, and3) Speaking to the individual responsible for the autoclave.PackagingAs the success of the decontamination /sterilization is dependent upon the penetration ofheat; how material is initially prepared will greatly affect the outcome. Considerationmust be given to the primary container (containing the contaminated waste), volume ofliquid, amounts of material, and the secondary container (containing the primarycontainer).The structural integrity of the container is an important consideration. Not all containerswithstand the demands placed on them during the autoclave process. Desirablecharacteristics are heat resistance, good thermal conductivity, puncture proof andimpervious to water.Good Choices:-borosilicate glass (Pyrex) has very low thermo expansion property and thereforeresistant to breaking due to heating.Polypropylene (PP) and polycarbonate (PC) are heat resistant plastics.-Stainless steel is a good heat conductor and thus facilitates sterilization.Poor Choices:Polystyrene (PS), Polyethylene (PE) and high density polyethylene (HDPE) do not resistheat well.If there is a risk of material melting ensure they are placed in a secondary containerwhich is resistant to heat.Transporting Packaged Material to the AutoclaveWhen transporting material to be autoclaved, use a cart with guard rails. Ensure the useof a secondary container to collect any spillage should the cart be knocked or jarredduring transport. Use a direct but not heavily populated route. Surface decontaminatesthe container prior to transport, unless there is no risk of contamination. This wasteshould be restricted to laboratory zones and not areas used by the general public. Shouldthis not be possible contact the EHSS for advice.3.5 unloading an autoclaveThe greatest risk of personal injury occurs during the process of unloading the autoclave.Not only is the risk of burns or scalding significant, but one may also be exposed to thevapor and gases generated by the inadvertent autoclaving of volatile chemicals. Super-heated liquids also pose of risk of exploding if they are shaken or moved during thecooling process. In addition glassware can break if the autoclave dooris opened too 13
  18. 18. quickly, and sufficient time is not provided for them to approach roomtemperature.Consequently, extreme caution must occur during this final stage.3.6 Procedures to follow:1. Wear all necessary personal protective equipment.2. The chamber pressure gauge of the autoclave should be zero before openingtheautoclave’s door.3. Crack door slightly and stand back to allow steam to escape. To minimize the risk ofaccidents caused by steam escape, the person who opens the autoclave door should standdirectly behind it.4. Slowly open autoclave door. Opening the autoclave door too quickly may resultIn a glassware breakage and/or steam burns to the skin.5. If boiling or bubbling is present, wait until it subsides. Assess the risk of super-heatedliquids.6. Over exposure of saline or water is not a critical factor (as it is with media), so theseliquids may be allowed to cool (for 10 min.) in the autoclave after cracking the door torelease the steam. This is also recommended for all other items.7. Bring the autoclave trolley to the chamber.8. Using heat resistant gloves, carefully transfer the containers (pans) to the trolley. Becareful not to jolt the containers as it could result in breakage.9. Move the containers to a draft free area.10. If not already cool wait 10 minutes, prior to storing sterilized material or preparingautoclaved waste for disposal.11. After every use, it is advised to close the autoclave door but do not seal the door asthis will shorten the life span of the rubber gaskets on the door.12. Verify that the temperature sensitive tape has changed color, or diagonal lines or thewords “autoclaved” has appeared. If no change appears on the tape, the load is requiredto be re-autoclaved after placing new tape on the material. Also verify the cycle logrecorder to check the temperature and time attained. If minimum time and temperature isnot attained on the second cycle, users should contact the person responsible formaintenance of the unit to initiate repairs. Leave a note on the autoclave stating theproblem and the it cannot be used until problem has be resolved.13. The container that could be contaminated by a liquid splash (due to boil over) or bydirect contact with contents of the waste bag (such as melted agar) should always bewashed after each use.3.7 Quality controlA number of tools are available to assess the performance of the autoclave; theseinclude physical, chemicaland biological indicators. It is important to note thatthese indicators will only respond to time, temperatureand moisture conditions,and not to organic load. 14
  19. 19. A, Physical Indicators:Pressure and temperature recording devices.Thermocouples can be placedinside the load to determine the temperatureachieved in the bag itself.B, Chemical Indicators:These indicators change color after being exposed to specific temperatures,forexample: heat sensitive tape. Upon exposure to the given temperature thechangewill occur; it is not time related. Therefore these indicators can only attestto thetemperature attained and not to exposure time and hence success ofsterilization.C, Biological indicators:Biological indicators are used in the efficacy testing of the autoclave processtoeffectively sterilize the contents being treated. Bacillusstearothermophilusspores are used, as they are the most resistant organism tosteam autoclaving.To determine the effectiveness of the autoclave process the biologicalindicatormust be placed in a typical test load (solid or liquid) and exposed to thetypicalcycle conditions. This is the standard method of validating theeffectiveness ofyour autoclave procedures. Testing using a biological indicatormust beundertaken daily, unless otherwise authorized by EHSS.3.8 General Procedures: 1. Read and follow the suppliers instructions. 