Portal cranes save space, impart safety At a time when costs surrounding concrete yard management are increasing, Mannesmann Dematic officials report that their rail-mounted cranes represent an efficient alternative to forklifts for moving precast from production to storage to shipping. The Cleveland, Ohio-based company's KSR Portal cranes, well established in European concrete operations, are reportedly gaining acceptance in the U.S. for their maintenance and productivity advantages.

When concrete facilities are built, upgraded or expanded, Mannesmann officials suggest that the most important question an owner should ask is: "With the land I have for storage and shipping, what is the best material handling equipment available to handle, store and ship my products at the lowest overall cost?"

Other considerations, they add, should include throughput, capacity, up-time, flexibility, safety aspects for employees, environmental advantages, and upgrade and expansion potential. When a precast producer looks at the costs and advantages of owning a portal crane versus forklift trucks over a 20-year span, it becomes increasingly clear what the savings potential can be with the former equipment type, Mannesmann officials note. With savings on land, personnel, product damage, maintenance and energy costs, they add, portal crane users can see a full return on investment in less than three years.

Traditionally, manufactured-concrete producers have handled product by forklift. While equipment costs are relatively inexpensive, Mannesmann staff points to certain forklift limitations:

Land restrictions. Forklifts can only stack material as high as the mast will allow, forcing owners to purchase and maintain large storage yards. Plus, the land must be developed, prepared, and maintained for vehicle usage and, in cold climates, plowed during winter months.

Damage. Long travel distances and uneven ground can mean finished-product damage rates as high as 2.5 percent.

High maintenance. Heavy abuse leads to a need for a large stock of spare parts, extra equipment to handle downtime and extensive repair requirements.

Personnel limitations. An average production facility of 160,000 tons per year with two shifts requires a total of seven operators and two maintenance technicians for handling equipment.

Mannesmann Dematic cites several key production issues underlying KSR Portal crane usage in yard management. As production facilities modernize and land becomes more scarce, issues involving the high cost of acreage have affected the overall bottom line for concrete producers. The portal cranes, which work from above in a bridge-type configuration, minimize land consumption by increasing the density of the product that can be stored in a given area. That means lower land acquisition costs and property taxes, minimal ground preparation and fewer fork truck alleys to maintain and clean during winter.

Forklift use can raise the risk of damage to concrete units during production, storage and shipping, Mannesmann officials contend. A typical facility with 160,000 tons of annual output, they add, yields a loss ratio of one percent - or 2,400 tons of product rated unusable. A portal crane can reduce the breakage rate by 80 percent with shorter travel distances, less product handling, minimized operator error and smooth transport on tie and ballast mounted rails.

For an average facility, one portal crane can replace two to four forklifts, minimizing personnel needs. Mannesmann Dematic figures that the portal equipment requires one operator per shift and two technicians every two weeks for a preventive maintenance shift only. That allows facility managers to transfer up to six employees to other production areas. The present investment cost can also be low due to the availability of long term leasing rates.

Mannesmann Dematic notes that up to 25 percent of forklift operating costs are for maintenance. Heavy abuse, expensive part requirements and the need for an equipped repair shop all contribute to the high cost. KSR Portal cranes, however, typically require minimal maintenance. For leasing the crane, it means no extra maintenance contract is needed. Few parts requirements and minimal maintenance lead to significantly lower downtime than forklifts, Mannesmann Dematic reports. An advanced design with flexibility for upgrade, they add, affords KSR Portal cranes a service life expectancy exceeding 20 years versus having to purchase forklifts every three to five years. Modern portal cranes' energy consumption, they add, is at least 50 percent lower than for mobile units.

While the initial investment cost is higher than a conventional forklift solution, Mannesmann Dematic officials note that portal type cranes, including their KSR series models, have a significantly lower cost when viewed over a 20-year span. The initial investment of a portal crane including the rail system can range from $400,000 to $1,000,000, while costs for purchasing forklifts can be $1,400,000 to $2,000,000 over the same period. This represents a potential savings of up to $1,000,000 by using a portal crane over a conventional forklift operated facility, Mannesmann Dematic contends. These calculations represent annual handling costs for a typical, 30-acre concrete pipe operation. Estimates are based on purchasing five forklift trucks ($70,000 to $80,000) every five years. Not included are cost savings in land acquisition and improvements, equipment maintenance, real estate taxes, and insurance premiums.