Introduction to medical equipments safety and testing

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Medical Equipment’s Safety and Testing

Mehaboob Rahman

A hazard is any biological, chemical, mechanical, environmental or physical agent that is reasonably likely to cause harm or damage to humans, other organisms, or the environment in the absence of its control.

Hazards

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Most hazards are dormant or potential, with only a theoretical risk of harm; however, once a hazard becomes "active", it can create an emergency. A hazardous situation that has come to pass is called an incident. Hazard and possibility interact together to create risk

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Hazards on Medical Equipments

Medical electrical equipment can present a range of hazards to the patient, the user, or to service personnel.

Many such hazards are common to many or all types of medical electrical equipment, whilst others are peculiar to particular categories of equipment.

The root causes for injures involving medical equipment include Human Error, Faulty Equipment Design & Poor Maintenance. However, It is unwise to assume anything until a through investigation is made and failure analysis is performed on the equipment.

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Electro-Surgery burns due to poor contact with grounding plate. Punctured intestine due to insulation breakdown on laparoscope. Death caused for an infant by vacuum & suction lines reversed on

portable suction machine. . Infant brain damage due to defective valve design on portable oxygen

unit. Microshock electrocution due to broken ground wire in die injector line

cord. Many such hazards are common to many or all types of

medical electrical equipment, whilst others are peculiar to particular categories of equipment.

Listed below are various types of common hazards.

A small sample of the problems that are found in the past are listed below.

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1 - Mechanical Hazards2 - Risk of Fire or Explosion3 - Absence of Function4 - Excessive or Insufficient Output5 - Infection6 - Misuse7 - Risk of exposure to spurious electric

currents8 - Radiation

Common Hazards of Medical Equipments.

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All types of medical electrical equipment can present mechanical hazards.

These can range from insecure fittings of controls to loose fixings of wheels on equipment trolleys.

The former may prevent a piece of life supporting equipment from being operated properly, whilst the latter could cause serious accidents in the clinical environment.

1 Mechanical Hazards

The EnclosureThe enclosure of the device must be sufficiently strong to retain its integrity under conditions of normal wear and tearHandles of portable equipment are tested with a force of four times the weight of the product. If there is more than one handle, this weight is distributed between the handles.Moving PartsMoving parts which could produce a safety hazard must be suitable guarded to prevent access, unless exposure is essential to the operation of the equipment.If movement of the equipment, or parts of the equipment can cause injury to the patient, this movement can only be achieved by continuous operation of the control by the operator.Any electrically controlled mechanical movement must have an emergency switch.Sharp EdgesThe device must not have sharp edges, corners, etc.Stability

Medical devices must not overbalance when tilted to an angle of 10°.

1 Mechanical Hazards …. Continues..

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All mains powered electrical equipment can present the risk of fire in the event of certain faults occurring such as internal or external short circuits.

In certain environments such fires may cause explosions. Although the use of explosive anesthetic gases is not common today, it should be recognized that many of the medical gases in use vigorously support combustion.

2 Risk of Fire or Explosion

Medical devices typically contain a number of electro-mechanical and chemical systems and power sources. Power can be supplied to an actuating mechanism, or fluids and gases can be handled through compression, dispersion or valving. The devices typically contain items that include foamed padding and/or structural plastics. All of these things in combination present an energy source for ignition, fuel and oxidizer – good conditions for fire ignition and propagation.

Risk of Fire or Explosion

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Since many pieces of medical electrical equipment are life supporting or monitor vital functions, the absence of function of such a piece of equipment would not be merely inconvenient, but could threaten life

This recommend the use of proper test equipments to verify the correct operation of the equipment.

3 Absence of Function

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In order to perform its desired function equipment must deliver its specified output.

Too high an output, for example, in the case of surgical diathermy units, would clearly be hazardous. Equally, too low an output would result in inadequate therapy, which in turn may delay patient recovery, cause patient injury or even death.

This highlights the importance of correct calibration procedures.

4 Excessive or insufficient output

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Medical equipment that has been inadequately decontaminated after use may cause infection through the transmission of microorganisms to any person who subsequently comes into contact with it.

Clearly, patients, nursing staff and service personnel are potentially at risk here.

5 Infection

Microbes can be carried from one person to another on the surface of any equipment that is shared between them unless it is decontaminated between use.Decontamination of medical equipment involves the destruction or removal of any organisms present in order to prevent them infecting other patients or hospital staff.

The process by which microbes are passed from one infected person, to cause infection in another, is known as 'cross-infection'. Decontamination reduces the risks of cross infection and helps to maintain the useful life of equipment.

Decontamination

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Decontamination process

Cleaning, disinfection and sterilization are all procedures that are used in the decontamination process.

Cleaning is the process that removes contaminants including dust, soil, large numbers of micro -organisms and organic matter

(e.g. blood, vomit). It is an essential prerequisite to disinfection and

sterilization. It also removes the organic matter on which micro-

organisms might subsequently thrive.

Disinfection is a process used to reduce the number of micro-organisms but not usually bacterial spores.

The process does not necessarily kill or remove all micro-organisms, but reduces their number to a level which is not harmful to health.

Sterilization removes or destroys all forms of microbial life including bacterial spores.

Hand hygiene

PPE

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Donning of PPE - Sequence

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Removal of PPE - Sequence

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Risk Application of Item Recommendation

High In close contact with broken skin or mucous membrane Introduced into sterile body areas

Cleaning followed by sterilisation. Irradiation (Gamma or E-Beam)Ethylene OxideSteam SterilizationDry Heat Sterilization

Medium In contact with mucous membranes contaminated with particularly virulent or readily transmissible organisms Prior to use on immunocompromised patients

Cleaning followed by sterilization or disinfection required. Where sterilization may damage equipment, cleaning followed by high level disinfection may be used as an alternative. Sodium Hypochlorite (Bleach)Ethyl AlcoholIsopropyl Alcohol (70%)Alconox, LiquinoxCidex (Glutaraldehyde)

Low In contact with healthy skin Not in contact with patient

Cleaning only with a detergent and water

Each instrument or piece of medical equipment which comes into contact with a patient is a potential source of infection.

These are divided into 3 groups of risk

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Following use on a patient or when requiring inspection or service, all medical devices must be checked for visible evidence of contamination by the user/clinician; however, as contamination is not always visible, all equipment must be cleaned following patient use. Every attempt must be made by the user to adequately decontaminate the equipment prior to transfer for repair or servicing. If it is not possible to decontaminate, then the equipment must be safely contained and clearly identified as ‘contaminated’ until advice is obtained from the Infection Prevention and Control Team and the Medical Electronics Department.

All equipment MUST be accompanied by the Trust Declaration of Decontamination Status of Healthcare Equipment Following Use and Prior to Service or Repair form,

Procedure following patient use and when sending medical devices for service or repair

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If items are dispatched to suppliers, or presented for service or inspection on the hospital’s premises without a declaration of decontamination, the receiver will refuse to accept the item and it will be returned to the ward/department until it is accompanied by the aforementioned form. In some instances total decontamination may not be possible at source i.e. point of use, due to internal contamination of the equipment, requiring additional tools to gain access to the affected parts. The equipment must be removed to a suitable designated area for appropriate decontamination prior to inspection, service or repair. In this instance, the nature of contamination must be clearly communicated to the receiving organisation using the Trust Declaration of Decontamination Status of Healthcare Equipment Following Patient Use and Prior to Service or Repair form.

