YY/T 1837-2022 English PDF (YYT1837-2022)
YY/T 1837-2022 English PDF (YYT1837-2022)
YY/T 1837-2022: Medical electrical equipment - General requirements for reliability
PHARMACEUTICAL INDUSTRY STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
CCS C 30
Medical electrical equipment - General requirements for
ISSUED ON: MAY 18, 2022
IMPLEMENTED ON: JUNE 01, 2023
Issued by: National Medical Items Administration
Table of Contents
Foreword ... 4
1 Scope ... 5
2 Normative references ... 5
3 Terms and definitions ... 5
4 General ... 9
4.1 Goals of reliability work ... 9
4.2 Basic principles of reliability work ... 9
4.3 Coordination of reliability work and other related work ... 10
4.4 Classification of reliability work ... 10
4.5 Description of reliability work requirements ... 10
4.6 Compliance guidelines ... 12
5 Reliability requirements analysis and requirements determination ... 12 5.1 User needs analysis ... 13
5.2 Environmental profile analysis... 13
5.3 Determination of reliability indicators ... 14
6 Reliability design and analysis ... 15
6.1 Establishment of reliability models ... 15
6.2 Reliability assignment ... 15
6.3 Reliability prediction ... 16
6.4 Design failure modes and effects analysis (DFMEA) ... 16
6.5 Failure tree analysis (FTA) ... 17
6.6 Development of reliability design criteria ... 18
6.7 Identification of reliability key parts ... 19
6.8 Selection and control of materials, components and parts ... 19
6.9 Finite element analysis ... 20
6.10 Derating analysis ... 20
6.11 Circuit tolerance analysis ... 21
6.12 Durability analysis ... 21
6.13 Reliability review ... 21
7 Reliability test and evaluation ... 22
7.1 Reliability R&D test ... 22
7.2 Reliability verification and evaluation ... 23
8 Manufacturing process reliability ... 25
8.1 Process failure mode and effects analysis (PFMEA) ... 25
8.2 Verification of manufacturing process reliability ... 25
8.3 Environmental stress screening ... 26
9 Collection and evaluation of use reliability information ... 26
Annex A (informative) Description of principle ... 27
Annex B (informative) Reliability requirements analysis ... 47
Annex C (informative) Environmental profile analysis ... 48
Annex D (informative) Reliability modeling ... 49
Annex E (informative) DFMEA form template ... 55
Annex F (informative) Failure tree FTA examples ... 57
Annex G (informative) Reliability evaluation of components and parts selection ... 60 Annex H (informative) Finite element analysis ... 61
Annex I (informative) Derating analysis method ... 62
Annex J (informative) Method and program of circuit tolerance analysis ... 66 Annex K (informative) Reference template for design review form ... 72
Annex L (informative) Growth test with known growth model ... 73
Annex M (informative) Reliability index verification - Examples of conventional test and accelerated test methods ... 80
Annex N (informative) Examples of item failures introduced by the manufacturing process ... 84
Annex O (informative) Environmental stress screening ... 85
Bibliography ... 88
Medical electrical equipment - General requirements for
This document specifies the general requirements and basic methods for carrying out reliability work during the life cycle of medical electrical equipment (hereinafter referred to as ME equipment) and medical electrical systems (hereinafter referred to as ME system).
This document is applicable to the reliability work of various types of ME equipment or ME system. This document does not contain relevant requirements and methods specific to software reliability.
NOTE: All chapters and clauses in the main text of this document have corresponding relevant principle explanations in Annex A.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. GB/T 2900.1-2008, Electrotechnical terminology - Fundamental terms
GB 9706.1-2020, Medical electrical equipment - Part 1: General requirements for basic safety and essential performance
YY/T 0316-2016, Medical devices - Application of risk management to medical devices
YY/T 1813, Methods for operational reliability information collection and evaluation of medical electrical equipment
3 Terms and definitions
For the purposes of this document, the terms and definitions defined in GB/T 2900.1- 2008, GB 9706.1-2020, YY/T 0316-2016 as well as the followings apply.