2. Place B. stearotheromophilus in centre of representative test load. 3. Process load in normal fashion 4. a) Extract and incubate B.stearothermophilus sample as instructedbymanufacturer.b. Use another ampoule (same lot #) not autoclaved to act as a positive control. 5. Check for color change at regular intervals during the incubation period(8, 12, 24, and 48 hours). If media is yellow and turbid the autoclave process hasFAILED. Immediately upon noting yellow coloration, re-run all samples withnew biological indicators. 6. If failure continues to be noted, either increases time of exposure orinitiaterepairs to the autoclave. Note the autoclave cannot be used againuntilvalidations procedure indicates that autoclave is now adequately sterilizingthe material. 7. Record all results (Positive and Negative). 15
  20. 20. CHAPTER FOUR:Maintenance and troubleshootingTypes of maintenance:1. Run-to-failure maintenance.2. Preventive maintenance.3. Corrective maintenance.4. Improvement maintenance.5. Predictive maintenance.Even though all of these maintenance types are needed, the two most commonly usedtypes of maintenance to keep normal functioning of steam autoclave are: preventive andcorrective type. 1. Corrective maintenance  Corrective maintenance is probably the most commonly used approach, but it is easy to see its limitations. When equipment fails, it often leads to downtime in production. In most cases this is costly business. Also, if the equipment needs to be replaced, the cost of replacing it alone can be substantial. It is also important to consider health, safety and environment (HSE) issues related to malfunctioning equipment.  Corrective maintenance can be defined as the maintenance which is required when an item has failed or worn out, to bring it back to working order. Corrective maintenance is carried out on all items where the consequences of failure or wearing out are not significant and the cost of this maintenance is not greater than preventive maintenance.Whenever certain biomedical equipment fails, there must be enough technician power inhospital to correct the devices’ failure. Besides, before failure there should also bepreventive maintenance activities to prevent the equipment from failure. The time andthe way how certain medical instrument maintained differ. 16
  21. 21. Figure.2. maintenance cycle.2. Generalpreventive maintenanceThe machine needs to be serviced in a particular way. Users are therefore advised tocomply with thebelow listed recommendations:� Periodically check the condition of the electrical system with particular attention to theconnectioncable.� Periodically clean the door, the seal and take particular care when cleaning theinternal part of theboiler, removing any scaling with the damp sponge (supplied withthe machine). Correct cleaningof these parts of the machine will ensure that thesterilizing cycle takes place in the right way.� the machine is not to be used for a long period of time, leave the door ajar and store Ifit at a roomtemperature of >8°C.� Use a damp cloth to clean the casing of the machine. Never ever use inflammableliquids for anyreason whatsoever.2.1 Daily routine maintenanceClear the door seal, door window and generally clean the outer and inner surfaces of themachine.Clean the black silicone door seal, the outer and inner edges and the part where the doorrests on thesterilizing chamber and on which the seal must tightly fit. Use the suppliedsponge to do this. The softpart of the sponge can be used to clean the seal while therough part can be used to clean the edge of thechamber.This cleaning operation must be carried out regularly to remove all impurities that couldlead to loss ofpressure inside the sterilizing chamber.Check the used water level and drain off the actual water into the sewer if necessary.Then wash out thecan under running water.2.2 Weekly routine maintenance 17
  22. 22. Clean the sterilizing chamber /cleaning the trays and tray holders. All traces of depositsmust be removed from thebottom of the chamber. Use the rough side of the suppliedsponge for this operation, attempting toeliminate any scaling that may have formed.Rinse everything with the same water used for the sterilizing process. The trays and tray-holders mustalso be cleaned in this way.Drain the water and clean the tray.2.3 Monthly routine maintenanceLubricate the pins and locking mechanisms.Check the movement of the hinge and door locking pin. Lubricate with Vaseline oil.Make sure that the door is well regulated. If it is excessively slack, it must be adjusted bymeans of thesupplied wrench. Turn the regulator at the rear of the door in acounterclockwise direction. This will increase thepressure exercised by the seal.Attempt to shut the door. If some difficulty is encountered, turn the regulator in aclockwise direction.Clean the entire autoclave cabinet with a slightly damp sponge, including the doorcasing.2.4 Periodic extraordinary maintenanceTo allow the autoclave to operate in a regular way, the manufacturer advises users tocarry out afunctional test to ensure that the temperature and pressure parameters of themachine comply with thestandards required for a correct sterilizing process.These tests must be conducted by personnel authorized by the manufacturer, usingcalibrated andperiodically certified instruments.The autoclave is able to accept probes for the sterilizing tests.It is advisable to have the appliance subjected to a Total Overhaul by After-sales Servicestaff at leastonce every 12 months.The operation of the safety valve installed at the rear of the machine must also bechecked at least onceevery 12 months. This is done by removing the protective casingand re-tightening the ring nut of thevalve by hand. To prevent accidents, this operationshould obviously be carried out when the machineis cold and off. 18
