A climbing harness is an item of climbing equipment for rock-climbing, abseiling, or other activities requiring the use of ropes to provide access or safety such as industrial rope access, working at heights, etc. A harness secures a person to a rope or an anchor point.
In its simplest form, a harness can be made from a length of rope or a nylon webbing tied round the waist. However this is extremely uncomfortable unless the wearer is very light. It can also ride up to the abdomen or even the diaphragm under load and cause serious injury. Looping the rope between the legs will prevent this, though care should be taken to avoid sensitive areas. More sophisticated harnesses exist in many patterns, designed to give greater comfort and security, and more options for carrying equipment.
While harnesses can be improvised, it is more common to use commercially produced harnesses, which often include padding and amenities such as gear loops. Most commercial climbing harnesses meet the guidelines and manufacturing standards of organizations such as the Union Internationale des Associations d'Alpinisme (UiAA) or European Committee for Standardization.
Harnesses should be attached to dynamic (stretchy) rope, except possibly when abseiling where the rope is always taut. Falling onto a system consisting entirely of static components e.g. slings over even a very short distance e.g. a metre or two is enough to deliver large forces to the body and possibly cause the equipment to fail altogether. For via ferrata, the harness is attached to lines via a shock absorber that can absorb some of the impact in the event of a fall.
Attachment of the rope to the harness is done using a knot called a figure-eight follow through, and often backed up with a stopper knot. Other knots are possible for the purpose, primarily a variation of the double bowline, but the figure-eight is usually preferred. Although it is harder to untie after a fall, it is inherently more secure, easier to tie, and easier to verify that it has been tied correctly. There are many variations of the bowline knot, and some will untie themselves when repeatedly stressed and unstressed, as is common in climbing.
In addition to the weight bearing parts of the harness, there are parts of the harness that are not designed to be part of the safety system. These include the gear loops, used for carrying equipment e.g. protection devices, carabiners, etc., and the elastic cords which pass behind the buttocks for the purpose of keeping the leg loops from slipping down while not under load. Any attempt to tie the safety system into these components could lead to failure and an unprotected fall. It is acceptable to attach the rope to a leg loop via a Prusik knot and carabiner, but this should only be done with the brake end of the rope in an abseil system in order to keep the Prusik clear of the belay plate. This end of the rope experiences considerably lower forces than the "live" end, due to the action of the belay device.
The invention of the climbing harness has been attributed to Jeanne Immink, a Dutch climber in the late nineteenth century. Some of the first climbing harnesses were devised in the U.K. in the early 1960s by Alan Waterhouse, Paul Seddon and Tony Howard who went on to form the Troll climbing equipment manufacturers. A harness designed by British climber Don Whillans was made by Troll for the 1970 Annapurna South Face Expedition. It went into mass production shortly afterwards and soon became popular worldwide.
The sit or seat harness was invented in the 1960s by Yosemite climbers. The first innovation was the Swami Belt, which was multiple loops of webbing around the waist. Then quickly came the Swami Seat, a sit harness tied from webbing, including leg loops and an integrated waist loop. Once the seat/sit harness came to be, suppliers of climbing gear started making them with stitching replacing the knots. The Swami Seat was revealed to the climbing world thru an article in Summit Magazine in the mid-60s. Sewn harnesses came later.
A sit harness consists of a waist belt and two leg loops which are normally connected in the front of the hips through a permanent webbing loop called a belay loop. Belay loops are extremely strong, but nonetheless still a single point of failure that caused at least one notorious death. For rock climbing, the rope typically goes through the two "tie-in loops" that are above and below the "belay loop". The figure-eight knot is mostly used for rock climbing. These are the most commonly used harnesses for recreational activities such as abseiling and rock climbing, as they afford a wide range of movement while still maintaining a high level of safety. Ensuring the harness fits correctly is key to avoiding pain in the upper thigh area caused by the leg loops being too tight around the upper legs and groin area, while at the same time ensuring that a climber flipped over in a fall does not slip out. The waist belt should be tightened snugly. Leg loops should not be particularly tight, but for obvious reasons neither should they have enough slack to allow extraneous parts of a male climber to get caught inside them.
A chest harness is worn around the shoulders, usually with a sit harness so as to provide an additional attachment point. This attachment point allows for better balance in some situations such as when carrying a heavy pack (as the centre of mass is below the connection to the rope) and when the person in the harness may be unable to maintain an upright position (due to injury or other influences).
A full-body harness is the combination of a sit harness and a chest harness which are permanently or semi-permanently connected to each other. This kind of harness normally offers a wide range of attachment points. It is most commonly used in industrial/rescue situations, and also commonly used by small children instead of a sit harness which is easier to slip out of.
In a study conducted, researchers came to a conclusion that there was no statistically significant evidence revealing a pattern between harness type and severity of climbing accidents. Direct rock contact in rock climbing was the main reason for injury, not the type of climbing harness used.
Most harnesses are generally made from webbing. This webbing is often nylon webbing as polyester webbing doesn't hold triglides and d-rings as well, and it's easier to untie nylon webbing. Specifically, Nylon 66 is the most common type of nylon used for this webbing. The webbing is often also tubular webbing, instead of flat webbing. Within a single harness, there are many different weaves of nylon based on the intended function of the specific part of the harness. These weaves sometimes include polyester. The buckles are typically made of anodized aluminum. For the leg loops and waist belt, companies use various methods to make the harness comfortable. The most common method is cushioning the harness with foam and mesh. However, for more lightweight harnesses, some companies use wider waist belts and unidirectional fibers going along the waist belt to distribute the weight evenly and minimize pressure points. Harness designers use increasingly advanced materials such as Ultra High Molecular Weight Polyethylene (UHMWPE), aramid fibers (Kevlar, Vectran, etc.), and sailcloth (e.g. the Black Diamond Vision harness) in order to make harnesses lighter and more comfortable. Different harnesses use different materials for these fibers across the leg loops and waist belt.