An analysis technology that analyzes the potential failure modes in the process of manufacturing, assembly and logistics and their impact on items and upper-level items and classifies and analyzes them according to the severity of the impact of the failure modes, so as to ensure that the produced items meet the design.
[Source: GB/T 2900.99-2016, 192-11-05, modified]
3.9 environment profile
A sequential description of the various main environmental parameters that the ME equipment or ME system will encounter during storage, transport, use.
3.10 accelerated test
To shorten the test time or find item defects, under the condition of not changing the failure mode and failure mechanism, the test that is carried out by means of stress increase or time compression or event compression.
[Source: GB/T 2900.99-2016, 192-09-08, modified]
The ability of ME equipment or ME system to perform a specified function under specified conditions and within a specified time.
NOTE: The ability to perform specified functions includes at least the ability of ME equipment or ME system to meet safety and effectiveness requirements.
[Source: GB/T 2900.99-2016, 192-01-24, modified]
3.12 reliability key parts
Parts that will seriously affect the safety and effectiveness of ME equipment or ME system in the event of failure, or are highly complex, or have high technological content, or are expensive, or have a high failure rate.
3.13 reliability work
A series of technical work to determine and meet the reliability requirements of ME equipment or ME system.
3.14 reliability diagram
A logical, graphical representation of the system, revealing how the reliability of the system's sub-items (represented by boxes) and their combinations affect system reliability.
[Source: GB/T 2900.99-2016, 192-11-03]
3.15 reliability model
Establish the reliability block diagram and mathematical expression of the failure logic relationship between the system and the unit. The model that is established for the distribution, prediction, analysis or estimation of the reliability of the item. [Source: GB/T 2900.99-2016, 192-11-02, modified]
3.16 operational reliability
The demonstrated reliability of ME equipment or ME system under actual conditions of use. It reflects the comprehensive influence of item design, manufacturing, installation, use, maintenance, environment and other factors.
NOTE: It mainly refers to the reliability of ME equipment or ME system after delivery. 3.17 design failure modes and effects analysis; DFMEA
An analytical technique that, in the design phase, ANALYZES each possible failure mode of the item and its impact on the item and the upper item, and CLASSIFIES and ANALYZES the solution according to the severity of the impact of the failure mode, so as to ensure that potential failure modes and their associated causes or mechanisms of failure are considered and addressed as far as possible before the item is delivered to production.
[Source: GB/T 2900.99-2016, 192-11-05, modified]
3.18 medical electrical equipment; ME equipment
Electrical equipment having an applied part or delivering or receiving energy to a patient or detecting such delivered or received energy. Such electrical equipment: a) has not more than one connection to a designated supply network; and b) its manufacturer intends to use it for:
1) diagnosis, treatment or monitoring of patients; or
2) elimination or alleviation of disease, injury or disability.
[Source: GB 9706.1-2020, 3.63]
3.19 medical electrical system (ME system)
As specified by the manufacturer, a combination consisting of several devices that are functionally connected or connected to each other using a multi-socket socket. At least one of the combinations is ME equipment.
[Source: GB 9706.1-2020, 3.64]
5.1 User needs analysis
User needs analysis shall be carried out as early as possible in the early phase of ME equipment or ME system R&D project approval. Provide information for the determination of reliability requirements to meet the actual use needs of ME equipment or ME system.
It can be developed from the following:
a) The frequency of clinical use of ME equipment or ME system or parts within a specified period of time can be the times of use, continuous working hours. Ergonomics can be used to identify scene factors (such as user behavior patterns, medical environments, places, and work patterns) and their impact on user needs and expected uses, as well as the habits, strength, and direction of different user groups operating and contacting the interface.
b) User needs research activities can be implemented using structured methods, such as customer feedback, through interviews, on-site investigations and collections. c) Refer to Annex B for the reliability requirements analysis.
