1. JIMMA UNIVERSITY
JIMMA INSTITUTE OF TECHNOLOGY(JIT)
MAINTENANCE METHODOLOGY TERM PROJECT BY
STUDENTS 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. Abstract:
The intention of this project is to have deep understanding of special biomedical
equipment called steam autoclave. It is an instrument used to sterilize microbiological
life which exists on surgical equipment. Every company producing this device has its
own manual for installation, maintenance and operation of the device. Without reading
this manual, one cannot simply make the power ON since the device is too harmful and
it has complex electric circuit which may cause shock if not properly operated. The thing
that motivates us to do this project on steam autoclave is due to such electric shock and
contamination caused by the operator’s error. Therefore it is aimed at minimizing this
and other problems concerning the device.
Acknowledgement:
We would like to thank our instructor AtoWondimu Fanta for his unexplainable moral
support and encouragement towards this project. We also show our gratitude to our
friends 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 access
for us to complete this project. Finally, we want to say thanks for God who made all this
possible.
ii

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. Result and conclusion…………………………………………20
Recommendation…………………………………………20
References ……………………………………………….21
Appendices ………………………………………………21
Lists 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. CHAPTER ONE:
Introduction:
The machine described in this project is a steam autoclave sterilizer that has
beenspecially designed to sterilize most of the materials and instruments used in dental
surgeries, doctors'surgeries and hospitals in general.
This project contains general information pertaining to autoclave operation, and is to be used as a
general reference.
When performing autoclave operations, all procedures must be performed in accordance withthe
specifications 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 lights
and by theposition of the controls.
An autoclave is a specialized piece of equipment designed to deliver heat under pressure
to 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 hazard
to people or environment, while sterilization is the total destruction of microorganisms
present.
This is achieved because heat damages the cell’s essential structures, including the
cytoplasmic membrane, rendering the cell no longer viable. This will only occurs if the
material is heated to the specific temperature for a given period of time. These
parameters will vary depending upon the nature of the microorganisms present and the
characteristics of the load itself.
To facilitate this transfer of heat, moisture is often added; but this does not guarantee
success. A number of other factors must be considered.
The common types of steam sterilization cycles are gravity-displacement, which
removes air from the chamber by gravity displacement as steam-entering chamber exerts
pressure on air; and the pre-vacuum cycle, which removes air by a vacuum pump while
steam is simultaneously injected into the chamber.
1

6. Background :
Sterilization means the use of physical or chemical procedure to destroy all microbial
life, including highly resistant bacterial endospores . Bacterial endospores are the most
resistant of all living organisms because of their capability to withstand destructive
agents.Although the physical or chemical process used to destroy all pathogenic micro-
organisms including spores is not absolute , when all parameters of the sterilization
process 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 been
achieved. Although thermally sensitive tapes and bag markers indicate exposure to
sterilization conditions, they do not verify that sterilization has been achieved. Results of
studies of the effectiveness of dental office sterilization have been variable, with 2% to
20% failure rates in monitored sterilization attempts. The majority of sterilization
failures have been found to be due to human error, rather than equipment’s failure.
From the above three categories of sterilization, High temperature/pressure sterilization
which is performed by steam autoclave is the only sterilization technique that is going to
be discussed throughout the end of this project.
Steam autoclave is the oldest, safest and the most cost effective method of sterilization
inthe medical equipment industry. It is an instrument used for sterilization of surgically
used equipment by using steam form of distilled water.
Problem statement
It is a statement form of a device’s problem. Whenever a certain device fails to work, it
must be repaired to be reused. For its correction or maintenance, there should be proper
problem statements concerning the device’s failure. For instance, in steam autoclave,
there may be many problems that make it non-functional. Examples of these problems
are briefly shown in this project under the topic of troubleshooting in chapter four.
2

7. Objectives:
General objectives: the general objectives of this project is to let students to
outstandingly understand what maintenance is, how it is done, when it should be done
and what procedures are needed to do. Besides, it is also used to understand installing,
operating, troubleshooting and maintaining general medical instruments. These
instruments differ in a way how to operate, maintain, install, and etc. Therefore, every
equipment has its own operational and maintenance manual. So, by looking through that
manual, one can achieve the intended performance or action of equipment.
Specific objectives:specifically, this project briefly explains special medical
equipment, steam autoclave. It is an instrument used for sterilization of surgical
equipment to kill out all microbial life. These text clearly talks about the equipment’s
operational principles, installation, purpose, building blocks, troubleshooting and
maintenance. Afterreading this project paper one can confidentially install, troubleshoot,
operate and brilliantly maintain every types of steam autoclave used in hospitals.
3

