Cylinders dichlorosilane

Dichlorosilane is a highly flammable, corrosive, and toxic gas at room temperature and atmospheric pressure. It causes severe bums on contact with eyes, skin, and mucous membranes. With water or moisture, it hydrolyzes rapidly to yield silica and silicon oxyhydride along with hydrochloric acid. It is shipped as a liquefied gas in low pressure cylinders at its vapor pressure of 9.1 psig (62.7 kPa) at 70°F (21.1°C). It can form flammable mixtures with air and oxidizing agents. 

Because of the reactivity of dichlorosilane, reverse flow into the cylinder may cause it to rupture. Always use a vacuum break or other protective apparatus in any line or piping from the cylinder to prevent reverse flow. 

A dichlorosilane fire will usually result if a spill contacts water. If flames are extinguished, explosive reignition may occur. Appropriate measures should be taken, for example, total evacuation of the area. Approach the area with extreme caution. Reverse flow into the cylinder may cause it to rupture. Corrosive vapors may be reduced with a coarse water spray. Shut off the leak if without risk. Ventilate the area, and prevent runoff from contaminating the surrounding environment. 

Steel cylinders that meet TC/DOT specifications 3A, 3AA, 3E4, 4A, 4B, and 4W are authorized for the shipment of dichlorosilane. 

The most common cylinder valve used for dichlorosilane is a stainless steel diaphragm valve with a Connection CGA 678 outlet. The cylinder valve body has a combination CG-4 type pressure relief device consisting of a fusible metal plug, melting about 165°F (74°C), which is protected from the cylinder contents by a frangible metal disk, i.e. a rupture disk, rated at 250 psig (1724 kPa). 

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