YY/T 1813-2022Methods for operational reliability information collection and evaluation of medical electrical equipment (English PDF)

3.1 Parameter estimation

Infer unknown total distribution parameters from a sample.

The process of estimating parameters or parameter functions used to characterize reliability indicators in the analysis of operational reliability data of ME equipment and ME systems. [SOURCE. GB/T 17560-1998, 3.1.1, modified]

3.2 Distribution model

A specific distribution or class of distributions. [SOURCE. GB/T 3358.2-2009, 2.5.3, modified]

3.3 Distribution function

A function of a random variable having a value less than or equal to the probability of any chosen value.

3.4 Fault

Loss of ability to perform as required due to intrinsic condition.

4.1 Sources of operational reliability information

It mainly comes from the relevant records of reliability information during the use process of ME equipment and ME system after delivery, such as operation records, repair records, maintenance records, etc.

4.2 Contents of operational reliability information

4.2.3 Environmental condition information

Environmental conditions for ME equipment and ME systems include temperature, humidity, atmospheric pressure, etc. The following factors also need to be recorded if they affect the reliability of ME equipment and ME system.

4.2.4 Operation condition

The information that can be collected from the operation condition of ME equipment and ME systems.

4.2.5 Fault information

Fault information than can be collected by ME equipment and ME systems.

4.2.7 Repair and maintenance information

The repair and maintenance information that may be collected by ME equipment and ME systems include.

4.3 Fault judgment and record

4.3.1 Fault classification

The fault classification method of ME equipment and ME systems are as follows.

4.3.2 Statistics principles of fault

According to the following principles, faults are classified, counted and judged.

5.1 Overview

5.1.1 Assess the reliability level achieved by ME equipment and ME systems under actual use conditions; and verify whether the ME equipment and ME systems meet the specified operational reliability requirements.

5.2 Determining the assessment indicators of operational reliability

5.2.1 When the ME equipment and the ME systems are maintainable, the mean time between failures (MTBF) can be selected as the indicator used for reliability analysis and evaluation, generally denoted as theta.

5.3 Determination of samples

Determine the product model, batch number, component model and batch number, serial number range, etc. of the ME equipment and ME systems to be analyzed, determine a specific fault mode, and determine the use time for analysis and evaluation samples (such as the expected useful life of the whole machine) as a screening factor for analyzing samples.

5.4 Preliminary collation of operational reliability information

5.4.2 Analysis of sample empirical distribution

The analysis of sample empirical distribution should be carried out through the histogram.

5.5 Inspection method of distribution type

5.5.1 Inspection by graph estimation method

According to the type of sample distribution, the inspection by graph estimation method can refer to the following methods.

5.6 Parameter estimation for continuous distributions

5.6.3 Refer to GB/T 34987-2017 for parameter estimation of Weibull distribution.

5.7 Preparation of assessment report of operational reliability

The content of the text of the operational reliability assessment report shall include elements such as ME equipment and ME systems information, data range, assessment method, assessment process, and assessment results, etc.