8. The basic topics of maintenance methodology:
1. maintenance activities
This methodology refers to the action taken by technicians for maintaining an
instrument. The maintenance activity should be done by experienced technician. Even if
the availability of qualified technicians to accomplish maintenance and repair is readily
available, the tasks of the maintenance man are extremely difficult for the ever
increasing usage of modern equipment. some of the modern day equipment are often too
complex, too costly, inappropriate and difficult to maintain in developing society. The
main definitions and types are briefly explained in chapter four of this project.
2. Faults
Faults are the failure that one equipment exhibits. It is the state of abnormality of the
equipment. 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 the
automatic expiration of the equipment. To diagnosis this problem, maintenance
procedures should be taken. In an autoclave, there may be many faults which are caused
by different problems such as: The timer fails to operate, The pressure gauge
remainsat a standstill even during thesterilizing cycle, Water remains in the
chamber, The machine fails to pressurizeduring the cycle, The pressure increases
veryslowly 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. 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. 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 process
It is the act of checking the correct performance of equipment. This process is very
crucial for the safety of the equipment. Unless reconditioning process carried out, some
devices may be non-functional.
11. Computerized maintenance management system for
medical equipment.
The appropriate program is required to control the cure cycle of the autoclave. Each cycle has a
designated rise in temperature and pressure, a precise cure period, and a specific decrease in
temperature and pressure. Such processes are commonly termed the up ramp, the cure cycle, and
the down ramp.
The operation of the autoclave requires the operator to select the controller or computer program
specified in the work order for each cure cycle. Any initial operation of the autoclave under a
new computer program must be carefully monitored, to ensure the program is within autoclave
parameters and accurate in meeting operational requirements. Only authorized personnel may set
or make changes to the autoclave program.
6

11. CHAPTER TWO
Operational principles:
Application:
Steam autoclave is used mostly for surgical instruments. This method is not well suited
for heat sensitive materials and instruments.
Many surgical instruments are not designed to withstand prolonged heat and moisture of
the steam sterilization process. This leads to alternative sterilization categories: chemical
sterilization and radiation sterilization, which allow heat and moisture sensitive materials
to be sterilized.
Steam by itself is not sufficient for sterilization, and pressure that is greater than
atmospheric is needed to increase the temperature of steam for thermal destruction of
microbial life. Steam, for a specified time at required temperature, must penetrate every
fiber and reach every surface of items to be sterilized. When steam enters the
sterilization 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. A
minimum temperature-time relationship must be maintained throughout all portions of
load to obtain effective sterilization. At the end of the cycle, re-evaporation of water
condensate must effectively dry contents of the load to maintain sterility.
1. technical specification for operation of steam autoclave
This autoclave as been designed and built in compliance with the operators' need for
functionality, 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. - 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 correctly
carried out.
These instruments must be made of NON-ferrous material since they could damage the
otherinstruments 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 remove
all deposits.
2. Place the instruments in the ultrasound machine with distilled water and detergent
solution 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 of
support art. M9050supplied as an optional.
7. If loose instruments must be sterilized, it is advisable to cover the trays with a paper or
fabricnapkin to prevent direct contact with the tray surface: do not place the instruments
straight on to thetrays.
8. Scissors and forceps should be slightly opened. Mirrors and containers should be
placed upsidedown for the sterilizing process.
9. It is advisable to keep the instruments separated from each other to achieve a better
sterilizingaction. Overloading will impair the sterilizing process.
10. If packaged instruments must be sterilized on the trays, place the packets with their
transparent 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 part
about sterilizing.
8

