viernes, 13 de abril de 2012

Pallet from Wikipedia


Pallet
From Wikipedia, the free encyclopedia

A pallet (play /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)

Automated palletizer of bread with industrial KUKA robots at a bakery in Germany

48" x 40" galvanized steel pallet. Galvanized steel pallets are fireproof and rust resistant


Contents
  [hide
·        1 Overview
·        3 Pallet construction
·        4 Alternative uses
·        5 Mean Pallet
·        6 Fire hazards
·        7 Food safety risks
·        8 See also
·        9 Notes and references
·        10 Further reading
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)
Wasted floor, ISO container
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
Military,[4] Cement
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
Military 1/2 ISO container, fits 36" standard doors[5]
1219 × 508
48 × 20
Unknown
Retail


European pallets
EuroPallet

Main article: EUR-pallet
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]
The four common sizes of EURO pallets[9] (alongside with ISO alternative sizes)[10] are:
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
Pallets being used in a warehouse in Finland.
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.
Old and discarded wooden pallets can be used in pallet crafts.
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
Wood pallets used to transport food can possibly harbor pathogens such as E. coli and Listeria.
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
http://upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/30px-Commons-logo.svg.png
Wikimedia Commons has media related to: Pallets
§  463L master pallet, a wood and aluminium air cargo pallet primarily used by the US Air Force.
§  CHEP, Commonwealth Handling Equipment Pool
§  Bulk box
§  ISPM 15, Regulation of wood packaging material in international trade
§  International Plant Protection Convention Dictates ISPM 15 (above)
§  Molded pulp pallet
§  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.
§  Unit Load
Notes and references
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
5.       ^ MIL-STD-1660, ibid., para. 4.8.3
7.       ^ "Optimal logistics units". DHL. Retrieved 2009-05-18.
8.       ^ "Equipment". Proficient Transport Ltd.
15.     ^ MIL-STD-1660, ibid.
19.     ^ a b Raballand, ibid., pg11
20.     ^ Hsmsearch.com
21.     ^ Packaging-int.com
22.     ^ MIL-STD-1660, ibid., 4.8.3
23.     ^ Pallets - Where Form Meets Function By Peter Hamner, Center for Unit Loan Design Virginia Tech
24.     ^ "Pallet Guitar". Archived from the original on Nov. 20, 2008.
26.     ^ Chemical & Engineering News, January 25, 2010, p. 18
27.     ^ Sigma Aldrich, MSDS, 2009
28.     ^ NFPA 13
Further reading
§  Brody, A. L., and Marsh, K, S., "Encyclopedia of Packaging Technology", John Wiley & Sons, 1997, ISBN 0-471-06397-5
§  ASTM D 1185 Test Methods for Pallets and Related Structures
§  ASTM D6253 Treatment and/or Marking of Wood Packaging Materials
§  Why Use Two If One Will Do?, Palletizer Magazine, 1944

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