DRY SPRINKLER SYSTEM
In accordance with National Fire Protection Association Standard # 25, Inspection, Testing and Maintenance of Water Based Fire Protection Systems, Dry Pipe Sprinkler Systems should be drained of water as necessary to prevent freezing. Special care should be taken when temperatures fall below 32 degrees Fahrenheit.
When the system is designed, low point drains (drum drips or blow down valves) are installed to facilitate draining condensate or excess water from the entire system. There may be numerous low point drains depending on the system.
You will see below a diagram of a low point drain. The procedure to drain a low point drain on a Dry Pipe Sprinkler System is as follows:
1. Close the Upper valve first.
2. Remove plug from outlet.
3. Open Lower Valve and allow water to drain.
4. Replace plug in outlet.
5. Close Lower Valve.
6. Open Upper Valve.