Tarpaulin

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An improvised tent using polytarp as a fly

A tarpaulin, or tarp, is a large sheet of strong, flexible, water-resistant or waterproof material, often cloth such as canvas or polyester coated with urethane, or made of plastics such as polyethylene. In some places such as Australia, and in military slang, a tarp may be known as a hootch. Tarpaulins often have reinforced grommets at the corners and along the sides to form attachment points for rope, allowing them to be tied down or suspended.

Inexpensive modern tarpaulins are made from woven polyethylene; this material is so associated with tarpaulins that it has become colloquially known in some quarters as polytarp.

Etymology[edit]

The word tarpaulin originated as a compound of the words tar and palling, referring to a tarred canvas pall used to cover objects on ships. By association, according to one theory, sailors became known as tarpaulins and eventually tars.[1]

When used for a tarpaulin, the word hoochie (also hootchie, hootch, or hooch) comes from the Japanese uchi (家, "house"). Huts in various parts of rural Asia are known by this or similar names, and during the Korean and Vietnam Wars English-speaking soldiers came to use the word to refer to their own makeshift shelters, which often consisted of little more than a tarpaulin.

In the mid-19th century, "paulin" was used for such a cloth; here General Rosecrans tells a subordinate how to improvise a boat:

"A boat has been ordered up, but to make sure a large paulin will be sent down to you, with which, spread under a lot of wagon-beds, you will be able to make a large scow." (War of the Rebellion: Official Records of the Union and Confederate Armies, series 1, volume 5, page 260, November 1861)

"Two wagon beds ... were placed upon frames ... Thus constructed, they were placed upon a duck paulin, which was drawn up tightly around the beds and secured." (same, page 275)

Uses[edit]

A tarpaulin is used at WrestleMania XXIV to prevent rain from falling on the performers and stage equipment.

Tarpaulins have multiple uses, including as shelter from the elements, i.e., wind, rain, or sunlight, a ground sheet or a fly in camping, a drop sheet for painting, for protecting the infield of a baseball field, and for protecting objects, such as unenclosed road or rail goods carrying vehicles or wood piles. Such was the demand for tarpaulins by the New South Wales Government Railways, up until 1990, they operated their own tarpaulin factory.[2] It is also used on outdoor market stalls to provide some protection from the elements of nature. Tarpaulins are also used for advertisement printing, most notably for billboards.

Another historical use of a tarpaulin is to cover seats in a stadium that would most likely not be sold except against a marquee opponent. The entire third deck of the Oakland-Alameda County Coliseum is also covered in tarp for Oakland Athletics games, but is uncovered for Oakland Raiders games.

Perforated tarpaulins are typically used for large-medium advertising, or for protection on scaffoldings, the aim of the perforations (from 20% to 70%) is to reduce wind vulnerability.

An example of perforated tarpaulin

Polyethylene tarpaulins have also proven to be a popular source when an inexpensive, water resistant fabric is needed. Many amateur builders of plywood sailboats turn to polyethylene tarpaulins for making their sails, as it is inexpensive and easily worked. With the proper type of adhesive tape, it is possible to make a serviceable sail for a small boat with no sewing.

Types of tarpaulins[edit]

Tarps can be classified based on a diversity of factors, such as material type (polyethylene, canvas, vinyl, etc.[3]), thickness, which is generally measured in millimeters or generalized into categories (such as "regular duty", "heavy duty", "super heavy duty", etc.[4]), and grommet strength (simple vs. reinforced), among others.

