Hazardous Atmospheres

Hazardous Atmospheres : 

Hazardous Atmospheres

Confined Spaces : 

Confined Spaces CFR 1910.146 Any space with limited access egress not designed for human occupancy or habitation By definition, NOT safe for people to enter for any sustained period of time!

Confined Spaces : 

Confined Spaces Transport vessels Storage tanks Grain bins Silos Wells and cisterns Manholes Pumping Stations Drainage culverts Pits Hoppers Underground vaults Mines Caves

Confined Spaces : 

Confined Spaces 60% of all confined space fatalities are rescuers!

Common Emergencies : 

Common Emergencies Falls Medical emergencies HAZMAT exposure Oxygen deficiency, asphyxia Explosions Structural, machinery entrapment

Confined Space Hazards : 

Confined Space Hazards Oxygen deficient atmospheres Toxic/explosive chemicals Engulfment Machinery Electricity Structural concerns

Oxygen Deficient Atmospheres : 

Oxygen Deficient Atmospheres Limited ventilation Decaying organic matter Presence of heavier-than-air gases O2 levels will have to be monitored before entry Ventilation systems may have to be set up to improve air exchanges

Toxic/Explosive Chemicals : 

Toxic/Explosive Chemicals CO2 (carbon dioxide) CO (carbon monoxide) CH4 (methane) H2S (hydrogen sulfide) NH3 (ammonia) Cl2 (chlorine) NO2 (nitrogen dioxide) N2O4 (nitrogen tetroxide) O2 (oxygen) Explosive dusts (grain, coal, metal)

Engulfment : 

Engulfment Risk of burial in grain, sand, coal, other particulate solids Risk of explosions from finely-divided particulates

Machinery : 

Machinery Augers Mixing blades Motors

Electricity : 

Electricity Risk for live current, stored energy Safety procedures Blank out all power to site Dissipate all stored charge Lock-out, tag-out all switches, breakers Ventilate area thoroughly

Structural Concerns : 

Structural Concerns Non-cylindrical shapes Space limiting support structures Limited light Restrictions on SCBA use because of space shape, size Personnel may have to resort to air lines Full-body harnesses may be needed in case emergency retrieval necessary

Workplace Protections : 

Workplace Protections Employers must develop rescue program with trained personnel Personnel who work in/around confined spaces trained in hazards Entry controlled by permit Atmospheric monitoring PPE, retrieval equipment Warning signs Detailed hazard information available on site

Rescuer Risks : 

Rescuer Risks Greatest danger is non-permitted sites (cisterns, culverts, natural caves) Do NOT enter or allow entry unless appropriately trained, equipped for specific environment

Trench Collapses : 

Trench Collapses

Trench Collapses : 

Trench Collapses Most involve trenches <12 feet wide and <6 feet deep Cubic foot of typical soil weighs 100 pounds Two feet of soil on patient’s chest, back can weigh 700 to 1000 pounds!

Reasons for Trench Collapses : 

Reasons for Trench Collapses Disregard of regulations Improper/absent shoring Spoil pile too close to trench Water seepage Ground vibration Previously disturbed soil

Trench Collapse Procedures : 

Trench Collapse Procedures Secure scene, perimeter Establish command Call for trench rescue team Interview on-site supervisor, witnesses Number of patients? Extent of entrapment/burial?

Trench Collapse Procedures : 

Trench Collapse Procedures Unnecessary personnel, equipment away from trench edges Trench properly shored before rescue begins Personnel in trench wear helmets, protective clothing Use hand-tools, not heavy equipment Determine location of ALL underground utility lines on site

Trench Collapse Procedures : 

Trench Collapse Procedures Priority--uncover patient’s face, chest; begin oxygen administration Keep weight away from patient’s chest Lie flat, stand on planks to spread weight, avoid compressing patient’s chest Do NOT pull on patient at any time Consider crush syndrome during prolonged rescues

Structural Collapses : 

Structural Collapses

Structural Collapse Procedures : 

Structural Collapse Procedures Secure scene, perimeter Establish command Carefully size up situation Consider nature of occupancy, time of day to assess extent of problem Interview bystanders, rescued occupants

Structure Collapse Hazards : 

Structure Collapse Hazards Broken water pipes May flood basements, other low areas Water may have to be shut off at meter, at street, or at main Pumping equipment may be needed to clear out flooded areas

Structure Collapse Hazards : 

Structure Collapse Hazards Domestic Gas Risk of fire, explosion, asphyxiation in closed spaces Service may have to be discontinued at meter, street, or main Discontinuation of gas service to large area requires house-by-house restoration to relight pilot lights

Structure Collapse Hazards : 

Structure Collapse Hazards Electricity All wires assumed to be energized Live wires handled by electric company personnel Electricity shut off at master switch near meter or fuse box or killed at pole by electric company personnel

Structure Collapse Hazards : 

Structure Collapse Hazards Sewers Flooding Escaping gases (toxic, flammable) Risk of exposure to pathogens

Structural Collapse Procedures : 

Structural Collapse Procedures Stage I: Immediate Rescue Persons who can be seen, heard Persons trapped in voids, other areas where their exact location is known

Structural Collapse Procedures : 

Structural Collapse Procedures Stage II: Exploration Searching places where trapped persons are likely to be found: Specially constructed shelters Under stairways Basements Near chimneys Spaces under partially collapsed floors Rooms with exits blocked by debris Fringe areas around explosions

Structural Collapse Procedures : 

Structural Collapse Procedures Stage III: Selected Debris Removal Takes place when persons are known to be missing but cannot be seen, heard Based on some combination of: Person’s last known location Location, condition of debris Direction person may have fallen in collapse Location of voids “Calling and listening” Removal of debris up to probably location of persons

Structural Collapse Procedures : 

Structural Collapse Procedures Stage IV: General Debris Removal Used if persons still missing after all other stages completed Consists of systematically stripping area Must be done carefully, methodically May require heavy equipment use NOT to be confused with site clean-up

Types of Collapses : 

Types of Collapses Lean To Pancake V-Type

Lean-To Collapse : 

Lean-To Collapse Sections collapse on one side, remain supported on other Produces large void on supported side Enter void on side where wreckage is supported Do not disturb debris

V-Type Collapse : 

V-Type Collapse Occurs when heavy loads are concentrated near center of floor Enter voids along walls Wreckage must be stabilized before trying to remove debris

Pancake Collapse : 

Pancake Collapse Floors collapse one of top of another onto lower floors or basement Voids are small, locations cannot be predicted Use “call and listen” method before removing debris