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In particular situations, for example when an item of equipment has been involved in an incident, its condition may be altered or influenced by the decontamination process. In such situations, advice must be sought from those investigating the incident, the Infection Prevention and Control Team and Medical Electronics.

Items that have been involved in an incident

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Any packaging must be sufficiently robust to withstand transport and if possible packaging specifically designed for the item of equipment must be used in accordance with the Carriage of Dangerous Goods Regulations 2007.

The condition of the item must be clearly labelled indicating content and contamination status. This is so that it can be clearly determined prior to opening the package. E.g. biohazard label if required and Trust Declaration of Decontamination Status of Healthcare Equipment Following Patient Use and Prior to Service or Repair form. Transport of contaminated equipment within the Trust must be in a suitable container via internal hospital transport. Where appropriate all external parts of large items of mobile equipment should be covered in orange clinical waste bags and suitably labelled.

Transporting equipments internally OR externally

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Standard/process/ issue

Monitoring and auditMethod By Committee Frequenc

yCorrect completion of Declaration of Decontamination Status of Healthcare Equipment Following Patient Use and Prior to Service or Repair form

Audit Medical TechnologyDepartment

Hospital Decontamination Group

Annually

Process for monitoring compliance

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Sample of Decontamination Confirmation form

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Misuse of equipment is one of the most common causes of adverse incidents involving medical devices.

Such misuse may be a result of inadequate user training or of poor user instructions.

Do not modify or alter devices, unless in the instructions for use it is clear that the manufacturer sanctions the modification or alteration.

6 Misuse

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All electrical equipment has the potential to expose people to the risk of spurious electric currents. In the case of medical electrical equipment, the risk is potentially greater since patients are intentionally connected to such equipment and may not benefit from the same natural protection factors that apply to people in other circumstances. Whilst all of the hazards listed are important, the prevention of many of them require methods peculiar to the particular type of equipment under consideration. For example, in order to avoid the risk of excessive output of surgical diathermy units, knowledge of radio frequency power measurement techniques is required. However, the electrical hazards are common to all types of medical electrical equipment and can minimized by the use of safety testing regimes which can be applied to all types of medical electrical equipment.

For these reasons, it is the electrical hazards thatare the main topic of this session.

7 Risk of exposure to spurious electric currents

8- Radiation Hazard

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The medical use of ionizing radiations, whether for diagnosis or therapy, not only results in the irradiation of the patient but may also result in some degree of exposure of radiologists, radiographers, other workers of the department.

Although many patients benefit from radiation’s ability to destroy cancer cells or capture real-time images of the human body, radiation can harm healthy cells wherever it enters the body. It is well documented that ionizing radiation can cause damage ranging from uncontrollable cell replication to cell death.

Ionizing vs. Non-IonizingRadiations

Ionizing Radiation A radiation that has

sufficient energy to remove electrons from atoms or molecules as it passes through matter.

Examples: x-rays, gamma rays, beta particles, and alpha particles

Non-Ionizing Radiation A radiation that is not as

energetic as ionizing radiation and cannot remove electrons from atoms or molecules.

Examples: light, lasers, heat, microwaves, and radar

Biological EffectsMechanisms of Injury

Ionizing Radiation

Cell Death

Cell Damage

Repair Transformation

Annual Occupational Dose Limits

Whole Body 5,000 mrem/year

Lens of the eye 15,000 mrem/year

Extremities, skin, and individual tissues

50,000 mrem per year

Minors 500 mrem per year (10%)

Embryo/fetus* 500 mrem per 9 months

General Public 100 mrem per year

* Declared Pregnant Woman

Radiation has the power to both save and harm lives. Radiologic technologists use radiation to provide quality medical imaging, but they must be aware of potential exposure to radiation’s detrimental effects. When proper time, distance, and shielding techniques are used, dangerous exposure levels can be avoided. Protection techniques are even more important for a pregnant radiologic technologist, who must safeguard her fetus from exposure. With an employer’s cooperation and appropriate protection in place, a pregnant technologist should be able to work in a radiology setting without harming her fetus.

TIME Minimize the amount of

time spent near sources of radiation.

The exposure is to be kept as short as possible because the exposure is directly proportional to time.

DISTANCE Distance from the radiation

source should be kept as great as possible

As the distance from a radioactive source doubles, the exposure rate decreases by a factor of four (inverse square Law)

Physical Law: Inverse Square Law

SHEILDING A lead protective

shield is placed between the x-ray tube and the individuals exposed, absorbing unnecessary radiation

TECHNOLOGIST . 25 mm LEAD

LEAD APRON, GLOVES THYROID SHIELD, GLASSESPATIENT – GONAD SHEILDING . 5 mm LEAD

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Why Test & CalibrationWhat you cannot measure you cannot control As components age and equipment undergoes changes in temperature or humidity or sustains mechanical stress, performance gradually degrades. This is called drift.

When this happens your test results become unreliable and both design and performance quality suffer.

While drift cannot be eliminated, it can be detected and either corrected or compensated for through the process of calibration.

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Definitions

• Calibration: process of comparing an unknown against a reference standard within defined limits, accuracies and Uncertainties

• Verification: process of comparing an unknown against a reference standard at usually one data point

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What to TEST for?

• Performance Testing• Safety Testing Electrical Safety Testing

Radiation safety Testing

• On newly acquired equipment prior to use • During routine planned preventative Maintenance.• After repairs have been carried out on equipment.

When to test

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Performance Testing

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Performance testing is the process of determining or ensuring that the equipment is performing to the expected standards of accuracy, reliability, free of hysteresis and linear (as designed).

Safe and effective devices need to be available for patient care , to meet the regulations, accreditation requirements and standards

Need for Performance TestingThe goal of any medical equipment maintenance program is to ensure that medical equipment is safe, accurate, and ready for patient use

Medical equipment testing is a critical task to ensure medical devices are performing correctly for patients, doctors, nurses and technologists alike. In order to ensure that we use proper Test Equipments to analyze the functioning of each

equipments

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These test devices are used to create signals and capture responses from electronic Devices Under Test (DUTs).

The proper operation of the DUT can be proven or faults in the device can be traced, repaired, and certified calibration.

In order to increase patient safety and reducing the risks of legal liabilities (in case of a patient mishap or accident shown to be the investigative cause due to faulty or un-calibrated test equipment.) These testing devices must be calibrated Periodically traceable to the National Institute of Science and Technology (NIST), National Metrology Institute (NMI), and comply with international standards ( i.e. ISO 9001:2008 registered, ISO/IEC 17025:2005 accredited, and ANSI/NCSL Z-540.1-1994 compliant.).

Test Equipments

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There are variety of Test Equipments that are used by a Bio-Medical Technicians. Some are listed.

Defibrillator Analyzer Patient Simulator Tachometer ESU analyzer Ultrasound Phantom Phototherapy Radiometer Electrical Safety Analyzer Ventilator analyzer Flow meter O2 Analyzer

Digital Thermometer Multi meter BP Simulator SPO2

Analyzer./Simulator Infusion Pump Analyzer pH meter Test Lung Spectrum Analyzer KV & Dose meter Pressure Meter

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Defibrillator testers are testing devices used in performing output measurement tests and performance verification on defibrillator equipment. Mostly, these multifaceted devices performs primary measurement of energy, peak voltage, peak current, pulse width, and charge time tests.

