A confined space davit arm or tripod is the frame that holds a winch or self-retracting lifeline above a manway so a standby worker can pull an entrant out without going in. Choose a tripod when the opening is clear and you need a portable frame, and a davit arm when the opening sits against a wall, a vehicle or an obstruction. This guide compares the two, explains what goes on top of them, and lists the 3M DBI-SALA, MSA Workman and Peakworks systems ERE Inc. supplies.
In this guide
- What is non-entry confined space rescue?
- Davit arm or tripod: which one do you need?
- What goes on the frame?
- Which confined space rescue systems does ERE supply?
- How to choose a confined space rescue system
- Frequently asked questions
What is non-entry confined space rescue?
Non-entry rescue means retrieving a worker from outside the space, using a line attached to the entrant's harness and a mechanical device that lifts. It is the preferred method because the rescuer never has to face the atmosphere or the hazard that downed the first worker. The CCOHS confined space program page says to rescue victims from outside the confined space if possible, and that no worker should enter to attempt a rescue unless fully trained and wearing the right protective equipment.
The CCOHS confined space introduction adds that an estimated 60% of the fatalities have been among the would-be rescuers. That is why the retrieval equipment is planned and staged before the entry permit is signed, not after an alarm. Atmosphere monitoring is the other half of that plan; see our guide to confined space gas monitoring requirements in Canada.
Requirements differ by province and by space, so the confined space hazard assessment for your site decides what rescue equipment is needed and how many trained people must be on hand.
Davit arm or tripod: which one do you need?
Use a tripod for vertical entries with open ground around the manway, and a davit arm where the opening cannot be straddled. Both put an anchor point and a pulley or winch directly above the opening. They differ in how they are positioned:
| Feature | Tripod | Davit arm system |
|---|---|---|
| Best for | Open manholes, tanks and vaults with room for three legs | Openings near walls, equipment or a vehicle, or where an offset reach is needed |
| Set-up | Legs spread and lock over the opening; the MSA Workman tripod sets up and dismantles without tools | Base is positioned, then the mast, offset upper mast and winch are assembled |
| Portability | One carried frame; the Peakworks kit is described as a single-person set-up | Modular pieces, for example the 3M DBI-SALA 5-piece system, so it can be added to over time |
| Reach | Directly over the centre of the legs | The 3M DBI-SALA Advanced davit has a 27 1/2 in. maximum offset mast |
If you are not sure, walk the entry point before the job. Where the legs of a tripod cannot be set on solid, level ground around the opening, a davit arm is usually the better answer.
What goes on the frame?
The frame holds a retrieval device, and that device is what actually lifts the worker. Most systems use one of two options:
- A rescue winch. A hand-cranked winch raises and lowers personnel or materials. The MSA 65 ft Workman Winch is rated by MSA for a 400 lb personnel workload and 620 lb for materials, and has a clutched drive, double braking and a foldable crank handle.
- A self-retracting lifeline with retrieval. An SRL mounted on the frame arrests a fall while the entrant works. Our guide to the self-retracting lifeline explains the CSA classes and what to check before you buy.
The entrant wears a harness with a rescue connection point, and a retrieval harness has the D-ring placement for a vertical lift. See our guide to the fall arrest harness and CSA Z259.10 classes for the harness side. Accessories such as a mounting base, a davit pulley assembly and a winch and SRL mating bracket complete the kit.
Which confined space rescue systems does ERE supply?
ERE Inc. supplies complete kits and individual parts from 3M DBI-SALA, MSA Workman and Peakworks. Specifications below come from the product listings, so confirm ratings and CSA classes on the manufacturer's data sheet for your configuration.
- 3M DBI-SALA Confined Space Aluminium Tripod has telescoping, locking legs, a top-mounted pulley system for up to three pulleys, and a 5,000 lb (22 kN) anchor point for a secondary fall arrest system. It supports up to three winches or SRLs.
