Lecture 5 Confined Space Entry.pdf

1 Industrial Safety And Maintenance Management CH-417 Lecture 5 2 Confined Space Large Enough to Enter YES Not a Limited Means Confined of Entry/Exit NO Space YES Not design for...

1 Industrial Safety And Maintenance Management CH-417 Lecture 5 2 Confined Space Large Enough to Enter YES Not a Limited Means Confined of Entry/Exit NO Space YES Not design for 3 Continuous Occupancy Examples Confined Spaces 4 Common Accidents of Confined Spaces 5 Common Accidents of Confined Spaces 6 Common Accidents of Confined Spaces 7 Why Confined Space Training is Necessary? 8 Why? 9 Signs 10 Confined Space Hazards Atmospheric Physical Mechanical 11 Confined Space Hazards Atmospheric Hazards Oxygen deficiency Oxygen-enriched atmospheres Flammable/combustible gases and vapors Toxic gases and Chemicals 12 Atmospheric Hazards Safe Oxygen Level 13 Atmospheric Hazards Oxygen-Deficient Atmospheres Causes of oxygen deficiency  Burning  Oxidation and Rusting  Decomposition of Organic material  Displacement by other gases 14 Atmospheric Hazards Oxygen-Enriched Atmospheres Causes of oxygen enrichment Effects of oxygen enrichment 15 Flammable Atmospheres Presence of 3 critical factors:  Flammable gas, or vapor  Oxygen content in the air  Ignition Source 16 Flammable Atmospheres Proper air/gas mixture can lead to explosion. 17 LFL– Lower Flammable limit UFL- Upper Flammable limit Toxic Atmosphere Occurrence of toxic substances  Product stored in confined space  Improper Isolation  Worked performed in confined space Common toxic chemicals  VOC  H2S  CO  HCL  NO2 18 Toxic gases and Chemicals VOC  Spaces associated with the oil and petrochemical industry  Heavier than air  VOC vapors are often toxic and flammable at very low concentrations  VOC vapors are commonly measured by means of photoionization detector (PID) sensors. 19 Toxic gases and Chemicals Hydrogen Sulfide Decomposition of organic materials, like human waste. Heavier than air Rotten egg odor at low concentrations Possibly no warning at high concentrations Permissible exposure limit is 10ppm for 8 hour 20 Toxic gases and Chemicals Nitrogen dioxide Most toxic substance of diesel emissions usually present in boilers and furnaces. Yellowish-brown gas with pungent odor. Irritation of the nose and throat. Combines with water in lungs to form nitric acid resulting pulmonary edema. 21 Toxic gases and Chemicals Carbon Monoxide Combustion by-product Odorless, colorless gas, slightly lighter than air. Quickly collapse at high concentrations Permissible exposure limit is 50ppm for 8 hour 22 Confined Space Hazards Physical Hazards  Engulfment in solid or liquid.  Extreme temperatures  Insufficient lighting  Noise  Wet surfaces  Falling objects 23  Physical Hazards Engulfment Can cause death by plugging respiratory system Can exert enough force on body to cause death by strangulation, constriction or crushing Example Loose, granular materials stored in bins and hoppers - grain, sand, coal, etc 24 Physical Hazards Extreme temperatures The enclosed nature of a confined space can  Increase the risk of heat stroke  Collapse from heat stress The risk may be intensified by  Personal protective equipment  Lack of ventilation.  Increased humidity 25 Physical Hazards Noise Amplified due to acoustics within the space Damaged hearing, affects communication Wet Surfaces Slips and falls Increased chance of electric shock 26 Physical Hazards Insufficient Lightening Emergency light should be provided to easily locate escape and exits Explosion proof lighting may be required. Falling Objects Topside openings expose workers inside confined space to falling objects 27 Confined Space Hazards Mechanical Hazards Configuration. Grinding, crushing, or mixing mechanisms. 28 Hierarchy of Safety Precaution for Confined Space Work  Eliminate: Avoid entering confined spaces  Prevent: Develop and implement a safe system of work;  Control: Devise Emergency plan. 29 Eliminate Avoid entering confined spaces If the intended work is really necessary or if you could  Modify  Work done from outside 30 Prevention Safe System of Work A competent person should be appointed to  Carry out Risk Assessment  Recommend Safety precaution  Develop Safe system of work 31 Prevention Check list for Safe System of Work  Appoint suitable person for Work  Isolation  Cleaning and Cooling before entry  Check the size of Entrance 32 Prevention Safe System of Work Check list Testing of Air  Provision of Ventilation  Provision for Special tools and lighting  Provision for PPE 33 34 Ventilation 35 Ventilation Remove contaminants heavier than air (eg H2S ) Remove contaminants lighter than air (eg CO) Determination of Purge Time Purge times can be estimated by : 37 T = 7.5 V/C T = purge time in minutes V = the volume of the space in ft3 C = effective blower capacity ft3/min Purging Time Example An estimation of purging time is needed for an 800 ft3 deep neck manhole. The 38 effective blower capacity is 250 CFM. T = 7.5 V/C 800/250 x 7.5 = 24 minutes Testing of Confined Space Duration Testing order 1. Oxygen 2. Combustible gases 3. Toxic gases and vapors. Sampling in layers Document all results 39 Hierarchy of Safety Precaution for Confined Space Work Emergency Exit Plan  Communication  Shutdown  First Aid Procedures  Drill  Emergency Services 40 Types of Confined Spaces 1. Non-Permit 2. Permit Required Entry 41 PERMIT What is the purpose of entry? How much time will be spent working inside the confined space? Who are the people authorized to enter the space? Who will be the attendant that stays outside the confined space? 42 PERMIT What are the atmospheric conditions in the confined space? What are the methods of communication between people inside the confined space and people outside the space? What kinds of equipment are being provided and used for safe entry? 43 PERMIT Are there any additional safety checklists that need to be completed? How have you have eliminated the hazards before you enter the confined space? 44 PERMIT 45 PERMIT 46 PERMIT 47 PERMIT 48 49 Duties of Attendants Knows the hazards. Maintains an accurate count of entrants. Remains outside the permit space until relieved by another attendant. 50 Duties of Attendants Knows the hazards. Maintains an accurate count of entrants. Remains outside the permit space until relieved by another attendant. 51 Duties of Attendants Maintains regular communication with entrants Monitors conditions inside and outside of the permit space.  Summon/Call for rescue services when needed. 52 Duties of Attendants Ensures unauthorized personnel do not enter permit space or affect operations. Performs non-entry rescues Performs no other duties that might interfere with primary duty to monitor and protect the entrant(s). 53 Get Out!  All activities should stop  The worker(s) should exit immediately  The hazard should be evaluated  Protective measures should be taken 54 Always Remember Test the atmosphere prior to entry and periodically. Never enter a confined space if the atmospheric conditions are not suitable. Ensure an attendant is outside the confined space at all times. Follow your company’s confined space 55 permit. 56