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 lubricating
oil 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 the
sterilizingprocess.
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 that
the 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. The
maximum load allowed is 1 kg.
d) Fill the chamber with distilled water using the supplied dispenser, which holds 250 cc
when full.
e) Shut the door using its handle.
f) Select the required sterilizing time using the timer. This time can vary depending on
the load
of 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 the
cycle ends or even during the dry phase, after making sure that the pressure gauge
setting is Ø.
i) Each time that a cycle is carried out, place an indicator (the TERMALOG or VAPOR
LINE EXTENDER) in the sterilizing chamber to confirm the sterilizing process.
j) When the display reaches Ø, sterilizing will have terminated. The door can then be
opened with caution, always after having made sure that the pressure gauge is on the Ø
setting.
k) The machine switches off automatically at the end of the cycle and issues an acoustic
signal.
9

14. l) If the instruments are still wet after sterilizing, proceed as follows to complete the
dryingprocess.
-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 from
the chamber.
n) Keep about 50 cm away from the appliance when the door is opened as residue steam
could 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 after
checkingthat the pressure gauge setting is Ø. If no resistance is opposed, the door will
open easilywhen the device is moved from the right towards the left.
p) If the door is not opened immediately after the sterilizing cycle ends, condensed
watery vapor could form on its surface and drip off on opening.
5-Schematic diagram
Figure1: schematic diagram of steam autoclave
6. 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. CHAPTER THREE
Installation and sterilization process of steam autoclave
3.1. Capacityof steam autoclave that must be known by the operator before
installation.
Description Unit values
Power source voltage rating v 230 AC
Power source frequency Hz 50/60
Machine power rating W 1000
Boiler volume mm 170x270
Operating pressure Bar 2.1-1.1
Gross weight Kg 20
Operating temperatures celsius 121 to 132
Table1. steam autoclave’s capacity.
3.2. Installation and preliminary inspections
The installer is obliged to make sure that the place in which the sterilizer is installed fits
for that purpose.
The machine is sent packed on a wooden pallet. Make sure that the packing has not been
damaged andthat everything is in a perfect condition. Handle the box by means of its
handles and place it on asurface in the immediate vicinity of the place in which the
machine is to be positioned (the weight ofthe model is given in chap. 2, in the technical
specifications).
Remove the machine from its wrapping by pulling it out of the box vertically, using 2
hooks (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 the
parts has been damaged and that the machine iscomplete with all the accessories
indicated in the consignment note. Immediately contact our reseller ifdiscrepancies are
discovered.
All the packing materials must be kept for guarantee purposes. Machines returned
without 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 of
about 5-10 cmall around the machine to allow for aeration.
Autoclave must be installed in a well-lighted place equipped with an electrical system
that 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 equipped
with an earth connection. Make sure that the mains voltage ratingcorresponds to the
value indicated on the label at the rear of the machine (230 Volts). It must only be filled
11

16. with distilled waterto ensure that the electrical and air-operated devicesoperate
efficiently and are long lasting.
Carry out a cycle of dry-run tests using one indicator (type TERMALOG or VAPOR
LINEEXTENDER).
Keep the receipt which should be attached to the installation form and sent off along
with 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 sea
level.
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 be
positioned is perfectly horizontal.
3.3 items for autoclaving
Although autoclaving provides an economical way of sterilizing and decontaminating
items, not all material can be autoclaved. Some materials are hazardous when they are
autoclaved causing the generation of toxic /noxious gas. To identify what may or may
not 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) or
corrosive chemicals (such as: phenol, ether, chloroform) etc.
- Material contaminated with chemotherapeutic agents
- Radioactive material (without prior approval)
- Some plastics.
3.4 loading an autoclave
This section will address the various steps to be undertaken when preparing and
autoclaving the material to be decontaminated or sterilized.. The following factors will
be discussed: packaging (primary and secondary), identification requirements, and the
fundamentals of loading an autoclave to maximize steam penetration. Each of these
plays 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 correctly
and has been meeting the validation requirements. This verification can be performed
by:
12

