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2 7.3 HAZARDOUS ATMOSPHERES

3 ENABLING OBJECTIVES DESCRIBE the hazards of flammable or toxic gases and vapors. DESCRIBE the physical characteristics of common gases, solvents and fuels. DESCRIBE shipboard locations of various explosive or toxic gases or mixtures of gases may be encountered. DESCRIBE the sources of explosive or toxic gases in the shipboard environment. Calculate the combined toxicity levels for combined concentrations of harmful gases

4 7.02 HAZARDOUS ATMOSPHERES REFERENCES: (a) 29 CFR , OSHA Permissible Exposure limits (b) NWP , Surface Ship Survivability OPNAVINST (series), NAVOSH Program Manual for Forces Afloat (c) NSTM 074 Vol. 3, Gas Free Engineering

5 WHY ARE TERMS AND DEFINITIONS IMPORTANT? You, the GFE, must be able to use and understand terms Prevents misunderstandings between you, military personnel, and civilian personnel (think liability!) Lends credibility to your qualifications and your program

6 IMMEDIATELY DANGEROUS TO LIFE OR HEALTH (IDLH) Any atmosphere that meets one or more of the following conditions JOxygen content 22% JFlammable vapors at a concentration of 10% or > LEL JPresence of toxicants above NIOSH IDLH limits (Found in Appendix G of 074 Vol. 3)

7 PERMISSIBLE EXPOSURE LIMIT (PEL) The maximum permissible concentration of a toxic agent to which personnel may be exposed. Published by OSHA Based on a TWA for a normal 8-hour day, 40 hour, 7-day week Expressed in parts per million (ppm) Single toxicants only

8 CONFINED SPACE Limited and restricted accesses Lack of natural ventilation May contain or produce hazardous contaminants or oxygen deficiencies or enrichment Not intended for continuous occupancy

9 CONFINED SPACE CHARACTERISTICS Large enough for worker to enter Contains or can contain hazardous atmosphere produced by sludge, chemicals, sewage Laid out so anyone who enters may be trapped or asphyxiated

10 Tanks Voids Interior machinery (boilers, condensers, oil sumps) Non-ventilated storerooms Ventilation & Exhaust ducts CONFINED SPACES

11 Gas Free Engineers: What Are You Testing For? O E T OXYGEN EXPLOSIVES TOXICANTS

12 OXYGEN Normal at Sea Level 22 % 20.9 % 19.5 % 12 % 10 % 8 % 6 % 4 %

13 OXYGEN Wide Awake, Hyper Vigilant 22 % 20.9 % 19.5 % 12 % 10 % 8 % 6 % 4 %

14 OXYGEN > 26 % O2, Spontaneous Combustion Can Occur > 22 % Oxygen is Considered IDLH Due to Exceptional Risk of Fire 22 % 20.9 % 19.5 % 12 % 10 % 8 % 6 % 4 %

15 OXYGEN Loss of Coordination, Loss of Perception, Lack of Judgment < 19.5 % Oxygen Considered IDLH by OSHA -- Entry Requires CO’s Permission 22 % 20.9 % 19.5 % 12 % 10 % 8 % 6 % 4 %

16 OXYGEN Blue Lips, Disorientation 22 % 20.9 % 19.5 % 12 % 10 % 8 % 6 % 4 %

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18 OXYGEN Vomit 22 % 20.9 % 19.5 % 12 % 10 % 8 % 6 % 4 %

19 OXYGEN Unconscious 5 min : Could recover 6 min: 50% Fatal 8 min: 100% Fatal 22 % 20.9 % 19.5 % 12 % 10 % 8 % 6 % 4 %

20 OXYGEN Coma in 40 Seconds 22 % 20.9 % 19.5 % 12 % 10 % 8 % 6 % 4 %

21 OXYGEN Just Remember... Oxygen Levels Greater than 22% or Less than 19.5% are IDLH ! Death X 22 % 20.9 % 19.5 % 12 % 10 % 8 % 6 % 4 %

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23 Reasons for Oxygen deficiency Eductors Eductors Fires Fires Rusting (Oxidation) Rusting (Oxidation) Inerting Inerting Decomposing Organic Matter Decomposing Organic Matter -- Sewage -- Fermentation of grains, sugars, etc. -- Rotting plant or marine life

24 % Vapor Concentration UEL LEL Too Rich Too Lean Explosive Range Explosivity 10% Levels Near LEL Leave No Buffer for Explosive Gas Build-Up Greater Than 10% LEL is Considered IDLH -- and Requires CO’s Permission for Entry EXPLOSIVES

25 Toxic Gas Common Shipboard Hazards Carbon Monoxide Hydrogen Sulfide Halon & Freon Carbon Dioxide Nitrogen Dioxide Methane Hydrogen Ammonia

26 Carbon Dioxide Carbon Monoxide Hydrogen Chloride Hydrogen Cyanide Hydrocarbons

27 Carbon Monoxide (CO) FROM INCOMPLETE COMBUSTION COLORLESS, ODORLESS, TASTELESS LIGHTER THAN AIR SUBTLE ASPHYXIANT FLAMMABLE Where Onboard Ship? P-100s, Post-Fire Atmosphere, Diesel Generators, Paint Drying

