Abstract: The present invention provides a calculated protective action zone, such as a safety zone which can be used for evacuation purposes, using simplified input methods and systems and simplified internal calculation methods to model the chemical data. Yet, it uniquely retains a significantly high degree of accuracy corresponding to more expensive, complicated, time consuming state of the art models for the chemical releases as described above. It may be used for dense gas dispersion and other releases. To accomplish this, the methods and systems of the present invention may use a post-processed modeled data base and selected multi-variable equations combined with qualitative and quantitative input and may include default values for various factors. The system may include a small, hand-held electronic calculating element such as a palmtop computer, with extended battery life for portability, although it is equally applicable for high end processors on stationary computers.

Abstract: The invention includes an axial-mounted high flow rate valve by fixedly mounting a rotatable valve sealing element so that it pivots on an axis which is substantially parallel to a central axis of the pipe or conduit to which the valve is connected. The rotatable valve sealing element can be not only circular, but non-circular as well, having an extended length along the pivot axis for even greater flow rates and may be particularly suited for installations in sprinkler systems which require greater flow than a normal valve of the same diameter and may even be used as a combination valve for hydrant and sprinkler system use, such as in residential applications. The present invention also may include a purge port to purge residual fluid remaining in the valve, downstream of the valve sealing element, to assist in preventing freezing of the valve and it may include an air port to allow air to enter the valve to alleviate a possible vacuum created by the purging and to enable more effective purging.