Pallet
From Wikipedia, the free encyclopedia
A pallet (
/ˈpælɨt/),
sometimes called a skid,
is a flat transport structure that supports goods in a stable fashion while
being lifted by aforklift, pallet jack, front
loader or
other jacking device. A
pallet is the structural foundation of a unit load which allows handling
and storage efficiencies. Goods or shipping
containers are
often placed on a pallet secured with strapping, stretch wrap or shrink wrap and shipped.
/ˈpælɨt/),
sometimes called a skid,
is a flat transport structure that supports goods in a stable fashion while
being lifted by aforklift, pallet jack, front
loader or
other jacking device. A
pallet is the structural foundation of a unit load which allows handling
and storage efficiencies. Goods or shipping
containers are
often placed on a pallet secured with strapping, stretch wrap or shrink wrap and shipped.
While most pallets
are wooden, pallets also are made of plastic, metal, and paper. Each material has advantages and
disadvantages relative to the others. (See the sections "Phytosanitary compliance"
and "Materials used"
below.)
The
classic wooden pallet
A
plastic pallet with nine legs, which can be lifted from all four sides
A
metal pallet with removable beams. These are often used by tree nurseries (to
stack trees)
48"
x 40" galvanized steel pallet. Galvanized steel pallets are fireproof and
rust resistant
Contents
|
Overview
Containerization for transport has
spurred the use of pallets because the shipping
containers have
the smooth, level surfaces needed for easy pallet movement. Most pallets can
easily carry a load of 1,000 kg (2,205 lb). Today, over half a
billion pallets are made each year and about two billion pallets are in use
across the United States alone.
Pallets make it
easier to move heavy stacks. Loads with pallets under them can be hauled by forklift trucks of different
sizes, or even by hand-pumped and hand-drawn pallet jacks.
Movement is easy on a wide, strong, flat floor: concrete is excellent. The
greatest investment needed for economical pallet use is in the construction of
commercial or industrial buildings. Passage through doors and buildings must be
possible. To help this issue, some later pallet standards (the europallet and
the U.S. Military 35 × 45.5 in/889 × 1,156 mm)
are designed to pass through standard doorways.
Organizations using
standard pallets for loading and unloading can have much lower costs for
handling and storage, with faster material movement than businesses that do
not. The exceptions are establishments that move small items such as jewelry or
large items such as cars. But even they can be improved. For instance, the
distributors of costume jewelry normally use pallets
in their warehouses and car manufacturers
use pallets to move components and spare parts.
The lack of a single
international standard for pallets causes substantial continuing expense in
international trade. A single standard is difficult because of the wide variety
of needs a standard pallet would have to satisfy: passing doorways, fitting in
standard containers, and bringing low labor costs. For example, organizations
already handling large pallets often see no reason to pay the higher handling
cost of using smaller pallets that can fit through doors.
Due to cost and a
need to focus on core business, pallet pooling becomes more and more common.
Some pallet suppliers supply users with reusable pallets, sometimes with
integral tracking devices. A pallet management company can help supply, clean,
repair, and reuse pallets.
Standardization and
regulation
Dimensions
In a pallet
measurement the first number is the stringer length and the second is the
deckboard length. Square or nearly square pallets help a load resist tipping.
Two-way pallets are
designed to be lifted by the deckboards. In a warehouse the deckboard side
faces the corridor. For optimal cubage in a warehouse, the deckboard dimension
should be the shorter. This also helps the deckboards be more rigid.
Four-way pallets, or
pallets for heavy loads, or general-purpose systems that might have heavy loads
are best lifted by their more rigid stringers. A warehouse has the stringer
side facing the corridor. For optimal cubage in a warehouse, the stringer
dimension should be the shorter.
Pallet users want
pallets to easily pass through buildings, stack and fit in racks, forklifts, pallet jacks and automated warehouses. To avoid
shipping air, pallets should also pack tightly inside intermodal
containers and
vans.
No universally
accepted standards for pallet dimensions exist. Companies and organizations
utilize hundreds of different pallet sizes around the globe.[1] While no single
dimensional standard governs pallet production, a few different sizes are
widely used.
