IEC 60601-1 the ultimate safety & performance guide

What is specified in IEC 60601-1?

Overall, IEC 60601-1 specifies requirements for basic safety and essential performance of medical electrical equipment. It covers specifications on everything from insulation, leakage current, shock, creepage, and air clearances, to product layout, environment, and design. The standard is divided into two subsections containing collateral standards and particular standards.

Collateral standards: Cover high level regulatory requirement that relates to safety of the most of the medical equipment that is tested to IEC 60601-1. These specify design standards for medical devices and are not necessarily pass/fail standards. There are 10 major collateral standards:

IEC 60601-1-x, where x equals the number of the collateral standard;

IEC 60601-1-1: Addresses medical electrical systems. First introduced in 1992 and revised in 1995 and 2000. It has since been withdrawn and is no longer a standalone document. The information in IEC 60601-1-1 has incorporated into the third edition of IEC 60601-1.

IEC 60601-1-2:2007: Introduced in 1993 to specify electromagnetic disturbances requirements and tests for electromagnetic compatibility (EMC) of medical equipment, medical electrical systems, information technology equipment for medical applications and any equipment used in medical electrical systems. Revised in 2001, 2004, 2010, 2014, and 2020. Equipment will not generate unwanted electromagnetic radiation and will not be unduly affected by it. Compliance with this standard ensures EMC Directive requirements are also met.

IEC 60601-1-3:2008: Radiation protection in diagnostic x-ray equipment; ensures stray radiation is minimized to protect both patient and operator.

IEC 60601-1-4: Programmable Electrical Medical Systems (PEMS). Standard for software. This is no longer a standalone document and has been incorporated into third edition of IEC 60601-1.

IEC 60601-1-6:2007: Usability; Manufacturers must take requirements in this collateral standard into consideration during the design process to increase ergonomics. Equipment should be intuitive and easy to use to avoid user error.

IEC 60601-1-8: 2007: Medical alarms; guidance and management of alarm systems within medical equipment and what the user should do if they encounter one.

IEC 60601-1-9: 2008: Environmentally Conscious Design; air, water, biosphere, use of raw materials, and transport and packaging should all be considered during design of new products.

IEC 60601-1-10: 2008: Physiologic Closed Loop Controllers; design criteria that should be considered for medical devices that control the parameters that they are measuring so they are stable and reliable.

IEC 60601-1-11: 2010: Home healthcare equipment; addresses safety of home healthcare equipment being used by non-specialist users and possibility of poor wiring in building.

Particular standards (IEC 60601-2-xx): provide additional information to collateral standards with about 80 particular standards that cover safety standards and performance for specific medical equipment such as mechanical ventilators, cardiac defibrillators, infant incubators, electrocardiographs, medical beds, X-ray equipment:

The following cover the requirements for the basic safety and essential performance for certain medical equipment: IEC 60601-2-xx, where xx equals number of the particular standard.

Means of Protection (MOP)

Means of protection (MOP) was added to IEC 60601-1 to address the risk of patients and equipment operators coming in contact with lethal mains voltage of medical devices. MOP can be achieved through protective earth connection (which protects against electrical shock), safety insulation, and minimum creepage and clearance distances. MOP can be classified as either 1 x MOP, which has basic insulation, or 2 x MOP, which has reinforced insulation.

One of the main specifications that means of protection addresses is creepage and clearance. Creepage and clearance in a supply offer space between conductive parts in a supply. Creepage measures this distance along the surface insulation, while clearance measures it through the air. It is important for medical equipment to have proper creepage to protect against deterioration caused by tracking, and proper clearance in order to prevent dielectric breakdown within the supply.

Minimum Creepage Distances and Air Clearances Between Parts of Opposite Polarity of the Mains Port

The manufacturer of the medical product is the one that will determine the likelihood of their product to come in contact with patient and operator, and whether operator protection (MOOP) or patient protection (MOPP) is needed.

Means of Operator Protection (MOOP)

Means of operator protection is that standard of protection that provides safety measures for the operator of medical equipment. This means it will be necessary for equipment that will not be in contact with a patient. If used in a laboratory setting 2 x MOOP is sufficient to protect the operators of the equipment.