5.2 Environmental profile analysis
Various environmental factors that may affect the equipment during the equipment life cycle shall be determined according to the characteristics of the ME equipment or ME system. Determine the main environmental parameters by analyzing the collected information. At the same time, the comprehensive effect of various environmental factors is considered, so as to obtain the environmental profile of the ME equipment or ME system. Environmental profile analysis can be used as input for ME equipment or ME system development and design. It can provide reference for reliability test. If applicable, mainly collect and analyze information on the following environmental factors.
a) The climate environment mainly includes the following factors:
- Temperature and humidity: investigate the temperature and humidity ranges inside and outside each place during the storage, transportation, turnover, installation, use, and maintenance of ME equipment or ME system.
- Atmospheric pressure: the range of atmospheric pressure in the area where the ME equipment or ME system is intended to be used.
- Salt spray.
- Acid rain.
- Air pollution: dust/haze; dust: particle size/dispersion/property
(organic/inorganic/mixed); haze: particle size/property/occurrence frequency. - Light radiation factors: direct or indirect solar radiation, ultraviolet lamp exposure, incandescent lamp exposure, etc.
b) Mechanical environment:
ME equipment or ME system may encounter mechanical environmental factors such as vibration, impact, wall collision and bumping during storage,
transportation, turnover, installation, use and maintenance. Investigate the vibration amplitude/frequency/period, impact number/intensity/waveform that ME equipment or ME system may experience.
c) Electromagnetic environment:
ME equipment or ME system may be subjected to levels of electromagnetic disturbance that exceed those defined in ISO 9706.102.
d) Biochemical environment mainly includes the following factors:
- Corrosive fluids in the process of cleaning, disinfection, sterilization, such as alcohol, ozone, sulfide, chloride and other corrosive liquids or gases. - Body fluids, such as sweat, urine, blood.
- Microorganisms, such as mold.
- Small animals, such as mice, spiders, cockroaches.
e) High energy radiation environment: ionizing radiation.
For environmental profile analysis, refer to Annex C.
5.3 Determination of reliability indicators
Reliability quantitative indicators suitable for ME equipment or ME system characteristics shall be determined, such as mean time between failures (MTBF), mean time to failure (MTTF), failure rate, reliability. The work of determining the reliability indicators of ME equipment or ME system shall pay attention to the following: a) When determining the reliability indicator requirements, factors such as the use requirements, cost, progress, technical level and reliability level of similar ME equipment or ME system shall be considered comprehensively.
completed, the responsibility for the indicators shall be assigned to the relevant design department. The general workflow and precautions for reliability assignment are as follows:
a) First determine the level of ME equipment or ME system that requires assignment. b) According to the reliability model established in 6.1, assign the reliability quantitative requirements to the specified ME equipment or ME system level. Use as a basis for reliability design and for proposing reliability quantitative requirements for outsourced and outsourced parts.
c) The specific reliability assignment value shall be included in the corresponding ME equipment or ME system R&D indicator requirements.
d) When assigning the reliability indicators, factors such as the complexity, technical level, working hours and environmental conditions of the ME equipment or ME system level to be assigned shall be fully considered to allocate the reliability indicators quantitatively.
6.3 Reliability prediction
The reliability indicator of ME equipment or ME system shall be estimated. Whether the proposed design scheme can meet the specified reliability quantitative requirements shall be evaluated. The general procedures, methods and precautions for reliability prediction work are as follows:
a) Carry out Reliability prediction for each level specified by ME equipment or ME system.
b) Use the reliability model established in 6.1 when predicting. Relevant estimation methods and data are given priority to the information obtained by the enterprise itself in the evaluation of historical reliability data. Also refer to GB/T 37963 or other data.
c) Estimates for mechanical, electrical and electromechanical equipment parts may be performed using data from similar ME equipment or ME system and other suitable methods.
d) The sources of reliability data involved shall be credible.