- 3M DBI-SALA Advanced 5-Piece Davit Hoist System is a modular davit with an adjustable offset upper mast, a 33 in. lower mast and a three-piece base. It includes a winch mounting bracket; the winch and SRL are sold separately.
- 3M DBI-SALA Advanced Adjustable Offset Davit Mast is the davit arm component with a 57 in. mast extension.
- 3M DBI-SALA SalaliftII Winch is a manual work support and rescue winch with 60 ft of 1/4 in. galvanized cable and a quick-mount bracket that mates with DBI-SALA support structures.
- MSA Workman Tripod has automatic hinge lock legs, skid-resistant feet, a maximum height indicator and an integral carrying strap.
- MSA Workman Confined Space Entry Kit bundles an 8 ft tripod, a 50 ft Workman Rescuer, a pulley and a carabiner for non-entry rescue.
- Peakworks CSK2-65 Confined Space Kit pairs an aluminum tripod with a 65 ft man and material winch rated for 151 kg (310 lb) combined weight, with non-slip safety feet and a safety chain.
For the person being retrieved, ERE also supplies the 3M Protecta Vest-Style Retrieval Harness and the DBI-SALA Rescue/Retrieval Y-Lanyard with Spreader Bar, which keeps the victim upright during rescue. For rescue and evacuation from an elevated work area rather than a vertical shaft, the Rollgliss R550 rescue and descent device is a different tool. The full range is in the fall protection collection.
Some older listings still describe winches by earlier CSA class names such as "Type 3 RSRL". Always read the class and rating on the current data sheet.
How to choose a confined space rescue system
- Walk the entry point. Note the opening size, the ground around it, any wall, vehicle or pipe that blocks the legs, and the depth.
- Pick the frame. A tripod for open, level access; a davit arm where the opening cannot be straddled.
- Choose the retrieval device. A winch for a manual lift, or an SRL where the entrant also needs fall arrest. Check cable length against the depth of the space.
- Check the ratings. Compare the winch or SRL working load with the entrant's weight plus tools, and read the anchor rating for the frame.
- Match the harness and connectors. Use a retrieval-rated harness and connectors compatible with the line.
- Write it into the rescue plan, then train. Practice set-up and a retrieval before the first live entry, as CCOHS advises for rescue procedures.
Our team at ERE Inc. can help you size a kit for a specific manway, tank or vault, and match it to the gas monitor and harness you already use.
Need a confined space rescue system for your site?
ERE Inc. has been Canada's environmental and safety equipment specialist for 30+ years. Tell us the opening size and depth, and we will match a tripod or davit, winch and harness.
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Frequently asked questions
What is a davit arm used for in confined space rescue?
A davit arm is a mast with an offset reach that holds a winch or self-retracting lifeline over a manway, so a standby worker can lift an entrant out without entering. It is used where a tripod's legs cannot be set around the opening.
What is the difference between a tripod and a davit?
A tripod stands on three legs directly over the opening. A davit arm mounts on a base beside the opening and swings the anchor point over it. Tripods are quick to set up for open entries, and davits suit tight or obstructed ones.
Can you use a tripod and winch for both entry and rescue?
Yes. A winch or SRL on a tripod can lower an entrant into the space and retrieve them, so the same equipment serves entry and rescue. Confirm that the winch is rated for personnel and that your site rescue plan covers it.
How much weight can a rescue winch lift?
It depends on the model. The MSA 65 ft Workman Winch is rated by MSA for 400 lb of personnel workload and 620 lb of materials, and the Peakworks MW-65G winch in the CSK2-65 kit is rated for 151 kg (310 lb) combined weight. Always read the rating on the data sheet for the unit you buy.
Related articles
- Self-retracting lifeline: CSA classes and how to choose
- Fall arrest harness: how to read CSA Z259.10 classes
- Confined space gas monitoring requirements in Canada
- Roof anchors: types, strength and how to choose
Lire en français : Potence ou trépied : choisir un système de sauvetage en espace clos