In dry pipe systems, branch lines must be pitched at least how many inches per 10 ft?

In dry pipe systems, it is essential for branch lines to have a proper pitch to facilitate the drainage of condensate that may form within the piping. The correct pitch of at least 1/4 inch per 10 feet ensures that any accumulated water will flow towards the drain points effectively, preventing water from remaining in the lines, which could lead to freezing or operational issues. This requirement is critical for maintaining the integrity of the dry pipe system, particularly in environments where temperatures may drop. Proper drainage helps maintain system reliability and ensures that the fire protection system can function effectively when needed. The other options do not align with the established standards for dry pipe systems, making them less suitable for ensuring the effective performance of the system.