zhongxinladder

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.

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.

    * 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 Aluminum step ladder as 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 our body, or other conductor, and discharges onto some object. For example, the shock we feel when we touch a doorknob 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 electric resistance: the resistance slows the transfer of charge from one point to another, offering increased protection during ESD events: ≥105 and < 1012 Ω / square ([e.g.])

    * 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 Aluminum step ladders 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. 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 still can fold away to be stored. It is available in standard aluminum or non-reflective black finish in 6 and 8 foot lengths.

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 a cave in Valencia, Spain. Bee Wilson (2004: p.5) 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.

from:answers

The idea that it is unlucky to walk under a Household ladder is one of the most widely known and practised superstitions of modern times, being by far the most often mentioned in replies to our 1998/9 Superstitions Survey. In most cases now it is simply said to be ‘unlucky’, but in previous times to walk under a ladder might result in you never marrying, or dying on the gallows. The first known reference to this belief is little more than 200 years old, in Grose's Provincial Glossary (1787:63).

For those unfortunate enough to have walked under a ladder, a number of traditional remedies are prescribed—spit through the ladder, spit over your left shoulder, or keep your fingers crossed till you see a dog, do not speak till you see a four-legged animal, make the sign of the cross, and so on. There have also been a number of attempts to explain the belief: the Devil lurked under the ladder at the Crucifixion, the ladder/wall/floor make a triangle which is symbolical of the Trinity, and the ladder stands for the gallows. Needless to say, none of these has a shred of evidence to support them. Unlike many superstitions, however, this one does have a pragmatic element, and many argue that their avoidance is ruled merely by considerations of safety and common sense.

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.
Rigid ladders are available in many forms, such as:

    * Fixed ladder, Two side members joined by several rungs; affixed to structure with no moving parts
    * Extension ladder or Telescopic ladder, 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
    * Aluminum step ladder , hinged in the middle to form an inverted V, with stays to keep the two halves at a fixed angle
    * 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
    * Household step ladders , step ladder with small horizontal platform at the top
    * Orchard ladder, three legged step ladder with third leg made so that it can be inserted between tree branches for fruit picking
    * Roof ladder, rigid ladder with large hook at the top to grip the ridge of a pitched roof
    * Cat ladder (US chicken ladder), lightweight ladder frame used on steep roofs to prevents workers from sliding
    * Hook ladder or pompier ladder, rigid ladder with a hook at the top to grip a windowsill; used by firefighters
    * Turntable ladder, extension ladder fitted to rotating platform on top of a fire truck
    * Bridge ladder, ladder laid horizontally to act as passage between two points separated by a drop.
    * Vertically rising ladder, a ladder designed to climb high points and facilitate suspending there.

Rigid ladders were originally made of wood,but in the 20th century tubular aluminum became more common because of its lighter weight. FRP ladder is used for working on or near overhead electrical wires, because fiberglass is an electrical insulator.

from:answers

In the US, more than 500,000 people a year are treated for ladder related injuries, according to the American Academy of Orthopedic Surgeons.  Of those injuries, about 300 people die.  I’m up on some type of a ladder almost every day so I’d like to pass along just a few tips. Since it’s gutter cleaning season, I’ll focus on the tall extension ladders.

Select the right Household ladder

Ladders have a duty rating from the American National Standards Institute.  This rating includes the maximum weight it’s designed to handle, which includes the user, material and tools.

Type III: light duty - up to 200 lbs
Type II: medium Duty - up to 225 lbs
Type I: Heavy Duty - up to 250 lbs
Type I-A: Extra Heavy Duty - up to 300 lbs*
Type I-AA: Special Duty - up to 375 lbs*

* If you and your load are getting close to or above 300 lbs, consider renting a lift.

Inspect Before Each Use

    * Check all bolts and rivets

    * Be sure the rungs are clean

    * Be sure the feet are secure and the rubber soles will grip

    * Check the rails and rungs for cracks or other damage

    * Check the movement and springs of the rung locks

    * Check the rope for fraying

    * Check the operation of the pulley

    * Check aluminum ladders for burrs - wood and fiberglass for splinters

Setting a Aluminum step ladder

First, read the labels on the ladder.  Second, watch out for overhead electric wires.

The most frequent injuries to inspectors is from setting the ladder on slippery decks, patios or walks.  I look for level, dry, compacted soil.  If there’s mulch, I’ll scrape it away.  If your house is on a slope, install adjustable levelers at the base of your ladder.

Getting the angle of the ladder is important.  Too steep and it could tip back.  Too low of a slope and it could kick out.  The ladder should be set 1 foot out for every 4 feet in height.  With your toes touching the feet of the ladder, hold out your arms straight.  Your finger tips should just touch the rails.

Working from a household step ladder

Don’t wear slippery or muddy shoes.  Use both hands while climbing or descending.  If your project involves using both hands, it shouldn’t be done from a ladder – one hand always needs to be holding on.  Always stay centered.  Don’t reach or lean to the sides.