There are basic insulation standards (1xMOOP) and reinforced insulation standards (2xMOOP) that can be applied to medical equipment. Products will also need to have minimum air clearances from the mains part in order to comply with MOOP.

Minimum Air Clearances Providing MOOP from the Mains Part

* Air clearances for working voltages above 20kVr.m.s. or 28 KVDC can be prescribed by particular standards if necessary.

Note: Air clearances are a function of peak voltage in the circuit. The r.m.s. voltage column is provided for the special case where the voltage has a sinusoidal waveform.

Means of Patient Protection (MOPP)

Means of patient protection will be necessary for equipment that will come into contact with patients. It reduces the leakage currents and risk of electric shock if the patient may come in contact with conductive parts and AC currents. The most stringent requirements will be needed for electrocardiogram, applied parts, floating cardio, and type CF parts. The safest applied parts are F-type isolated applied parts in which patient connections are isolated from other parts of the equipment.

Like means of operator protection, means of patient protection has basic insulation standards (1xMOPP) and reinforced insulation standards (2xMOPP) to follow.

Minimum Creepage Distances and Air Clearances Providing MOPP

A product with 2 x MOPP will usually have the highest level of protection for a medical setting. It has the most stringent requirements of the MOP classifications including 4000VAC isolation, and creepage distance of 8mm.

Environmental Tests

Medical equipment needs to be tested to meet proper temperature, humidity, and atmospheric pressure conditions as indicated by IEC 60601-1.

Protection against Electrical Hazards

IEC 60601-1 outlines protections and limitations that medical equipment will need to have for electrical hazards like shock, water/particulate matter, and leakage current. It also outlines the standards required for methods of protecting against electrical hazards like protective earthing, MOOP, MOPP, leakage, insulation, creepage and air clearances, and layout.

Protection Against Mechanical Hazards

Medical equipment needs to have proper protection against certain mechanical hazards such as moving parts, expelled parts, instability, acoustic energy and vibration, and pneumatic and hydraulic pressure. IEC 60601-1 addresses the hazards that are associated with these moving parts and how the risk created from moving parts coming in contact with one another can be reduced.

Protection Against Unwanted/Excessive Radiation

Medical equipment is prone to exposure to unwanted or excessive radiation, given the environment it is used in. IEC 60601-1 outlines radiation limitations for x-radiation, alpha, beta, gamma and neutron particle radiation, microwave radiation, infrared radiation, and UV radiation.

Isolation

Isolation is the separation of incoming high voltage (mains) to the low voltage output. Isolation helps prevent voltages from passing between components and can help prevent electrical shock and breaks ground loops. According to IEC 60601-1, medical equipment needs to isolate its circuits form the supply mains on all poles simultaneously and have very low leakage current.

Leakage

Leakage current is the current that still flows input to output during supply operation. It is important for leakage current in medical power supply to be low because any additional current that reaches the patient or the caregiver, that is not intended, could cause serious harm. Leakage requirements in a medical power supply are determined by IEC 60601-1.

*These values are only applicable to equipment having multiple applied parts.

Note: Above chart is based on information from IEC 60601-1 Ver. 3 and may not necessarily be the most current information.

To help reduce leakage current, medical power supplies should be properly grounded, double insulated or reinforced for to meet the requirements of the standard.

Shock

Shock is a huge risk when it comes to medical supplies because shock an electric shock from a power supply could severely harm a patient or caregiver. Means of Operator Protection (MOOP) and Means of Patient Protection (MOPP) laid out in IEC 60601-1 outline how supplies can be designed and tested to reduce the risk of electric shock to both the operator and the patient. Both MOOP and MOPP have to meet specific dielectric strength, creepage/clearance, and protective earth connection requirements to be certified as IEC 60601-1 and appropriate for medical devices.

Properly isolating components like the AC input, DC output, and the supply itself can help reduce the risk of shock and damage to the supply. Isolation is especially important around conductors.

