Effective stormwater management is critical to building safety, and roof drains play a central role. The Zurn Z105 Control-Flo Roof Drain is specifically designed to regulate the flow of water from roofs into storm piping systems. By controlling the discharge rate, the Z105 helps prevent municipal system overload, minimizes flooding risks, and ensures compliance with stormwater codes. This guide explores the drain’s features, benefits, installation considerations, and includes a real-world case study.

Zurn Z105 Control-Flo Roof Drain

What Is the Zurn Z105 Control-Flo?

The Z105 is a primary roof drain with a built-in flow control device. This unique feature limits the maximum flow of water from the roof, releasing it at a regulated rate into storm piping. By doing so, it prevents downstream systems from being overwhelmed during heavy rainfall events. The Z105 is manufactured with a durable cast iron body, a secured flashing clamp, and a domed strainer that allows for high intake capacity while resisting debris buildup.

Key Features & Benefits

• Flow Regulation: Built-in Control-Flo device manages water discharge to match design requirements.
• Durable Cast Iron Body: Ensures long service life and resistance to corrosion.
• Dome Strainer: Maximizes intake area while preventing clogging from leaves or gravel.
• Watertight Membrane Clamp: Provides a secure seal with roofing membranes to protect against leaks.
• Code Compliance: Helps facilities meet stormwater management regulations.

Zurn Brand Quality

Applications

• Commercial buildings in urban areas with stormwater system restrictions
• Municipal and institutional buildings subject to local discharge codes
• Industrial facilities requiring controlled release of stormwater
• Projects where flow regulation is mandated by design or environmental codes

Installation Considerations

When installing the Z105, it is critical to coordinate with hydraulic design specifications to ensure the control device matches required flow rates. Proper positioning at roof low points and correct sealing of the membrane flashing clamp are essential for watertight performance. Access should be maintained for inspection and cleaning of the dome strainer, and flow control elements should be tested during commissioning.

Z105 Installation Schematic

Case Study: Office Tower Stormwater Management

Challenge: A downtown office tower needed to reduce peak stormwater discharge rates to comply with municipal regulations. Traditional roof drains released water too quickly, overwhelming city storm sewers during storms.

Solution: Engineers specified Zurn Z105 Control-Flo Roof Drains across the tower’s flat roof. The built-in flow control device limited discharge to the approved rate, while the domed strainer ensured reliable intake during heavy rainfall.

Outcome: The system successfully regulated roof drainage during multiple storm events. The building maintained compliance, avoided penalties, and reduced the risk of localized flooding. Maintenance crews also reported fewer emergency interventions thanks to the consistent performance of the Z105 drains.

Conclusion

The Zurn Z105 Control-Flo Roof Drain is an advanced drainage solution that balances durability, performance, and regulatory compliance. By integrating flow control into the drain itself, the Z105 helps protect municipal infrastructure, minimize flooding risks, and extend the lifespan of roof systems. For projects in code-sensitive environments, the Z105 offers peace of mind and proven reliability.