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Basic Air Monitoring PPT-045-01 1 Bureau of Workers Comp PA Training for Health & Safety (PATHS)

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1 Basic Air Monitoring PPT-045-01 1 Bureau of Workers Comp PA Training for Health & Safety (PATHS)

2 Program Purpose PPT-045-01 2 Various means of detection exist for solids, liquids and gases. This program is an overview of monitoring the means to be used in some safety applications or to aid in responding to an event.

3 Main Topics PPT-045-01 3 Hazards Chemical and physical properties of target materials Some gas properties Resources Propane as an example Detector types Calibrating detectors Field monitoring Sewer entry policy as an example Working a situation Bibliography

4 Hazardous Atmospheres PPT-045-01 4 Residential CO (carbon monoxide) Gas leaks into buildings Radon Intruding emissions from adjacent properties

5 Hazardous Atmospheres PPT-045-01 5 Industrial Process areas Storage locations Gas leaks Flammable liquid spills Drums and containers Special activities Hazardous material events

6 Municipal Operations PPT-045-01 6 Water treatment plants Sewer plant operations Valve pit work Garage work

7 Specific Field Work PPT-045-01 7 Confined space Trenching and shoring

8 Environmental Issues PPT-045-01 8 Clean air determinations Emissions control Waste sites

9 Emergency Response PPT-045-01 9 Industrial rescue or hazardous materials response Emergency services

10 Hazardous Atmospheres PPT-045-01 10 Special types of atmospheres Carbon monoxide LGP/LNG Radon Hydrogen sulfide Carbon dioxide Specialty gases Radiological concerns Other potential hazards

11 Basic Air Monitoring PPT-045-01 11 Each of the previous situations could benefit from air monitoring. Detectors are generally used to determine: –Oxygen content –Presence of flammable vapors or gases –Presence of toxic materials Terms pertaining to characteristics of materials for which monitoring might be used should be discussed first.

12 Hazard Property Terms PPT-045-01 12 IDLH: Immediately dangerous to life and health values Exposure Limits: OSHA PEL: permissible exposure limits TWA: Time weighted average limits expressed in PPM which should not be exceeded during an 8-hour work shift in a 40-hour work week PPM: Parts per million. Can be converted into percentage by volume by dividing the PPM given by 10,000.

13 Chemical & Physical Properties PPT-045-01 13 MW: Molecular weight will help you determine if the vapor or gas is heavier or lighter than air; the vapor density. Vapor density can be determined by dividing the material’s molecular weight by 29: MW 29

14 Vapor Density PPT-045-01 14 A comparison of a gas or vapor’s weight to air Air is assigned a vapor density of 1.0 Gases or vapors with a vapor density greater than 1.0 are that many times heavier than air. Gases or vapors with a vapor density less than 1.0 are lighter than air. This will help you determine if you will monitor high or low in an area to obtain a reading. May also be expressed as RGasD: relative gas density

15 Flashpoint Temperature PPT-045-01 15 Fl.P.: Flashpoint The lowest temperature at which vapors are produced by a liquid that, when ignited, will flash No continued combustion at this temperature Sustained burning is at the fire point (temperature above the flashpoint temperature)

16 IP PPT-045-01 16 IP: Ionization potential in electron volts (eV) for a vapor or gas This will signify a photoionization detector may be used to detect the presence of material Lamp rating must be at or greater than IP of test gas or vapor for a precise reading

17 Hazard Characteristics PPT-045-01 17 Before starting, fully understand the hazards of the material for which you’ll monitor: Vapor density Flammable limits Health hazards Exposure limits Signs and symptoms of exposure

18 RGasD PPT-045-01 18 RGasD: Relative gas density will indicate if gas/vapor is heavier or lighter than air If we divide the MW by 29 (the weight of air) this should also approximate the vapor density of the gas/vapor

19 Gas/Vapor Behavior PPT-045-01 19 Gases can stratify in air based on their vapor density Take readings from various depths and points in below-grade situations You may need to take readings in rooms at different elevations and points as well

20 LEL/UEL PPT-045-01 20 UEL/LEL: Upper and lower explosive limit Range in between is the flammable range Safety Rule of Thumb Monitor until you find 10 percent of the LEL inside a building Outside: stop when you determine 20 percent LEL is evident

21 UEL/LEL PPT-045-01 21 Will aid in determining the perimeter and extent of gas/vapor spread (100 percent of LEL, dangerous) Only ignition source needed to ignite gas/vapor You do not want to be within a flammable environment!