ISO pallets
The International Organization for Standardization (ISO) sanctions six
pallet dimensions, detailed in ISO
Standard 6780: Flat pallets for intercontinental materials handling—Principal
dimensions and tolerances:[2]
Dimensions, mm (W × L)
|
Dimensions, in (W × L)
|
Region most used in
|
|
1219 × 1016
|
48.00 × 40.00
|
11.7% (20 pallets in 40ft ISO)
|
North America
|
1000 × 1200
|
39.37 × 47.24
|
6.7%
|
Europe, Asia;
similar to 48x40".
|
1165 × 1165
|
45.87 × 45.87
|
8.1%
|
Australia
|
1067 × 1067
|
42.00 × 42.00
|
11.5%
|
North America, Europe, Asia
|
1100 × 1100
|
43.30 × 43.30
|
14%
|
Asia
|
800 × 1200
|
31.50 × 47.24
|
15.2%
|
Europe; fits many doorways
|
North American
pallets
Of the top pallets
used in North America, the most commonly used by far is the Grocery
Manufacturers' Association (GMA) pallet, which accounts for 30% of all new wood
pallets produced in the United States.[3] The ISO also
recognizes the GMA pallet footprint as one of its six standard sizes.
Dimensions, mm (W × L)
|
Dimensions, in (W × L)
|
Production Rank
|
Industries Using
|
1219 × 1016
|
48 × 40
|
1
|
Grocery, many others
|
1067 ×1067
|
42 × 42
|
2
|
Telecommunications, Paint
|
1219 × 1219
|
48 × 48
|
3
|
Drums
|
1016 × 1219
|
40 × 48
|
4
|
|
1219 × 1067
|
48 × 42
|
5
|
Chemical, Beverage
|
1016 × 1016
|
40 × 40
|
6
|
Dairy
|
1219 × 1143
|
48 × 45
|
7
|
Automotive
|
1118 × 1118
|
44 × 44
|
8
|
Drums, Chemical
|
914 × 914
|
36 × 36
|
9
|
Beverage
|
1219 × 914
|
48 × 36
|
10
|
Beverage, Shingles, Packaged Paper
|
889 × 1156
|
35 × 45.5
|
Unknown
|
|
1219 × 508
|
48 × 20
|
Unknown
|
Retail
|
European pallets
EuroPallet
In Europe, the EURO
pallet, also called a CEN pallet,
is widely used in many industries. It measures 800 by 1200 by 144 mm.[6]Manufacturers of EURO pallets must be
sanctioned by the European Pallet Association (EPAL), which governs the
smallest details, even which types of nails and lumber may be used. The strict
standardization is based on the existence of europool pallet swap organizations
- their mutual swap agreements across country boundaries only include EURO
pallets of a specific EPAL/EUR type (mostly restricted to type 1). Most freight forwarders will accept pool
pallets, handling the cost clearing between sender and receiver even for
international transport to countries that take part in the europool system. The
ongoing harmonization of freight handling within the European Economic Area has led to a decline
of the europool system. The EURO pallet does not fit efficiently within the ISO shipping
container[7] and slightly wider
containers are often used for this reason.[8]
EURO pallet type
|
Dimensions, mm/in (W × L)
|
ISO pallet alternative
|
EUR, EUR 1
|
800 × 1,200 mm/31.50 × 47.24 in
|
ISO1, same size
as EUR
|
EUR 2
|
1,200 × 1,000 mm/47.24 × 39.37 in
|
ISO2
|
EUR 3
|
1,000 × 1,200 mm/39.37 × 47.24 in
|
|
EUR 6
|
800 × 600 mm/31.50 × 23.62 in
|
ISO0, half the
size of EUR
|
600 × 400 mm/23.62 × 15.75 in
|
quarter the size
of EUR
|
|
400 × 300 mm/15.75 × 11.81 in
|
one-eighth the
size of EUR
|
Australian Standard
Pallets
The Australian
Standard Pallet is a pallet size commonly found in Australia but found rarely
elsewhere. It is a square hardwood pallet 1,165 by 1,165 mm (45.87 by 45.87 in)
in size which fits perfectly in the RACE container of the Australian
Railway, but is ill suited to fitting in the standard ISO containers used around the
globe. However, with two Australian pallets side-by-side, there is still
22 mm (0.87 in) "spare". If the pallets are loaded
correctly (without any overhang), this means there is an average of 7 mm
in between the container wall, the pallets and the opposite container wall.
While this is a tight fit, it means there is less need for dunnage (stuffing)
between the container walls and the pallets.
The Australian
Standard Pallet dates back to WWII, while ISO containers date to the late
1950s. This explains why ISO containers do not suit the ASP.
