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CONFINED SPACE ENTRY

Precautions & Procedures to be followed

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What is a Confined Space?

“Confined Space” means any space by reason of its construction as well as in relation to the nature of work carried therein and where hazards to the persons entering into working inside exist or likely to develop during working

Schedule XIX Pt I, Gujarat Factories Rules 1963

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What is a Confined Space?

Any item of plant, equipment or civil structure enclosing a space at least large enough for a person to bodily enter, and where dangerous fumes, deficiency in oxygen & other unsafe conditions are liable to be present that can pose acute safety and health hazards

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Examples of a Confined Space

1. Closed vessels, reactors, storage tanks, agitated pressure nutche filters, mixers, boilers, big pipelines, large drying ovens

2. Pits, sumps / septic tanks, sewers, manhole, trenches, shafts, tunnels, ducts

This is an indicative list only

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How to identify a Confined Space?

1. It is large enough and so configured that a person can bodily enter and perform work

2. There are limited openings for entry & exit

3. Not designed for continuous occupancy

4. Favorable natural ventilation does not exist

5. Holes on ground with more than 1 m depth, depending on hazard situation

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Types of Hazards in a Confined Space

There are four types of Hazards:

1. Presence of Hazardous Atmosphere

2. Configuration Hazard

3. Engulfment Hazard

4. Conditions Changing from Non Hazardous to Hazardous while working

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Types of Hazards in a Confined Space

There are four types of Hazards:

1. Presence of Hazardous Atmosphere

2. Configuration Hazard

3. Engulfment Hazard

4. Conditions Changing from Non Hazardous to Hazardous while working

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1. Hazardous Atmosphere

Five types of Hazardous Atmospheres:

a) Oxygen Enriched / depleted

b) Presence of Toxic, flammable Gases / liquids

c) Temperature Extremes

d) Presence of Dust

e) Absence of Free flow of air in & out

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1. a) Oxygen Enriched / Depleted

Man can live

• 3 weeks without food

• 3 days without water

• only 3 min without oxygen

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1. a) Oxygen Enriched / Depleted

The acceptable range of Oxygen inside a confined space is between

19.5% to 23.5%

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1. a) Oxygen Enriched / Depleted

Oxygen is required by Human Body to carryout cellular metabolism

Less Oxygen (<19.5%) – Asphyxiation. Death

More Oxygen (>23.5%) – Faster Combustion

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1. a) Oxygen Enriched / Depleted

Oxygen % Impact on Humans19.5 Minimum Acceptable Oxygen Level

15 - 19 Decreased ability to work strenuously. Impair Coordination

12 – 14 Respiration rate increases. Poor Judgment

10 – 12 Lips turn Blue. Gasping for breath

8 –10 Mental failure, Nausea, Vomiting, Fainting.

6 – 8 8 min exposure is fatal, 6 min exposure is 50% fatal, 4-5 min possible recovery

4 – 6 Coma in 40 seconds. Death

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1. a) Oxygen Enriched / Depleted

Most common reason for Oxygen depletion which lead to fatality is:

Accidental use of Nitrogen in place of compressed air for providing forced ventilation

into confined space

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1. a) Oxygen Enriched / Depleted

Enriched Oxygen Atmosphere (> 23.5% O2) can cause flammable & combustible materials to burn quickly & violently when ignited.

CAUTION: NEVER USE PURE O2 FOR VENTILATION

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1. b) Toxic, Flammable Gases / Liquids

Handling of chemicals, reactions can lead to trapping of toxic / flammable gases in a confined space.

Bio decomposition can lead to H2S, Methane in sewage systems.

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1. b) Toxic, Flammable Gases – H2S

H2S ppm Hours Effect on Humans10 8 Permissible Exposure Limit

50 – 100 1 Mild irritation of eyes, throat

200 – 300 1 Significant Irritation

500 – 700 ½ - 1 Unconsciousness, Death

> 1000 Minutes Unconsciousness, Death

0.005 - Odor Threshold Value

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1. b) Toxic, Flammable Gases – CO

CO ppm Hours Effect on Humans50 8 Permissible Exposure Limit

200 3 Slight headache, discomfort

600 1 Headache, discomfort

1000 – 2000 2 Confusion, nausea, headache

1000 – 2000 1 Tendency to stagger

1000 – 2000 ½ Slight heart palpitation

2000 – 2500 ½ Unconscious

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1. c) Temperature Extremes

• Extremely hot or cold spaces

• Warm spaces decreases working efficiency and can make person tired soon. Prone to more mistakes

• Humidity Factors. Increased Fatigue

• Steam heating while cleaning

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1. d) Presence of Dust

• Sensitizing, toxic dusts

• Hampers visibility & work

• Breathing difficulties

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1. e) Absence of free air flow

• Confined space not designed for permanent worker occupancy

• After readying, the space should maintain the characteristics while work is going. Entrant exhales carbon dioxide

• Hence free flow of fresh air is required in & out of the vessel

• Lack of it can lead to build of hazardous atmosphere

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Types of Hazards in a Confined Space

There are four types of Hazards:

1. Presence of Hazardous Atmosphere

2. Configuration Hazard

3. Engulfment Hazard

4. Conditions Changing from Non Hazardous to Hazardous while working

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2. Configuration Hazard

Examples of configuration Hazards:

1. Agitators in reaction vessels

2. Slicks, wet surfaces. Slippery to work

3. Very narrow openings that inhibit emergency evacuation

4. Surface configuration such that toxic residues stick and cleaning prior to entry is difficult

5. Falling objects with top opening vessels.

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2. Configuration Hazard

Configuration Hazards are determined by the structure of the confined space and devices / equipments connected to it.

