8 - Orthogonal approach to a detection zone

The standard refers to two different situations regarding the detection zone orthogonal to the approach zone:

• Reaching into a safeguarded space toward a hazard zone
• Reaching out of a safeguarded space toward an SRMCD

In the first case, an additional distance D_DO is used to prevent undetected access, and the equation for calculating the minimum separation distance between the barrier and the hazardous zone becomes:

S = (K × T) + D_DO + Z

The value of D_DO can be obtained from the Table 2 when the height of the electrosensitive safeguard is fixed and the height of the hazard with respect to the reference plane is known.

In the second case, it can be possible to gain support on the protective structure when reaching over the detection zone. The separation distance S shall not be less than the reaching distance over a protective structure D_GO determined according to the standard ISO 13855 :2024, 8.2.

The separation distance is calculated with the following equation:

S = (K × T) + D_DT + Z                        

• K=2000 [mm/s]    &    D_DT=8∙(d_e-14)

• K=1600 [mm/s]    &    D_DT=8∙(d_e-14)

• K=2000 [mm/s]    &    D_DT=208+12∙(d_e-40)

• K=1600 [mm/s]    &    D_DT=208+12∙(d_e-40)

• K=1600 [mm/s]    &    D_DT=850 [mm]

The following values are considered to prevent inadvertent undetected access to hazard zones when reaching under a detection zone in an orthogonal approach. These values cannot always prevent intentional undetected access.
The maximum height of the lower edge of the detection zone from the reference plane H_DB shall not exceed 300 [mm], H_DB ≤ 300 [mm]. Instead, the separation distance S from the detection zone to the hazard zone shall be calculated according to the following equation:

S = (K × T) + D_DU + Z        

Where:
K=1600 [mm/s]
D_DU=8∙(d_e+H_DB-14)+Z  and never < 0 [mm]