17. 1) Reviewing the previous cycle log recordings,
2) Examining the results of the daily* verification records, and
3) Speaking to the individual responsible for the autoclave.
Packaging
As the success of the decontamination /sterilization is dependent upon the penetration of
heat; how material is initially prepared will greatly affect the outcome. Consideration
must be given to the primary container (containing the contaminated waste), volume of
liquid, amounts of material, and the secondary container (containing the primary
container).
The structural integrity of the container is an important consideration. Not all containers
withstand the demands placed on them during the autoclave process. Desirable
characteristics are heat resistance, good thermal conductivity, puncture proof and
impervious to water.
Good Choices:
-borosilicate glass (Pyrex) has very low thermo expansion property and therefore
resistant 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 resist
heat well.
If there is a risk of material melting ensure they are placed in a secondary container
which is resistant to heat.
Transporting Packaged Material to the Autoclave
When transporting material to be autoclaved, use a cart with guard rails. Ensure the use
of a secondary container to collect any spillage should the cart be knocked or jarred
during transport. Use a direct but not heavily populated route. Surface decontaminates
the container prior to transport, unless there is no risk of contamination. This waste
should be restricted to laboratory zones and not areas used by the general public. Should
this not be possible contact the EHSS for advice.
3.5 unloading an autoclave
The 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 the
vapor 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 the
cooling process. In addition glassware can break if the autoclave dooris opened too
13

18. quickly, and sufficient time is not provided for them to approach room
temperature.
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 opening
theautoclave’s door.
3. Crack door slightly and stand back to allow steam to escape. To minimize the risk of
accidents caused by steam escape, the person who opens the autoclave door should stand
directly behind it.
4. Slowly open autoclave door. Opening the autoclave door too quickly may result
In 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-heated
liquids.
6. Over exposure of saline or water is not a critical factor (as it is with media), so these
liquids may be allowed to cool (for 10 min.) in the autoclave after cracking the door to
release 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. Be
careful 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 preparing
autoclaved waste for disposal.
11. After every use, it is advised to close the autoclave door but do not seal the door as
this 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 the
words “autoclaved” has appeared. If no change appears on the tape, the load is required
to be re-autoclaved after placing new tape on the material. Also verify the cycle log
recorder to check the temperature and time attained. If minimum time and temperature is
not attained on the second cycle, users should contact the person responsible for
maintenance of the unit to initiate repairs. Leave a note on the autoclave stating the
problem 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 by
direct contact with contents of the waste bag (such as melted agar) should always be
washed after each use.
3.7 Quality control
A number of tools are available to assess the performance of the autoclave; these
include physical, chemicaland biological indicators. It is important to note that
these indicators will only respond to time, temperatureand moisture conditions,
and not to organic load.
14

19. A, Physical Indicators:Pressure and temperature recording devices.
Thermocouples can be placedinside the load to determine the temperature
achieved 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 the
changewill occur; it is not time related. Therefore these indicators can only attest
to thetemperature attained and not to exposure time and hence success of
sterilization.
C, Biological indicators:
Biological indicators are used in the efficacy testing of the autoclave process
toeffectively sterilize the contents being treated. Bacillus
stearothermophilusspores are used, as they are the most resistant organism to
steam autoclaving.
To determine the effectiveness of the autoclave process the biological
indicatormust be placed in a typical test load (solid or liquid) and exposed to the
typicalcycle conditions. This is the standard method of validating the
effectiveness ofyour autoclave procedures. Testing using a biological indicator
must 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 instructed
bymanufacturer.
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 has
FAILED. Immediately upon noting yellow coloration, re-run all samples with
new biological indicators.
6. If failure continues to be noted, either increases time of exposure or
initiaterepairs to the autoclave. Note the autoclave cannot be used again
untilvalidations procedure indicates that autoclave is now adequately sterilizing
the material.
7. Record all results (Positive and Negative).
15

20. CHAPTER FOUR:
Maintenance and troubleshooting
Types 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 used
types of maintenance to keep normal functioning of steam autoclave are: preventive and
corrective 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 in
hospital to correct the devices’ failure. Besides, before failure there should also be
preventive maintenance activities to prevent the equipment from failure. The time and
the way how certain medical instrument maintained differ.
16