22 Respirator PPT-045-01 22 NIOSH Respirator recommendations assist in determining the level of needed respiratory protection depending upon the PPM (Mg/M 3 ) for a material

23 Asphyxiation Hazards PPT-045-01 23 Simple Asphyxiants: Displace breathable oxygen in an area (example: carbon dioxide) Chemical Asphyxiants: Bond with red blood cells and restrict the body’s ability to metabolize oxygen (examples: carbon monoxide and hydrogen cyanide)

24 Some Gas Particulars PPT-045-01 24 IDLH IP Gas LEL% (10%LEL) PPM % in eV Carbon Monoxide12.51.251,500.1513.98 Hydrogen Cyanide 5.6.5650.00513.6 Hydrogen Sulfide 4.3.43300.0310.46 LPG 1.9.1919,0001.910.95

25 Carbon Monoxide PPT-045-01 25 IDLH1200 ppm PELTWA 50 ppm IP14.01 eV RGasD.97 LEL12.5% UEL74%

26 LPG/LNG PPT-045-01 26 IDLH2000 PPM (10% LEL) PEL1000 PPM IP10.95 eV RGasD1.45 – 2.0 LEL2.1% (propane) 1.9% (butane) UEL9.5% (propane) 8.5% (butane) Sa/SCBA2000 PPM

27 Hydrogen Sulfide PPT-045-01 27 IDLH 100 ppm PEL C 20 ppm* 50 ppm (10 min max peak) IP10.46 eV RGasD1.19 LEL4.0% UEL44.0% Sa/SCBA100 ppm *C=ceiling level value

28 Carbon Dioxide PPT-045-01 28 IDLH40,000 ppm (4%) PELTWA 5000 ppm (.5%) 8 hours IP13.77 eV RGasD1.53 LEL/UELNon-flammable gas Sa/SCBAYes

29 Carbon Dioxide PPT-045-01 29 CO2 %Max Exposure By VolumeLimit, Minutes 0.5 Indefinite 1.0 Indefinite 1.5 480 2.0 60 3.0 20 4.0 10 5.0 7 6.0 5 7.0 Less than 3 Compressed Gas Assn. Handbook, 3 rd Ed, page 293 A Total Flood carbon dioxide system will displace the breathable oxygen and asphyxiate those inside

30 Other Potential Hazards PPT-045-01 30 Caution: Many materials have several hazards associated with them. Some may be flammable and possess poisonous characteristics. Toxic and corrosive gases may be encountered. Example: Hydrogen sulfide (H 2 S) deadens the sense of smell and may falsely lead someone to think it has dissipated. (LEL and UEL are 4 percent to 44 percent, respectively - flammable and poison)

31 Specialty Gases PPT-045-01 31 Specialty Gases Boron trichloride Diborane Phosphine Silane Radiological Hazards Radon Industrial events

32 Action Levels PPT-045-01 32 Assigned by policy When a given level is read, personnel are warned to take action or to leave the area 29 CFR 1910.146 for confined spaces. 10 percent LEL: permit revocation Determine action levels for gases/vapors you may encounter

33 Resources PPT-045-01 33 Safety Data Sheets (SDS) NFPA standards (National Fire Protection Association) NFPA Fire Protection Handbook

34 Resources PPT-045-01 34 Technical manuals: Sax’s “Dangerous Properties of Industrial Materials” Emergency guides: “Emergency Response Guidebook” Each cited source has valuable information toward monitor planning

35 Resources PPT-045-01 35 “NIOSH Pocket Guide to Chemical Hazards” The following slides give an overview of the NIOSH categories to aid in your monitoring operations

36 NIOSH Information Categories PPT-045-01 36 Name of material Formula CAS# RTECS# IDLH Conversion: PPM to Mg/M 3 Synonyms/trade names Exposure Limits Measurement methods Chemical and physical properties PPE Respirator recommendations

37 NIOSH Categories PPT-045-01 37 Incompatibilities and reactivities Exposure routes, symptoms, target organs First aid

38 Propane as an Example PPT-045-01 38 Using Selected Categories: –Formula: CH 3 CH 2 CH 3 –CAS#: Chemical abstract service number 74-98-6 –RTECS#: Registry of toxic effects of chemical substances TX2275000 –IDLH: 2100 PPM (10% LEL) –Conversion: 1ppm = 1.80 mg/m 3 –OSHA PEL: TWA 1000 PPM (1800 Mg/M 3 ). 1000 PPM/10,000=0.1 percent

