Flammability tests on D0 Run II muon PDT Gas and P-10 Gas

Haggerty, Herman F. ; Marshall, James L. Priest and Tom

Fermi National Accelerator Laboratory

关键词: Flammability;    Methane;    Pulse Rise Time;    43 Particle Accelerators;    37 Inorganic, Organic, Physical And Analytical Chemistry;   

DOI  :  10.2172/782881
RP-ID  :  FERMILAB-TM-2146
RP-ID  :  AC02-76CH03000
RP-ID  :  782881

美国|英语

来源: UNT Digital Library

【 摘 要 】

The authors have done a series of measurements with mixtures of Argon, CF4 and CH4 to demonstrate that the mixture chosen for RunII (84% Argon, 8% CH4, 8% CF4) is not flammable. The tests were conducted in the Meson Detector Building in a test cell similar in construction to a cell of a Muon PDT. In order to establish the viability of the test set-up, they first repeated the demonstration that P-10 gas (90% Argon, 10% CH4) is in fact flammable, contrary to the classification by the US DOT. US DOT regulation 173.115 defines flammable gas as: (1) is ignitable (at 14.7 psi) when in a mixture of 13% or less with air; or (2) has a flammability range (at 14.7 psi) with air of at least 12% regardless of the lower explosive limit (LEL). P-10 has a LEL of about 40% and a flammability range of about 10%, so P-10 is not flammable according to the US DOT definition. The point here is that the DOT classifications are to serve the DOT's function to ensure transportation safety, and are not necessarily appropriate for other situations. The first configuration of their test cell, however, apparently failed to ignite P-10. With the guidance of Bill Nuttall of CERN, they modified their test cell to make it more like the standard flammability testing setups, with a large viewing window and a spark gap in the middle of the cell. In this second configuration P-10 was easily and reliably ignitable. After becoming more familiar with the visible indicators of combustion of P-10 (water vapor cloud formation, pressure changes and gas venting) they retested with the initial configuration, and found that the mixture actually had been burning, and that they had just missed all the indications. The data from CERN showed that P-10 burns rather slowly, with about a one second rise time for the pressure to reach the maximum of four atmospheres overpressure. In the tests they saw no signs of any flame, but only a water vapor cloud. Some preliminary tests with the same cell using Argon-Ethane and air had a much more impressive burn, with rapid venting and a red flash clearly visible.