SGI’s BS 341 British Standard Cylinder Valve Outlets and Connections:British standard valve outlet connections follow a few simple rules: - If the gas mixture has a flammable and toxic component, then the BS 15 connectors are used. - If the gas mixture has a flammable component but no toxic component, then the BS 4 connectors are used. - If the gas mixture has a toxic component but no flammable component, then BS 14 connectors are used. - If the gas mixture has neither a toxic nor a flammable component, BS 3 connectors are used.
