Machine Safety Distance Calculator
Calculate minimum safe mounting distance for light curtains or laser scanners.
Application Parameters
Typ. 2000 mm/s (S ≤ 500mm) or 1600 mm/s (S > 500mm).
Finger: ≤ 14mm, Hand: ≤ 30mm.
Minimum Safety Distance (S)
Understanding Minimum Safety Distance
In industrial automation, ensuring the safety of personnel around hazardous machinery is paramount. Calculating the minimum safety distance is a critical step governed by the international standard ISO 13855. This standard provides the methodology to determine the required distance between a protective device (such as a light curtain or scanner) and the machine’s hazard zone.
The Core Formula
According to ISO 13855, the minimum safety distance (S) is calculated using the following general formula:
S = (K × T) + C
- S: The minimum safety distance (in mm).
- K: The approach speed of the human body or limb (in mm/s). Typical values are 2000 mm/s for hand/arm approaches and 1600 mm/s for walking speeds.
- T: The overall system stopping time (in seconds). This is the sum of the protective device’s response time and the machine’s actual stopping time.
- C: The intrusion distance (or additional distance), which accounts for the reach over, under, or through the protective device before it is actuated.
Why System Stopping Time (T) is Crucial
The total stopping time T is the most critical variable in the safety distance calculation. It is not sufficient to rely solely on the theoretical stopping time from a manufacturer’s manual. A physical stop-time measurement must be performed on the actual machine under worst-case operating conditions. Any delay in the control system, pneumatic valves, or braking mechanisms must be accounted for.
Implementing Safety Distances
A safety distance calculator helps engineers input their specific K, T, and C values to instantly determine the required separation. This ensures compliance with ISO 13855 and protects workers from interacting with moving parts before the machine comes to a complete stop.