Defibrillator Analyzer

Also, the device performs cardioversion analysis, Output Energy Measurement (in Joules), On-demand Pacemaker Testing, and generates simulated performance waves used in defibrillator testing as well as several additional tests. Lastly, technicians can store, print data, or possibly transfer it to an automated computerized maintainence management system for archival.

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Patient Simulators (also known as ECG testers or "Chicken-Hearts") are testing devices used in performing output measurement tests and performance verification on electrocardiograph and/or defibrillator equipment. Mostly, these multifaceted devices performs primary measurements of a twelve-lead ECGs performance waves (e.g. heartrates, NSR w/ PVCs, V-Tachycardia, V-Fibrillation, Asystole, Bigeminy, Pacer, Trigeminy, ST+, Block, Square Waves), Respiration, Invasive Blood Pressure, Cardiac Output , and Temperature measurements.

Patient Simulator

Lastly, technicians can store, print data, or possibly transfer it to an automated computerized maintenance management system for archival

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Blood Pressure simulators are testing devices used in performing output measurement tests and performance verification on blood pressure, vital signs, or physiological monitoring equipment. Mostly, these multifaceted devices performs primary measurements of Auscultatory Non-Invasive Blood Pressure (NIBP) performance waves (e.g. adult and infant blood pressure Waves), leak tests, over-pressure tests, inflate or deflate times, systolic and diastolic pressures, manometer readouts, heart-rate measurements.

Blood Pressure Simulator

Lastly, technicians can store, print data, or possibly transfer it to an automated computerized maintenance management system for archival

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Electrosurgical Unit (ESU) testers are testing devices used in performing output measurement tests and performance verification on electrosurgical or Bovie equipment. Mostly, these multifaceted devices performs primary measurement of energy, Load Impedance (50 Ohms), peak-to-peak voltage, crest factor, selected load impedance value, RF current, and RF power tests. Also, RF Leakage tests, including active and dispersive electrode leakage to ground used in electrosurgical testing as well as several additional tests.

ESU Analyzers

The technicians can store, print data, or possibly transfer it to an automated computerized maintenance management system for archival

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Conductivity meters are testing devices used in performing output conductivity measurements (in µS/cm)and performance verification for laboratory equipment in a solution. Commonly used in hydroponics, aquaculture and freshwater systems to monitor the amount of nutrients, salts or impurities in the water. Lastly, technicians can store, print data, or possibly transfer it to an automated computerized maintenance management system for archival.

Conductivity Meter

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A digital voltmeter (DMM) is an instrument used for measuring the electrical potential difference between two points in an electric circuit. Analog voltmeters move a pointer across a scale in proportion to the voltage of the circuit; digital voltmeters give a numerical display of voltage by use of an analog to digital converter.

Digital Voltmeter

A multimeter can be a hand-held device useful for basic fault finding and field service work or a bench instrument which can measure to a very high degree of accuracy. They can be used to troubleshoot electrical problems in a wide array of industrial and household devices such as electronic equipment, motor controls, domestic appliances, power supplies, and wiring systems.

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Infusion pump testers are testing devices used in performing output measurement tests and performance verification on infusion pumps, syringe pumps, Patient Controlled Analgesia (PCA) Pumps, and infusion controller equipment. Mostly, these multifaceted devices performs primary measurements of Average Flow Rates, Bolus, and Total Volume Delivered and Timing measurements, Occlusion and Back Pressure, and generates simulated performance waves used in infusion testing as well as several additional tests.

Infusion Pump Analyzers

Technicians can store, print data, or possibly transfer it to an automated computerized maintainence management system for archiva

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An Ultrasound Watt-meter (Radiometer) are testing devices used in performing output measurement tests and performance verification on ultrasound equipment. Mostly, these multifaceted devices performs primary measurements of total-pulsed or continuous-average power (in watts) measurements.

These devices are tested using either demonized/distilled and/or degassed water (never use regular tap water for performing measurement checks--will result in inaccurate readings). l.

Ultrasound Wattmeter

Lastly, technicians can store, print data, or possibly transfer it to an automated computerized maintainence management system for archival.

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A Pulse Oximeter (SpO2) testers are testing devices used in performing output measurement tests and performance verification on pulse oximeter equipment. Mostly, these Multifaceted devices performs primary measurement of Rate, Saturation Percentage, and Pulse Amplitude.

Pulse Oximeter Simulator

Technicians can store, print data, or possibly transfer it to an automated computerized maintainence management system for archival.

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A ventilator testers are testing devices used in performing output measurement tests and performance verification on insufflators, medical gas and vacuum outlets, pressure gauges, flow-meters, aspirators and suction devices, and anesthesia equipment. Mostly, these multifaceted devices performs primary measurement of high- or low-flow and pressure, Air, O2, CO2, N2, N2O, He measurements, Breath rate (in breaths per minute (bpm)), Inspiratory time, Expiratory time, Positive end-expiratory pressure (PEEP), Mean airway pressure (in CM H2O), and Flow (in liters per minute (lpm)) tests

Ventilator Tester

Technicians can store, print data, or possibly transfer it to an automated computerized maintainence management system for archival.

FlowAnalyser™ PF-300 ventilator tester

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Phototherapy Radiometer is designed for the accurate measurement of light radiation in the blue part of the spectrum from 400-480 nanometers. Phototherapy exposure in this range is used in the treatment of hyperbilirubinemia in newborn children.

It provides continuous measurement of irradiation by simply placing the detection probe under the phototherapy light (fluorescent lamps only). In addition to verifying output power, the DALE40 saves costs by eliminating premature replacement of lamps.

Light measurement is according to the percent response given the wavelength characteristics curve. The detector probe, included with the unit, has a wide angle lens which matches the cosine receiving function of human skin.

Phototherapy Analyzer

Measurements are taken in µW/cm2, with a range of 0-1999. This unit of measurement can be compared directly to other units of measurement.

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A Pressure Meter are testing devices

used in performing output measurement tests and performance verification on Ophthalmology lasers, dialysis machines, automatic tourniquets, drainage devices, IV pumps, diagnostic and surgical suction devices, ventilators, and pressure gauges equipment. Mostly, these multifaceted devices performs primary measurement of gas or liquid pressures Measurement (in mmhg or cmH2O) as well as several additional tests.

Digital Pressure Meter

Technicians can store, print data, or possibly transfer it to an automated computerized maintainence management system for archival

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A spectrum analyzer are testing devices used in performing output measurement tests and performance verification on audio and telemetry devices. Mostly, these multifaceted devices performs primary measurement of EMC/EMI, Frequency Range, Bandwidth, Average Noise Level, Sweep Time, and Amplitude tests. There are analog and digital spectrum analyzers: An analog spectrum analyzer uses either a variable band-pass filter whose mid-frequency is automatically tuned (shifted, swept) through the range of frequencies of which the spectrum is to be measured or a superheterodyne receiver where the local oscillator is swept through a range of frequencies.

A digital spectrum analyzer computes the discrete Fourier transform (DFT), a mathematical process that transforms a waveform into the components of its frequency spectrum. Some spectrum analyzers (such as "real-time spectrum analyzers") use a hybrid technique where the incoming signal is first down-converted to a lower frequency using superheterodyne techniques and then analyzed using fast fourier transformation (FFT) techniques.

Spectrum Analyzer

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The thermometer is a device that measures temperature or temperature gradient using a variety of different principles. Thermometers that include an electronic device and attached sensors that detect and transduce changes in temperature into variations of some electric characteristic (e.g., resistance, voltage). These variations of the electric characteristics are processed in electronic circuits and, in turn, displayed as temperature readings.

