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An extension ladder

A ladder is a vertical or inclined set of rungs or steps. There are two types: rigid ladders that can be leaned against a vertical surface such as a wall, and rope ladders that are hung from the top. The vertical members of a rigid ladder are called stringers (US) or stiles (UK). Rigid ladders are usually portable, but some types are permanently fixed to buildings. They are commonly made of metal, wood, or fibreglass, but they have been known to be made of tough plastic.

Variations[link]

Rigid ladders are available in many forms, such as:

• Attic ladder, pulled down from the ceiling to allow access to an attic or loft
• Bridge ladder, a ladder laid horizontally to act as a passage between two points separated by a drop
• Cat ladder (US chicken ladder), a lightweight ladder frame used on steep roofs to prevent workers from sliding
• Extension ladder or "telescopic ladder", a fixed ladder divided into two or more lengths for more convenient storage; the lengths can be slid together for storage or slid apart to maximize the length of the ladder; a pulley system may be fitted so that the ladder can be easily extended by an operator on the ground then locked in place using the dogs and pawls
• Trestle ladder, an "A-Frame"-style ladder with a telescoping center section
• Fixed ladder, two side members joined by several rungs; affixed to structure with no moving parts
• Folding ladder, a ladder in the step ladder style with one or more (usually no more than three) one-way hinges. Ideal for use on uneven ground (i.e. stairs), as a trestle or when fully extended a Fixed ladder. Some variations feature a central one-way hinge with extensible locking legs
• Hook ladder or pompier ladder, a rigid ladder with a hook at the top to grip a windowsill; used by firefighters
• Orchard ladder, a three legged step ladder with the third leg made so that it can be inserted between tree branches for fruit picking
• Platform steps, a step ladder with a small horizontal platform at the top
• Roof ladder, a rigid ladder with a large hook at the top to grip the ridge of a pitched roof
• Sectional ladder, also known as a builder's ladder, has sections that come apart and are interchangeable so that any number of sections can be connected together
• Step ladder, hinged in the middle to form an inverted V, with stays to keep the two halves at a fixed angle
• Telescoping ladder, commonly used to refer to a hybrid between a step ladder and an extension ladder with 360-degree hinges; has three parts and can be taken apart to form two step ladders; i.e. Little Giant
• Turntable ladder, an extension ladder fitted to rotating platform on top of a fire truck
• Vertically rising ladder, designed to climb high points and facilitate suspending there

Rigid ladders were originally made of wood, but in the 20th century tubular aluminium became more common because of its lighter weight. Ladders with fiberglass stiles are used for working on or near overhead electrical wires, because fiberglass is an electrical insulator.^[1]

Safety[link]

For safety, a rigid ladder should be leaned at an angle of about fifteen degrees to the vertical. In other words, the distance from the foot of the ladder to the wall should be about one quarter of the height of the top of the ladder. At steeper angles, the ladder is at risk of toppling backwards when the climber leans away from it. At shallower angles, the ladder may lose its grip on the ground. Ladder stabilizers are available that increase the ladder's grip on the ground. One of the first ladder stabilizers or ladder feet was offered in 1936 and today they are standard equipment on most large ladders. ^[2]

A ladder standoff, or stay, is a device fitted to the top of a ladder to hold it away from the wall. This enables the ladder to clear overhanging obstacles, such as the eaves of a roof, and increases the safe working height for a given length of ladder.

Uses[link]

• Rope ladders are used where storage space is extremely limited, weight must be kept to a minimum, or in instances where the object to be climbed is too curved to use a rigid ladder. They may have rigid or flexible rungs. Climbing a rope ladder requires more skill than climbing a rigid ladder, because the ladder tends to swing like a pendulum. Steel and aluminium rope ladders are sometimes used in vertical caving.
• Dissipative ladders are portable ladders built to ESD (Electrostatic Discharge) standard. Electrostatic Discharge is a natural occurrence in which electricity is passed through the body, or other conductor, and discharges onto some object. For example, the shock sometimes felt when a doorknob is touched is an ESD. This natural occurrence is becoming a very hot topic in the field of electronics assembly due to the costly damage ESDs can cause to sensitive electronic equipment. Dissipative ladders are ladders with controlled electrical resistance: the resistance slows the transfer of charge from one point to another, offering increased protection during ESD events: ≥10⁵ and < 10¹² Ω / square.
• Pool ladders. A ladder is also used on the side of a boat, to climb into it from the water, and in a swimming pool. Swimming pool ladders are usually made from plastic steps with special grip and metal bars on the sides to support the steps and as handrails for the user.
• Assault ladders. These are designed to be used by units which may need to board or assault vessels or buildings. They can be used when a full sized ladder is not required or when working in confined spaces. They are suited for covert operations such as sniper placement and vessel boardings. It was developed and designed for tubular assaults including buses and trains and for first story breaching. Its extra wide design gives the user greater stability, but it can still fold away to be stored. It is available in standard aluminium or non-reflective black finish in 6 and 8 feet lengths.

