GB/T 41344.3-2022Safety of machinery—Risk early-warning—Part 3: Classification (English PDF)

3.1 Danger zone; hazard zone

Any space inside and/or around the machine in which the person is exposed to danger. [Source: GB/T 30174-2013, 2.27]

A, B, C --- The corresponding weights of people, machines, and the environment, ai --- The corresponding weight of the element index value of people is alphai, and Gi is the monitored value; sumai=1, and sumalphai=1; when the system detects the element, Gi=1; when the system does not detect the element, Gi=0; bj --- The corresponding weight of the element index value of the machines is betaj, and Gj is the monitored value; sumbj=1, and sumbetaj=1; when the system detects the element, Gj=1; when the system does not detect the element, Gj=0; ck --- The corresponding weight of the element index value of the environment is gammak, and Gk is the monitored value; sumck=1, and sumgammak=1; when the system detects the element, Gk=1; when the system does not detect the element, Gk=0.

5.2 Basic requirements

Appropriate elements such as people, machines, and the environment shall be selected according to the actual application and demand.

The weight of each element changes dynamically, and the weight determination method described in 6.1 shall be used to optimize the weight value according to the updated historical data.

After the elements and weights of the risk value calculation model are determined, the maximum and minimum values of formula (1) shall be calculated. During the calculation of the risk value in real-time, the risk value (Rv) shall be normalized according to the maximum and minimum values, and the normalized risk value is expressed as RvN (0<=RvN<=1).

Under specific circumstances, some human, mechanical, and environmental elements have the highest level; if these elements reach the preset values, then the normalized risk value (RvN) reaches a maximum value of 1.

The early-warning level shall be determined according to the interval range of the normalized risk value (RvN).

5.3 Determination of elements

Examples of the monitoring variables for the status information of people, the status information of machines, and the status information of the environment are given in Appendix A of GB/T 41344.2-2022. One or more of them can be used as the elements of risk calculation.

6.1 Weight determination method

The weight of each element can be determined by the mathematical statistics methods such as Delphi method, the principal component analysis method, the analytic hierarchy process, the priority diagram method, and the entropy weight method. The weight values obtained by different methods will be different.

6.2 Elements considered in weight determination

6.2.1 People

6.2.1.1 Overview

During the determination of the element weight of people, the working space limitation of people and the frequency and duration of abnormal behaviors of people are mainly considered.

6.2.1.2 Working space

The scope of human activities is divided into three parts: safety zone, early-warning zone, and danger zone. When people are in the early-warning zone, they can be classified into the early-warning zone I, the early-warning zone II, and the early- warning zone III according to their distance from the danger source; their weight values increase in turn. The safety zone, the early-warning zone, and the danger zone can be determined according to the calculation method of the safety distance in GB/T 23821 and GB/T 19876.

6.2.1.3 Frequency and duration of abnormal behavior

Frequency of the abnormal behavior --- The number of abnormal human behaviors that occur in unit time, for example, the number of occurrences that operators fail to wear protective equipment complying with regulations while operating the machines within a period. The weight value increases in turn with the frequency being from low to high.

Duration of the abnormal behavior --- The persistent period of the abnormal human behavior, for example, the exposure time of the person after entering the early-warning zone. The weight value increases in turn with the duration being from short to long.

6.2.2 Machines

The frequency and duration of abnormal cases of the machine are mainly considered during the determination of the weight of the machine.

The frequency of the abnormal case of the machine --- The number of mechanical abnormal cases that occur per unit time, for example, the number of the cases that the machine does not follow the set action flow. The weight value increases in turn with the frequency being from low to high.

The duration of the abnormal case of the machine --- The persistent period of the mechanical abnormal case, for example, the period during which the machine does not follow the set action flow. The weight value increases in turn with the duration being from short to long.

6.2.3 Environment

6.2.3.1 Production environment

The production environmental elements that need to be mainly considered include but are not limited to the following aspects.

Noise --- Excessive noise will have adverse effects on human physical and mental health, so the limit of the noise shall meet the requirements of GB 3096-2008.

Determine the weight value of different noise levels according to the requirements of the work site.

Lighting --- Inadequate lighting in the work environment may lead to maloperation by staff. Determine the weight value of different lighting conditions according to the requirements of the work site.

Color --- The color of the workshop environment will affect the operator's response speed and operational accuracy when working. Determine the weight value of different colors according to the requirements of the work site.

Dust --- The dust in the workplace air exceeding the allowable concentration will affect the safe production. Determine the weight value of different dust concentrations according to the requirements of the work site.

6.2.3.2 Natural environment

The natural environment elements that need to be mainly considered include but are not limited to the following aspects.

Temperature --- It includes the workplace ambient temperature and the temperature of the machine itself. Determine the weight value of different temperature values according to the requirements of the work site.

Humidity --- The humidity of the working environment. Determine the weight value of different humidity values according to the requirements of the work site.