Thermo meter

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The probe is designed using the latest advances in micro system technology and provides a complete in line real time monitoring system with unique versatility and design. The sensor proves his reliability when testing the performance of any anesthesia delivery and monitoring systems or the accuracy of CO2 monitoring devices. The MultiGasAnalyser™ sensor head measures infrared light absorption at several different wavelengths and exactly determines the gas concentrations of the

mixtures.

MultiGas Analyser

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PH meter

A device used to measure the pH of a liquid

PH meter

Test LungA device used to check the function of ventilator

Infant Test LungTest Lung Tacho meter

A device that measures speed of rotation

Tacho meter

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The Firefly endoscope-testing device is a handheld instrument designed to measure the luminous radiation of standard medical endoscopic light sources, fiber optic cables and endoscopes. The Firefly consists of an integrating sphere, light meter and adapters to interface with endoscopic equipment common in surgical applications

Firefly

The Oxygen Analysers are used to measure the concentration of the oxygen in a gas sample

Oxygen Analyzer

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An electrical-safety testers are testing devices used in performing safety tests and performance verification on medical equipment. Mostly, these multifaceted devices performs primary electrical safety tests, including mains voltage, protective earth resistance, insulation resistance, device current, earth, chassis, and patient leakages, lead-to-lead leakage, generates simulated performance waves used in defibrillator testing as well as several additional tests.

Electrical Safety Analyzer

technicians can store, print data, or possibly transfer it to an automated computerized maintainence management system for archival.

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KV Meter and Dosi Meter Digital kV Meter is a test device for

quality control and acceptance testing in radiographic, mammographic, CT, fluoroscopic and dental x-ray systems. It enables the user to measure the new IEC quantity "practical peak voltage" as well as non-invasive kVp, relative mAs and exposure time

Dosimeters measure an individual's or an object's[ exposure to something in the environment radiation dosimeter, which measures exposure to ionizing radiation

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Testing

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√ Ensure patient safety Protect against macroshock Protect against microshock

√ Test for electrical internal breakdown / damage to power cord, AC mains feed, etc.

√ Meet codes & standards AAMI, IEC, UL, NFPA, etc.

√ Protect against legal liability In case of a patient incident

Why do we do electrical safety .?

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Program Standards and guidance documents Physiological effects of electricity Electrical hazards Electrical safety testing Risk management

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International Electrotechnical Commission

The International Electrotechnical commission[1] (IEC) is a non-profit, non-governmental international standards organization that prepares and publishes International Standards for all electrical, electronic and related technologies – collectively known as "electrotechnology".

IEC standards cover a vast range of technologies from power generation, transmission and distribution to home appliances and office equipment, semiconductors, fibre optics, batteries, solar energy, nanotechnology and marine energy as well as many others. The IEC also manages three global conformity assessment systems that certify whether equipment, system or components conform to its International Standards.

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International Electrotechnical Commission

They also first proposed a system of standards, the Giorgi System, which ultimately became the SI, or Système International d’unités (in English, the International System of Units).

Today, the IEC is the world's leading international organization in its field, and its standards are adopted as national standards by its members. The work is done by some 10 000 electrical and electronics experts from industry, government, academia, test labs and others with an interest in the subject.

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IEC, ISO, ITU, IEEE The IEC cooperates closely with the

International Organization for Standardization (ISO) and the International Telecommunication Union (ITU). In addition, it works with several major standards development organizations, including the IEEE with which it signed a cooperation agreement in 2002, which was amended in 2008 to include joint development work.

Other standards developed in cooperation between IEC and ISO are assigned numbers in the 80000 series, such as IEC 82045-1.

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List of IEC standards IEC standards have numbers in the range 60000–79999 and their titles

take a form such as IEC 60417: Graphical symbols for use on equipment. The numbers of older IEC standards were converted in 1997 by adding 60000, for example IEC 27 became IEC 60027.

IEC 60027 Letter symbols to be used in electrical technology... IEC 60034 Rotating electrical machineryIEC 60038 IEC Standard Voltages IEC 60044 Instrument transformers IEC 60050 International Electrotechnical VocabularyIEC 60062 Marking codes for resistors and capacitors IEC 60063 Preferred number series for resistors and capacitorsIEC 60065 Audio, video and similar electronic apparatus - Safety requirements IEC 60068 Environmental Testing IEC 60071 Insulation Co-ordination IEC 60073 Basic Safety principles for man-machine interface, marking and identification

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List of IEC standards IEC 60601 Medical Electrical Equipment IEC 62304 Medical Device Software - Software Life Cycle Processes IEC 62366 Medical devices—Application of usability engineering to medical

devices IEC 62464 Magnetic resonance equipment for medical imaging

– the IEC 60601-1-xx series of collateral standards for MEDICAL ELECTRICAL EQUIPMENT;– the IEC 60601-2-xx series of particular standards for particular types of MEDICAL ELECTRICAL EQUIPMENT; and– the IEC 60601-3-xx series of performance standards for particular types of MEDICAL ELECTRICAL EQUIPMENT

IEC 60601-x-xx

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IEC 60601-x-xx IEC 60601-1-2, Medical electrical equipment – Part 1-2: General

requirements for safety Collateral standard: Electromagnetic compatibility – Requirements and tests

IEC 60601-1-3, Medical electrical equipment – Part 1: General requirements for safety – 3. Collateral standard: General requirements for radiation protection in diagnostic X-ray equipment

IEC 60601-1-6, Medical electrical equipment – Part 1-6: General requirements for safety Collateral standard: Usability

IEC 60601-1-8, Medical electrical equipment – Part 1-8: General requirements for safety Collateral standard: General requirements, tests and guidance for alarm systems in medical electrical equipment and medical electrical systems

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Electrolysis (mainly near d.c.) Neuromuscular effects (mainly 10-100Hz) Heating (mainly 100KHz-30Mhz)

Physiological Efects of Electricity on the Body

Physiological Effects of Electricity

Human body can easily bear electrical current of 1 milliampere passing through its body without appreciable risk or damage. However, as the amount of current increases the body may suffer different type of damages like. Fibrillation, Burns to parts of the body due to heat generated by electricity, Damage to nervous system causing loss of nervous control.

When the current passes through brain it can lead to unconsciousness and permanent damage to the brain. including death or electrocution

The physiological effects of electrical shock include the following.

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Physiological Effects of Electricity

The human body can easily detect macro shock and violent reactions occur to high current flow level in the body…

Below 1 ma (1,000 µa), it is often much more difficult to detect

the presence of a shock hazard from simple perception…

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The movement of ions of opposite polarities in opposite directions through a medium is called electrolysis and can be made to occur by passing DC current through body tissues or fluids.

If a DC current is passed through body tissues for a period of minutes, ulceration begins to occur.

Such ulcers, while not normally fatal, can be painful and take long periods to heal.

Electrolysis

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Na+ Na+ Na+

Cl- Cl- Cl-

_ +

Sodium atomscreated at electrode

Chlorine atomscreated at electrode

Ionic Current

The formation of sodium atoms at the negative electrode and chlorine atoms at the positive electrode causes local chemic al actions which kills the cells.

