unit load principleunit load principle

The unit load is a single item, a number of items or bulk material which is arranged and

restrained so that the load can be stored, and picked up and moved between two locations

as a single mass

unit-load storage system

• facility or building - right protection for company assets.

• mobile- or captive-aisle vehicle - product is transferred from one location to another and that there is excellent labor productivity.

• inventory control system - right product is assigned to the right storage position, is transferred at the right time, at the correct quantity.

• storage equipment (racking) - proper product accessibility and that there is maximum utilization of space.

storage and retrieval equipment vs.

material transport equipment

primary function-- to house material for staging or building inventory and to

retrieve material for use.

Unit load Storage (Racking) Equipment

Classifications • unit load systems - typically house

large loads

• small load systems

KIND RACK CONFIG

TYPE OF LOAD LANE DEPTH CAPACITY

Block Stacking No rack Must be easily stackable

Effective for multiple pallets per SKU

2-10 loads deep of storage lanes on the

floor

Stacking Frame

Portable Do not conveniently stack upon themselves

2-10 loads deep of storage lanes on the

floor

Single-Deep Selective Rack

Simple construction

of metal uprights and

cross-members

Do not need to be stackable.

May be varying height or width

Effective for small quantities of SKU

One load’s depth

May be necessary to provide load supports

or decking

Double-Deep Rack

Two loads’ depth

Drive-in Rack Upright columns with

horizontal rails

5 to 10 loads deep capacity

KIND RACK CONFIG LANE DEPTH CAPACITY

Drive-through Rack

Upright columns with horizontal rails

5 to 10 loads deep capacity

Pallet Flow Horizontal (one way, or two way)

[(Aisle width X Lot Size) / (2 X Load Length X Stack Height)]1/2

Cantilever upright posts, support arms, legs and bracings.

Arms 2 5 feet long

Mobile have pair of vertical uprights, horizontal

beams and cross braces for stability. It has

wheels or floor-mounted rails

dependent on the size of the rack

Pushback Nested carts on inclined rails

2 – 6 pallets deep

standard pallet gravity flow racks

KIND STACKING CAPACITY

UNIT LOAD ACCESS

CAPITAL EXPENSE

Block Stacking From 2 loads high to a

height determined

by acceptable safe limits or

by the building clear

height

Portable

Loads on top of the stack must first be

removed

Do not conveniently stack upon themselves

Lowest among all kinds

Stacking Frame

Low, but with racks investment

Single-Deep Selective Rack

For average pallet

storage, 2 to 4 beam

Provides immediate access to each load

stored

Lowest “Cost Per Pallet Position”

Double-Deep Rack

Comparatively low investment cost

Drive-in Rack :Requires similar-width

loads

designed for one-way forklift entry

generally lower costs

KIND STACKING CAPACITY

UNIT LOAD ACCESS

CAPITAL EXPENSE

Drive-through Rack

Requires similar-width loads

two access aisles for loading and

picking.

generally lower costs

Pallet Flow dependent on pallet size

FIFO $200-$300 per storage position (very expensive)

Cantilever 20-6000lb per arm Easy access. mid

Mobile dependent on the size of the rack

Manual, mechanized or

automated carton order-pick system

high

Pushback 3-4 pallets high LIFO, frontonly retrieval from single

aisle

High (requires forklift truck)