What is Required for IEC 60601-1 Compliance?

Gaining IEC 60601-1 compliance can be a difficult and long process. The first step to in the process is to determine which standard is needed for your device. Factor such as country and application will determine which IEC 60601 classification is needed. Particular standards and collateral standards will also need to be determined at this stage. This will include more specific requirements such as electric shock, applied parts, protection against harmful matter such as water and particulate matter, humidity test, mode of operation, isolation etc. Planning tools like an isolation diagram can help during the early design phase to avoid expensive redesigns later down the line.

The next step toward achieving IEC 60601-1 compliance is to classify the critical components will be needed for your device and to get the spec sheets for them. These components can include flammable components, line filters, mains components etc.

After that, essential performance will need to be identified and documented to help determine a test plan for your device. This will include performing risk analysis per essential performance clauses and specifying performance limits between fully functional and total loss in normal and single fault conditions. Essential performance typically applies to critical care equipment, but can also apply to less critical equipment as well. The risk management file will need to comply with ISO 14971. After this step has been completed, a test plan can be drafted.

IEC 60601-1 requires ‘type testing’ which means a test must be performed on a representative sample of the device to determine if it meets requirements of the standards. The test plan can cover tests for multiple standards, with the only exception being EMC (IEC 60601-1-2) which requires a separate test plan.

Following the test plan, marking and labeling requirements should be reviewed so that your device is properly labelled and documented. This will include review of the markings on your device, the user manual and/or quick start guides, technical description, collateral and particular standard labelling requirements, and readability requirements. It should be ensured that legibility and durability of markings is appropriate for the product and environment.

The next item that will need to be reviewed is the construction of the device against IEC 60601-1 standards. This includes items like spacing, power supply, physical requirements, and enclosure materials. Following this step, you can finalize the risk management file and essential performance, making any necessary updates. You may also want to consider pre-testing your device, in-house or by using a lab.

You will then need to contact a test lab to verify certification. Make sure you have spare parts on hand, drawings and labels, and supporting documentation. Production line test equipment must also be set up to meet IEC 60601-1. The test lab will then determine if you have reached IEC 60601-1 certification. Please note, these steps are just a general guideline. More details can be found on this website.

IEC 60601-1 Glossary of Terms

Term	Description	Symbol
EUT	Equipment under testing; the equipment that is being tested	–
DUT	Device under testing; device that is being tested	–
Applied part	Part of equipment that is designed to, or is likely to, come into physical contact with the patient	–
Patient Connection	Connections or metal parts intended to connect with the patient from applied part	–
Patient Environment	Area in which patient can come to contact with medical equipment or contact between people touching the medical equipment and the patient can occur	–
F-Type Applied Part	Applied part that is electrically isolated from earth and other parts of medical equipment. Floating F-type parts are either Type BF or Type CF applied parts	–
Type B Applied Part	Applied part complying with specifications against electric shock; earth referenced; not suitable for direct cardiac application
Type BF Applied Part	F-Type applied part that complies with a higher degree of protection against shock than Type B; not suitable for direct cardiac application
Type CF Applied Part	F-Type applied part the complies with the highest degree of protection against electric shock than Type B
Medical electrical equipment	Equipment used for diagnosing or monitoring patients powered by one connection to main supply; contact with patient is not necessarily required	–
Medical Electrical system	Combination of equipment in which at least one is classified as medical electrical equipment and is connected by functional connection or use of multiple portable socket outlets	–
Class I	Protection against electrical shock by basic insulation through connecting exposed conductive parts to protective earth in fixed wiring of an installation.
Class II	Protection against electrical shock by supplementary insulation (more than basic insulation). No provision for connection of exposed metalwork of equipment to protective conductor and no reliance on precautions taken in fixed wiring of installation. Class II is also known as ‘double insulated’
Creepage	Shortest distance between two conductive parts that is measured along the surface of insulation	–
Clearance	Shortest distance between two conductive parts through the air	–
Ingress Protection (IP)	Protection against fluids and dust	–

The most up to date information on IEC 60601-1 can be found on the IEC website for download.