Fire sprinkler systems are equipped with drainage systems to remove water from the system. There are several NFPA standards that dictate the design and requirements of these fire sprinkler drains. It’s an integral part of the overall design and functionality of your building’s fire sprinkler system.

But do you know where your fire sprinkler drains are located? Or where they drain to? Location is a very important thing when draining your sprinkler system. Whether you’re draining your system for maintenance, testing alarms, or in an emergency situation, it’s important to know where your drains are, how to operate them, and where they drain.

Location of drains

 There are multiple types of fire sprinkler drains. It all depends on the type of sprinkler system that’s installed. The main type of drains are the main drain (installed at the riser), the inspectors’ test drain (installed at the end of the system), and the auxiliary drain (installed to drain a low lying area of a sprinkler system).

The main drain is located at the fire sprinkler system riser. Its purpose is to discharge water outside and away from your building or to a connection that can manage the flow of the drain and also to measure the water pressure in the system.

For systems with discharge drain connections, the connections depend on the size of the riser. The amount of water flowing through the main drain is based on the size of the sprinkler system. NFPA code determines the size of the drain connection based on the size of the riser. All types of sprinkler systems (dry, wet, preaction, and deluge) have different methods of drainage, but with the same purpose. Main drains are required to be permanently marked with identification signs hung from the pipe below the valve for which they are listing.

The inspectors test drain, or test and drain valve, is traditionally located at the end of the sprinkler system. This drain helps facilitate flow testing and is typically used in multi-story buildings. If you’re in a multi-story building, you will probably have sectional valves in the stairwell on each floor with a test and drain assembly that would test the alarm switch on that sectional valve as well as drain the system if needed. The testing part of the drain is a preinstalled restricted orifice that would simulate a sprinkler head discharge. There is a certain position the handle of the valve would need to be in in to flow through this restricted orifice.

The auxiliary drain is located where the pipe changes direction. Its purpose is to prevent any water remaining in the system after discharge by allowing you to drain water from a “trapped” or low lying area of the system. Though in wet systems, the piping is already full, so no discharge is needed. On dry systems, these drains can be located in areas susceptible to freezing and help in drainage of the system. All sprinkler types require auxiliary drains if there is danger of trapped water. Like the main drain, these drains must also have permanent identification signs secured to the pipe and below the valve. Additional signage is also required near the control valve. This signage will indicate the number of auxiliary drains and location of each drain.

How to operate drainage system

It’s important to know how to drain your system in the event of emergency when a professional cannot be there in time. Improper drainage of your fire sprinkler system can cause damage to the components of the sprinkler system. Draining of your system should be performed by a qualified fire protection technician or specialist when possible.

“In the event of a broken sprinkler head or pipe/fitting the system would need to be immediately shut down. That would constitute the owner or owner’s rep to shut down and drain the system down,” explains Gary D., Fire Systems, Inc. Sprinkler Division Service Manager.

If you need to drain your system, it’s important to notify appropriate parties of the procedure and expected duration of the shutdown. This includes your monitoring company, insurance company, local fire department, and employees of your building. Authorization must be given prior to drainage. The purpose of this notification is to let the responding fire department know the status of the system so if there is an emergency, the department can respond accordingly.

Where your fire sprinkler drain drains  

Location of drains is as important as where drains drain. Fire sprinkler systems typically use water to extinguish fire. Where does that water go should your system discharge?

“Knowing the location of all sprinkler drains in your building will help with inspections and service, expedite response time in an emergency (broken piping or sprinkler head), and save property from being damaged by rerouting the flow of water from any critical areas (door ways, vehicles, landscaping),” explains Gary.

Water can be damaging in many ways, so understanding the drainage system of your building’s fire sprinkler system can be quite helpful. For example, do they drain to a nice new slab of poured concrete that could potentially stain? Do your drains drain into a landscaped area? It’s important to know the location of drainage so that you can prevent any damage to these areas.

Design & installation

If not considered early in the fire protection system design for a project, disregard for drainage requirements can have a negative impact on the overall building design coordination.

Drainage for sprinkler systems should be considered on multiple levels. While drainage is usually associated with its usefulness in facilitating fire system maintenance and repair operations, it’s also useful in:

  • Freeze protection
  • Removal of wastewater from secondary fire system components (e.g. fire dept. and pump test connections, backflow preventers, pressure relief valves, etc.)
  • System testing
  • Alarm testing
  • Monitoring/verification of system water supplies
  • Containment and control of hazardous materials and associated fire spread
  • Minimizing water damage and property loss in sensitive occupancies

Fire Systems, Inc. can help

Fire Systems can evaluate the locations of drains and the flow of drains to assist the customer in any corrective action needed with any of their drains associated to their sprinkler system. Evaluations can be done during a scheduled inspection or can be done on an individual requested basis. We can design, install, inspect, and repair almost any fire sprinkler system. Contact us today at 770-333-7979 or visit our website for more information on our extensive offerings and expertise.