Posted: 12 Dec '16

Confined Space Hazard Levels

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Various jurisdictions and groups have created ranking systems to classify the level of hazard in a confined space. Though various systems exist, they all have similarities. All Confined Space entries on the OSSA Members worksites must comply with the OSSA Regional Code of Practice. 

OSSA has classified Confined Spaces into three categories: Level 1, Level 2 and Level 3

Confined Space Level 1
Immediately Dangerous to Life or Health (IDLH). Includes, but not limited to Oxygen Deficient, Flammable/Explosive Atmospheres and/or concentrations of toxic substances. 

Characteristics
Considered Level 1 if the entry is either the first or initial entry OR if any of the following apply:
a) The hazards are unknown/not been determined
b) The hazards in the confined space include one or all of the following:
- Oxygen concentration less than 19.5% or more than 23% by volume
- Explosive or flammable atmosphere between 10.0% and 20.0% Lower Explosive Limit (LEL)
- The area atmosphere exceeds the protective limits of air purifying respiratory equipment

Required Controls
a) Approved hazard assessment
b) Supplied breathing air 
c) Continuous atmospheric testing
d) Entrants and Monitors trained in the use of supplied breathing apparatus
e) PPE as per hazard assessment
f) Qualified Confined Space Monitor in attendance at all times
g) A specific Rescue Plan approved by the equipment owner and the Emergency Response Representative
h) Valid Confined Space Entry Permit
i) Valid Level One Entry Tag at each entrance
j) Documented Evacuation Plan
k) Confined Space signage as per the Level of Entry

Note: Any time a Level 1 entrance is left unattended the entrance must be barricaded physically and a "Danger, Do Not Enter" sign hung at the entrance. This sign overrides all other signs at the entrance of the confined space. 

Confined Space Level 2
A Confined Space that is not Immediately Dangerous to Life or Health, but has the potential for causing injury or illness if preventative measures are not used. 

Characteristics
A confined space will be considered Level 2 if all identified hazards are controlled and the following applies:
a) Oxygen concentration is between 19.5% and 23.0% by volume; and
b) Either of the following exists or is likely to exist:
- Explosive or flammable atmosphere greater than 1% and less than 10% Lower Explosive Limit (LEL)
- Concentration of toxic substances exceeds 50% of the Occupational Exposure Limit (OEL)

Required Controls
a) Approved hazard assessment
b) Qualified Confined Space Monitor in attendance at all times
c) Valid Confined Space Entry Permit
d) Valid Safe Entry tag at each entrance
e) Documented Evacuation Plan
f) Valid Rescue Plan
g) PPE as per hazard assessment
h) Continuous atmospheric testing if there is potential for the atmosphere to change unpredictably
i) Confined Space signage as per the Level of Entry

Note: A "Confined Space Monitor and Permit Required for Entry" sign is used to signify a space is safe to enter PROVIDED you are authorized to enter, have a valid permit and there is a Confined Space Monitor present at the entrance. 

Confined Space Level 3
A confined space in which the potential danger to life or health would not require any special modifications of the work procedure. 

Characteristics
A confined space will be considered Level 3 if all identified hazards are controlled, the potential for change is unlikely and all of the following apply: 
a) Oxygen concentration is between 19.5% and 23.0% by volume
b) Concentration of explosive gases is less than 1% of LEL
c) Airborne concentration of toxic substances is less than 50% of OEL

Controls Required
a) Approved hazard assessment
b) Qualified Confined Space Monitor may be required
c) Valid Confined Space Entry Permit
d) Valid Safe Entry tag at each entrance
e) Documented Evacuation Plan
f) Valid Rescue Plan
g) PPE as per hazard assessment
h) Confined Space signage as per the Level of Entry

Note: If the hazard assessment determines that a Confined Space Monitor is not required, a competent worker must be designated to be in communication with the worker(s) in the confined space. 

A "Confined Space Permit Required for Entry" sign must be used at the entry where a Confined Space Monitor is not required.  
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