What I will be sharing here is to help you identify what a confined space is by giving you scenarios that can help in your decision making.
Requirement under the legal act
If you read the confined space definition carefully, it must meet both of these 2 criteria to be a confined space.
Criteria 1. Any chamber, tank, manhole, vat, silo, pit, pipe, flue or other enclosed space
Criteria 2. It must have dangerous gas that can cause fire/explosion or lack of oxygen or risk of engulfment.
It needs to fulfil not just one, but both criteria.
Criteria 2 includes the job you are going to do later in the enclosed area, whether it will introduce toxic gases, snap up oxygen inside or cause engulfment.
Real life examples
If you go to a normal swimming pool which is basically a big pit with chlorine water, you don’t see anyone calling it a confined space.
But when you remove the chlorine water and pour crude oil inside, immediately everyone calls it a confined space.
So, for something to be called a confined space, it must fulfil the first and second criteria. If only one of the 2 factors exist, it is not a confined space.
This goes the same for a process tank.
If the process tank is newly manufactured, no toxic chemicals are used inside before, it does not fulfil the 2nd point of the confined space mentioned above, basically new.
Then, it is not a confined space even though it is a process tank (this is assuming you do not introduce these hazards in criteria 2 when your workers work inside).
*As a client when you buy a new process tank, always treat it as a confined space because you will never know what chemicals the manufacturer used to polish the insides of the tank to make it look clean for sale. It might have off gases from the chemicals.
If you are a manufacturer and you are confident that nothing toxic is used in the new process tank, then you do not have to treat it as a confined space when you enter. (Again, it depends on what you do inside. If your work produces smoke or gases, then it will be classified as a confined space. If just inspecting using your eyes then it is fine.)
Criteria to be a confined space
So, classification of a confined space is flexible, it can change and it is based on：
- Whether it fits criteria 1 and 2
- What works you are going to do inside
Although you may have put the confined space in the confined space inventory list, you can declassify it as a confined space if the situation does not call for it to be a confined space for that job.
Quoted from Workplace Safety and Health (Confined Spaces) Regulations