6.4 Design failure modes and effects analysis (DFMEA)
Failure mode and effects analysis (FMEA) is a systematic procedure for the systematic analysis of ME equipment or ME system to identify potential failure modes, failure mechanisms, failure causes and their effects on ME equipment or ME system, parts, components. Determine all possible failure modes of ME equipment or ME system, parts or components by systematic analysis, as well as the mechanism, cause, inspection method and effect of each failure mode. Identify potential weaknesses. Propose improvement measures. Design failure modes and effects analysis (DFMEA) refers to the FMEA performed during the design phase. Manufacturers can perform analysis of specific objects based on the characteristics of the ME equipment or ME system. When carrying out DFMEA work, it is advisable to refer to the following: a) DFMEA shall be carried out as early as possible in the ME equipment or ME system development cycle. DFMEA work is an iterative process synchronized with the design process.
b) A complete DFMEA is a team effort. Teamwork guarantees open-mindedness and ensures the necessary accumulation of know-how.
c) DFMEA shall fully consider the potential failure modes of the ME equipment or ME system. Analyze the impact of failure modes on reliability.
d) The manufacturer's accumulated experience with historical failure analysis of ME equipment or ME system is an important input source for DFMEA.
e) Analysis can be carried out with reference to the procedures and methods provided by GB/T 7826.
f) For the template and filling of DFMEA, refer to Annex E.
6.5 Failure tree analysis (FTA)
Failure tree analysis can be carried out as required. Failure tree analysis is one of the tools for system reliability analysis. Failure tree analysis can provide a complex diagram to help the user visualize possible preventive/corrective actions. When carrying out the failure tree analysis of the item, it is advisable to refer to the following:
a) The application of failure tree analysis usually starts with a failure, that is, the top event.
b) On the basis of the general FMEA, the failure event with high severity identified in the FMEA is taken as the top event. Perform a failure tree analysis. c) Failure tree analysis is especially useful in the early stages of design. Especially when the designed ME equipment or ME system is very complex, the failure tree is a process of repeated in-depth and gradual improvement.
d) Failure tree analysis can be carried out with reference to GB/T 7829. 6.7 Identification of reliability key parts
Reliability key parts refer to the parts whose failure will seriously affect the safety and effectiveness of ME equipment or ME system, as well as the parts that are complex or expensive or have a high failure rate. The following aspects shall be paid attention to when determining the reliability key parts:
a) Reliability key parts can be determined by FMEA, FTA, similar ME equipment or ME system history failure combing or other analysis methods.
b) Comprehensively consider the complexity of ME equipment or ME system, new technology content, cost and other factors.
c) Identify the main root causes of failures of r reliability key parts. Implement effective control measures.
d) Information required for safety and efficacy analysis can be clarified in conjunction with risk management.
e) Determine whether to add or delete the list of reliability key parts through review. 6.8 Selection and control of materials, components and parts
Clearly control the selection and use of materials, components and parts for ME equipment or ME system. Ensure that the materials, components and parts used in ME equipment or ME system have a good and stable quality level and a good reliability level.
The selection and control of materials, components and parts shall refer to the following: a) According to the characteristics of the developed ME equipment or ME system, formulate the selection and use control requirements of materials, components and parts. Form control documents.
b) Develop a preferred library and qualified supplier catalog for materials, components and parts.
c) Formulate selection guidelines for components and parts.
d) There is confirmation process with qualified suppliers and preferred lists. e) Control the use of device selection outside of qualified suppliers and preferred libraries. There shall be a clear confirmation procedure for the selection of materials, components and parts other than qualified suppliers and preferred libraries.
f) Formulate reliability evaluation test methods and batch reliability sampling inspection methods for materials, components and parts.
g) Refer to Annex G for component and part selection reliability evaluation form. 6.9 Finite element analysis
Analyze and evaluate the mechanical strength and thermal response characteristics of ME equipment or ME system during the design process. Carry out early detection of weak links in load-bearing structures and materials ...