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.
This article also includes a literature review of the most important research concerning the handling of silane. © 2007 American Institute of Chemical Engineers Process Saf Prog, 2007