One of the worlds biggest misconceptions. Confined Space! Small, cramped, little spaces with only one entry point , right?
Wrong! In Ontario a confined space is listed as an enclosed or partially enclosed space, not both designed and constructed for continual human occupancy and may contain an atmosphere hazard. It goes on to say the atmosphere hazard must be immediately dangerous to life and health in that it will cause an immediately life threatening condition or render an entrant unable to exit under their own power.
But what does all this mean?
Well, it means that it doesn't have to have four walls or a roof to be a confined space. Although it may contain an atmosphere hazard. How is this possible? Won't it just float out through the open spaces? Won't the inside air be the same as the outside air if I open it up and leave it for awhile?
This is where we have to remember that gases that may be in the space have different weights to them. So the gases can layer or stratify. Hydrogen sulfide often results from the bacterial break down of sulfites in non-organic matter in the absence of oxygen, such as in swamps and sewers (anaerobic digestion). It also occurs in volcanic gases, natural gas and some well waters. The odor of H2S is commonly misattributed to elemental sulfur, which is in fact odorless. H2S gives an odour akin to rotten eggs or flatulence. H2S is a heavy gas and will locate in the bottom third of a space. You may not even notice it's presence in the upper areas of a space. Other gases are different weights so can be in the top, middle or bottom of the space. Many gases displace oxygen. Opening a space and "airing it out" will not necessarily clear out toxic gases from the space. The space must be tested to determine the presence of gases or lack of oxygen.
Then we have "not both designed and constructed for continual human occupancy". Vague? Not really if we look at the Ministry of Labour Guidelines. The MOl uses the term continuous human occupancy to refer to a space that has been designed and constructed in accordance with recognized codes and standards that contain provisions for structural adequacy, access and egress, ventilation and lighting such that a human could continually occupy that space.
I find this is the most confusing issue of all. Many believe that if there is an atmosphere hazard or potential for one that it must be a confined space. Remember, under the definition it must have both criteria and just an atmosphere hazard does not make it a confined space. That doesn't mean it isn't dangerous to work in that area and still must be controlled for access to and working in that area. You may still need to perform air quality tests and other tests to ensure the safety of the work area. You may still need to have rescue capabilities to get workers out of that area if an event occurs. You may have to do almost everything you would need to do for a confined space except there is no need for a Confined Space Permit. Your employer still needs to do everything reasonable to protect your health and safety. So , bottom line is , the space may not meet all the criteria to be a confined space but still needs assessment to be worked safely.
Now we look at the atmosphere hazard must be immediately dangerous to life and health in that it will cause an immediately life threatening condition or render an entrant unable to exit under their own power. So, something immediate, not an affect in years to come like a carcinogen or that it may do lung or skin damage over the years. These are still covered under the regulations but in different areas than confined space. Immediately Dangerous to Life and Health (IDLH) means just that! Something that is life threatening immediately. It can cause unconsciousness. It can cause severe difficulties breathing or stop breathing. It can cause your heart to stop beating. Immediate danger, not long term. If an atmosphere can render an entrant unable to exit under their own power (i.e: dizziness, fatigue, disorientation etc.) it still falls under the same definition.
So a confined Space? Possibly. Not a confined space but a hazardous work area? Possibly. This is why the regulations call for a complete assessment on the space to determine how to work in this space safely.