39 Propane as an Example PPT-045-01 39 Physical Description MW (Molecular Weight): 44.1 (44.1/29=1.52 vapor density) Fl.P (Flashpoint): NA (Not applicable due to being a gas) IP (Ionization Potential): 11.07 eV. A photoionization detector could be used to detect propane as long as the lamp used has an ionization energy greater than the IP of the material

40 Propane PPT-045-01 40 RGasD: Relative gas density; heavier or lighter than air Propane has an RGasD of 1.52 making it 1.52 times heavier than air Monitor low in an area Propane is a hydrocarbon and will “huddle” in confined areas Always be thorough in your monitoring

41 Propane PPT-045-01 41 UEL/LEL: 9.5 percent to 2.1 percent. If monitoring to stop when 10 percent by volume is found, 10 percent of the LEL of 2.1 percent is.21 percent Respirator recommendations for propane: (NIOSH) SA (supplied air) and/or SCBA (self- contained breathing apparatus) at or above 2100 PPM

42 Detectors PPT-045-01 42 General types include: Passive badges and dosimeters Tubes/pumps Combustible gas indicator (CGI) Single gas Multiple gas Flame ionization detector (FID) Photoionization detector (PID) Radiological

43 Dosimeters PPT-045-01 43 Passive Monitors Permeation of gases through a membrane onto a collection medium Film Badge Desorbed with carbon disulfide Analyzed by gas chromatograph *Air Monitoring for Toxic Exposures,” Shirley A. Ness, Van Nostrand Reinhold, 1991, page 85

44 Tubes PPT-045-01 44 Test atmosphere is drawn into tube Tubes are gas/vapor specific Presence of gas/vapor changes reagent color in tube PPM and percentage gradients on tube indicate amount of gas/vapor in atmosphere

45 Tubes and Pumps PPT-045-01 45 Specific number of pump strokes required for precise reading if using a manual pump Pump assemblies are calibrated to draw either 50cc or 100cc on each stroke when set

46 Solid State Sensors PPT-045-01 46 Semiconductors can be used for: –General survey monitors –Specific gases and hydrocarbons –Toxic gases Reads electrical resistance decreases across a Wheatstone bridge

47 Combustible Gas Indicators PPT-045-01 47 Also called CGIs Catalytic combustion Voltage drop is read across a Wheatstone bridge

48 Single Gas PPT-045-01 48 Sensor is gas-specific Electro-chemical principle Chemical specificity is due to electrodes and electrolytes used “Ticker” used by gas companies specific to their product Note sensing he ad

49 Multiple Gas PPT-045-01 49 Visual and audible alarms Specific detector heads may be incorporated based on your hazards This one detects: Oxygen content Percent LEL Carbon monoxide Hydrogen sulfide

50 Multiple Gas PPT-045-01 50 Read oxygen level first to verify correct level between 19.5 percent to 23.5 percent or reading for LEL will be incorrect for the challenge gas/vapor

51 Multiple Gas PPT-045-01 51 With pump for wand attachment –May be delay in sample reading based on length of sampling wand/hose –Monitor slowly so as to not wander into hazard zone Without pump it will still detect, but as a diffusion detector With Pump and wand port

52 Multiple Gas PPT-045-01 52 Pump brings in a measured volume of air to be tested More exact than hand pump Without pump the measurement is dependent upon the amount of ambient air coming into contact with sensing heads With Pump: Drawn sample is more exact Without Pump: Diffusion

53 Flame Ionization Detector PPT-045-01 53 Also called FID OVA (organic vapor analyzer) Carbon counter Current corresponds to positive ion collection count Organics ionized by a hydrogen flame (not by a lamp like the PID) and counted

54 Photoionization Detector PPT-045-01 54 Also called PIDs Can be hand-held or used to monitor a fixed location Reads most organic and some inorganic compounds UV (Ultraviolet) lamp converts ionizing materials to electric signal (not a flame like the FID)

55 Radiological PPT-045-01 55 Personal dosimeters -Self-readers -Dosimeters Radiation field units also read: - Alpha -Beta -Gamma -Neutron

56 Radiological PPT-045-01 56 Radiation causes ionization in the detecting media Ions produced are counted electronically Relationship established between number of ionizing events and quantity of radiation present

