Confined Spaces

Confined Spaces: "Any place, including any chamber, tank, vat, silo, pit, pipe, sewer, flue, well or any similar space in which, by virtue of its nature, there is a foreseeable risk of any specified occurrence"

It the vast majority of situations where a worker must enter a confined space he or she should be wearing a full body harness and be attached to a rope. This arrangement serves two purposes; 1) you are able to locate the the worker 2) you will likely be able to pull the worker out from the work site encase of emergency. By nature confined spaces are often dark, lighting should be considered carefully as any explosive environment will require Atex lighting.

To be able to position the worker additional equipment is required. This may include hauling systems incorporating PPE Pulleys combined with lowering/raising mechanisms to form a bespoke system or alternatively a pre-rigged system may be used. When entering silos or manholes a confined space access tripod can be an invaluable piece of equipment.

When purchasing harnesses for confined space access it is worth considering the angle at which the worker will be suspended upon entry/exit. Most full body harnesses have a rear dorsal attachment, this attachment is located high on the users back. Due to the position of this attachment the worker will be prone to hanging at an angle. A harness designed specifically to lift the user vertically will be required, the Petzl Newton fitted with the Petzl Lift Spacer provides a adaptable alternative.

Confined spaces - specified occurrence

  • Fire or explosion; or
  • the loss of consciousness or asphyxiation of any person at work there arising from gas, fumes, vapour or the lack of oxygen.
  • the drowning of any person at work there; or
  • the asphyxiation of any person at work there arising from a free flowing solid; or
  • the loss of consciousness of any person at work there arising from a high ambient temperature

 

A confined space can be found in virtually any working situation. At present we are unable to offer advise specific to confined space working, we are pursuing further knowledge in this area and hope to offer sound advise with a more diverse product range in the near future. We are however able to offer advise regarding access and egress methods. We provide Atex lighting but only with the details of its relevant certification, it is up to the user to check that its certification is suitable for their needs.

Examples of pulley systems by Petzl typically used during confined space access

Petzl combined lowering and raising pulley system This combined Petzl lowering/raising pulley system requires only the addition of a Petzl Ascension to switch between lowering or raising the load. The Petzl Paw rigging plate has been used to provide suitable anchor points for components. The Petzl I'd has a dual purpose in the system, providing an auto block for raising the load and friction when lowering a load. The disadvantage of this system is that the length of rope pulled is equal to four times the distance gained or lost in height.  
Petzl independant lowering and raising pulley system This independent lowering and raising method maintains an equal distance of rope pulled to height gained (green rope). The disadvantage of this system is the rigging transition between lowering/raising and vice-versa. The raising pulley system implements a 'plug on' style connection to a rope  using the Petzl Basic. This can be a useful system for recovering injured or stranded persons already in suspension on their own ropes.
Petzl tripod rigging set up This example shows how Petzl products can be used in conjunction with a tripod for confined space access. The user above ground has been protected with a restraint lanyard, like the Petzl Jane for example. Here a combined lifting and raising system has been used. The user accessing the confined space has modified their harness with the Petzl Lift Spacer to provide a vertical attachment point. Note that for heavy loads or longer lifting applications larger pulleys such as the Petzl Twin and Petzl Minder have greater sheave diameters which provide enhanced efficiency.

Wire ladders often provide excellent additional means of access to confined spaces reducing the need for complex pulley systems for general access. Users can be protected by a belay or 3 way fall arrest block while ascending or descending. To read more about our range of wire ladders please view our Wire Ladders page.