Not all confined spaces are created equal; some are permit-required confined spaces, others are not. Only permit-required confined spaces are regulated by OSHA 1910.146. The standard defines an opening as a permit-required confined space when it has one or more of the following characteristics:
- Contains or has a potential to contain a hazardous atmosphere.
- Contains a material that has the potential for engulfing an entrant.
- Has an internal configuration such that an entrant could be trapped or asphyxiated by inwardly converging walls or by a floor which slopes downward and tapers to a smaller cross-section.
- Contains any other recognized serious safety or health hazard (such as a fall hazard). If a space is identified as a permit-required confined space and an employee will need access to the space, the employer must develop a written program that complies with OSHA 1910.146.
Confined space fall protection
A major consideration is the type of fall protection equipment that will keep your workers safe from falls and assist in rescue situations. Remember this: when it comes to selecting fall protection equipment for confined space entry and retrieval, make sure you select a reliable system that works quickly, easily and safely…every time.
Fall arrest systems must be comprised of an anchor, connector and harness. For confined spaces, these three components come in a variety of shapes and sizes. The system you select depends entirely on the type of work and the particular environments that the workers are entering.
Anchorage options include:
- Tripods. Typically used for manhole entry and retrieval applications, tripods are lightweight, portable and can be easily set up by one worker.
- Davit Arms or Davit Posts. Davits are an alternative to the basic tripod. They have a variety of base configurations that adjust to different openings. Some have adjustable bases to hoist the worker over the larger openings; others are fixed in a “V” shape and placed adjacent to the opening.
- Counterweight System. This system uses weights to provide a sturdy support structure to offset the weight of a worker. Counterweight systems are useful when the confined space does not allow the legs of the tripod or the davit arm system to be placed adjacent to the opening.
- Side Entry System. When a horizontal entry is necessary, the side entry system clamps or bolts to the side of a tank to provide an anchorage point and base for attaching a winching mechanism.
For confined spaces, connectors usually come in the form of winching mechanisms. The winching mechanism’s key factor is its mechanical advantage, meaning that a 90-pound worker could potentially hoist a 350- pound worker out of the opening. The winching mechanism also provides a braking system, protecting the worker should the winch operator lose control. When using a winch, a worker can descend and ascend slowly and in a controlled fashion. This allows for communication between the operator and worker.
When selecting your connector or a winching mechanism, consider:
- Line Material. The industry standard is stainless steel or galvanized cable. Synthetic lines should be used to reduce the amount of metal exposed in volatile environments, which are common in permit-required confined spaces.
- Fall Protection Capability. Most personnel- rated winches for confined space use provide raising and lowering capabilities. Some retractable type winching mechanisms with a built-in retrieval mechanism are equipped with an inertia break that activates to stop a fall in action. These systems are known as three-way devices because they raise, lower and provide fall protection.
- Rope and Pulley System. A rope and pulley system allows the person making the entry to pull him or herself out of the confined space, if necessary. A stand-by person can also perform the raising or lowering operation. The rope runs through a series of pulleys that creates the mechanical advantage for this system. This is an alternative to the traditional winching mechanism.
Comfort and ease of use are the top two considerations for harnesses. The person going into the confined space should be wearing a full-body harness with rescue capabilities. He should be connected to the winch line while making the entry and working in the space. If the worker is fully connected, a rescuer can perform the rescue without entering the area, which could potentially endanger his or her life. Workers may need to disconnect and move about within the confined space, but having the emergency retrieval equipment available is crucial.
Confined space entry is made simple with the use of specialized harnesses outfitted with D-rings or connecting points on top of each shoulder strap. A separate device, shaped like an upside down “Y,” is attached to the harness. One of the Y-legs attaches to each of the shoulders and then the single line would connect to the winching mechanism’s connection line. This allows for straight, vertical lifting, which is important if working in a very small, confined space opening. If the person being raised is simply connected to the dorsal D-ring of a normal harness, he or she would be diagonally positioned while being lowered or raised. The person could also get caught in the surrounding structure, resulting in serious bodily injury if not freed in a timely manner.