Fire Protection Engineering Theses and Dissertations

Permanent URI for this collectionhttp://hdl.handle.net/1903/2772

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Development of the ASTM E681 Standard
(2016) Lomax, Peter; Sunderland, Peter; Fire Protection Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
ASHRAE 34, based on ASTM E681, was improved by identifying and rectifying deficiencies in ASTM E681. An ASTM E681 apparatus and procedure was developed with gaseous refrigerant testing in mind. The plumbing was improved by ensuring that the pressure readings could be constantly monitored while decreasing leakage potential. An original electrical system was designed and constructed for the ignition system. Additionally, a control panel was constructed to isolate hazardous electrical elements, and facilitate the testing, while simultaneously organizing the critical plumbing and ignition components. 3D printing efficiently produced heat-resistant, nonreactive, and structurally stable lower electrode spacers, propellers, and propeller bars. The heating system was designed to ensure even temperature throughout the apparatus. The humidity system was designed to accurately condition the air. Recommendations to improve ASTM E681 are provided. The research can be built on to improve the accuracy and reproducibility of ASTM E681.
Improved Venting for Flammability Limit Testing Using ASTM E681 Apparatus
(2016) McCoy, Conor Graham; Sunderland, Peter B; Fire Protection Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
The literature on the determination of flammability limits was reviewed and experts on the ASTM E681 standard were interviewed to identify new means of improving the reproducibility of the ASTM E681 test. Venting was identified as a variable of flammability limits not yet addressed. Limitations of the current system for sealing and venting (a rubber stopper) were identified and addressed by the development of a custom burst disc. The burst disc was evaluated for its ability to hold and maintain a vacuum, its ability to vent at pressures of interest, and for its venting phenomena. The burst disc was deemed to be a satisfactory alternative to the rubber stopper and is recommended to be included in the ASTM E681 standard.
Pressure Measurements for Refrigerant Flammability Limit Testing Using ASTM E681 Apparatus
(2017) Klieger, Alexandra Eve; Sunderland, Peter B; Fire Protection Engineering; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Improvements to the ASHRAE 34 and ASTM E681 standard test apparatus and procedure have been identied to make the test more repeatable and reproducible. Currently, the test apparatus centers around a glass flask with visual flammability criteria that can be subjective and dependent on a wide variety of factors. Additionally, the current test apparatus vents close to the time where the visual criteria is evaluated which can impact flame propagation. A high frequency pressure transducer was added to the testing apparatus to understand the pressure development in the test vessel throughout flame propagation. Initial test pressures below atmospheric were studied to reduce the likelihood of premature venting. Quenching effects from the electrode rods of the test apparatus were quantied as well. Ultimately, a fractional pressure rise of 40% from a mixture starting at 91.2 kPa was proposed as a new pressure-based flammability criteria to potentially replace the current visual criteria. This new criteria would result in an lower flammability limit of 14.0% for R32.