Confined space by meaning itself means that very limited or closed area. From the definition, what can be seen that something present in very few quantity which is oxygen in this case. This is the term used in oil, gas, and petrochemical industry. This is actually as requirement for personnel when dealing with entrance of the unit operation. All the personnel that involved must have entrance permit to confined space which will be issued by the doctor examined the personnel to assure that he/she is fit to conduct the job.
This confined space must be blown with air by blower in order to sustain the oxygen content so that personnel inside can breathe as usual. Besides, when entering the confined space, personnel must present their identification card to hole watcher or safety officer. This is mainly because of the safety consideration that needs to be addressed so that can monitor number of the personnel in that particular equipment to avoid crowd.
People might be asking why respective personnel need to enter the equipments and when they have to. This is mainly done during turn-around where the plant (mainly downstream) will be shutdown as planned shutdown to inspect the equipments such as vessels, towers, reactors, etc. It is not only conducted during planned shutdown but also unplanned whereby unwanted scenario happens. This is basically happens during plant upset or any unit operation upset due to any failure, rupture, leakage, etc. Therefore, there must be somebody need to go in the affected equipment(s) to inspect any findings could be observed. From the findings found, there would be some initiatives to be taken to rectify the problem and come out with plan to prevent in future.
People might be asking also why need to go inside the equipment even there are monitoring (corrosion) points as given the diagram below. Unit operation might have all those indicators but most of the time the indicators only can show us the result of from the impact such high pressure drop, off-spec product, corrosion behavior, etc. So, in order to rectify it related personnel from operation, maintenance, and inspection need to go inside to conduct detail study.
Here are sample of the signs that can be seen near to area that classified as confined space and require permit to enter with presence of safety officer.