21. Figure.2. maintenance cycle.
2. Generalpreventive maintenance
The machine needs to be serviced in a particular way. Users are therefore advised to
comply with thebelow listed recommendations:
� Periodically check the condition of the electrical system with particular attention to the
connectioncable.
� Periodically clean the door, the seal and take particular care when cleaning the
internal part of theboiler, removing any scaling with the damp sponge (supplied with
the machine). Correct cleaningof these parts of the machine will ensure that the
sterilizing 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
If
it at a roomtemperature of >8°C.
� Use a damp cloth to clean the casing of the machine. Never ever use inflammable
liquids for anyreason whatsoever.
2.1 Daily routine maintenance
Clear the door seal, door window and generally clean the outer and inner surfaces of the
machine.
Clean the black silicone door seal, the outer and inner edges and the part where the door
rests on thesterilizing chamber and on which the seal must tightly fit. Use the supplied
sponge to do this. The softpart of the sponge can be used to clean the seal while the
rough part can be used to clean the edge of thechamber.
This cleaning operation must be carried out regularly to remove all impurities that could
lead 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. Clean the sterilizing chamber /cleaning the trays and tray holders. All traces of deposits
must be removed from thebottom of the chamber. Use the rough side of the supplied
sponge 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 maintenance
Lubricate 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 by
means of thesupplied wrench. Turn the regulator at the rear of the door in a
counterclockwise direction. This will increase thepressure exercised by the seal.
Attempt to shut the door. If some difficulty is encountered, turn the regulator in a
clockwise direction.
Clean the entire autoclave cabinet with a slightly damp sponge, including the door
casing.
2.4 Periodic extraordinary maintenance
To allow the autoclave to operate in a regular way, the manufacturer advises users to
carry out afunctional test to ensure that the temperature and pressure parameters of the
machine comply with thestandards required for a correct sterilizing process.
These tests must be conducted by personnel authorized by the manufacturer, using
calibrated 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 Service
staff at leastonce every 12 months.
The operation of the safety valve installed at the rear of the machine must also be
checked at least onceevery 12 months. This is done by removing the protective casing
and re-tightening the ring nut of thevalve by hand. To prevent accidents, this operation
should obviously be carried out when the machineis cold and off.
18

23. Troubleshooting:
FAULTS CAUSES REMEDIES
The 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 replace
at 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 the
chamber. remains on and the water is draining solenoid valve.
not drained.
The machine fails to - The heating element has - Replace the heating
pressurize 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 the
theselected cycle with setting is incorrect. thermostat in the clockwise
indicatorlights 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 as
Slowly. 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 and
when 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. CHAPTER FIVE
Results and Discussion
Steam sterilization inactivates microorganisms through the application of saturated steam under
pressure. It generally denotes heating in an autoclave employing saturated steam under a certain
pressure to achieve the desired chamber temperature. The process thermally damages the
bacterial cell structure, including the outer and cytoplasmic membrane, and rendering the cell no
longer viable. The inactivation of bacterial cell vital mechanisms depends on the bacterial cell
structure, the temperature and duration of the heat exposure to which they are exposed. In
practical terms which means that it would take a longer time at lower temperatures to sterilize a
population than at a higher temperature. For example, bacterial colony survival decreases with
increasing duration of time of autoclaving at elevated temperature and automated pressure.
Recommendations
Most operators do not know how to use steam autoclave and thus they become the
victim of contamination. Therefore, based on this fact we want to write the following
recommendations.
➢Always wear personal protective equipment in compliance with the directives that
establish 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 or
plugged 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 distance
from themachine to prevent accidental contact with hot parts.
➢ Never ever operate the appliance unless the power cable is in a perfect condition and
the 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 operation
and 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 to
prevent it from being scalded by steam. Keep about 50cm. away from the machine when
opening the door.
As specified in the technical specifications, these autoclaves operate at apressure that can
reach 2.2 Bar at most. Do not use the autoclave in animproper way and do not carry out
maintenance operations while thesterilizing cycles are in progress. Remember that the
pressure 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 to
completely cool.
20

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” video
produced by School of Public Health, University of Minnesota under contract with
National 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, Michigan
StateUniversity.
Safety Net - Effective Use of Autoclaves, University of California - Davis,
`Environmental
Health and Safety, University of California
Biological Safety Update, UCSF Autoclave Quality Control Program, University of
California -San Francisco, Environmental Health and Safety.
Medical Waste Management Program, University of California
APPENDICES:
Here are some abbreviations and symbols used in this text.
Symbols Their full name
mmHg Millimeter mercury
Cm centimeter
Kg kilogram
mA Milli-ampere
V volt
Hz hertz
21