Zurn Z100-89 Roof Drain
The Zurn ZC100-89 overflow roof drain is a high quality cast iron roof drain that is installed as a “backup” to the main roof drain.
The overflow roof drain will go into service if the primary or main roof drain become blocked with debris. This “failsafe” mechanism can prevent rainwater from ponding on the flat roof. It can literally prevent the flat roof from collapsing under the stress caused by the excessive load of standing rainwater. It is a plumbing code requirement for this reason.