  23. 23. Troubleshooting:FAULTS CAUSES REMEDIESThe timer fails to operate. -Power is not reaching the -replace the board. board. -check t fuse on the board -board burnt-out. with the tester.The pressure gauge remains -pressure gauge blocked or -clean the tube or replaceat a standstill even during broken. the pressure gauge.the sterilizing cycle. -no water in the chamber. -repeat the cycle.Water remains in the - The dry indicator light - Replace or check thechamber. remains on and the water is draining solenoid valve. not drained.The machine fails to - The heating element has - Replace the heatingpressurize during the cycle. burnt out. element. - The wire has detached - Re-connect the wire. from the heating element. - Press the reset alongside - The safety thermostat has the control panel. tripped.Insufficient pressure for - The bulb thermostat - Slightly turn thetheselected cycle with setting is incorrect. thermostat in the clockwiseindicatorlights permanently - Not enough water in the direction.ON. boiler. - Comply with the - Leaks from the door seal. instructions. - Clean the seal and the chamber.The pressure increases very - Chamber very dirty - Clean the chamber asSlowly. inside. described in the - Heating insufficient. maintenance section. -Too much vapor issues - Heating element rods from the breather union. loosened. - Replace the complete breather union.The machine is not powered - Defective switch. -Replace the switch andwhen the switch is turned -No power is reaching the check the wires.ON. mains socket. - Check the socket and - Fuses in the machine electricity main. burnt out. - Remove the casing and replace them with fuses of an equal value after having made sure that there are no short-circuits. 19
  24. 24. CHAPTER FIVEResults and DiscussionSteam sterilization inactivates microorganisms through the application of saturated steam underpressure. It generally denotes heating in an autoclave employing saturated steam under a certainpressure to achieve the desired chamber temperature. The process thermally damages thebacterial cell structure, including the outer and cytoplasmic membrane, and rendering the cell nolonger viable. The inactivation of bacterial cell vital mechanisms depends on the bacterial cellstructure, the temperature and duration of the heat exposure to which they are exposed. Inpractical terms which means that it would take a longer time at lower temperatures to sterilize apopulation than at a higher temperature. For example, bacterial colony survival decreases withincreasing duration of time of autoclaving at elevated temperature and automated pressure.RecommendationsMost operators do not know how to use steam autoclave and thus they become thevictim of contamination. Therefore, based on this fact we want to write the followingrecommendations.➢Always wear personal protective equipment in compliance with the directives thatestablish thecurrent accident-preventing provisions.➢Do not approach the machine with inflammable materials.➢Do not carry out repairs or maintenance work whilst the machine is operating orplugged into theelectricity main or when parts of it are hot.➢Only responsible adults may use the machine in places inaccessible to children.➢ Use the machine in a dry place, sheltered from the rain.➢Periodically inspect the power cable to make sure that it is in a good condition.➢If there are several persons in the place of work, remember to keep at a safe distancefrom themachine to prevent accidental contact with hot parts.➢ Never ever operate the appliance unless the power cable is in a perfect condition andthe structureundamaged.➢It is advisable to keep the door half-open when the appliance is not in use.➢Do not move the machine when the tank is full of water.Pay the utmost attention to those parts of the appliance that become hotduring operationand that still remain hot after it has been switched off.Keep your face well away from the top part of the machine when thedoor is opened toprevent it from being scalded by steam. Keep about 50cm. away from the machine whenopening the door.As specified in the technical specifications, these autoclaves operate at apressure that canreach 2.2 Bar at most. Do not use the autoclave in animproper way and do not carry outmaintenance operations while thesterilizing cycles are in progress. Remember that thepressure is shownby the pressure gauge installed on the front of the machine itself.Wait at least 20 minutes after the appliance has been switched off, toallow the boiler tocompletely cool. 20
  25. 25. REFERENCES- Laboratory Biosafety Guidelines, Health Canada, 3rd Edition-Draft, Sept. 20, 2001- Laboratory Biosafety Manual, 2nd Edition, World Health Organization, Geneva- “Using a Gravity Displacement Steam Autoclave in a Biomedical Laboratory” videoproduced by School of Public Health, University of Minnesota under contract withNational Institute of Allergy and Infectious Disease.- Cooney,Timmothy E., Techniques For Steam Sterilizing Laboratory Waste,AMSCOresearch and development.- Autoclave Procedures, Office of Radiation, Chemical and Biological Safety, MichiganStateUniversity.Safety Net - Effective Use of Autoclaves, University of California - Davis,`EnvironmentalHealth and Safety, University of CaliforniaBiological Safety Update, UCSF Autoclave Quality Control Program, University ofCalifornia -San Francisco, Environmental Health and Safety.Medical Waste Management Program, University of CaliforniaAPPENDICES:Here are some abbreviations and symbols used in this text.Symbols Their full namemmHg Millimeter mercuryCm centimeterKg kilogrammA Milli-ampereV voltHz hertz 21