Dry Pipe System
A sprinkler system employing automatic sprinklers attached to a piping system containing air or nitrogen under pressure, the release of which (as from the opening of a sprinkler) permits the water pressure to open a valve known as a dry pipe valve. The water then flows into the piping system and out of the opened sprinklers.
Source: Resolution A.800(19), Revised Guidelines for Approval of Sprinkler Systems Equivalent to that Referred to in SOLAS Regulation 11-2/12, 23 November 1995, International Maritime Organization. Regulatory Guidance