Australia used to
require that imported pallets be completely bark free, but as of 2010, they
have adopted the globally accepted ISPM 15 wood packaging
material regulations.[11]
Standard-setting
organizations
A number of different
organizations and associations around the world work towards establishing and
promulgating standards for pallets. Some strive to develop universal standards
for pallet dimensions, types of material used in construction, performance
standards, and testing procedures. Other organizations choose to focus on
pallet standards for a specific industry (such as the groceries) or type of
material (such as wood).
ISO Technical
Committee 51: Pallets for unit load method of materials handling
ISO TC 51 states its
scope of work entailing the "standardization of pallets in general use in
the form of platforms or trays on which goods may be packed to form unit loads
for handling by mechanical devices".[12] The Technical
Committee works in conjunction with other Technical Committees focused on
transportation infrastructure to develop interrelated standards. TC 51 is
responsible for developing ISO
Standard 6780: Flat pallets for intercontinental materials handling—Principal
dimensions and tolerances as
well as sixteen other standards related to pallet construction and testing.
National Wood Pallet
and Container Association
The National Wood
Pallet and Container Association (NWPCA) is a trade organization based in the
United States devoted to representing the interests of wood pallet and
container manufacturers. The NWPCA defines its mission as helping its
membership create cost-effective, environmentally friendly solutions to
customers' needs.[13] Towards that end, the
NWPCA developed a bevy of resources to assist its membership, including the
Pallet Design System (PDS), which allows users to develop and analyze pallet
designs.[14]
U.S. DOD, Dept. of
Navy, Naval Sea Systems Command
This organization
maintains MIL-STD-1660, the standard description of palletized unit loads for the U.S. Military
and some allies.[15]
DOD Unit loads
generally use 40 × 48 in (1,016 × 1,219 mm)
pallets, are less than 4,000 lb (1,814 kg), weatherproof, and stack
16 ft (4.88 m) high. They often use steel pallets, steel straps with
notched seals, outdoor plywood, and plastic film. The standard describes tests
for stacking, transport, sling, forklift and pallet jack, impact, drop tests,
tip, water-retention, and disassembly.
European Committee
for Standardization (Comité Européen de Normalisation)
In addition to the
other standards it publishes, the European Committee for Standardization, also
known as the Comité Européen de Normalisation (CEN), produces standards for
pallets. While the standards are voluntary in nature, many companies and
organizations involved in transportation have adopted them. The major standard
for pallets produced by CEN is ICS:
55.180.20 General purpose pallets[16]
Phytosanitary
Compliance
Due to the International Plant Protection Convention (abbreviated IPPC),
most pallets shipped across national borders must be made of materials that are
incapable of being a carrier ofinvasive species of insects and plant diseases. The
standards for these pallets is specified in ISPM 15.
Pallets made of raw,
untreated wood are not compliant with ISPM 15. To be compliant the pallets (or
other wood packaging material) must meet debarked standards,[17] and must be treated
by either of the following means under the supervision of an approved agency:
§
Heat
treatment The
wood must be heated to achieve a minimum core temperature of 56 °C (132.8 °F) for at least 30
minutes. Pallets treated via this method bear the initials HT near the IPPC logo.
§
Chemical fumigation The wood must be
fumigated with methyl bromide.
Pallets treated via this method bear the initials MB near the IPPC logo.
From 19 March 2010 the use of Methyl Bromide as an acceptable treatment
according to ISPM15 [18] has now been phased
out.
Pallets made of
non-wood materials such as steel, aluminum, plastic, or engineered wood products, such as plywood, oriented strand board, or corrugated fiberboard do not need IPPC
approval, and are considered to be exempt from ISPM 15 regulations.
Pallet construction
Types of pallets
Although pallets come
in all manner of sizes and configurations, all pallets fall into two very broad
categories: "stringer" pallets and "block" pallets. Various
software packages exist to assist the pallet maker in designing an appropriate
pallet for a specific load, and to evaluate wood options to reduce costs.
Stringer pallet
Stringer pallets use
a frame of three or four parallel pieces of timber (called stringers). The top deckboards are then
affixed to the stringers to create the pallet structure. Stringer pallets are
also known as "two-way" pallets, since a pallet-jack may only lift it
from two directions instead of four. Forklifts can lift a stringer pallet from
all four directions, though lifting by the stringers is more secure.
Block pallet
Block pallets (also
referred to as Manoj pallets) are typically stronger than stringer pallets.
Block pallets utilize both parallel and perpendicular stringers to better
facilitate efficient handling. A block pallet is also known as a
"four-way" pallet, since a pallet-jack may be used from any side to
move it.
