This work presents field test results of silane releases from a cylinder valve into an open environment and into a gas cabinet. The following release tests were performed: (1) Leak from the valve outlet connector with and without a restrict flow orifice (RFO), (2) Leak directly from the two leak check holes of a capped Diameter Index Safety System (DISS) after the cylinder valve with and without a RFO, (3) Leak from cylinder valve stem retainer thread (via the loosened valve), and (4) High pressure releases from a 0.32-and 0.64-cm tube into a ventilated single cylinder gas cabinet.Release pressures varied from 120 psig to the full cylinder pressure of 1,250 psig. Both digital video and high speed cameras were used to record the ignition, pop, and explosion behavior. The results confirmed that the ignition behavior of a silane leak is strongly related to the release pressure, flow rate, aperture, and the exit environment.This study has shown that silane leaks from a fully opened cylinder valve (without an RFO) or the loosened retainer thread will not autoignite while a silane leak from fully opened cylinder valve (with an RFO) or a loosened DISS cap with and without an RFO will ignite immediately even at full cylinder source pressures.The RFO results show that the RFO increases the likelihood of the autoignition of the release, and significantly decreases release rate and the intensity of the flame. This information is important when designing systems and developing safe practices for handling silane cylinders in the semiconductor and thin-film transistor liquid crystal display (TFT-LCD) industries. The results also demonstrates safe cabinet ventilation rate to prevent explosions.

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Dynamic and steady release tests have been performed to uncover the precise condition for pure silane ignition upon its release into air. Two regimes (dynamic and steady) are studied. In dynamic tests, silane is released from a vessel with a known pressure. It is found that prompt ignition is not observed even with the source pressure down to 0.15 MPa. In steady flow tests, a reproducible critical exit velocity is found above which silane can be released indefinitely into air without any ignition. With the aid of the laminar boundary layer theory, it is found that ignition always occurs in a well-defined mixture fraction called the most reactive mixture fraction. The critical exit velocity and the most reactive mixture fraction suggest that silane release without prompt ignition is most likely caused by flow strains or by scalar dissipations, which prevent chemical reactions of silane oxidation.