28 ORGANIC DECAY COLORLESS GAS ROTTEN EGG SMELL HEAVIER THAN AIR FLAMMABLE Attacks Nerves: Apnea, Coma Anaerobic Organic Decay WHERE H2S HIDES: FIREMAIN AFFF SYSTEM ROTTING FOOD GARBAGE GRINDER SEWAGE SPACES Hydrogen Sulfide (H 2 S): #2 Killer of Sailors

29 AEROBIC: (with oxygen) decomposition and stabilization. ANAROBIC: (without oxygen) decomposition.

30 FREON (R-12, R-113, R-134) Colorless, Odorless, Heavier Than Air NON-FLAMMABLE: RUSSIA USES FREON FOR F/F Frostbite Blunt Asphyxiant, Attacks Nervous System, Dry Land Drowning Colorless, Odorless, Heavier Than Air NON-FLAMMABLE: RUSSIA USES FREON FOR F/F Frostbite Blunt Asphyxiant, Attacks Nervous System, Dry Land Drowning Reefer Decks, A/C Plants Phosgene

31 HALON 1301 (BromoTriFlouroMethane) Colorless, Odorless 5 Times Heavier Than Air Frostbite Attacks Nervous System, Dry Land Drowning Decomposes at High Temps: HF, HCl, HBr

32 HALON % for 10 min: No Health Danger % : Dizziness, Tingling Extremities, Mild Anesthesia > 10 % : Very Dizzy, Nearly Unconscious, Lose Physical & Mental Dexterity

33 Colorless, Odorless, Tasteless, Inert HEAVIER THAN AIR Blunt Asphyxiant NON-FLAMMABLE Carbon Dioxide (CO2) Portable CO2 CO2 Flooding

34 DARK BROWN, PUNGENT GAS CHOKING AGENT -- Absorbed HEAVIER THAN AIR NON FLAMMABLE Nitrogen Dioxide (NO 2 ) Produced From Hot Work, Fires, & Internal Combustion Engines Smoldering Polyester, Wool & Nylon Tank Pressed Up & Heated

35 COLORLESS, ODORLESS GAS LIGHTER THAN AIR EXTREMELY EXPLOSIVE AEROBIC ORGANIC DECAY Methane (CH4)

36 PUNGENT ODOR LIGHTER THAN AIR FLAMMABLE CHOKING AGENT Ammonia (NH3) CLEANING PRODUCTS, URINALS

37 ODORLESS, COLORLESS GAS LIGHTER THAN AIR EXTREMELY EXPLOSIVE Hydrogen (H) LEAD-ACID BATTERIES RUST

38 CMETHANE C-CBUTANE C-C-C-C-CPENTANE C-C-C-C-C-C-C-COCTANE BENZENE TOLUENE XYLENE BENZENE TOLUENE XYLENE Finding Hydrocarbons Fuel Vapors Paints Solvents

39 How do you know what toxicants to test for in a space? Appendix E How do you know what Draeger Tubes are available? Appendix L How do you know the PEL and IDLH limits for Toxicants? Appendix G

40 IDLH Respiratory Protection Optional Respiratory Protection Mandatory (Filter Type Respirator or Supplied Air Respirator as Appropriate) Respiratory Protection Mandatory (Filter Type Respirator or Supplied Air Respirator as Appropriate) Supplied Air Respirator in pressure demand mode (SCBA) or Supplied Air Respirator (SAR)w/ 15 minute backup Air (SCBA) Required Supplied Air Respirator in pressure demand mode (SCBA) or Supplied Air Respirator (SAR)w/ 15 minute backup Air (SCBA) Required PEL

41 UNITY EQUATION “If there is more than one toxicant product in a space undergoing testing, the cumulative effects of the two or more products may be above unity, even though the PELs for any one of the products has not been exceeded.” NSTM (p74-14)

42 UNITY EQUATION C1/T1 + C2/T = 1 WHERE: C is the Measured Concentrations of Toxic Substances and T is the Toxic Limit : PEL or TLV (whichever is lowest)

43 DETERMINE IF THE COMBINED TOXIC EFFECTS OF THE FOLLOWING GASES EXCEEDS THE ALLOWABLE PERMISSIBLE EXPOSURE LIMIT ON A TWA. ACTUALPEL Toluene 80 ppm200 ppm Carbon Monoxide 25 ppm 50 ppm Xylene 40 ppm100 ppm (Remember, C1/T1 + C2/T = 1) UNITY EQUATION

44 Ce/Te + Ct/Tt + Cn/Tn < = 1.3 > 1 SO IT EXCEEDS LIMIT Therefore, Respiratory Protection is Mandatory ACTUALPEL Toluene 80 ppm200 ppm Carbon Monoxide 25 ppm 50 ppm Xylene 40 ppm100 ppm = 1.3 UNITY EQUATION

45 Questions???? SUMMARY – We described the hazards of flammable or toxic gases and vapors. We described the physical characteristics of common gases, solvents and fuels. We described shipboard locations of various explosive or toxic gases or mixtures of gases may be encountered. We described the sources of explosive or toxic gases in the shipboard environment. We calculated the combined toxicity levels for combined concentrations of harmful gases

46 REVIEW Questions - When is the Oxygen Level Considered IDLH? Greater than 22%, Less than 19.5% When are Explosives Considered IDLH? Greater than 10% LEL Name 4 Toxicants that are HEAVIER than Air: CO2, H2S, HALON, FREON Name 3 Toxicants which are LIGHTER than Air: CO, Ammonia, Hydrogen, Methane Name 2 Toxicants that can Cause a Sailor to Choke: Nitrogen Dioxide, Ammonia


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