57 Radiological PPT-045-01 57 Detector Detects Ion detection tubes Gamma and X-radiation Proportional detection tubesAlpha Geiger-Mueller tubesGamma and/or Beta Scintillation detectionAlpha or Gamma

58 Other Detection Means PPT-045-01 58 Samples are obtained by either: Bag sample or Swipe sample Then subjected to sophisticated equipment (e.g., gas chromatographs and spectrophotometers) Each of these has its merits, but can be time-consuming Gas Chromatograph Spectrophotometer

59 Detector Safety PPT-045-01 59 Intrinsically safe: unit won’t contribute an ignition source; per NEC (national electrical code) rated for various class, group and division uses Class: type of flammable material Group: types of gases or vapors Division: location of the atmosphere

60 Detector Safety PPT-045-01 60 Explosion proof: allows entrance of flammable gases but is built to contain an explosion

61 Calibration PPT-045-01 61 Why calibrate? “The calibration check is the only way to determine the meter is working properly.” Some calibration gases: -Methane -Pentane -Hexane Check user’s manual Carol J. Maslansky & Steven P. Maslansky, “Air Monitoring Instrumentation,” Van Nostrand Reinhold, 1993, page 73

62 Calibration PPT-045-01 62 Calibrate detector on a scheduled basis and before use to ensure readiness Calibration gas can contain various PPM of selected gases for a single connection and calibration of multiple heads Calibration assures detector will function within necessary parameters for accurate readings

63 Calibration PPT-045-01 63 Dosimeter Air check on combustible gas meter

64 Calibration Means PPT-045-01 64 Multigas: replace detector heads or calibrate with gas CGI: calibration gas FID: electronically zeroed PID: calibrated with gas of known PPM. Adjustments made using a span potentiometer to fine tune monitor; a new lamp may also be used

65 Match Detector to Hazard PPT-045-01 65 Match the detector to the hazard! In one situation, a field team used a CGI in an acid spill atmosphere Detector heads were “poisoned” due to contact with the acid vapor Detector heads had to be replaced and unit overhauled

66 Detector Heads PPT-045-01 66 Rated for the type of hazard Sampling range is also important Intrinsically safe for specific atmosphere?

67 Capabilities and Limitations PPT-045-01 67 Presence of several vapors or gases in the same atmosphere may mask individual readings Time required to read a sample Some detectors are not meant to enter into a flammable atmosphere; they may serve as the ignition source Ensure your detector is “intrinsically safe” Temperature and humidity may affect readings Altitude may affect reading Obtain a monitor with the greatest versatility

68 Minimum Response Time PPT-045-01 68 This is the time for the sample to be drawn into the equipment and for the sensor to react to the chemical if it is present. Add time to "minimum response time" if you have attached a hose or probe extension to the inlet. Some units indicate that 5 to 8 seconds per foot of attachment might be required before the sample is drawn into the sampling chamber of the detector. Check manufacturer’s specifications with the unit. OSHA Fact Sheet, DSTM 9/2005 pertaining to Confined Space Entry

69 Conversion Factors PPT-045-01 69 Conversion factors (also referred to as relative response): Used to correct detector readings for gases other than calibrating gas. Some gases/vapors are either hot-burning or cold-burning gases. This indicates how rapidly or slowly the sample releases its heat relative to the calibration gas in the meter’s sampling chamber. The calibrating gas (calibration standard) creates a straight line on the graph relative to its heat release.

70 Conversion Factors PPT-045-0 1 70 In sampling, the heat release of the calibrating gas will rise in a straight line across the graph. If monitoring for the gas with which the detector was calibrated, i.e., Methane, the reading will need no conversion adjustment. Hot Burning Gas Cold Burning Gas

71 Conversion Factor PPT-045-01 71 Hot-burning gases will travel more immediately up on the graph. Their conversion factor will be less than 1.0 Cold-burning gases travel beneath the calibration gas on the graph. Their conversion factors will be greater than 1.0 to adjust the reading Hot Burning Gas: CF <1.0 Cold Burning Gas: CF >1.0

72 Conversion Factor: Example PPT-045-01 72 Example: You obtain a meter reading for a gas of 15 percent LEL - the conversion factor for the gas is 2.5 due to it being a cold-burning gas To obtain a true reading: 2.5 x 15 percent=37.5 percent This is a dangerous atmosphere that you may wish to vacate immediately You could be entering a highly flammable area