If you need to climb onto a roof, the ladder should extend above the roof edge by at least three rungs.  Strap or clamp the ladder securely to the roof edge or gutter.  Always step on or off the roof using a rung well below the point where the ladder meets the edge.Stepping above the edge and the bottom of the ladder can kick out.

Unless you have the right equipment, never set a ladder on a roof to get to a higher roof.  Finally, never leave a ladder up unattended.

from:oldhouseweb

Why use a Household ladder ? Because the most important thing to notice, is that there are different levels of participation, ranging from full participation to fake participation, from being in-control to being under control.

After this one, other ladders of participation have been described: for example the
Ladder of Children’s Participation (also called the Ladder of Youth Participation), from (1997) Roger Hart, Children’s Participation: The Theory And Practice Of Involving Young Citizens In Community Development And Environmental Care
MOBILE AND SAFETY STAIRS – Mobile Stairs for access to mezzanine floors or for use in warehouse applications. There are flexible top platform configurations to allow exit ‘to front’ or ‘to side’ off the top platform.

WAREHOUSE STEPS – Also known as Ladder stabilizers or rolling ladders they have a large stable platform at the top from which to work. These ladders are fitted with wheels to allow them to be moved easily and the wheels have some form of locking mechanism. The top platform has a guardrail to protect the operator. These steps are also available as folding steps which can be flat packed when not in use.

RETAIL/OFFICE STEPS – There are very few height access products which don’t look like they belong on a building site. The one exception to this is the Stepmobile Range of retail stepladders. This product is available in a range of 5 bright colors and can be easily cleaned. There are a range of platform heights available from 0.5m to 1.25m. The units have a very small turning circle allowing them to be used even in the most confined situations. Perhaps the cleverest element of these Aluminum step ladders is the wheels. The unit will move freely until weight is applied then the wheels retract and the unit locks into position.

FIRE ESCAPE LADDERS – Emergency escape ladder that provides a safe way to exit your home in the event of fire. Escape ladders are available in wire, chain, and webbing or in rope ladder format.

LADDER ACCESSORIES – Everything from new rubber feet to ladder racks for storage. Ladder Locks, Ladder Stabilisers, Little Giant Work Platforms and ladder stand-offs. The two most popular accessories we sell are the Roof Hook Kits which convert a standard aluminium ladder into a roof ladder and the ladder clamps used to secure a ladder to the roof rack of a vehicle.

LITTLE JUMBO SAFETY STEPS – This range of small step ladders is available as a 2 step, 3 step and 4 step. Ideal for retail outlets or offices, this folding step ladder is one of the best safety steps in the marketplace.

CUSTOM LADDERS AND FIXED LADDERS – We can solve your Aluminum fixed ladder access problems with a range of custom made ladders manufactured to customer’s specifications. Typically these fixed ladders are installed to gain access to flat roofs or to service equipment like air conditioning units located at height. In order to quote for these products we require a suitable drawing of the project. We can then generate a quotation and timescale for the custom ladder or walkway.

MOBILE ALUMINIUM PLATFORMS – This is a relatively recent development in height access equipment. Looking like a standard work platform where the operator is completely enclosed by guard rails this unit is fitted with a foot operated drive unit. Once the operator is on the platform they can then move the platform into other positions using the steering handle and foot pedal. The are 4 models in the range from a maximum platform height of 1.2m to 2.1m. Each model has 3 platform height settings. Most importantly with this mobile work platform there is no certified training required. The maximum workload capacity is 200kg.

LOFT LADDER AND ATTIC LADDERS – A retractable attic ladder will provide access to a loft or attic and slides or folds away when not required. Available as a sliding aluminium ladder or as a folding ladder in wood. There are also telescopic and concertina attic ladders Types and the full specifications and Attic Ladder Fitting Instructions are on the web site. Attic ladders are covered by two BS standards.

from:blog.ladders

Handrails
Requirements for handrails are as follows:
 Handrails and top rails of the stair rail systems must be able to withstand, without failure, at least 200 pounds (890 n) of weight applied within 2 inches (5 cm) of the top edge in any downward or outward direction, at any point along the top edge.
 Handrails must not be more than 37 inches (94 cm) high nor less than 30 inches (76 cm) from the upper surface of the handrail to the surface of the tread.
 Handrails must provide an adequate handhold for employees to grasp to prevent falls.
 Temporary handrails must have a minimum clearance of 3 inches (8 cm) between the handrail and walls, stair rail systems and other objects.
 Stairways with four or more risers, or that rise more than 30 inches (76 cm) in height— whichever is less—must have at least one handrail.
 Winding or spiral stairways must have a handrail to prevent use of areas where the tread width is less than 6 inches (15 cm).

Midrails
Midrails, screens, mesh, intermediate vertical members or equivalent intermediate structural members must be provided between the top rail and stairway steps to the stair rail system. When midrails are used, they must be located midway between the top of the stair rail system and the household step ladders .

