Tripods are transportable and are therefore certified to EN 795-B. They are designed for work in confined spaces when access is through a manhole.
Thanks to tripods, work requiring access from a manhole can be performed autonomously, since it does not require the prior installation of fixed anchor point or other protective items.
In this case, work is from the base mounted on one of the tripod legs.
The use of a fall arrester with a retrieval system is the most convenient and safest way of working, given the fact that:
In addition to the retriever and to the mounting base on the tripod leg, in order to operate this system, it is also necessary to fix a pulley to the tripod anchorage in order to re-send the cable coming from the base of the tripod leg.
Lever-based retrieval is not the only way to work with the tripod.
Other retrieval systems include:
The key difference between these two retrieval methods compared to the first method is that these are mounted on the tripod anchor point instead of on the tripod leg base intended for the lever-based retriever.
Like the tripod, the Davit arm is considered to be transportable, used for multi-site operation and certified to EN 795-B.
The great advantage of the Davit Arm is that is rotates on its own axis, so that, in addition to retrieval, it allows the rescued person to be released on a safe platform.
However, unlike tripods, most Davit arms require the prior installation of sockets in order to subsequently insert the masts. Once the socket has been installed, it is extremely quick and easy to insert the arm.
Some Davit systems do not require these fixture sockets, however they are not as quick to assemble. And, in general, they are expensive systems.
This is the most popular type of support. It is permanently installed for use in confined spaces requiring constant access.
Secured to vertical surfaces, these are also intended for frequent work as they are permanently installed.
Intended for bibs with a minimum thickness of 200mm and maximum of 400mm, the prior installation work is quick and they can be moved from one place to another.
Intended for lifting and lowering loads of a maximum weight of 250kg, the load winch fits into one of the Davit arm brackets and also to the tripod.
As already mentioned throughout this section, work in confined spaces requires the use of PPE that permit the urgent lifting of a person at serious risk.
Due to convenience and ease of use, the most popular systems are retractable fall arresters incorporating a retrieval function.
Retrieval is generally by lever. Although a chain retrieval system can also be used, which is also the best form of retrieval with regard to permanent anchorage.
People with a high level of expertise in work at heights, also generally mount rope hoists using pulleys, blocks, etc, to achieve customised systems.
The most popular and simplest to use
In this video we'll explain the operation of a fall arrester with a lever retrieval system. Suitable for tripods and Davit arms alike.
This type of retrieval is better when performed from a fixed anchor point.
It can also be mounted on a tripod. Suspended from a Davit arm, it is almost impossible to do so comfortably.
The great disadvantage of using this system is that the movement generated by the fall generates movements in the fall arrester, so that it is not as convenient to use as the lever-based retriever that is correctly secured to the tripod socket or the Davit arm.
Moreover, retrieval is much slower and time consuming with this chain system.
The mounting of a hoist of this type is complex. It requires a great deal of time and people trained to correctly complete the mounting process.
This is generally used by emergency professionals, such as fire fighters. People with profiles and great expertise in the work at height sector.
At Elytra we would advise our customers to use simpler techniques, such as those set out in the two sections above. They are easier to use and ensure that any emergency work is carried out correctly.