Safe flow and reducing hazards at the source

Why it matters

Material traveling less distance is often useful; however, the line the carrying follows is not independent of the safe work area. Crossing a doorway diagonally shortens the distance but may bring the pedestrian into the part of the vehicle's path outside its view. A layout evaluation therefore does not consist only of a meter and second calculation. It also shows where people, vehicles and loads can meet. In method study, an unnecessary movement removed must not pass the hazard on to another person. For K02, who replenishes, a narrowing passage cannot be left outside the shortened reach for K01. The boundary of the flow is chosen to cover all the movements affected by the job.

The number of crossings describes how many times a pedestrian movement cuts the vehicle route in the selected observation group. In this lesson each passing event is counted separately; using the same point again is a new event. The number of crossing points on a map is a different indicator. Many passes can be made through a single point. A reduction in the count may reduce the need for encounters; however, by itself it does not give an accident probability or a safety score. Vision, overhang of the load, direction of movement, supervision of the crossing and the places where people can wait are examined separately. It is not right to dissolve the few hazardous crossings that remain into the total.

Reducing a hazard at its source means first questioning the job or the need for shared space that creates the encounter. Changing the delivery point of the material, physically separating the pedestrian path from the vehicle area or removing the need for reversing can be options. Painting a line on the floor and asking for attention does not provide the same effect as physical separation. Each measure is evaluated by its own function. Directing the pedestrian at the end of a separated route to a blind doorway only moves the problem. How the new layout will be used under replenishment, cleaning, maintenance and shift-change conditions also becomes part of the design; a single trial in an empty area is not enough.

The numbers in this lesson serve to discuss the operational effect of options that meet the safety condition. A feasible safe arrangement is developed first, then distance and time are compared. A hazardous option is not considered superior because it is shorter. Presenting the reduction in crossings as an equal reduction in risk is also inappropriate. The result record explains which movement was removed, which was preserved and what verification is needed for the remaining movement. If the safe arrangement does not meet the production need, the solution is not to remove the protection; capacity, replenishment frequency or layout are reconsidered. That way the time target does not turn into a justification for accepting the hazard.

Formula