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Published byBridget Horn Modified over 9 years ago
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Air Monitoring Presented By: Etech Environmental & Safety Solutions, Inc.
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Field Air Monitoring Instruments Collection of “Real Time” data to aid in the decisions concerning Collection of “Real Time” data to aid in the decisions concerning –Hazards & Risks to Public & Personnel –Selection of Personal Protective Equipment –Site Work Zones –Effects on Environment –Mitigative Actions
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Field Instruments Desired Characteristics Portable & Rugged Portable & Rugged Easy to Operate Easy to Operate Inherently Safe Inherently Safe Reliable & Useful Results Reliable & Useful Results
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Reliable & Useful Results Response Time Response Time Sensitivity Sensitivity Selectivity Selectivity Accuracy Accuracy Precision Precision
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Hazardous Atmospheres (NEC) Concentration between the Lower Explosive Limit and Upper Explosive Limit (LEL – UEL) Concentration between the Lower Explosive Limit and Upper Explosive Limit (LEL – UEL) Presence of an Ignition Source Presence of an Ignition Source Exothermic Reaction Exothermic Reaction
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Definitions Intrinsically Safe - Designed so that parts are not exposed to explosive atmosphere or, if so, there is insufficient energy for ignition Intrinsically Safe - Designed so that parts are not exposed to explosive atmosphere or, if so, there is insufficient energy for ignition Explosion Proof – Designed to contain an explosion and cool gases to prevent spread Explosion Proof – Designed to contain an explosion and cool gases to prevent spread Purged System – Inert gas filled system; positive pressure to prevent explosive gases or vapors from entering Purged System – Inert gas filled system; positive pressure to prevent explosive gases or vapors from entering
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Instrument Protection Criteria Class I, Division 1, Group A,B,C, & D Class I, Division 1, Group A,B,C, & D –Intrinsically Safe –Explosion-Proof –Purged System Class I, Division 2, Groups A,B,C, & D Class I, Division 2, Groups A,B,C, & D –Non-Incendive Class II, Division 1 & 2, Groups E,FD, & G Class II, Division 1 & 2, Groups E,FD, & G –Dust-Ignition Proof
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Typical Instruments Used Oxygen Indicators Oxygen Indicators Combustible Gas Indicators Combustible Gas Indicators Toxic Atmosphere Monitors Toxic Atmosphere Monitors Radiation Survey Meters Radiation Survey Meters
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Oxygen Indicators Exterior Sensor Exterior Sensor Interior Sensor Interior Sensor –Manual Pump –Automatic Pump Combination Units Combination Units
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Oxygen Indicators (cont.) Limitations & Precautions Limitations & Precautions –Atmospheric Pressure (Altitude) –Interfering Gases –Operating Temperature
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Combustible Gas Indicators Manual vs. Automatic Manual vs. Automatic Super-Sensitive Unit Super-Sensitive Unit Combination Units (CGI-O 2 ) Combination Units (CGI-O 2 )
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Combustible Gas Indicators (cont.) Limitations & Precautions Limitations & Precautions –Temperature –Oxygen Requirements –Interfering Gases Lead Lead Sulphur Sulphur Silicone Silicone Hydrogen Chloride Hydrogen Chloride Hydrogen Fluoride Hydrogen Fluoride –Relative Response
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Combustible Gas Indicators (cont.) Always monitor for Oxygen levels before checking for combustible gases
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Toxic Atmosphere Monitors Detector Tube Systems Detector Tube Systems Specific Agent Specific Agent –H 2 S –CO Total Vapor Analyzers Total Vapor Analyzers –Photoionization Detectors (PIDs) –Flameionization Detectors (FIDs)
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Detector Tube Systems Pump Pump –Bellows –Piston Tubes Tubes –Specific Chemicals –General Chemicals –Concentration Ranges
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Detector Tube Systems (cont.) Limitations & Precautions Limitations & Precautions –Accuracy –Temperature, Humidity, Pressure –Expiration Date –Lot Numbers –Color Change Endpoint –Pump Strokes, Volume –Interferences –Reusable
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Toxic Vapor Analyzers PIDs Uses Uses –Analyze for a broad range of contaminants –Can be calibrated to analyze for specific chemicals –Sensitivity
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Toxic Vapor Analyzers PIDs (cont.) Considerations Considerations –Lamp Energy & Chemical IP –Dust & Humidity –High Methane –Electromagnetic Radiation –Lamp Aging –Relative Response –High Concentrations
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Toxic Vapor Analyzers FIDs Uses Uses –Accuracy to specific hydrocarbons –Data is usually very accurate
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Toxic Vapor Analyzers FIDs (cont.) Considerations Considerations –Detects only organics –Sensitive to methane –Relative response –Hydrogen gas needed –Electromagnetic Radiation
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Toxic Vapor Analyzers Chemical Specific Uses Uses –Good for personal monitors in known atmospheres –Accuracy
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Toxic Vapor Analyzers Chemical Specific (cont.) Considerations Considerations –Sensor Wear –Dust & Humidity –Unknowns –Calibration –Electromagnetic Radiation
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