Historical usage[link]

Ladders are ancient tools and technology. A ladder is depicted in a Mesolithic rock painting that is at least 10,000 years old, depicted in the Spider Caves in Valencia, Spain.^[3] references the rock painting which shows two naked humans carrying baskets or bags that are employing a long wobbly ladder, which appears to be made out of some kind of grass, to reach a wild honeybee nest to harvest honey. Modern ladders are believed to have been conceived by Hebrews and Egyptians.

Superstition[link]

It is commonly said that walking under a ladder is bad luck. A natural explanation would be that an erected ladder most likely meant that someone was working above and to pass under it would make a person susceptible to injuries due to falling objects.

See also[link]

• Escalade
• Habala
• Stairway

• Dog and pawl.jpg

  Photo of a dog and pawl on an extension ladder.

• La-cat.gif

  Sketch of Cat Ladder (UK terminology) an aid when working on steep roofs.

• La-main.gif

  Sketch of double extension ladder

References[link]

External links[link]

• Ladder Safety including Ladder Types (Type I, Type II, Type III)
• Ladder safety manuals
• OSHA Ladder guidelines including OSHA approved rung spacing requirements, etc.

This biographical article needs additional citations for verification. Please help by adding reliable sources. Contentious material about living persons that is unsourced or poorly sourced must be removed immediately, especially if potentially libelous or harmful. (March 2011)

Andrew Belle is an American singer-songwriter. Andrew (born Drew Fortson) is originally from Wheaton, Illinois. Andrew moved to Nashville in 2009.

History[link]

He grew up listening to bands like Third Eye Blind, Counting Crows, and The Verve Pipe, and looks to these bands for musical inspiration. Andrew began his musical career towards the end of his time at Taylor University in Upland, Indiana. During this time, he played with numerous local bands. Upon graduation, he launched his solo career in Chicago, performing at various local restaurants and venues, including Rockit Bar and Grill, Elbo Room, SPACE and Schubas Tavern.

He is currently touring clubs and universities across the country, and is also a member of the critically acclaimed national tour Ten Out of Tenn. He has shared the stage with numerous artists including Ben Folds, Brian Vander Ark (The Verve Pipe), Greg Laswell, Barcelona (indie rock band), and Boyce Avenue (band).

Andrew released his debut EP All Those Pretty Lights in September 2008, containing songs featured in hit TV shows including CW's “90210”, MTV's “The Real World”, CBS's Ghost Whisperer, and E!'s “Keeping Up with the Kardashians”. His debut full-length album The Ladder was released in February 2010. Songs from The Ladder have been featured on hit TV shows including Grey's Anatomy and CW's The Vampire Diaries and One Tree Hill and ABC Family's Pretty Little Liars and The Lying Game . His song "Sky's Still Blue" was featured in a Microsoft commercial/documentary promoting the Windows 7, Windows Live and Windows Phone 7 exosystem. It was made available as a free download from Microsoft. His song 'In My Veins' recently featured in the final scene of the fourth season finale of Castle, which was released 7 May 2012.

His songs have garnered nationwide airplay including Chicago’s WXRT, Nashville’s WRLT, Philadelphia's WXPN, Indianapolis's WTTS, and Los Angeles's KCRW. Andrew was named “Best Breakout Artist, Chicago” by MTV in 2009. His music and vocal stylings draw comparisons to Coldplay, The Fray, and John Mayer.

He recently announced in February 2012, that he is engaged and plans to marry in June of 2012.

Discography[link]

Singles

1. In My Veins, June/July 2010
2. Have Yourself A Merry Little Christmas, November 2011
3. " Static Waves" Feat. Katie Herzig
4. "Tower"
5. "Add It Up"
6. "Reach"

EPs

1. All Those Pretty Lights, September 2008
2. The Daylight EP, February 28 2012

LPs

1. The Ladder, February 2010 (produced by Thomas Doeve)

Live Recordings

1. Sundays at Rockit, September 2009
2. Live At Hotel Cafe March 2010

References[link]

Press[link]

The Washington Post, "Live!", September 24, 2009

Dayton City Paper, Ascending the Ladder, January 28, 2010

Fringe, "Andrew Belle: Looking Beyond All Those Pretty Lights", pg. 33, January/February 2010

Kalamazoo Gazette, "Pop-rocker Andrew Belle strikes out on his own, stops into Kalamazoo", February 4, 2010

American Way, "All That Jazz", pg. 55, February 15, 2010

Chicago Tribune, "Andrew Bird vs. Andrew Belle: Two Chicago indie performers", March 25, 2010

Radio[link]

Chicago Public Radio, WBEZ 91.5 FM, "Singer-Songwriter Andrew Belle Makes Musical Waves", March 16, 2010

Mad Toast Radio Show http://www.blubrry.com/madtoastlive/682379/episode-106-andrew-belle-allen-stone

Maybe Hip: Chicago Rocks - Andrew Belle http://www.dailymotion.com/video/xcqhp1_maybe-hip-chicago-rocks-andrew-bell_music

WXPN, My Morning Download, 2/25/10