The Challenge

Grocery retailer Sobeys, located in Vaughan Canada, operates a 500,000 square foot distribution centre utilizing ASRS technology by Witron. Since this facility opened in 2009, they had been faced with maintenance challenges at height. Two specific problems needed to be urgently addressed. First, their ASRS unit load pallet cranes utilize heavy idler wheels and cable shives 70’ feet above floor level. They must be serviced in 5 year intervals at minimum.  But, how to do this safely?  The ASRS system uses very narrow aisles, so conventional man-lifts (aerial work platforms) are out of the question. The only existing method to reach this location is to ‘climb’ the crane, with tools, and man handle the 30 pound idler wheel and the 70 pound cable shive.  A very dangerous and difficult task indeed.  Second, because of the high density nature of the unit load ASRS area, there is no method of reaching the ceiling to service and repair the fire suppression system. Even one malfunctioning sensor reflector will trigger a series of events that require 24/7 monitoring by personnel as the system would then be deemed ‘out of order’.  The only way these areas could be accessed would be to cut a hole in the ceiling and access the areas from above.  A very expensive and unacceptable proposition

The Solution

Sobeys engaged in a program to develop IRONguard Safety’s MARC (Maintenance and Retrieval Cart) design to solve these specific problems. The resulting MARC – Plus (Personnel Lift Up System) created a safe, defined and predictable process to solve the challenges.  The MARC – Plus platform is captured to the unit load teleforks and employs sensors which in turn are connected to the crane controller by a plug-in communication cable cord. In tandem with additional safety sensors, the MARC can be confirmed as in the correct position and captured to either the crane or double deep rack system. In conjunction with a dedicated e-stop, this package now becomes an engineered ‘safe zone’. The MARC – Plus is also now an approved anchor location, as is validated and documented by an accredited professional engineer and a dedicated safety professional providing the risk assessment. However, the MARC – Plus platform in itself can only be positioned as high as the top pallet position. So, a Power Tower aerial work platform was integrated to ensure access to a reach height of 20’ above the 60’ top pallet position. The Power Tower was modified to be affixed to the MARC – Plus using a slew ring bearing with lock positions every 45 degrees.  With the maintenance technician in the Power Tower, the crane operator can rotate the entire Power Tower assembly to the desired rotation. The most important being 180 degrees, and fully proud of the rack structure and closest to the crane. This is the ideal location to access the serviceable crane components

The Results

The result is a system that is safe, operationally efficient, and alleviates the risk associated with failed components and devices that cannot be accessed. In addition, the MARC-Plus can be used for additional tasks that include rack maintenance and repair, spilled product clearing at height, and Sobeys even discovered a new application that was not part of the initial specification. That was to service and repair their pallet stretch wrap machines.  In addition to all the tasks the MARC – Plus accomplishes as an assembly, there is the added bonus that the Power Tower can be removed and utilized as a stock aerial work platform. The impact of creating safe solutions for operators at height in a complex ASRS environment is profound. For maintenance technicians the new process has positively changed their work lives. Also, the entire premise of the Sobeys / Witron facility is about efficiency. The deployment of IRONguard’s MARC Plus creates a benefit from both perspectives.

Simply put, that’s just good business.