Presentation on theme: "Safety Testing of Medical Electrical Equipment"— Presentation transcript:
1 Safety Testing of Medical Electrical Equipment Soojoud al rujoub & hadeel ArArToNezar amro
2 1 Hazards of Medical Electrical Equipment 1.1 Mechanical Hazards1.2 Risk of fire or explos1.3 Absence of Functionion1.4 Excessive or insufficient output1.5 Infection1.6 Misuse1.7 Risk of exposure to spurious electric currents
4 2.7- effect of frecqency on neuro-muscular stimulation
5 3 Classes and types of medical electrical equipment 4.1- class I equipmentFigure 6. Symbols seen on earthed equipment
6 3.2 class IIequipmentFigure 7. Symbol for class II equipment.
7 SELV (Safety Extra Low Voltage ) 3.3 Class III equipmentSELV (Safety Extra Low Voltage )SELV :is defined in turn in the relevant standard as a voltage not exceeding 25V ac or 60V dc.
8 4.4 Equipment types Type Symbol Definition B BF CF 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) applied part 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.
9 3 Leakage currents 3.1 Causes of leakage currents a- the voltage on the conductor.b- the capacitive reactance between the conductor and earth.c- the resistance between the conductor and earth
10 3.2 Earth leakage current types BF & CF ALL CLASS I 500micr A
11 4.3 Enclosure leakage current for class I,II, TYPES B&BF 100micrA, TYPE CF 10 micr A
12 4.4 Patient leakage current type B &BF 100micrA type CF10micrA per part of apply part Patient leakage current path from equipment Patient leakage current path to equipment.
13 4.5 Patient auxiliary current classI&II for type B&BF&CF 10 micrA
14 6.10 Leakage current summary Type BType BFType CFEarth0.51Earth for fixed equipment510Enclosure0.1Patient0.010.05Mains on applied part-Patient auxiliary
15 5 Testing regimes and relevant documentation 5.1 Type tests and routine tests5.2 HTM 85.3 BS 5724 or IEC 606015.4 Hospital Equipment Information 955.5 DB9801 Supplement 15.6 Medical Devices Directive5.7 ESCHLE5.8 IEC 610105.9 Hospital Equipment Information 140
16 5.10 When to testMedical electrical equipment should be inspected and tested on the following occasions.a- On newly acquired equipment prior to being accepted for useb- During routine planned preventative maintenance.c- After repairs have been carried out on equipment.
17 5.11 Recording test results 5.12 Equipment Management Software Packages
20 6 Electrical Safety Tests 6.1 Normal condition and single fault conditions*Normal operation means provided for protection against safety hazards are intact*Single fault is a condition in which signal means of protectionAgainst safety hazard is defective or external abnormal condition is present such as:1- interruption of one protective earth conductor2-the intrupt of on supply conductor of equipment3 -the short circuiting of either constituent part ofdouble insulation
21 6.2 Protective Earth Continuity Applicable toClass I, all typesLimit:0.2DB9801 recommended?:Yes, at 1A or less.HEI 95 recommended?:Notes:Ensure probe is on a protectively earthed point
22 6.3 Insulation Tests Applicable to Class I, all types Limits: Not less than 50MΩDB9801 recommended?:YesHEI 95 recommended?:Notes:Equipment containing mineral insulated heaters may give values down to 1MΩ. Check equipment is switched on.
23 Applicable toClass II, all types having applied partsLimits:not less than 50MΩ.DB9801 recommended?:HEI 95 recommended?:YesNotes:Move probe to find worst case
25 6.5 Earth Leakage Current Applicable to Class I equipment, all types Limits:0.5mA in NC, 1mA in SFC or 5mA and 10mA respectively for permanently installed equipment.DB9801 recommended?:Yes, in normal condition only.HEI 95 recommended?:Notes:Measure with mains normal and reversed. Ensure equipment is switched on.
26 6.6 Enclosure leakage current Applicable toClass I and class II equipment, all types.Limits:0.1mA in NC, 0.5mA in SFCDB9801 recommended?:Yes, NC onlyHEI 95 recommended?:Yes, class I SFC earth open circuit, class II NC.Notes:Ensure equipment switched on. Normal and reverse mains. Move probe to find worst case.Figure 13. Measurement of Enclosure Leakage Current.
27 6.7 Patient leakage current Applicable toAll classes, type B & BF equipment having applied parts.Limits:0.1mA in NC, 0.5mA in SFC.DB9801 recommended?:NoHEI 95 recommended?:Yes, class I SFC earth open circuit, class II normal condition.Notes:Equipment on but outputs inactive. Normal and reverse mains.
28 Measurement of patient leakage current for each applied part in turn Applicable toClass I and class II, type CF (B & BF for DB9801 only) equipment having applied parts.Limits:0.01mA in NC, 0.05mA in SFC.DB9801 recommended?:Yes, all types, normal condition only.HEI 95 recommended?:Yes, type CF only, class I SFC earth open circuit, class II normal condition.Notes:Equipment on but outputs inactive. Normal and reverse mains. Limits are per electrode.
29 6.8 Patient auxiliary current Applicable toAll classes and types of equipment having applied parts.Limits:Type B & BF - 0.1mA in NC, 0.5mA in SFC. Type CF mA in NC, 0.05mA in SFC.DB9801 recommended?:No.HEI 95 recommended?:Notes:Ensure outputs are inactive. Normal and reverse mains
30 6.9 Mains on applied parts Applicable to Class I & class II, types BF & CF having applied parts.Limit:Type BF - 5mA; type CF mA per electrode.DB9801 recommended?:No.HEI 95 recommended?:NoNotes:Ensure outputs are inactive. Normal and reverse mains. Caution required, especially on physiological measurement equipment.