Perimeter base pallet
All stringer and some
block pallets have "unidirectional bases," i.e. bottom boards
oriented in one direction. While automated handling equipment can be designed
for this, often it can operate faster and more effectively if the bottom edges
of a pallet have bottom boards oriented in both directions. For example, it may
not need to turn a pallet to rack it, and operation is less sensitive to pallet
orientation.
Quality improvements
The least expensive
way to improve a pallet is usually to specify better nails. With non-wood
pallets, a controlled coefficient of friction is often helpful to prevent the
pallet from slipping from forks and racks. Stiffer pallets are more durable,
and are handled more easily by automated equipment. If a pallet does not need
to be lifted from all four sides, two-way pallets with unnotched stringers may
be used, with the additional benefits of added rigidity and strength.
Specifying tolerances on flatness and water content may help the supplier meet
target requirements. Inspection of pallets, whether in person or by a
third-party (such as "SPEQ" inspected pallets) offer additional assurance
of quality.
Materials used
Wooden
pallet being dismantled.
The cheapest pallets
are made of softwood and are often
considered expendable, to be discarded as trash along with other wrapping
elements, at the end of the trip. These pallets are simple stringer pallets,
and liftable from two sides.
Slightly more complex hardwood block pallets,
plastic pallets and metal pallets can be lifted from all four sides. These
costlier pallets usually require a deposit and are returned to the sender or
resold as used. Many "four way" pallets are color coded according to
the loads they can bear, and other attributes.
Wooden pallet
construction specifications can depend on the pallet's intended use: general,
FDA, storage, chemical, export; the expected load weight; type of wood desired:
recycled, hard, soft, kiln dried or combo (new & recycle); and even the
type of fasteners desired to hold the pallet together: staples or nails.
Paper pallets are often used for
light loads, but engineered paper pallets are increasingly used for loads that
compare with wood. Paper pallets
are also used where recycling and easy disposal is important.
Plastic pallets are often made of new HDPE or
recycled PET (drink
bottles). They are usually extremely durable, lasting for a hundred trips or
more,[19]and resist
weathering, rot, chemicals and corrosion. They often stack. Plastic pallets are
exempt by inspection for biosafety concerns, and easily sanitize for
international shipping. HDPE is impervious to most acids and toxic chemicals
clean from them more easily. Some plastic pallets can collapse from plastic creep if used to store
heavy loads for long periods. Plastic pallets cannot easily be repaired, and
can be ten times as expensive as hardwood,[19]so they
are often used by logistics service providers who can profit from their
durability and stackability. The large supply chains have increased the use of
plastic pallets as many organisations seek to reduce costs through waste,
transport and health & safety. Pallets and dolly combined
for example the Pally[20] eliminate pallet
instability and the need for additional lifting equipment, but also create
valuable space in busy operating environments and deliver significant time and
cost savings by reducing supply chain handling.[21]
Steel pallets
are strong and are used for heavy loads, high-stacking loads, long term dry
storage, and loads moved by abusive logistic systems. They are often used for
military ammunition.[22] Metal pallets make up
less than 1% of the market. Materials include carbon steel, stainless steel,
and aluminum. Of these, carbon steel offers excellent durability at the lowest
cost. Stainless steel doesn’t require a paint coating, and is preferred for
such applications as clean room environments. Aluminum offers the durability of
steel at a lighter weight. Carbon steel units are expensive compared to wood,
and stainless and aluminum cost about 2-3 times that of carbon steel. Long term
costs, however, can be lower than wood. General advantages of metal pallets are
high strength and stiffness, excellent durability, bug free, no splinters,
sanitary, and recyclable. Disadvantages include a higher initial price,
significant weight, low friction, and susceptibility to rusting (carbon steel).
Metal is primarily used in captive or closed loop environments where durability
and product protection are key performance requirements. Metal units today are
increasingly price competitive and lighter in weight. Primary industries that
use metal pallets include automotive, pharmaceutical, lawn tractors,
motorcycles, and tires.[23]
Aluminum pallets are stronger
than wood or plastic, lighter than steel, and resist weather, rotting, plastic
creep and corrosion. They are sometimes used for air-freight, long-term outdoor
or at-sea storage, or military transport.
Alternative uses
Stacked
pallets.
Discarded wooden
pallets should not be used for fire wood or crafts unless it has been
determined that the wood in these pallets has not been treated with wood
preservatives, fungicides and/or pesticides. Various pyrethrins and
propiconazole are common treatments for wooden pallets. In addition, imported
palletized goods are routinely fumigated with highly toxic pesticides. During
use, harmful materials or chemicals also may spill on the pallet wood and be
absorbed.