Tarps can also be classified by size—a common determining factor for consumers in acquiring tarps—and measured in width by length. Actual tarp sizes are generally about three to five percent smaller than the advertised size. (Thus, a tarp advertised as 20 ft. × 20 ft. will actually measure about 19 ft. × 19 ft.[5]) Some other factors that may influence a purchase decision include color (often they come in blue, green, black, or silver), grommet type (aluminum, stainless steel, etc.), and grommet-to-grommet distance (these often run between 18 inches and 5 feet). The weave count, a measure of tarp strength, often runs between (8 and 12 per square inch) and the greater the count, the greater its resistance against ripping in high wind conditions.[6] Tarps may also be washable or non-washable and waterproof or non-waterproof, and mildewproof vs. non-mildewproof. Tarp flexibility refers to its ability to remain pliable during cold winter months; some tarps offer more flexibility than others in cold weather. Some manufacturers also advertise their tarps as "rot-proof",[7] but this may be more an subjective than an objective measurement.

Type of material[edit]

Polyethylene[edit]

A tarp is used to identify a business.

A polyethylene tarp ("polytarp") is not a traditional fabric, but rather, a laminate of woven and sheet material. The center is loosely woven from strips of polyethylene plastic, with sheets of the same material bonded to the surface. This creates a fabric-like material that resists stretching well in all directions and is waterproof. When treated against ultraviolet light, these tarpaulins can last for years exposed to the elements, but non-UV treated material will quickly become brittle and lose strength and water resistance if exposed to sunlight.

Canvas[edit]

Canvas tarps are not 100% waterproof, though they are water resistant. Thus, while a little bit of water for a short period of time will not affect them, when there is standing water on canvas tarps, or when water cannot quickly drain away from canvas tarps, the standing water will drip through this type of tarp.[8]

Vinyl[edit]

Yellow vinyl tarps are super-industrial-heavy-duty-grade tarps. They are often 10 oz coated yellow vinyl tarps, are waterproof and have high abrasion resistance. They resist oil, acid, grease and mildew. The vinyl tarp is ideal for agriculture, construction, industrial and trucks. They also have a high tear strength.[9]

Silnylon[edit]

Main article: silnylon

Tarp tents may be made of silnylon.

Color[edit]

For years manufacturers have used color to indicate the grade of tarps, but not all tarp manufactures follow this traditional method of tarp grading. Following this color-coded system, a blue tarp indicates a lightweight tarp, and typically has a weave count of 8x8 and a thickness of 5–6 mils (note: a mil is a thousandth of an inch). A silver tarp is a heavy-duty tarp and typically has a weave count of 14x14 and a thickness of 11–12 mils.[10]

Some of the more common colors in that scheme are:

  • Blue - light-duty tarp - approx. 5–6 mils (about 0.14 mm) thick
  • Yellow/Orange - medium-duty tarp - approx. 7–8 mils (about 0.19 mm) thick
  • Green - medium-duty tarp - approx. 9–10 mils (about 0.24 mm) thick
  • Silver - heavy-duty tarp - approx. 11–12 mils (about 0.29 mm) thick
  • Brown - super-heavy-duty tarp - approx. 16 mils (about 0.41 mm) thick

See also[edit]

References[edit]

  1. ^ Tar, Online Etymology Dictionary
  2. ^ Johnson, Frank. A short History of the Tarpaulin Factory at Enfield. Australian Railway Historical Society Bulletin. September, 1999. pp. 343-347
  3. ^ Poly Tarps. Tarp Plus. Retrieved 30 March 2013.
  4. ^ Tarpaulins. Tarp Supply. Retrieved 30 March 2013.
  5. ^ 20'x20' Heavy Duty Tarp. Model Number: 2356905. Menards. Retrieved 30 March 2013.
  6. ^ Common Questions: What is a tarp? Tarp USA. Retrieved 30 March 2013.
  7. ^ Seachoice Tarp Green Poly 20' X 20'. Star Marine Depot. Retrieved 30 March 2013.
  8. ^ Canvas Tarps. Retrieved 2 April 2013.
  9. ^ Heavy Duty Yellow Vinyl Tarps. Tarp Plus. Retrieved 2 April 2013.
  10. ^ Common Questions: What is a tarp? Retrieved 2 April 2013.