What Does
Davit Arm Mean?
A davit arm is a mechanical device with a movable arm attached to a vertical pole. It has a tilting head and an attachment point at the top, known as a davit. The movable arm is connected to a winch or tackle that lifts and lowers loads.
These systems can be temporary or permanent. A temporary davit arm is mounted to a portable base and is used for lighter applications or situations where it has to be deployed quickly (such as a confined space rescue). Permanent ones are mounted securely to a fixed base and used for heavy-duty applications.
While most davit arms are made of steel, some are built using wood or wood reinforced with steel.
Davit arms are versatile and have a range of configurations, making them adaptable to different applications, including:
- Helping workers enter confined spaces, such as manholes, tanks, vaults, and silos
- Rescue operations (lifting people who are unconscious, incapacitated, or cannot exit a confined space without assistance)
- Raising and lowering loads in construction projects
- Lifting and lowering lifeboats in ships
OSHA Standards for Davit Arms
Since davit arms are used for fall protection as well as rescue and retrieval from confined spaces, employers must include them in a written fall protection or confined space safety program that satisfies all applicable OSHA requirements.
Here are some OSHA standards concerning davit systems:
- 1910.66 (f)(3)(iii) covers davit installation requirements for roof-rigged systems, ground-rigged systems, rotating davits, and transportable davits
- 1910.140(c)(13) and 1910.27(b)(1) outline fall protection requirements when a rope descent system is used with davit booms
- 1910.28 outlines requirements for an installation with permanent davit arms and davit bases but without a powered platform
Using the Davit Arm
Davit arms must always be in proper working condition. They should be carefully inspected before and after each use. A damaged or poorly installed davit arm can cause injury to the worker suspended from it, injury to personnel working below, and damage to property.
Davit arms are designed to only lift a specific amount of weight. Overloading the system can lead to failure, which can have a number of undesirable outcomes:
- Workers supported on a davit system can be injured severely if the system fails
- Rescue operations can be compromised if the davit system fails
- Materials dropped from a davit arm can harm workers below or damage the structure underneath it
- The davit system itself could be damaged and need to be replaced
Tips for Attaching a Davit Arm
Once the base (moveable or fixed) is set up, the vertical post (or mast) of the davit system is inserted into the sleeve. Then, the offset arm is attached to the elbow of the system. The elbow is then secured to the post with pins.
Once the mast and arm are secure, the hoist system is attached to the mounting bracket on the back of the mast. An additional bracket can be added if the davit system is being used for fall protection or confined space rescue.
The end of the hoist bracket is slid over the bar and pinned securely in place. Slack is let out in the line to feed over the roller and then pulled over the davit arm.
Safeopedia Explains Davit Arm
Where and How Davit Arms are Used
When used as a fall protection system, a safety belt is secured around a worker’s waist and tied off to the davit. Since it is secured into a stable structure, the davit acts as anchorage for the fall protection equipment.
This application is used to keep workers safe in a variety of jobs performed at heights, such as:
- Cleaning windows
- Painting
- Inspecting structures
- Repairing external walls
Davit arms have an advantage over anchor points, since they can provide up to 2 meters of outward reach, minimizing the need for ropes.
Confined spaces are hazardous work environments. Every year, many workers are injured on the job or die after entering a confined space. According to the U.S. Bureau of Labor Statistics (BLS), occupational injuries involving confined spaces took the lives of 1,030 workers between 2011 and 2018.
A davit arm can act as a fall arrest system for workers entering a confined space, as well as a rescue and retrieval system for workers who have been injured in a confined space. It is ideal for accessing confined spaces without a primary means of access, like steps or a fixed ladder.
Rescue Operations
Rescue operations require rescue personnel to enter confined spaces to remove people who are trapped in them. These rescues are dangerous, and rescuers must use every means available to help them save lives without risking their own.
Davit arms can:
- Help rescuers enter the confined space safely
- Facilitate their retrieval if something goes wrong
- Assist in moving fallen workers out of the confined space.
It is also easily transported and quickly deployed, making it ideal to use in an emergency.
Other Uses
- Marine: Lifting and lowering of lifeboats and anchors from ships, raising boats from the water, loading and unloading of cargo
- Construction: Raising and lowering scaffolding platforms, moving construction material
- Routine Work: Suspend personnel working at heights or in confined spaces
Why is it called a davit arm?
The word “davit” is derived from “daviot”, a Middle English word that roughly equates to “little David.”
While there is no clear record explaining why this name was chosen, some speculate that it is a reference to David and Goliath, since the davit arm is a small device but mighty enough to lift large vessels.
What is the difference between a davit arm and jib crane?
Davit arms and jib cranes have a number of similarities. Both are made of steel, use similar mechanisms, and are used for lifting and lowering equipment.
There are, however, some important differences between the two devices.
Davit arms are versatile, portable, and easier to install than jib cranes. They can also be used in temporary applications, since they don’t require a solid, permanent foundation.
Jib cranes, on the other hand, are preferable for lifting heavier loads and for many permanent applications. They can be installed in a manufacturing facility, for instance, where objects will need to be lifted in the same location on a regular basis.
Davit Arm
- Mounting requires only 6 inches of reinforced concrete (or other suitable material)
- Made of lightweight components that make it more portable
- The wire rope hoist lifts faster than the chain hoist on a jib crane, making it ideal for higher lifts
- The winch is located at the back of the crane, making it easier to operate
- The telescopic boom has an adjustable angle
- The hand winch allows it to be operated without a power supply
- Can be expanded with different accessories, such as a wall mount or different cable lengths
Jib Crane
- Installation requires a poured foundation at least 30cm deep
- More expensive and less versatile than a davit arm
- Fixed location and boom
- Electric chain hoist requires a power supply to operate
- The chain hoist system makes it slower and less suitable for higher lifts
- The boom can only be rotated by reaching out and pulling the load
Types of Davit Arm Systems
Moveable Base
Moveable davit arm systems are versatile and portable devices that can be used for fall protection and rescue operations. They are lightweight and take approximately five minutes to install.
Davit arms with moveable bases are ideal for temporary projects and emergency situations.
Fixed Base
Fixed base davit arms are secured in place and require less room than a moveable system. They are sturdy and can act as an anchorage point for rescue systems or winches.
The davit arm can be removed from the base and moved to another site where a fixed base has been installed.
They are commonly used for accessing confined spaces.
Wall Mount
Davit arms can also be mounted to a wall rather than a base. Wall mounts are fixed and must be installed in concrete or steel walls only, since other materials are not able to provide the support needed for a davit system.
Like fixed bases, wall mounted davit arms can be removed from the wall mount and moved to another site where another mount has been installed.
Vehicle hitch mount
This system allows vehicles to be used as the davit base. The vehicle can then be driven to the confined space and used to access areas that are difficult to reach.
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