Fixed protective devices are the most common and cost-effective method of protecting against mechanical risks. However, in practical applications, due to various factors, fixed protective devices often require openings. For example, at the customer's request, protective netting may be used to isolate hazardous areas; design requirements may necessitate openings for cable routing; or the installation method of the machine guard may inevitably leave gaps between it and other protective devices. In these situations, balancing the size of the opening with the required safe distance to mitigate risks becomes a crucial issue. EN ISO 13857, "Safety of machinery — Safety distances from upper and lower limbs to prevent contact with hazardous areas," provides a sufficient explanation and answer.
Figure 1 shows the correspondence between regular openings and safe distances ( for individuals aged 14 and above + upper limbs). When the length of the rectangular opening is less than or equal to 65 mm and the width is between 20 and 30 mm , the required safe distance can be reduced to 200 mm .
Figure 1
Figure 2 shows the correspondence between irregular openings and safe distances ( for individuals aged 14 and above + upper limbs).
First, determine the following data based on the irregular opening:
1. The perimeter of the smallest square that can cover the opening.
2. The width of the smallest rectangle that can cover the opening.
3. The diameter of the smallest circle that can cover the opening.
Based on these three data points and according to Figure 1 , three safety distances can be derived. The minimum value among them is selected as the required safety distance for the irregular opening.
Figure 2
Figure 3 shows the correspondence between opening and safe distance ( persons aged 14 and above + lower limbs). When the length of the rectangular opening is less than or equal to 75mm and the width is between 15-35mm , the required safe distance can be reduced to 50mm .
If the width of a rectangular opening is greater than 180mm , the side length of a square opening, or the diameter of a circular opening is greater than 240mm , then it is considered that a person's entire body can enter through it.
Figure 3
Do you now understand the requirements for opening size and safety distance in fixed protection? If you still have questions or want to learn more about mechanical safety standards, Pilz can provide mechanical safety expert training to help users better and faster understand the standard requirements.
