Confined Space – Definition, Hazard & Control measures

           Definition :
Confined Space is generally recognized as:
  • has limited or restricted means of entry or exit.
  • is large enough for a person to enter bodily to perform work.
  • is not design for configured for continuous human occupancy.
 
Examples :

1. Vessel, tanks, furnaces, underground pipe lines, pits and manholes, sewers and drains etc.
2. Excavation more than 1.2 meter.
3. Entry on floating roof tank when roof is 3 meter down.
4. Ac ducting and large diameter pipes.


Confined Space safety
Hazardous atmosphere:
Means an atmosphere that may expose employees to the risk of death, incapacitate, and impairment of ability to self-rescue, injury, or acute illness.
Inert Atmosphere:
The atmosphere is surrounded and dispersed by nitrogen gas where oxygen level going below 5% declared as inert atmosphere.
 
Isolation:
Process by which a confined space area is isolated from service and completely protected against the release of energy and material into the Area by such means as blinding, maligning or removing sections of lines, pipes, or ducts, a double block and bleed system, lockout or tag out of all sources of energy, or blocking or disconnecting all mechanical linkages.
 
Line breaking:
The lines carrying flammable, toxic and corrosive material an inert gas that has chances of causing injuries while working on confined area need to be intentionally cut off or blinded is called as line breaking.
 
Confined Space Hazards:
1.      Oxygen deficiency (less than 19.5%).
2.      Presence of toxic, corrosive or hazardous materials (H2S, Hydrocarbons, NH3, Sulphur and coke dust).
3.      Presence of flammable, combustible, explosive or phosphoric material (e.g. sludge).
4.      Restricted access – a Limited number of entry/exit points (e.g. single manway).
5.      Restricted to freedom of movement inside confined space (e.g. Trays in towers and pipes in excavations).
6.      Falling/tripping hazards.
7.      Poor illumination / visibility / communication.
8.      High temperature and humidity.
9.      Electrical, static or radioactive hazards.
10.  Mechanical Hazards (e.g. tank mixers, falling objects such as tools, refractory).
 
Confined Space Safety precautions:
1.      Confined space entry authorization require with the permit.
2.      Ensure positive isolation of vessel-like line breaking or blinding.
3.      Use multi-lock system for an electrical device if having in confined space.
4.      Confined area shall be free of any combustible or inert gas by means of purging or venting.
5.      Gas testing shall be carried out to ensure toxic/flammable/combustible gases are not present.
6.      Valid confined space entry card is compulsory for worker to work inside.
7.      Personnel H2S gas monitor is required with working crew.
8.      Attendant shall be present with CSE attendant sheet and communication device like radio.
9.      Proper illumination/lighting inside Confined Space must be explosion-proof and should be operated on 24-volt power supply.
10.  Proper ventilation either through natural or fan.
11. Signboard shall be displayed on entry.
12.  Wear appropriate PPE.
 
Confined Space safety
 
Questions:
1.      What are the hazards in ConfinedSpace?
2.      Example and definition of Confinedspace?
3.      Precautions for ConfinedSpace?
4.      What is isolation?
5.      What is inerting?
6.      What is confined space?
7.      ConfinedSpace entrant and attend card validity.

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