Electrolysis

Physiological Effects of Electricity

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Neuromuscular Effects

Macro shock: is the most common type of shock received and occurs when the human body becomes a conductor of electric current passing by means other than directly through the heart. This effect can readly occur with the use of medical electrical equipment as the natural resistance of the skin to current flow is often reduced or bypassed by electrodes and electorde paste or by invasion into mucous membrane.

Large current passing through the skin - a small proportion may pass through the heart

Macroshock has the potential for both burns and cardiac arrhythmias. Currents pass through the extremities mostly through the muscles. A current flowing from arm to arm, or arm to leg, must pass through the thorax. In the thorax the current is split between the chest wall and the great vessels, which obviously deliver the current directly to the myocardium.

Physiological Effects of Electricity

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Microshock refers to currents delivered directly to the heart via intracardiac electrodes or catheters. Because the current is delivered to a very small area, only a very small current is required to reach the fibrillation threshold.

Microshock

The currently accepted minimum current is 10 A (microamps = 1/1000 of milliamps

For a (15-100Hz) current passing between the hands, the following effects are expected

0.5-1mA Perception 10mA Can’t let go

100mA Severe pain. Interference with breathing and heart function

1A Sustained heart contraction

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Heating Effects - Surgical Diathermy

In Surgical Diathermy the heat is concentrated at the tip of the probe because the current density (A/m2) is very high but at the plate it is low. Heating will occur at the plate if he contact area reduces (plate comes loose)

Skin Internal Skin

Current = I

Low current density at return electrode

Current = I

Very high current density at active

electrode

Physiological Effects of Electricity

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Terminologies of EST Classes and Types L1 - Hot L2 - Neutral Earth - Ground Mains Line - Voltage Applied Parts - Patient

Leads Enclosure/Case - Chassis Protective Earth -Ground Wire Earth Leakage Current

Leakage in Ground Wire

Enclosure Leakage - Chassis Leakage

Patient Leakage - Lead Leakage Patient Auxiliary - Leakage

between Patient Leads Mains on Applied Parts - Lead

Isolation Insulation Resistance -

Dielectric Strength or Insulation Resistance between Hot and Neutral to Ground

Earth Resistance - Ground Wire Resistance

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All electrical equipment is categorised into classes according to the method of protection against electric shock that is used. For mains powered electrical equipment there are usually two levels of protection used, called "basic" and "supplementary" protection. The supplementary protection is intended to come into play in the event of failure of the basic protection.

Classes and types of medical electrical equipment

Equipment ClassI,II,III method of protection against electric shock Equipment TypeB,BF,CF degree of protection

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Class I equipment has a protective earth. The basic means of protection is the insulation between live parts and exposed conductive parts such as the metal enclosure. In the event of a fault that would otherwise cause an exposed conductive part to become live, the supplementary protection (i.e. the protective earth) comes into effect. A large fault current flows from the mains part to earth via the protective earth conductor, which causes a protective device (usually a fuse) in the mains circuit to disconnect the equipment from the supply.

It is important to realise that not all equipment having an earth connection is necessarily class I. The earth conductor may be for functional purposes only such as screening. In this case the size of the conductor may not be large enough to safely carry a fault current that would flow in the event of a mains short to earth for the length of time required for the fuse to disconnect the supply.

Class 1

term referring to electrical equipment in which protection against electric shock does not rely on BASIC INSULATION only, but which includes an additional safety precaution in that means are provided for ACCESSIBLE PARTS of metal or internal parts of metal to be PROTECTIVELY EARTHED

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Class I medical electrical equipment should have fuses at the equipment end of the mains supply lead in both the live and neutral conductors, so that the supplementary protection is operative when the equipment is connected to an incorrectly wired socket outlet.

Further confusion can arise due to the use of plastic laminates for finishing equipment. A case that appears to be plastic does not necessarily indicate that the equipment is not class I. There is no agreed symbol in use to indicate that equipment is class I.

Where any doubt exists, reference should be made to equipment manuals. The symbols below may be seen on medical electrical equipment adjacent to terminals.

Class 1 …contd

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The method of protection against electric shock in the case of class II equipment is either double insulation or reinforced insulation. In double insulated equipment the basic protection is afforded by the first layer of insulation. If the basic protection fails then supplementary protection is provided by a second layer of insulation preventing contact with live parts.

Reinforced insulation is defined in standards as being a single layer of insulation offering the same degree of protection as double insulation.

Class II medical electrical equipment should be fused at the equipment end of the supply lead in either mains conductor or in both conductors if the equipment has a functional earth.

The symbol for class II equipment is twoconcentric squares indicating double insulation

as shown.

Class II

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shock relies on the fact that no voltages higher than safety extra low voltage (SELV) are present. SELV is defined in turn in the relevant standard as a voltage not exceeding 25V ac or 60V dc.

In practice such equipment is either battery operated or supplied by aSELV transformer.

If battery operated equipment is capable of being operated when connected to the mains (for example, for battery charging) then it must be safety tested as either class I or class II equipment. Similarly, equipment powered from a SELV transformer should be tested in conjunction with the transformer as class I or class II equipment as appropriate.

It is interesting to note that the current IEC standard relating to safety ofmedical electrical equipment does not recognize Class III equipment sincelimitation of voltage is not deemed sufficient to ensure safety of the patient. All medical electrical equipment that is capable of mains connection must be classified as class I or class II. Medical electrical equipment having no mains connection is simply referred to as "internally powered

Class III

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As described above, the class of equipment defines the method of protection against electric shock. The degree of protection for medical electrical equipment is defined by the type designation. The reason for the existence of type designations is that different pieces of medical electrical equipment have different areas of application and therefore different electrical safety requirements. For example, it would not be necessary to make a particular piece medical electrical equipment safe enough for direct cardiac connection if there is no possibility of this situation arising.

All medical electrical equipment should be marked by the manufacturer with one of the type symbols.

Table below shows the symbols and definitions for each type classification of medical electrical equipment.

Types of Medical Equipments

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Type Symbol Definition

B

Equipment providing a particular degree of protection against electric shock, particularly regarding allowable leakage currents and reliability of the protective earth connection (if present).

BFAs type B but with isolated or floating (F - type) appliedpart or parts.

CFEquipment providing a higher degree of protection against electric shock than type BF, particularly with regard to allowable leakage currents, and having floating applied parts.

Type Symbols for Medical equipments

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A part of the equipment which in normal use: necessarily comes into physical contact withthe

patient for the equipment to perform its function; or can be brought into contact with the patient; or needs to be touched by the patient

Applied Part - Parts that contact PATIENTS

tableNo applied part

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Part of equipment which can be touched without the use of a tool.

EXAMPLE 1 Illuminated push-buttons EXAMPLE 2 Indicator lamps EXAMPLE 3 Recorder pens EXAMPLE 4 Parts of plug-in modules EXAMPLE 5 Batteries

Accessible Parts

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Current that is not functional. several different leakage currents are defined according to the paths

that the currents take. Earth Leakage Current Enclosure Leakage Current Patient Leakage Current Patient auxiliary current

Leakage currents

Causes of Leakage currentsIf any conductor is raised to a potential above that of earth, some current is bound to flow from that conductor to earth. The amount of current that flows depends on:

1- the voltage on the conductor. 2- the capacitive reactance between the conductor and earth.

3-the resistance between the conductor and earth.

