MEDICAL EQUIPMENT CLASSIFICATION

CLASS AND TYPES

PRESENTED BY

SANGEETHA SASIDHARAN

CLASSIFICATION OF MEDICAL EQUIPMENT

A medical device is designed to improve patient’s health in diagnosis, therapy or surgery.

Medical devices are classified into three classes based on the US classification system, which defines the amount of risk involved with the medical device and proper procedures that must be followed when using and manufacturing the device.

The medial devices are categorized by class for the purpose of informing patients, doctors and manufacturers the amount of risk involved and the intention for the medical device.

DIAGNOSTIC EQUIPMENT

THERAPUTIC EQUIPMENT

CLASS I MEDICAL DEVICES

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.

CLASS II MEDICAL DEVICES 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.

CLASS III MEDICAL DEVICES

Class III equipment is defined in some equipment standards as that in which protection against electric 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.

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.

EQUIPMENT TYPES

 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.

TYPES OF MEDICAL EQUIPMENT

TYPE B EQUIPMENT

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).

Type B is the least stringent classification, and is used for applied parts that are generally not conductive and can be immediately released from the patient.

TYPES OF MEDICAL EQUIPMENT

TYPE BF EQUIPMENT

Floating isolated applied part.it is only intended for connection to patients skin but has floating input circuits.no connection between patients and earth.

BF As type B but with isolated or floating (F - type) applied part or parts.

Type BF is less stringent than CF, and is generally for devices that have conductive contact with the patient, or having medium or long term contact with the patient.

TYPES OF MEDICAL EQUIPMENT

TYPE CF EQUIPMENT

CF Equipment 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 CF is the most stringent classification, being required for those applications where the applied part is in direct conductive contact with the heart or other applications as considered necessary.

EQUIPMENT SYMBOLS

CODES AND STANDARDS

A code is a document that contains mandatory requirements.it uses the word shall.is generlly adopted into law by autority that has jurisdiction.

A standard is a document that contains mandatory requirements,but compliance tends to be voluntary

CODES AND STANDARDS

FDA -Food and drug administration IEC -International electrochemical committee NFPA -National fire protection association ANSI -American national standards institute AAMI -Advancement of medical instrumentation BSI -British standards institute ISO -International organization for standardization ECRI -Emergency care research institute HEMA -Health industry manufacturers assoiciation NEMA -National electrical manufacturers association NEC - National electrical code

IMPORTANT STANDARDS AND CODES

IEC :International electrotechnical committee

NFPA99 :Standards for health care facilities

ANSI/AAMI ES1-1993 :Safe current limits for electromedical

BS 5724 : Electrical safety of medical equipment

ELECTRICAL SAFETY

The increased use and complexity of medical systems result in 10,000 device related injuries in the USA each year.

Hazardous sources include electricity, fire, water, chemicals, drugs, germs, x-rays, EM fields, …etc.

There are now performance standards that were written for medical devices.

Our main objectives are to understand the possible electrical hazards and fault scenarios and learn how to improve deigns of medical instruments

EQUIPMENT DESIGN TO ENSURE PATIENT SAFETY

•Reliable grounding of equipment•Reduction of leakage current •Operation at low voltage •Driven- right-leg circuit •Use of current limiters •Electric isolation of patient circuit •Equipotential grounding •Ground faults interrupters •Proper wiring distribution and gr •Line isolation system and monitors

THANKYOU