GB/T 41344.4-2022Safety of machinery—Risk early-warning—Part 4: Measures (English PDF)

3.1 Light signal

Visual identification signs of different levels of risk represented by lights of specific colors.

3.2 Acoustical signal

An auditory alarm emitted by the risk early-warning system according to the level after The types of early-warning measures mainly include information measures, manual measures, and mechanical measures. Select one or more types as required to achieve the purpose of hazard elimination or risk reduction.

Note: See Appendix A for examples of the application of early-warning measures.

6.1.2 Information measures

Information measures mainly include visual signals, auditory signals, text files, etc.

a) Visual signals shall be selected according to different risk levels, and shall have a great degree of discrimination; at the same time, it is necessary to consider the definition of the display of the signal in the environment. Visual signals include but are not limited to:

1) Light signals: lights or combinations of different colors, for example, blue->yellow->orange->red;

2) Screen display: display warning graphics on the screen;

3) Warning signs: highlight the warning signs set in place.

b) Auditory signal: Select the corresponding acoustical signal according to different risk levels, and the signal shall have a high degree of identification; at the same time, it is necessary to consider some influencing factors, such as the acoustical signal's capability of passing through obstacles, the duration, and hearing threshold of human. The influencing factors include at least, but are not limited to:

1) Sound of the alarm;

2) Voice warning.

c) The text file is used to release the early-warning information; the content of the file includes the early-warning time, the information on which the early-warning is classified, the method of early-warning classification, the result of early- warning classification, etc. The documents shall be archived, and the enterprise can determine the retention period and the scope of use of the documents according to its own conditions for subsequent use.

6.1.3 Manual measures

6.1.3.1 Immediate measures

Immediate measures shall be taken for manual intervention when the following situations occur:

--- When the risk is low, but the manual operation is necessary;

--- When the early-warning hasn't been responded to and the risk upgrades;

--- When automatic measures are insufficient to prevent the dangers. Manual intervention measures include, but are not limited to:

--- Manually issue the warnings, etc.;

--- Manually and forcibly control the machines and equipment to perform an emergency stop, power-off, and other operations.

6.1.3.2 Non-immediate measures

Non-immediate measures mainly include behavior management measures, equipment management measures, etc.

a) Behavior management measures include, but are not limited to:

1) Safety education: enable personnel to consciously wear protective equipment as required and operate according to operating procedures;

2) Skill training;

3) Establish a sound safety management system.

b) Equipment management measures include, but are not limited to:

1) Set up warning signs on residual risk equipment;

2) Give information about the use of equipment;

3) Inspect and maintain the equipment regularly.

6.1.4 Mechanical measures

Mechanical measures mainly refer to the measures taken by the machine itself, such as deceleration and shutdown of the robots, the operation of avoiding obstacles by the automatic guided vehicles (AGVs) automatically after encountering people.

6.2 Levels of the measures

According to the early-warning levels classified in GB/T 41344.3-2022, the early- warning measures shall be divided into four levels: level-IV measures, level-III measures, level-II measures, and level-I measures; see Table 1 for details. robot fixture will cause the workpiece to fly out and hurt people; the strength of the holding force can be judged by monitoring the air supply pressure;

d) Workplace's ambient temperature (theta) and humidity (H): Abnormalities of theta and H will accelerate the wear of robot parts and cause the occurrence of the malfunction of the robot; the ambient temperature and humidity of the workplace can be monitored through the temperature and humidity sensor.

A.4 Determination of models and weights

Select the risk value calculation model of formula (1) of GB/T 41344.3-2022. By analyzing historical data and using the expert consultation weight method, determine the weight of each element as shown in Table A.2. Among them, if the limiting cases are monitored, such as the distance between the person and the machine is 0 mm< L< 1000 mm, the vibration acceleration value of the robot fastening screw is a>=10x10-3 m/s2, the air supply pressure of the fixture is 0 kPa< P<=470 kPa or 530 kPa<=P< 1000 kPa, the temperature is theta< 5 °C or theta>45 °C, and the relative humidity is 95%<=H< 100%, then the risk value RvN=1; at this time, the early-warning level is level- I.

The calculation of the risk value (Rvi) of the single factor according to formula (A.1): Where: M1 --- Element of the index; M2 --- Early-warning index; M3 --- Risk value of the factor;

M4 --- Monitored value; if an element is monitored, then M4=1; if it is not monitored, Except for the limiting case where the risk value is RvN=1, the real-time risk value (Rvi) can be calculated by applying formula (1), formula (A.1), and Table A.2 of GB/T 41344.3-2022; see formula (A.2).

When alpha1, beta1, beta2, gamma1, gamma2 is taken as the maximum value respectively, the maximum risk value is Rvmax=0.75.

When alpha1, beta1, beta2, gamma1, gamma2 is taken as the minimum value respectively, the minimum risk