The Skip-resistant Sprinkler Concept -- An Experimental Evaluation

A sprinkler with a shield designed to mitigate drop impingement from nearby operating sprinklers is shown experimentally to reduce skipping as compared to the same sprinkler without a shield. As described in a companion article, a model for the response time of a shielded sprinkler has been developed and validated with a Plunge Tunnel apparatus. In this article, results from intermediate-scale spray fire tests employing Froude modeling principles with a 1 : 3 scale ratio are used to evaluate sprinkler performance both with and without the shield. By comparing the operation times of adjacent shielded and unshielded sprinklers, the intermediate-scale tests can identify test arrangements where the shielded sprinkler operates while the unshielded sprinkler does not operate. The identified arrangements are then used in a full-scale environment where a series of pan fire tests serve as a proof-of-concept that proper shielding of a sprinkler can reduce skipping in terms of both the sprinkler operation pattern and total number of sprinkler operations. This study successfully demonstrates that proper shielding of a sprinkler can significantly reduce skipping.