According to NFPA 13, how should branch lines be pitched?

According to NFPA 13, branch lines should be pitched at a slope of 1/4 inch for every 10 feet. This specific pitch is essential for ensuring that water can efficiently drain out of the branch lines, preventing any accumulation of water which could lead to freezing or other issues associated with standing water in the piping system. This gradual slope helps to facilitate proper drainage and maintain the reliability of the sprinkler system, particularly in systems that may be subject to temperature fluctuations wherein water could freeze. The other specified pitches, while they may have benefits in different contexts, do not align with NFPA 13's requirements for branch line installation in relation to drainage.