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current flowing from the MAINS PART through or across the insulation into the PROTECTIVE EARTH CONDUCTOR

EARTH LEAKAGE CURRENT

Under normal conditions, a person who is in contact with the earthed metal enclosure of the equipment and with another earthed object would suffer no adverse effects even if a fairly large earth leakage current were to flow. This is because the impedance to earth from the enclosure is much lower through the protective earth conductor than it is through the person. However, if the protective earth conductor becomes open circuited, then the situation changes. Now, if the impedance between the transformer primary and the enclosure is of the same order of magnitude as the impedance between the enclosure and earth through the person, a shock hazard exists.

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Enclosure leakage current /Touch current

LEAKAGE CURRENT flowing from the ENCLOSURE to earth or to another part of the ENCLOSURE through a conductor other than the protective earth conductor.

LEAKAGE CURRENT flowing from the ENCLOSURE to earth or to another part of the ENCLOSURE through a conductor other than the protective earth conductor.

93

Patient leakage current Patient leakage current is

the leakage current that flows through a patient connected to an applied part or parts.

It can either flow from the applied parts via the patient to earth or from an external source of high potential via the patient and the applied parts to earth.

Patient leakage current is the leakage current that flows through a patient connected to an applied part or parts.

It can either flow from the applied parts via the patient to earth or from an external source of high potential via the patient and the applied parts to earth.

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Patient auxiliary current The patient auxiliary

current is defined as the current that normally flows between parts of the applied part through the patient, which is not intended to produce a physiological effect

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By applying mains voltage to the applied parts, the leakage current that would flow from an external source into the patient circuits can be measured.

Although the safety tester normally places a current limiting resistor in series with the measuring device for the performance of this test, a shock hazard still exists. Therefore, great care should be taken if the test is carried out in order to avoid the hazard presented by applying mains voltage to the applied parts. Careful consideration should be given as to the necessity or usefulness of performing this test on a routine basis when weighed against the associated hazard and the possibility of causing problems with equipment.

The purpose of the test under IEC 60601-1 is to ensure that there is no danger of electric shock to a patient who for some unspecified reason is raised to a potential above earth due to the connection of the applied parts of the equipment under test. The standard requires that the leakage current limits specified are not exceeded. There is no guarantee that equipment performance will not be adversely affected by the performance of the test. In particular, caution should be exercised in the case of sensitive physiological measurement equipment. In short, the test is a "type test".

Mains on applied Part

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Protective Earth Resistance.

The resistance of the protective earth conductor is measured between the earth pin on the mains plug and a protectively earthed point on the equipment enclosure (see figure 6). The reading should not normally exceed 0.2 O at any such point. The test is obviously only applicable to class I equipment.

In IEC60601, the test is conducted using a 50Hz current between 10A and 25A for a period of at least 5 seconds. Although this is a type test, some medical equipment safety testers mimic this method. Damage to equipment can occur if high currents are passed to points that are not protectively earthed, for example, functional earths. Great care should be taken when high current testers are used to ensure that the probe is connected to a point that is intended to be protectively earthed.

HEI 95 and DB9801 Supplement 1 recommend that the test be carried out at a current of 1A or less for the reason described above. Where the instrument used does not do so automatically, the resistance of the test leads used should be deducted from the reading.

If protective earth continuity is satisfactory then insulation tests can be performed.

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For a plugged-in system, it is worth doing a mains insulation test on the system as a whole to check the integrity of the interconnecting mains wiring and the MSO if fitted.

For installations, this test is impractical and may be dangerous. If the test is to be performed, a number of preliminary steps are required. The equipment / system must be disconnected from the electrical supply. Allowance should be made for discharging large capacitors, which may hold considerable charge for some time after the machine is disconnected. Also any Uninterruptible Power Supplies (UPS) must be identified and disconnected.

Insulation Test

Electrical Safety Testing

Electrical Safety Testing Procedure

Visual Inspection

Earth Resistance Test

Insulation Test

Leakage Current Test

Earth Leakage Current Touch Current Patient Leakage

Current

Electrical Safety Testing

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Visual Inspection

Electrical Safety Testing

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For systems, inspection should include ensuring that the system’s components are all labelled and have all been tested individually during acceptance testing. For routine testing, the tester should ensure that the system has not been re-configured or items substituted.

For installations, visual inspection may include: Electrical works test certificates Electrical safety certificate for installations MEIGaN test certificate for sockets wiring, earth wiring and equipotential

bonding Review of suppliers’ EST Test certificates of other plug-in medical equipment or systems in the

patient area

Visual Inspection

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Protective Earth Continuity The resistance of the protective earth conductor is

measured between the earth pin on the mains plug and a protectively earthed point on the equipment enclosure (see figure 6). The reading should not normally exceed 0.2Ω at any such point. The test is obviously only applicable to class I equipment.In IEC60601, the test is conducted using a 50Hz current between 10A and 25A for a period of at least 5 seconds. Although this is a type test, some medical equipment safety testers mimic this method. Damage to equipment can occur if high currents are passed to points that are not protectively earthed, for example, functional earths

Applicable to Class I, all types Limit: 0.2Ω DB9801 recommended?: Yes, at 1A or less. HEI 95 recommended?: Yes, at 1A or less. Notes: Ensure probe is on a protectively earthed point

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Earth Resistance TestEquipment

ConfigurationProtective Earth

Resistance

Stand alone 200 m System without MSO 200 m

System with MSO 400 mPermanently installed 100 m

Electrical Safety Testing

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Earth Resistance Test

Plug-in equipment

Electrical Safety Testing

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Earth Resistance Test

A(IEC 60601)

B(IEC XXXX)

MSO

SIP/SOP

6V, 1A

< 400 mΏ

a.c.

Plug-in system

Electrical Safety Testing

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Earth Resistance Test

DUT 1

DUT 2

ERB

IncomingPE Conductor

Bonding Tester

Test to all exposed conductive parts on each DUT in turn

< 0.1

< 0.2

Bonding Tester

Installation

Electrical Safety Testing

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Insulation Tests Class I HEI 95 and DB9801 recommended that for

class I equipment the insulation resistance be measured at the mains plug between the live and neutral pins connected together and the earth pin. Whereas HEI 95 recommended using a 500V DC insulation tester, DB 9801 recommended the use of 350V DC as the test voltage.

Applicable to Class I, all types Limits: Not less than 50MΩ DB9801 recommended?: Yes HEI 95 recommended?: Yes Notes: Equipment containing mineral insulated heaters may give values down to 1MΩ. Check equipment is switched on

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Insulation Tests Class II HEI 95 further recommended for

class II equipment that the insulation resistance be measured between all applied parts connected together and any accessible conductive parts of the equipment. The value should not normally be less than 50MΩ

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Insulation TestEquipment Configuration Insulation Resistance

Stand alone >50 M

System without MSO >50 M

System with MSO >50 M

Permanently installed > 50 M

Electrical Safety Testing

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Insulation Test

Electrical Safety Testing

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hygroscopic mineral-insulated heating elements, which may exhibit low values until run for some hours to desiccate;

interference-suppression and discharge devices such as in Visual Display Units; a compromise struck with competing requirements e.g. conductivity of operating theatre

electrical warming mattress. For a plugged-in system, it is worth doing a mains insulation test on the system as a whole to

check the integrity of the interconnecting mains wiring and the MSO if fitted. For installations, this test is impractical and may be dangerous. If the test is to be performed,

a number of preliminary steps are required. The equipment / system must be disconnected from the electrical supply. Allowance should be made for discharging large capacitors, which may hold considerable charge for some time after the machine is disconnected. Also any Uninterruptible Power Supplies (UPS) must be identified and disconnected.

