Ultimately to reduce risk, tasks in confined spaces should be engineered out where possible. Where this is not possible and entry must take place, several options are available for vertical entries.
Confined space entry and recovery via vertical insertion has always raised challenges, due to several issues, space around the entry point, fall from height hazards, Topman attachment, man-riding winches, and backup systems, along with the requirement for rescue provision. This may be compounded with the possibility that equipment (pumps, valves, welding tools, etc) may need to be inserted or recovered.
The frequency of the confined space task will determine the equipment purchased or hired to complete the job. In this article, we examine the pros and cons of each method.
Clash of the Titans, which confined space equipment comes out on top?
Historically the tripod was the first of the 3 to become the “go-to” piece of equipment where it was used to lower and raise personnel and kit with ropes. The tripod developed over time with the addition of man-riding cable winches for Bosuns chairs. When the Lifting Operation Lifting Equipment Regulations came into force in 1998 a man riding winch was required to have a backup system and with the evolution of equipment and the 2005 Work at Height Regulations, the fall arrest recovery block was born.
The tripod and attached equipment makes for “a very busy” insertion recovery point and Top Man work area. The Topman should also be connected to some form of fall protection to prevent him from falling into the entry point.
For simple insertion down ladders, the tripod provides great protection and simple recovery using a fall arrest recovery system.
Tripods are rarely rated for the carriage of goods and equipment, this may mean a separate piece of lifting equipment is required. Stability can sometimes be brought into question when recovering entrants away from the entry point.
Inspection of this equipment falls under the LOLER regulations. The cost of ownership is relatively inexpensive.
Davits evolved from systems similar to those used for lowering lifeboats from ships. The davit system is the ideal piece of equipment where access is required over an open edge, it can be permanently installed or a number of bases can be installed around a site and a transportable davit moved around the site to the required point. The davit can also be useful where a counterbalance system has been identified as the best method of insertion and recovery. Able to be fitted with man-riding winches, fall arrest recovery blocks and can be utilised with a “H” base around manholes, several other attachments for vehicles, steel piling, and walkways makes the Davit an extremely versatile system.
Range of Davits
Accessibility around the entry point is better than with a tripod and some manufacturers’ equipment is rated for abseiling, ideal for use as window cleaning systems as well as confined space entry.
Great for harbourside applications.
The downside to the davit system, once more these are rarely rated for the carriage of equipment and goods and all the many permanently installed bases around site must be inspected at least annually, This can make the cost of ownership and installation expenses. A great solution where you have many entry points where other portable systems cannot get access or the surface is unsuitable for the feet.
The Gantry is not a new invention and historically these can be found anywhere from a shipyard to your local garage. However, one manufacturer has identified the requirement that confined space entry equipment may need to have the ability to be used for the insertion of equipment, lifting, valves, pumps, etc, and even have the ability for a team member to accompany the load via abseiling.
Porta Gantry in use
The lightweight gantry can come in many different spans, heights, and beam ratings from 500kg upwards The gantry can come with either wheeled feet or pads depending on the task requirement. The ability to man ride and lift equipment makes the portable gantry system extremely versatile with the ability to add electronic winches and the many useful fall arrest recovery systems on the market. It is a great all-round solution not just used for personnel, reasonably cost-effective and transportable
The equipment identified for the task will always be dependent on the risk assessment. No single system can be identified purely on cost. The more complex the task the more input is required from those involved. Getting a casualty out of a medium-risk confined space entry can be challenging with the correct equipment and impossible without it.
For simple manhole entries, a high anchor tripod may suffice for attachment of fall arrest and rescue equipment, where large covers and deep dry/wet wells may require a vehicle-mounted davit or gantry system.
Best value for money will always be the most versatile equipment that can be used to cover the majority of tasks on your site with the least maintenance costs and best safety factor.
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