Craft publications
have advised readers to use pallets to build skateboarding obstacle called a manual pad, barricades during amateur paintballgames, or
other sport-related items. Other publications have suggested using pallet wood
for small animal cages or fences. Pallet wood has been recycled for use as
furniture wood by at least one company.
The well-known
American quality acoustic guitar maker Taylor Guitars famously produced
their high quality "pallet guitar"[24] made from pallet
wood, in order to demonstrate their prowess and the importance of construction
technique versus expensive exotic woods. "The original pallet guitar was
made for fun and to prove a point: we can work with non-traditional wood and
still make a great guitar. Oh yeah, and we had fun." - Bob Taylor.
The two Austrian
students Andreas
Claus Schnetzer and Gregor Pils from the University
of Vienna created
a home entitled Pallet
house and
as the name suggests, reuses pallets to form a modular, energy efficient and
affordable housing. The idea was born in 2008 during a competition and the
Pallet house has been exhibited in several European cities including Venice,
Vienna, Linz and Grenoble. It could become a clever approach to low income
housing.[25]
Items made from
pallet wood are likely to be durable and demonstrate good weather resistance
due to these treatments. However, close contact with pallet wood or inhalation
of dusts from sanding or sawing can be a source of exposure to pesticide and
fungicide chemicals. It is likely that the January, 2010 recall of Johnson and
Johnson Tylenol[TM] and other drugs were due to their being stored on wooden
pallets that had been treated with the fungicide/pesticide 2,4,6-tribromophenol.
This chemical can be degraded by molds to produce 2,4,6-tribromoanisole whose
strong, musty odor caused consumers to complain.[26] There is no acute or
chronic health data on 2,4,6-tribromoanisole,[27] but it is believed
that the contaminated drugs caused nausea and other health effects in some
people.
Mean Pallet
A useful barometer to
worldwide economic activity, the mean pallet describes a best estimate of the
average location of all pallets, both laden and empty, across the planet.
Although generally confined to analysis in logistics research, the measure
is increasingly being used due to the ongoing evolution of computer processing
speed and the ability to carry out calculations with ever increasing speeds of
data input.
The Mean Pallet has
been estimated since the early 1960s. Initially, the estimate placed the Mean
Pallet over the Eastern Mediterranean just south of
Marmaris in Turkey. However, it is currently located above the Dead Sea and moving south east
with an average velocity of 0.24 km/day. This eastward movement has been
attributed to the higher than average economic growth of the Tiger Economy countries.
Fire hazards
Both wood and plastic
pallets are possible fire hazards. The National Fire Protection Association requires that both
types "shall be stored outside or in a detached structure" unless
protected by fire sprinklers.[28]
Food safety risks
A release by the National Consumers League announced the testing
of 70 wood pallets and 70 plastic pallets that have been loaded with perishable
products and shipped to an end user was shipped overnight to an independent
microbiology lab for testing. The results came back with 10 percent of the wood
pallets positive for E. coli and 1.4 percent positive on the plastic pallets.[29]
See also
 |
§
CHEP, Commonwealth Handling Equipment Pool
§
Bulk box
§
ISPM 15, Regulation
of wood packaging material in international trade
§
Stillage, a
stackable pallet-like device with sides or a cage to contain the load.
§
ULD, lightweight
aluminium and plastic pallet or container for aircraft.
Notes and references
1.
^ Raballand,
Gaël and Aldaz-Carroll, Enrique, "How Do Differing Standards Increase
Trade Costs? The Case of Pallets" (February 2005). World Bank Policy
Research Working Paper No. 3519.
2.
^ ISO 6780:2003 - Flat pallets for intercontinental
materials handling -- Principal dimensions and tolerances
4.
^ Design Criteria for Ammunition Unit Loads.
U.S. DOD, Dept of the Navy, Naval Sea Systems Command. 8 April 1970.
MIL-STD-1660. Archived from the original on 2007-11-24. Retrieved
2008-01-01, para. 4.8.3, mil-std pallets are 4-way: 4.3.1
23.
^ Pallets
- Where Form Meets Function By Peter Hamner, Center for Unit Loan Design
Virginia Tech
Further reading
§
Brody, A. L., and Marsh, K, S.,
"Encyclopedia of Packaging Technology", John Wiley & Sons, 1997, ISBN 0-471-06397-5
§
Why Use Two If One Will Do?,
Palletizer Magazine, 1944
§
An Inspection Guide for the Construction and Inspection
of Wood Pallets, U.S. Navy, 1954
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