How OR helps warehouse workers stay COVID-safe

The COVID-19 pandemic has disrupted global supply chains and the working environment in most organisations. It is also highly likely that a lasting impact of the pandemic will be fewer consumers doing in-person shopping in favour of a greater use of online shopping – resulting in more businesses fulfilling orders via warehouse-based picking, packing and posting.

New research into picking operations shows how operational research can optimise efficiency whilst also making the warehouse workforce as COVID-safe as possible.

In the study COVID-19 Pandemic Implications for Order Picking Operations, published by Scientific Research, a number of routing, storage and picking strategies were examined to find the best approach for promoting worker safety and maintaining ‘social distancing’, whilst also considering efficient service and cost control.

The research team looked at different approaches to routing around facilities and storage. They studied the use of one-way aisles, traversal (or serpentine) routing and optimal routing algorithms. They also tested how different storage strategies impacted safety and service, such as random storage, class-based storage and volume-based storage.

The research found that the use of traversal routing with occasional use of midpoint routing can “yield near optimal results and enable physical distancing”.

Traversal routing is when a picker enters each aisle with relevant items in at one end and leaves via the other end. They move throughout all relevant aisles in a continuous, often S-shaped route, finishing at the drop-off point with all the items in the order.

Midpoint routing divides the warehouse into two sections, with pickers moving up the aisle to the midpoint before turning back. They move in a single route around the warehouse to access each part of the aisles they require, making it easy to avoid crossing paths with other workers.

The study also recommended the following practices to promote COVID-safety:

• All employees should wear clean masks to protect others and that care should be taken when putting on and removing masks.
• Creating work zones to separate workers into teams to reduce the number of coworkers each worker is exposed to.
• Reducing the number of workers onsite by staggering shifts, having more work shifts, or increasing the hours of operation.
• Modify workstations or using physical barriers to separate workers.
• Maintaining physical distancing by using one-way travel is aisles using signs, coloured tape or stickers on the floor.
• Using touch-free workstations or frequent cleaning of commonly touched surfaces.
• Keeping the warehouse well-ventilated with fresh air.

The study can be accessed on the Scientific Research website.