Is fire-rated glass really necessary if I use sprinklers? Can't I just use tempered or heat strengthened glass with a water "deluge" system?

Theoretically, it is possible, and one sprinkler company even promotes such a special sprinkler product. However, the likelihood of such a system working properly is questionable and is not recommended. In order for a sprinkler system to protect non fire-rated glass, it would have to activate early, bathing every inch of the glass completely and continuously. While tests at Underwriters Labs showed this could be accomplished under very specific conditions (fire starts away from the glass surface, no horizontal frame members, etc), it also proved that when conditions were not perfect, the glass can shatter and fall from the frame in less than five minutes. There are additional "real world" issues that need to be addressed with such an installation. For example, the sprinkler manufacturer's literature indicates that drapes, blinds, shutters, etc., are not allowed in front of the glass as that would prevent water from the sprinkler covering the glass. However, a stroll through most ...  more