Slope Requirements for Fire Sprinkler Pipe

Pipe slope is a critical element in reducing water collection following a sprinkler system drain. Water removal is important in that the largest detriment to sprinkler system life, corrosion, occurs across interfaces between air and water. Here is a quick summary of the minimum pipe slope requirements for fire sprinkler systems.

	Non-Refrigerated	Refrigerated
Wet Systems	Branch & Main Pipe: Level ​(NFPA 13 2002 8.15.2.2.1, 2007/2010/2013/2016 8.16.2.2.1)	N/A
Dry Systems	Mains: 1/4 inch per 10 feet Branches: 1/2 inch per 10 feet ​ (NFPA 13 2002 8.15.2.3.1, 2007/2010/2013/2016 8.16.2.3.1)	Branches & Mains: ​1/2 inch per 10 feet (NFPA 13 2002 8.15.2.3.4, 2007/2010/2013/2016 8.16.2.3.3)
Pre-Action Systems	Mains: 1/4 inch per 10 feet Branches: 1/2 inch per 10 feet ​ (NFPA 13 2002 Edition does not require slope for pre-action systems in non-freezing areas per 8.15.2.3.3, 2007/2010/2013/2016 does require slope per 8.16.2.3.2)	Branches & Mains: ​1/2 inch per 10 feet ​ (NFPA 13 2002 8.15.2.3.4, 2007/2010/2013/2016 8.16.2.3.3)