73 Reading PPT-045-01 73 Knowing the correction factor, determine the meter reading Example: your true meter reading should not exceed 80 PPM; the gas’s correction factor is.8 True meter reading of 80 PPM divided by CF of.8 = Monitor until meter reads 100 PPM True Reading (80 PPM) Meter Correction Reading X Factor (100 PPM) (.8)

74 Reading PPT-045-01 74 True Meter Reading (125 PPM) Meter Correction Reading X Factor (138 PPM) (.9) Another example: The exposure limit for a gas should not exceed 125 PPM The correction factor for the gas reading is.9 So, monitor until your meter reads 138 PPM (Divide true meter reading by correction factor to get meter reading at which to stop)

75 Field Monitoring PPT-045-01 75 Determine zones Hot, warm, cold zones Downwind hazard areas Conduct hazard & risk assessment

76 Hazard and Risk Assessment PPT-045-01 76 Know the hazard characteristics Match the correct detector to the hazard Understand the detectable ranges Will conversion factors apply to the target hazard? Will temperature or humidity affect readings? Is monitor intrinsically safe? Can it be calibrated? Are capabilities and limitations understood? What other safety concerns also apply? -PPE-Fire protection-Backup -Ventilation-Lock-out/tag-out

77 Field Monitoring PPT-045-01 77 Perform tasks to make area safe for monitoring Map the release area Select a pattern to use in the search area Brief the monitoring team

78 Field Monitoring PPT-045-01 78 Monitor the suspect location for initial readings Continue to monitor throughout an event since conditions can change due to the possible intrusion of gases or vapors When LEL or PPM readings are exceeded, vacate the location

79 Detector Selection PPT-045-01 79 Always match the detector to the hazard Obtain user information from the manufacturer Determine full capabilities of monitor Lack of preparation may put you into an analogous situation

80 Detector Selection PPT-045-01 80 Never attempt to use the equipment until fully and properly trained Understand the function of each setting Run simulated incidents with your staff

81 Detector Selection PPT-045-01 81 Ensure your staff is confident in the use Have all questions answered completely by the vendor during the turn-over briefing and staff training. “Know before you go”

82 Detector Selection PPT-045-01 82 Maintain equipment in accordance with manufacturer’s recommendations If in doubt regarding maintenance and calibration, consider contracting with the vendor to perform these services

83 Detection Sequence PPT-045-01 83 Monitor first for oxygen content since oxygen depletion or enrichment will result in an incorrect reading in other categories Then monitor for the LEL Then for levels of other materials for which the detector is calibrated

84 Sewer Entry PPT-045-01 84 Per 29 CFR 1910.146 Appendix E Entrants should be equipped with atmospheric monitoring which sounds an audible alarm, in addition to its visual readout, when: –Oxygen concentration is less than 19.5 percent, –Flammable gas or vapor is at 10 percent or more of the lower flammable limit (LFL); or –Hydrogen sulfide or carbon monoxide is at or above 10 PPM or 35 PPM, respectively, measured as an 8-hour time- weighted average

85 Sewer Entry PPT-045-01 85 The oxygen sensor/broad-range sensor best suited for initial use in situations where actual or potential contaminants have not been identified Substance-specific instruments may then be used when hazard is identified

86 Work a Situation PPT-045-01 86 Working with one of your in-house SDSs Select an in-house gas or flammable liquid Identify hazard characteristics Select a monitor Plan your response Create your in-house policy and procedure

87 Remember PPT-045-01 87 These instruments are not toys They are very capable within the realm for which they were designed They also have limitations When in doubt - check with the detector manufacturers or vendors Do not take their use for granted. The lives of your staff may be in the balance.

88 Bibliography PPT-045-01 88 Shirley A. Ness, “Air Monitoring for Toxic Exposures,” Van Nostrand Reinhold, 1991 Carol J. Maslansky & Steven P. Maslansky, “Air Monitoring Instrumentation,” Van Nostrand Reinhold, 1993 “Handbook of Compressed Gases,” Compressed Gas Association, Inc., 3 rd Edition, 1990 “NIOSH Pocket Guide to Chemical Hazards,” Department of Health and Human Services, CDC, NIOSH Publication No. 2005-149, 2005 OSHA Fact Sheet, DSTM 9/2005

89 Questions PPT-045-01 89

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