Insulation TestEquipment exhibiting values an order of magnitude lower may be permissible, if they involve the following:

Electrical Safety Testing

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Measurment of Earth Leakage CurrentFor class I equipment, earth leakage current is measured as shown in figure 12. The current should be measured with the mains polarity normal and reversed. HEI 95 and DB9801 Supplement 1 recommend that the earth leakage current be measured in normal condition (NC) only. Many safety testers offer the opportunity to perform the test under a single fault condition such as live or neutral conductor open circuit

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Enclosure leakage current/touch current

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Patient leakage current Test

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Measurement of patient leakage current

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Measurement of Patient auxiliary current

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Leakage Current TestCurrent Earth

LeakageTouch

Current Normal

Touch Current

SFC

Patient Leakage Normal

Patient Leakage SFC

Limit 5 mA 100 μA 500 μA 100 μA B, BF10 μA CF

500 μA B, BF50 μA CF

Electrical Safety Testing

The following table summarises the leakage current limits (in mA) specified by IEC60601-1 (second edition)

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Leakage Current Test

Plug-in equipment

Electrical Safety Testing

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Leakage Current Test

Plug-in system

Electrical Safety Testing

A(IEC 60601)

B(IEC XXXX)

MSO

SIP/SOP

MD

MD

MD

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Leakage Current Test

Installation

DUT 1

DUT 2

ERB

IncomingPE Conductor

MD

A

B

< 5 mA

Electrical Safety Testing

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Mains on applied parts Test

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Leakage Current Test(Plug-in Equipment)

Electrical Safety Testing

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An electrical-safety testers are testing devices used in performing safety tests and performance verification on medical equipment. Mostly, these multifaceted devices performs primary electrical safety tests, including mains voltage, protective earth resistance, insulation resistance, device current, earth, chassis, and patient leakages, lead-to-lead leakage, generates simulated performance waves used in defibrillator testing as well as several additional tests.

Electrical Safety Tester

technicians can store, print data, or possibly transfer it to an automated computerized maintainence management system for archival.

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Frequency of Safety Tests

Electrical Safety Testing

Type of equipment User checks Formal visual inspection Combined inspection and test

Equipment loan or hire e.g. medical equipment library, trial device

Visually inspect cable and case Before issue / after return According to category

MDD Risk Class I equipment generally Yes On acceptance, after repair or

incident

If earthed, on acceptance, after repair or incident1 to 2 years

MDD Risk Class IIa; medium risk Yes 6 months to 1 year 1 to 2 years. Include leakage currents tests

MDD Risk Class IIb; medium to high risk Yes 6 months to 1 year

6 months to 1 year or after repair or incident. Include leakage currents tests

MDD Risk Class III; high risk Yes 6 months to 1 year6 months to 1 year or after repair or incident. Include leakage currents tests

Equipment used by the public, e.g. in hotels, patients own equipment from home

By member of staff 3 months When arrives or 1 year

Cables and plugs, extension leads Yes 6 months to 1 year (intrusive) 1 year

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The Old Model Safety Tester 1973

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Automated Electrical Safety Analyzer 601PRO Series XL – Fluke Biomedical

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Standard Features The most advanced Electrical Safety Analyzer on the market EN60601-1, EN601010-1, and AAMI & ESI test loads (user selectable) into one

device The One-Touch-Testing user interface Allows user to perform rapid tests on various medical devices Multiple enclosure-leakage points Multiple patient-applied-part types • Power ON/OFF delay • DC only for patient- and auxiliary-leakage tests • User-programmable test sequences • Offers manual, auto, step, and computer-control mode operations• ASCII data transfer • Memory for up to 1000 device-information records• Conducts electrical safety testing in accordance with IEC 601-1, VDE 751, VDE

701, HEI 95, IEC 1010, AAMI, and AS/NZS 3551 requirements

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Standard Features• Flags failures, and simulates

performance, ECG, and arrhythmia, waveforms.

• Results automatically analyzed and saved in non-volatile memory

• Accepts device information that is input using an – External keyboard, – Integrated keypad, – Barcode keyboard wedge

Optional Feature • Onboard thermal printing

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Specifications

Voltage Range: 0 to 300 V True RMS (single and dual lead)Accuracy: DC - 100 Hz ± 1.5 % of reading ± 1 LSD

Insulation Resistance Range: 0.5 to 400.0 MΩ

Accuracy: ± 5 % of reading ± 2 LSDCurrent

Consumption Range: 0 to 15 A ac True RMS

Accuracy: ± 5 % of reading ± 2 LSDMains on Applied

PartApplied Voltage: ≥ 110 % of mains voltage

Accuracy: ± 2 % of reading ± 6 µAProtective Earth

Resistance Range: 0.000 to 2.999 Ω

Accuracy:± 5 % of reading ± 4 mΩ (1 A, 10 A, and 25 A test currents) (Refer to Operator’s Manual for additional specs qualifying the effects on accuracy of variations in load inductance and phase angle.)

Supply Voltage 90 to 265 Vac, auto switching

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Specifications60

1PRO

Ser

ies

XL IEC601-1 and AAMI Leakage Currents

Range: 0 to 8000 µA True RMS

Accuracy:(per IEC601-1 or AAMI filter),

-DC - 1 kHz ± 1 % of -reading ± 1 µA-1 to 100 kHz ± 2 % of reading ± 1 µA

- 100 kHz to 1 MHz ± 5 % of reading ± 1 µA

DC-Only Frequency Response: DC - 5 Hz (approx)

ECG Simulation and Performance Testing ECG Complex: 30, 60, 120, 180, 240 BPM

PerformancePulse: 30, 60 BPM, 63 ms pulse width

600 to 700 µs rise and fall time

Sine Waves: 10, 40, 50, 60, 100 HzSquare Wave: 0.125, 2.000 Hz (50 % duty cycle)Triangle Wave: 2 Hz, 2 mV

Dimensions 16.62 in L x 11.75 in W x 5.56 in H

Weight 17lb / 7.7kg

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Available Electrical Safety Tests

Mains Voltage Dual Lead Voltage Dual Lead Leakage Current Consumption Insulation Resistance Protective Earth

Resistance Earth Leakage Current Enclosure Leakage

Current Patient Leakage

Current

Mains on Applied Part Leakage

Patient Auxiliary Current Accessible Voltage Accessible Leakage Equivalent Device

Leakage Equivalent Patient

Leakage

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Accessories

Probe/Safety Lead, Red - 1 Probe/Safety Lead, Black - 1 Adapter, Banana/Alligator - 5 Operators Manual - 1 Large Clamp, Red - 1 Warranty Card - 1 Printer Paper Roll (original) - 1 Printer Paper Roll (new style) - 1

• Carry Case• RS232 Cable (9M-9F)• Printer Cable• Barcode, Keyboard, Wedge• Adapter, Banana, ECG• Keyboard English• Powercord Set Australian• Powercord Set Schuko • Powercord Set US 120 V• Powercord Set UK

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System Characteristics

Keys grouped by color and functionality

Red keys -used to access menu options Include previous key, the four SOFT KEYS, and

the enter key

Black keys -gain access to additional functions

Include the esc/stop key, the view present settings key, the print header key, and the print data key.

