Presentation on theme: "Mine Rescue Gas Detection"— Presentation transcript:
1Mine Rescue Gas Detection Pa. Bureau of Deep Mine Safety
2What do I need to know? What gases make up fresh air What are the hazards of mine gasesSpecific Gravity of each gasOrigin of mine gasesExplosive rangeExposure limitsWhat detection device(s) do I use
3Category of Gases Noxious – Asphixiant due to a lack of oxygen. Toxic – Poison, either long or short term exposure.
4Physics of GasesSpecific Gravity : The combinations of gases that make up air is what other gases are compared with. Air is considered to have a specific gravity of 1.0Temperature: Cold gases will diffuse slowly, hot gases will diffuse quickly.Graham's Law: The rate of diffusion, the lower the specific gravity, the faster it will diffuse.Barometric Pressure: The lower the pressure, the faster a gas will diffuse.Solubility: The ability to dissolve in water.
5Exposure LimitsThreshold Limit Value (TLV) The allowable amount of gas exposure for an 8 hour day for 5 days a week without harmful effects.Short Term Exposure Limit (STEL) The allowable amount of gas exposure for 15 minuets.
6Measurement of Gases (4) Parts Per Million (PPM)- The most accurate measurement of a contaminant in the atmosphere.(4)PERCENT PPM,000… 1,000………
7Mine Gases & their Components AIRChemical Formula: NoneSpecific Gravity: 1.000Source: AtmosphereCharacteristics: No color, odor, or tastePure dry air at sea level contains the following:Oxygen %Nitrogen … %Argon %Carbon Dioxide %
8Oxygen Specific Gravity: 1.105 Chemical Formula: O2 Oxygen will not burn or explodeSource: AtmosphereCharacteristics: No color, odor or tasteNote: When another gas is introduced into the atmosphere of an artificial environment, such as a mine, tunnel or man holes, oxygen can be displaced causing asphyxiation.
10Noxious Gases (Explosive) MethaneChemical Formula: CH4Specific gravity:Needs 12.5% O2 to igniteExplosive Range: 5-15%Ignition Temperature: 1100o-1300o FSource: Carbon products decaying in anoxic environmentCharacteristics: No color, odor or tasteDetection method: Methane detector, Flame safety lamp, Chemical analysis
11Acetylene Chemical Formula: C2H2 Specific Gravity: 0.9107 Explosive Range: %Ignition Temperature: 581oFSource: Methane heated in a low oxygen atmosphereOdor: GarlicWill auto-ignite when over pressurized
12Hydrogen Chemical Formula: H2 Specific Gravity: 0.0695 Needs 5% oxygen to igniteExplosive Range: %Ignition temperature: 1030o oFSource: Water on super hot fires, battery charging
13Noxious Gases(Non Explosive) NitrogenChemical formula: N2Specific Gravity: 0.967TLV: 810,000 PPMSource: Atmosphere, released from coal seamCharacteristics: No color, odor, or taste
14Carbon Dioxide Chemical Formula: CO2 Specific Gravity: 1.529 TLV: 5000 PPMSTEL: 15,000 PPMSource: Product of complete combustion, slow oxidation of carbon products, breathingCharacteristics: No color or odor,acidic taste above 10%
15Toxic Gases(Explosive) Carbon MonoxideChemical Formula: COSpecific Gravity: 0.967Needs 6% O2 to igniteIgnition Temperature: 1100oFExplosive Range: %TLV: 50 ppmSTEL: 400 PPMSource: Incomplete combustion, diesels, gasoline enginesCharacteristics: No color, odor, or tasteEffect on the body: 300 times more attracted to hemoglobin than oxygen.
16Toxic Gases (Explosive) con’t. Hydrogen SulfideChemical Formula: H2SSpecific Gravity: 1.191Ignition Temperature: 700oFTLV: 10 ppmSTEL: 15 PPMSource: Sulfur dissolving in water in a poorly ventilated area, rotting mine timbersCharacteristics: Colorless, sweet taste, rotten egg smellEffect on the body: Paralysis of respiratory system
17Toxic Gases (Non-Explosive) Nitrogen DioxideChemical Formula: NO2Specific Gravity: 1.589TLV: 5 PPMSTEL: 10 PPMSource: Explosives after-product, diesel exhaust, weldingCharacteristics: Burnt powder odor, reddish brown in high concentrationsEffect on the body: Forms nitric acid in lungs causing pulmonary edema
18Toxic gases(con’t) Sulfur Dioxide Chemical Formula: SO2 Specific Gravity: 2.264Source: Burning of sulfide ores, diesel exhaust, gob firesTLV: 5 ppmSTEL: 10 PPMCharacteristics: Heavy sulfur odorEffect on the body: Same as nitrogen dioxide
19SmokeTiny particles of solid and liquid matter suspended in air as a result of combustionDiesel Particulate MatterBy-products of burning beltsCarbon materialsUsually noxious and toxic gases are presentCan be carcinogen(cancer causing)
20Mine dampsThe word damp is a derivative of the German word “damf” which means vapor. It was used by the immigrant German miners in the anthracite fields to describe a certain atmosphere condition.Black damp: Carbon dioxide, nitrogen, and low oxygen.White damp: Carbon monoxideFire damp: MethaneStink damp: Hydrogen SulfideAfter damp: By-products of a fire or explosion
21Detection Devices Hand held detectors Air Sample Gas Monitors Permanent sensor locationsFlame Safety Lamp