Field-produced JP-8 standard for calibration of lower exposive limit meters used by jet fuel tank maintenance personnel.
Martin-S; Jensen-P; Pleil-J
American Industrial Hygiene Conference and Exposition, June 2-7, 2001, New Orleans, Louisiana. Fairfax, VA: American Industrial Hygiene Association, 2001 Jun; :74
Thousands of military personnel and tens of thousands of civilian workers perform jet fuel tank entry procedures. Before entering the confined space of a jet fuel tank, OSHA regulations (29CFR I910.146) require the internal atmosphere be tested with a calibrated, direct-reading instrument for oxygen content, flammable gases and vapors, and potential toxic air contaminants. These checks are typically done using lower explosive limit (LEL) meters which provide the percent LEL and oxygen level in the atmosphere, and many have other sensors installed (e.g., carbon monoxide, hydrogen sulfide, etc.). Most manufacturers suggest the meters be calibrated using a known methane or pentane standard. However, a previous NIOSH study found that manufacturer-recommended calibration techniques do not match instrument performance when monitoring jet fuel vapors. JP-8 and Jet-A fuels are generally C9 to C16 compounds. Because most LEL meters are calibrated against n-alkanes less than C9, some meters may underestimate the explosive potential of jet fuel vapor in the tanks after removal of the most volatile components. Also, maintaining a stock of pure calibration gases can be troublesome, particularly in the case of military deployments. In this study, liquid jet fuel was introduced into tedlar bags and the atmosphere inside the bag allowed to equilibrate. Once equilibrated, the concentration of the jet fuel vapors can be easily calculated using the ambient temperature and known vapor pressure vs. temperature curves. Furthermore, the vapor concentration can be controlled by temperature. Thus, actual jet fuel calibration standards can easily and routinely be produced in the field and used to calibrate LEL meters. Comparing the performance of various LEL meters and a Foxboro TVA 1000B, with flame-ionization detector, calibrated per manufacturer instructions and using the field-developed standards shows the field-produced standards work very well for the calibration of LEL meters.
Military-personnel; Jet-engine-fuels; Fuels; Flammable-liquids; Flammable-gases; Vapors; Vapor-detectors; Oxygen-deficient-atmospheres; Exposure-levels; Exposure-limits; Explosive-atmospheres; Explosive-gases; Explosive-hazards; Temperature-effects; Samplers; Sampling-equipment; Sampling-methods
American Industrial Hygiene Conference and Exposition, June 2-7, 2001, New Orleans, Louisiana