Confined space classification is basically on organization’s discretion as there is no legal requirement nor HSE guidance on classification scheme.
However, confined space classification has some advantages, which includes;
- Helps identify equipment requirements,
- Helps allocate a range of controls
- Helps specify competency requirements,
- Helps group hazard types together,
- Helps benchmark your activities, etc.
Forms Of Confined Space Classification
Different forms of classification exits. Some quarters classify a confined space thus:
– Fundamental classification
- Is the space large enough and shaped so an employee can enter and work?
- Does the space have a limited or restricted means of entry or exit?
- Is the space NOT designed for continuous human/ worker occupancy?
– Permit required space classification
- Does the space contain, or have the potential to contain, a hazardous atmosphere,
- Does space contain a material with potential to engulf a worker
- Does space have an internal shape such that a worker could be trapped or suffocated by inwardly converging walls, floor or ceiling?
- Does space contain other recognized safety or health hazards,
- Will welding, cutting, torch work, or other hot work be performed?
Another form of classification is “The Classification and Management of Confined Space Entries by Water UK”
Here, confined space entries is defined under 4 categories, NC.1 to NC.4.
NC.1 – Low risk shallow entry with adequate natural or mechanical ventilation, where access is simple and unobstructed and there is no likely risk of flooding, e.g. meter pits, valve chambers, booster pumping stations, PRV chambers.
NC.2 – Vertical direct unobstructed access with continuous access to a man riding hoist or similar mechanical rescue device.
NC.3 – When it is not possible to have persons attached to a safety line. Usually it will be a team entry that moves away from the entry point, e.g. man entry sewers, utility subway service tunnels, aqueducts and complex wet wells. Working without an attached rescue line and away from the point of entry.
NC.4 – Non standard entries involving complex operations which include additional risks and require specific controls and rescue arrangements, e.g. mechanical hazards, physical complexity of system introduced hazards, enhanced specific intrinsic hazards.
The last classification method we will highlight here is “The City and Guilds 6150 competency assessment scheme uses a risk based approach”
Low Risk – entries do not require the use of escape breathing apparatus, either because the risk of a hazardous atmosphere is very low or the time taken to get out of the space would be less than the time taken to don an escape set.
Medium Risk – entries require the use of escape breathing apparatus, either because the risk of a hazardous atmosphere is significant or the time taken to evacuate increases risk to entrants, e.g. distance travelled or where there is more than one entrant. There is a realistic expectation of encountering a specified risk either due to the intrinsic hazards or introduced / task hazards.
High Risk – entries generally require full working breathing apparatus. This is because, either because there is a known hazardous atmosphere or because the risks of a hazardous atmosphere occurring are significant. This may be due to intrinsic hazards within the space or introduced / task hazards.
Before I end this article, it is important that I recap a statement made at the beginning of this article regarding the confined space classification.
NOTE: Confined space classification is basically on organization’s discretion as there is no legal requirement nor HSE guidance on classification scheme.
However, classification has advantages as listed in this article.
Confine space entry procedures that works
Type of fire extinguishing agent that should not be used in a confine space