Confined Space Hazards

We Will Discuss: Types of confined spaces Confined space hazards Physical reactions to atmospheric hazards Methods of eliminating or controlling hazards

Typical Confined Spaces Utility Vault Culvert Trenches Manhole Pit Pipeline Pumping Station Septic Tank Silo Storage Tank Barges Sewer

General Safety Hazards Mechanical hazards Communication problems Entry and exit Physical Thermal effects Noise Vibration General / physical Surface residues Structural hazards Fall hazards Engulfment hazards

Atmospheric Hazards Oxygen Deficient Atmospheres Less than 19.5% by volume Oxygen Enriched Atmospheres Greater than 23.5% by volume Flammable Atmospheres Toxic Atmospheres

Asphyxiation Is the Leading Cause of Death in Confined Spaces.

Oxygen Deficiency Can Be Caused by CONSUMPTION. “Hot work” Breathing Chemical reactions (ex. Oxidation of chemicals or metal) Biological action (ex. Decomposing organic matter)

Oxygen Deficiency Can Be Caused by DISPLACEMENT. Argon Nitrogen Helium Carbon monoxide, carbon dioxide Cleaning agents, adhesives, or other chemicals

Oxygen Deficient Atmospheres 19.5 % Minimum acceptable oxygen level 15 - 19% Decreased ability to work strenuously, Impaired coordination 12-14% Respiration increases, Impaired judgment 10-12% Resp. increases, poor judgment, lips blue 8-10% Mental failure, fainting, unconsciousness, nausea and vomiting 6-8% 8 minutes – 100% fatal / 6 minutes - 50% fatal / 4-5 minutes - possible recovery 4-6% Coma in 45 seconds, death

Oxygen Enriched Atmospheres Oxygen level above 23.5%. Causes flammable and combustible materials to burn violently when ignited. Hair, clothing, materials, etc. Oil soaked clothing and materials. Never use pure oxygen to ventilate. Never store or place compressed tanks in a confined space.

Toxic Atmospheres Product stored in a confined space: Gases released when cleaning. Materials absorbed into walls of confined space. Decomposition of materials in the confined space. Work performed in a confined space: Welding, cutting, brazing, soldering. Painting, scraping, sanding, degreasing. Sealing, bonding, melting. Areas adjacent to a confined space.

Carbon Monoxide Odorless, colorless chemical asphyxiant / flammable gas / by-product of combustion PPM Effect Time 35 Permissible Exposure Level 8 hours 200 Slight headache, discomfort 2-3 hours 400 Headache and nausea 1-2 hours 800 Headache, dizziness, nausea 45 min. 1,600 Headache, dizziness, nausea 20 min. 3,200 Headache and dizziness 5-10 min. 6,400 Headache and dizziness 1-2 min.

Hydrogen Sulfide Very strong asphyxiant w/ rotten egg odor / flammable gas / by-product of the decomposition of organic matter / 4 times heavier than air PPM Effect Time 10 Permissible Exposure Level 8 hours 50 - 100 Mild Irritation - eyes, throat 1 hour 100 Desensitizes olfactory nerve 2-5 min. 250 - 350 Unconsciousness, death 4-8 hrs. 500 -600 Unconsciousness, death 30-60 min. >1000 Unconsciousness, death minutes

Flammable Atmospheres Critical Factors: Oxygen content in the air. Flammable gases or vapors Flammable dust (visibility of 5’ or less) Proper air/gas mixture can lead to explosion Typical Ignition Sources: Sparking or electric tool. Welding / cutting operations. Smoking

Lower Explosive Limit vs. Upper Explosive Limit AIR COMBUSTIBLE TOO LEAN TO BURN EXPLOSIVE RANGE TOO RICH TO BURN LEL UEL Gasoline 1.4% Flammable range 7.6% by volume 0% 100% 0% 100% LEL

Causes of Fatalities in Confined Spaces 65% Hazardous atmospheres 13% Engulfment 7% Struck by falling objects 6% Heat stress / exposure 5% Electrocution 4% All others

Common Factors in Confined Space Fatalities Failure to recognize a confined space Failure to recognize the hazards involved in confined space entry Tendency to trust physical senses Tendency to under-estimate the danger. Complacent attitude Attempt to save a co-worker

All Confined Space Fatalities Occur Approximately 60% of All Confined Space Fatalities Occur Among Would Be Rescuers!!

Confined Space Fatalities Can Be Avoided Through Confined space safety training The implementation of a systematic approach to confined space entry

Training and Education All workers who must enter confined spaces All attendants and rescue team members. Prior to initial work assignment. Retraining: Job duties change. Change in permit-space program. New hazards are present. Job performance indicates deficiencies.

Systematic Approach 1. Recognition 2. Testing, evaluation and monitoring 3. Control

Recognition 1. Is this a confined space? 2. Is it a permit required confined space? 3. What are the hazards associated with this space?

Testing, Evaluation and Monitoring Test the atmosphere before entry! Evaluate: methods for isolating the space safe entry procedures special tools needed communication equipment needed Monitor the atmosphere continuously to determine any changes

Testing The Atmosphere 1910.146 App. A Evaluation testing Verification testing Test for at least the minimum response time of the instrument Order of testing Oxygen Combustibles Toxics Stratified atmospheres

Always test the air at various levels to be sure that the entire space is safe. Good Air Poor Air Good air near the opening does NOT mean there is good air at the bottom! Deadly Air

IDLH Immediately Dangerous to Life or Health All Confined Spaces should be considered IDLH until proven otherwise!

Acceptable Atmospheric Conditions Oxygen concentration Flammable gas, vapor, or mist Toxic gas, vapor, or mist 19.5% to 23.5% below 10% of the products LEL below the PEL of the product

Approximately 1/3rd of All Confined Space Fatalities Occur After the Space Has Been Tested Safe for Entry.

Control Ventilation Isolation PPE / Respirators Stand-by rescue Entry permitting