Employers must train all employees to recognize hazards related to ladders and stairways, and instruct them to minimize these hazards. For example, employers must ensure that each employee is trained by a competent person in the following areas, as applicable:
 Nature of fall hazards in the work area;
 Correct procedures for erecting, maintaining and disassembling the fall protection systems to be used;
 Proper construction, use, placement and care in handling of all stairways and household ladders ; and
 Maximum intended load-carrying capacities of ladders used.
Note: Employers must retrain each employee as necessary to maintain their understanding and knowledge on the safe use and construction of ladders and stairs.

cleat —A ladder crosspiece of rectangular cross section placed on edge upon which a person may step while ascending or descending a ladder.
double-cleat ladder —A ladder with a center rail to allow simultaneous two-way traffic for employees ascending or descending.
failure — Load refusal, breakage or separation of components.
fixed ladder — A aluminium step ladder that cannot be readily moved or carried because it is an integral part of a building or structure.
handrail — A rail used to provide employees with a handhold for support.
job-made ladder — A ladder that is fabricated by employees, typically at the construction site; noncommercially manufactured.
load refusal — The point where the structural members lose their ability to carry the load.
point of access — All areas used by employees for work-related passage from one area or level to another.

portable ladder — A ladder that can be readily moved or carried.
riser height — The vertical distance from the top of a tread or platform/landing to the top of the next higher tread or platform/landing.
side-step fixed ladder — A fixed ladder that requires a person to get off at the top to step to the side of the ladder side rails to reach the landing.
single-cleat ladder — A step ladder consisting of a pair of side rails connected together by cleats, rungs or steps.
stair rail system — A vertical barrier erected along the unprotected sides and edges of a stairway to prevent employees from falling to lower levels.
temporary service stairway — A stairway where permanent treads and/or landings are to be filled in at a later date.
through fixed ladder — A fixed ladder that requires a person getting off at the top to step between the side rails of the ladder to reach the landing.
tread depth — The horizontal distance from front to back of a tread, excluding nosing, if any.

from:osha.gov

The rules covering stairways and their components generally depend on how and when stairs are used. Specifically, there are rules for stairs used during construction and stairs used temporarily during construction, as well as rules governing stair rails and handrails. Stairways Used During Construction The following requirements apply to all stairways used during construction:

 Stairways that will not be a permanent part of the building under construction must have landings at least 30 inches deep and 22 inches wide (76 x 56 cm) at every 12 feet (3.7 m) or less of vertical rise. Stairways must be installed at least 30 degrees
—and no more than 50 degrees—from the horizontal.
 Variations in riser height or stair tread depth must not exceed 1/4 inch in any stairway system, including any foundation structure used as one or more treads of the Aluminum step ladder .
 Doors and gates opening directly onto a stairway must have a platform that extends at least 20 inches (51 cm) beyond the swing of the door or gate.
 Metal pan landings and metal pan treads must be secured in place before filling.
 Stairway parts must be free of dangerous projections such as protruding nails.
 Slippery conditions on stairways must be corrected.
 Workers must not use spiral stairways that will not be a permanent part of the structure.

Temporary Stairs
The following requirements apply to stairways used temporarily during construction. Except during construction of the stairway,
 Do not use stairways with metal pan landings and treads if the treads and/or landings have not been filled in with concrete or other materials unless the pans of the stairs and/or landings are temporarily filled in with wood or other materials. All treads and landings must be replaced when worn below the top edge of the pan.
 Do not use skeleton metal frame structures and steps (where treads and/or landings will be installed later) unless the stairs are fitted with Ladder stabilizer and landings.
Note: Temporary treads must be made of wood or other solid material and installed the full width and depth of the stair.

Stair Rails
The following general requirements apply to all stair rails:
 Stairways with four or more risers or rising more than 30 inches (76 cm) in height— whichever is less—must be installed along each unprotected side or edge. When the top edge of a stair rail system also serves as a handrail, the height of the top edge must be no more than 37 inches (94 cm) nor less than 36 inches (91.5 cm) from the upper surface of the stair rail to the surface of the tread.
 Stair rails installed after March 15,1991, must be not less than 36 inches (91.5 cm) in height.
 Top edges of stair rail systems used as handrails must not be more than 37 inches (94 cm) high nor less than 36 inches (91.5 cm) from the upper surface of the stair rail system to the surface of the tread. (If installed before March 15, 1991, not less than 30 inches [76 cm]).
 Stair rail systems and handrails must be surfaced to prevent injuries such as punctures or Household ladder and to keep clothing from snagging.
 Ends of stair rail systems and handrails must be built to prevent dangerous projections, such as rails protruding beyond the end posts of the system. In addition,
 Unprotected sides and edges of stairway landings must have standard 42-inch (1.1 m) guardrail systems.
 Intermediate vertical members, such as balusters used as guardrails, must not be more than 19 inches (48 cm) apart.
 Other intermediate structural members, when used, must be installed so that no openings are more than 19 inches (48 cm) wide.

from:osha.gov