867 2" DUEL ROOF DRAIN

on flat commercial roofs.

🔧 What it is

• Series: ** 867 roof drain system**
• Type: Dual (often written “duel”) roof drain = primary + overflow
• Size: 2" outlet connection
• Application: flat roof drainage system

From catalog listings, this is specifically a:

• Combination roof drain + overflow unit
• Used in low-slope or flat roofing systems

⚙️ What it does

• Collects rainwater from a roof membrane (primary drain)
• Provides a backup overflow path if water rises too high or the main drain clogs
• Sends both flows into a 2-inch drainage piping system

$Q = A \cdot v$

🧱 Key features

• Two-function system (primary + overflow protection)
• Dome strainer to block debris like leaves and gravel
• Clamping ring system to secure waterproof roofing membrane
• Designed for commercial roof membranes (TPO, EPDM, PVC systems)
• 2" outlet for gravity drainage piping

🏗️ Typical applications

• Commercial flat roofs
• Schools and warehouses
• Retail buildings
• Mechanical rooms with roof penetrations
• Any code-required overflow-protected roof system

🧠 Simple explanation

It’s basically a 2-inch roof drain that has a built-in emergency overflow drain so water can’t build up on a flat roof if the main drain gets blocked.