CONFINED SPACE SAFETY , HAZARD & CONTROL MEASURES

 Confined Space – Definition, Hazard & Control Measures

Definition :

Confined Space is generally recognized as:

1. Has limited or restricted means of entry or exit.

2. is large enough for a person to enter bodily to perform work.

3. 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.

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 HAZARDS

 CONFINED SPACE ENTRY

A confined space is an enclosed or partially enclosed space that:

1. is not primarily designed or intended for human occupancy
   
2. has a restricted entrance or exit by way of location, size or means 
3. Can represent a risk  for the health and safety of anyone who enters, 

 

Due to one or more of the following factors:

1. ·       its design, construction, location or atmosphere
2. ·       the materials or substances in it
3. ·       work activities being carried out in it, or the
4. ·       mechanical, process and safety hazards present

Confined spaces can be below or above ground. Confined spaces can be found in almost any workplace. A confined space, despite its name, is not necessarily small.

 

CONFINED SPACE HAZARDS

All hazards found in a regular workspace can also be found in a confined space. However, they can be even more hazardous in a confined space than in a regular worksite.

Hazards in confined spaces can include:

·       Poor air quality: There may be an insufficient amount of oxygen for the worker to breathe. The atmosphere might contain a poisonous substance that could make the worker ill or even cause the worker to lose consciousness. Natural ventilation alone will often not be sufficient to maintain breathable quality air.

·       Chemical exposures due to skin contact or ingestion as well as inhalation of 'bad' air.

·       Fire Hazard: There may be an explosive/flammable atmosphere due to flammable liquids and gases and combustible dusts which if ignited would lead to fire or explosion.

·       Process-related hazards such as residual chemicals, release of contents of a supply line.

·       Noise.

·       Safety hazards such as moving parts of equipment, structural hazards, entanglement, slips, and falls.

·       Radiation.

·       Temperature extremes including atmospheric and surface.

·       Shifting or collapse of bulk material.

·       Barrier failure resulting in a flood or release of free-flowing solid.

·       Uncontrolled energy including electrical shock.

·       Visibility.

·       Biological hazards.

CONFINED SPACE - SAFE ENTRY PROCEDURE

Prior to entry into an enclosed space or tank the following procedure should be applied:

a) A Safety meeting should be held prior to the survey to discuss all aspects of safety measures including at least all items below.

b) Entry Permit should be obtained for the space to be entered.

c) Identify the hazards and assess the risks.

e) Evaluate ventilation of the space: - Check that the tank or enclosed space is empty, cleaned and ventilated.

f) Evaluate need for isolation of the space.

g) Ensure that a standby and/or rescue team is in place.

h) Check and evaluate gas measurements taken.

The surveyor should always use his personal gas measuring equipment during the survey.

i) Evaluate need the for precaution against extreme temperature.

j) Evaluate the lighting arrangement.

k) Evaluate if special clothing and/or equipment are required.

A checklist with the items above is recommended to be used for evaluation if the space is safe to enter.

If extensive work is to be carried out within a large space, such as a cargo tank, it is recommended that a full assessment of the tank atmosphere is undertaken after the initial tests have been satisfactorily carried out and recorded. The tank atmosphere should be checked frequently during this entry, with particular attention being placed on testing the work location(s) and places that are inaccessible for testing from the deck. On satisfactory completion of this additional atmosphere test, the results should be recorded as required by the appropriate safety procedure in the Safety Management System.