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Setting Up the 601PRO

1. Using Factory Default Settings

2. Selecting the Test Standard3. Selecting the Printer Output4. Selecting the RS232 Baud

Rate5. Activating the Beeper6. Setting the Time and Date

7. Configuring the Enclosure Leakage for the Auto mode Sequence

8. Selecting Language Options9. Selecting the DC Option10. Selecting the Auto/Step Tests:

Controlled Power Sequences or 601CE Conventional Test

11. Sequences enabling Stop on Failure

12. Configuring for Device Records or Templates

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Manual Mode1. Connecting the Device Under Test2. The Power-Up Sequence3. Selecting the Test Standard4. Selecting the Class/Type5. Saving Standard, Class, Type and Test Current6. Using View Present Settings7. Manual Operation

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1. Selecting Auto or Step Mode Testing2. Executing Auto and Step Mode Tests3. Creating/Editing a Device Record or Template

Auto/Step Modes

135

Test Records

1. Sending Test Results from the 601PRO to the Host2. Computer3. Test Data Record: Serial Output4. Printing Test Records5. Deleting Test Records

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1. Connecting the 601PRO and the Host Computer

2. Sending Device Information Records from the 601PRO to the Host Computer

3. Receiving Device Information Records from the Host computer

4. Device Information Record: Definition of Fields

5. Device Information Record Format6. Deleting Device Records and Templates

Device Records and Templates

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Testing Devices1. Permanently Wired Devices2. Portable Devices3. Portable Devices in Isolated Power Systems4. Testing Three-Phase Portable Devices5. Testing Conductive Surfaces6. Detachable Power Supply Cable7. Battery-Powered Equipment

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1. Accessing System Setup2. Selecting the Test Standard3. Referring to Test Limits for the Selected Standard

Standards and Principles

137

Common Electrical Hazards

138

The risk of sustaining an electric shock can be reduced by adopting the following practices:

1. A suitable Permit-to-Work system should always be in place and operated, to ensure the effective isolation of hard-wired equipment before repair or maintenance work commences.

2. Due care must always be exercised when switching off main power supplies to ensure that only the intended circuits are isolated. Lock-off systems must be used, where necessary.

3. Switch off and withdraw the plug on items of portable electrical equipment prior to making any alterations or modifying any circuitry.

4. Do not handle any equipment with wet hands and do not work in close proximity to water supplies or other earthed metalwork where there may be a risk of putting one hand on earthed metal and the other on live equipment. If equipment is suspected of being live, switch off, and have its electrical status tested by a competent person. Record the test.

General Safety Precautions

139

5. The external metal casing of electrical apparatus and associated cables and conduits must be earthed as a legal requirement. Water and gas pipes, however, must not be used as earth points. Such pipes must be effectively bonded, to ensure that they remain at an equal electrical potential. Checks should be carried out at least annually, to ensure that this continues to be the case.

6. On no account must a three-phase socket outlet be used to supply single-phase apparatus. 7. Where supplies to experimental equipment are obtained from terminals, these must be

insulated and a control/emergency switch must be close by. 8. Standard types of electrical fittings, such as 3-pin plugs, sockets and switches, should

always be used as specified by manufacturers and in accordance with good practice (e.g. switches must not be mounted upside down and single pole switches must not be wired into the neutral lead.)

9. If it is possible to do so, always use low voltage equipment. 10. The use of high voltage equipment must be strictly controlled, and suitable assessments of

risk, and control features, prepared prior to use.

General Safety Precautions …. contd

140

Typical Voltages at the Wall Socket

Note :the preferred method of hand wiring plugs: Long earth wire, short live

Electrical Hazards

141

Typical Hazards in the plug

Electrical Hazards

142

Leakage Current

In Class I equipment, most leakage current is caused by capacitance between the leads in the mains cord and a small amount due to stray capacitance within the equipment itself.

Electrical Hazards

143

Leakage Current

If the earth lead becomes detached, then the current that would normally have flowed along it will now be available on the case of the equipment and, in the case of a Type B applied part, it will also flow through the patient

Electrical Hazards

144

Standard Filter Circuit

Choke

Choke

Supply

Transient Suppressor

Electrical Hazards

145

Medical Filter Circuit

Choke

Choke

Supply

Transient Suppressor

Electrical Hazards

146

Loss of Earth in Class 1 Equipment

This is the most common and most serious hazard since a simple failure of basic insulation will then produce a deadly situation of the metal case being at live mains voltage

Loss of earth will only be found by testing

MP

Class 1

Electrical Hazards

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Extension LeadsExtension leads are not permitted in clinical areas of RCH organisations. They may cause high earth resistance and excessive earth leakage current. An extension lead can allow equipment to be powered from areas other than the relevant protected treatment area. The power from the other area may not be protected to the same level as the power in the treatment area. As the connection between the extension lead and the equipment mains cable is often on the floor there is a high danger from fluid spills, tripping and damage to the mains cable by trolleys when an extension lead is used.

Double AdaptorsDouble adaptors must not be usedin RCH organisations. They may notsit securely in a wall outlet, may not be able to provide adequate earth protection and may cause overloading,

overheating, fire or loss of electrical supply

148

Multiple Socket Outlets (MSO)

Risk with using domestic types

Electrical Hazards

149

Connecting Medical with Non-Medical Equipment

IEC 60601 IEC XXXXXA/PFunctional

Connection

The medical equipment might draw large currents via the I/O port which, under a SFC, could appear on the applied part (Type B) or on the enclosure for Class I

Electrical Hazards

150

Connecting Medical with Non-Medical Equipment

IEC 60601 or XXXXX IEC XXXXX

Functional

Connection

Earth with potential difference

PatientEnvironment

In case of an interruption of protective earthing for an equipment in the patient environment, this potential difference may appear on the

enclosure of the equipment causing a safety hazard for the operator or for the patient

Electrical Hazards

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Humidity in the plugs of blood and fluid heaters causing device failure (Andersen C, Pold R, Nielsen HD. Ugeskr Laeger 2000; 162(6))

Accidental toppling of a fluid container causing spillage onto a blood pressure monitor (Singleton RJ, Ludbrook GL, Webb RK, Fox MA. Anaesth Intensive Care 1993; 21(5))

Electric shocks to anaesthetists after touching a faulty device and the chassis of another device simultaneously (Singleton RJ, Ludbrook GL, Webb RK, Fox MA. Anaesth Intensive Care 1993; 21(5))

Incidents of Electrocution in Hospitals

Electrical Hazards

152

An anaesthetised patient was connected to an ECG device that had been wired wrongly with the earth and neutral connections transposed. After noticing electrical interference with the ECG signal, the anaesthetist instructed an assistant to plug the monitor into a 2nd wall socket. Unknown to the assistant, the 2nd socket was wired with reverse polarity causing the chassis of the monitor to go live and suffered a minor shock. Unfortunately the patient experienced an intense shock since she was also connected to a surgical diathermy plate. She became cyanotic and her pulse stopped but later recovered completely (Atkin DH, Orkin LR. Anesthesiology 1973; 38(2))

Incidents of Electrocution in Hospitals

Electrical Hazards

153

A 9-month old baby was found dead on a bed after admission to hospital with suspected pneumonia. The patient apparently put an uncovered oval shaped lamp switch (pendant switch) into his mouth and died of electric shock after contacting the exposed wires (Yamazaki M, Bai H, Tun Z, Ogura Y, Wakasugi C. J Forensic Sci 1997; 42(1))

Incidents of Electrocution in Hospitals

Electrical Hazards

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