It is space / equipment specific & hence difficult to list.

All such hazards shall be assessed by visiting the activity site and appropriate preventive measures shall be taken.

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Types of Hazards in a Confined Space

There are four types of Hazards:

1. Presence of Hazardous Atmosphere

2. Configuration Hazard

3. Engulfment Hazard

4. Conditions Changing from Non Hazardous to Hazardous while working

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3. Engulfment Hazard

Engulfment is when the entrant is fully drowned / trapped by falling material, thereby suffocating him. Examples are:

1. A well digger is engulfed by falling sand

2. Powder stored in a hopper above can fill reactor

3. Flooding of confined space

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Types of Hazards in a Confined Space

There are four types of Hazards:

1. Presence of Hazardous Atmosphere

2. Configuration Hazard

3. Engulfment Hazard

4. Conditions Changing from Non Hazardous to Hazardous while working

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4. Changing conditions of space

As work proceeds, the condition of the confined space alters, either due to work or due to presence of the entrant inside:

1. While welding toxic fumes are generated

2. Generation of dust, fumes while scraping or cleaning

3. Human beings exhale CO2 whose concentration can increase, depleting oxygen

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Prepare space FIT for entry

1. Hazards have a potential to acutely affect the entrant and cause injury, even death

2. The entrant must be assured that the confined space has been made safe for entry

3. This process must be controlled through “work permit” and the entry must be approved by competent persons only

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Confined Space Entry: 5 STEPS

1. Assessment through Work Permit

2. Preparation & Certification for entry

3. Precautions while entering

4. Completion & Permit Closure

5. Training

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Confined Space Entry: 5 STEPS

1. Assessment through Work Permit

2. Preparation & Certification for entry

3. Precautions while entering

4. Completion & Permit Closure

5. Training

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1. Assessment through Work Permit

a) Assessment shall be done by authorised person who is conversant with the process & engineering aspects of the confined space after a visit to the location

b) Assess the necessity of entry. Can the intended work be done without entry?

c) If entry is necessary, decontamination requirement, isolation requirement must be specified on permit for implementation

d) Precautions to be taken while entry must be listed in the permit along with PPE requirement

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Confined Space Entry: 5 STEPS

1. Assessment through Work Permit

2. Preparation & Certification for entry

3. Precautions while entering

4. Completion & Permit Closure

5. Training

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2. Preparation & Certification for Entry

a) Permit must be correctly and accurately filled. The location details, purpose for entry and validity period must be clearly mentioned

b) No entry shall be allowed without the permit

c) A permit shall not be valid for more than 8 hours

d) Entry can begin only after the sign of and approval by the authorized person

e) Permit should be closed at the end of work

f) Names of entrant & standby person to be mentioned in permit along with required PPE for entry

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2. Preparation & Certification for Entry

g) Discontinue Processing in the confined space

h) Isolate of confined space from all process & material incoming lines. Physically disconnect or at least provide tail blind

i) If agitators exist, then de energize through electrical lock out. Display cards at place of work & MCC room

j) Clean the space thoroughly and remove all materials liable to present a hazard

k) Ventilate the space with fresh, uncontaminated air. Ventilate at the rate of at least 4 volumes per hour

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2. Preparation & Certification for Entry

l) Test the atmosphere for oxygen concentration & absence of other hazardous fumes. Record observations in permit

m) Test all areas of confined space. Gases heavier than air tend to concentrate at bottoms and vice versa

n) As far as possible, avoid use of breathing apparatus as it becomes cumbersome in emergencies. Level of cleaning must ensure this

o) Ensure the entry hole is sufficient for the person to enter

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Confined Space Entry: 5 STEPS

1. Assessment through Work Permit

2. Preparation & Certification for entry

3. Precautions while entering

4. Completion & Permit Closure

5. Training

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3. Precautions while entering

a) The entrant must be a trained person. He must be aware of hazards and precautions associated with work.

b) A Rescue attendant be provided who will keep a watch on the entrant and who will respond in case of any emergency to the entrant.

c) Rescue attendant must be conversant with emergency procedures

d) A safety harness (belt) to be worn by the entrant to extricate in case of emergency

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3. Precautions while entering

e) Recommended PPE must be worn.

f) Ensure adequate fresh air is supplied during entry

g) Avoid self breather apparatus as it enhances combustibility hazards. First choice is Air mask with fresh air connection

h) Ensure availability of emergency equipment nearby

i) While entry, if there is a need to test the space, it should be done

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Confined Space Entry: 5 STEPS

1. Assessment through Work Permit

2. Preparation & Certification for entry

3. Precautions while entering

4. Completion & Permit Closure

5. Training

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4. Completion & Permit Closure

a) In case of extension, the safety measures taken must be reconfirmed & entry must be re approved

b) Oxygen check must be done afresh after an interruption

c) At the end of the work, the permit must be closed and signed off

d) Before taking the space back for processing, confirm the absence of people in confined space and then close the same

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Confined Space Entry: 5 STEPS

1. Assessment through Work Permit

2. Preparation & Certification for entry

3. Precautions while entering

4. Completion & Permit Closure

5. Training

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5. Training

a) Training to Entrant on all the likely hazards and about his responsibilities

b) Training to Rescue attendant on the same and also on emergency procedures

c) Training to Authorised persons (permit issuers) on Hazard assessment and also on above

d) Training records must be available