After all of the advances in automated guided vehicles (AGVs) in the last few years, I didn't think I could be surprised by what one of these things could do. That changed earlier this week when I read that someone was killed by one.
It happened at a Kraft Food warehouse in Granite City, Ill. Early Tuesday morning an employee was discovered pinned between a laser-guided AGV and a metal racking unit. This employee was responsible for overseeing the operation of the facility's AGVs.
OSHA and the Granite City Police Department are still investigating this accident, but one thing seems certain: if proper safety procedures were followed this shouldn't have happened. There's a standard that vehicle manufacturers and users are supposed to follow: The ANSI/ITSDF B56.5-2012 Safety Standard for Driverless, Automatic Guided Industrial Vehicles and Automated Functions of Manned Industrial Vehicles.
Now, it's way too early to know exactly how this tragedy happened, but it's always the right time to use events like this as teachable moments. And that's why this ANSI/ITSDF document should be within every AGV or lift truck user's reach. If anything it will bring people like me, who are easily impressed by what these vehicles can do, down to earth with a plain statement of stark reality:
“Automatic guided industrial vehicles can cause injury or damage if improperly used or maintained and if the potential risks specified in user training associated with hazard zones and restricted areas are not respected by persons within or adjacent to these areas.”
It also states what's supposed to happen with a properly equipped AGV.
“The braking system in conjunction with the object detection system and the response time of the safety control system shall cause the vehicle to stop prior to impact between the vehicle structure and other mounted equipment, including its intended load, and an obstruction being sensed in advance of the moving vehicle in the main direction of travel.”
But the following section should be printed in bold type:
“Although the vehicle braking system may be performing correctly and as designed, it cannot be expected to function as designed and specified should an object suddenly appear in the path of the vehicle and within the designed safe stopping distance. Examples include, but are not limited to, an object falling from overhead or a pedestrian stepping into the path of a vehicle at the last instant.”
That's why training is so critical for both operators and the people working around these vehicles. This document states that:
• A training program for operators and other user personnel likely to be exposed to the system in operation, including visitors, shall include the system supplier's documented operating instructions and procedures and the user's local applicable requirements if any.
• The initial training shall be presented by the system supplier to all operators and other user personnel and not condensed or eliminated for those claiming previous experience.
• Oral, written, or operational performance tests and evaluations should be given during and at the completion of all training.
But it's the failure to heed the following pointer that explains why we still see fatalities associated with industrial trucks:
• Periodic, ongoing training or refresher training sessions shall then be conducted by the user for the benefit of existing users as well as for new user personnel and visitors. Refresher training sessions, which may be condensed versions of the initial training sessions, and periodic on-the-job evaluation, are as important as initial training, especially when new personnel are hired or otherwise introduced to the system following initial deployment.
I talked to a member of the Industrial Truck Association about this tragedy at the Kraft facility, just to see if he shared my surprise that someone could be killed by an AGV. He shared indeed.
“Even in a maintenance situation, if a truck is designed in a fail safe mode and you disconnect the optical sensing, it should still fail in the safe position which is non operation,” he said.
The ANSI standard defines fail-safe as a design in which no single failure can cause an unsafe condition. We'll eventually know whether the victim in this case might have been involved in multiple failures at one time, but this should be a wake-up call for every user of automated material handling equipment: Never fail to train.
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