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Auxiliary Drain Valve | Model DD-1 | Tyco

Tyco's fully-assembled DD-1 drum drip is an NFPA 13 auxiliary drain designed to reduce installation time and minimize potential leaks. With a single-piece condensate barrel that replaces standard nipple/reducer assemblies, this device is perfect for draining sections of "trapped" piping that hold 5 gallons of water or more.

Tyco Model DD-1 Drum Drip (Williag™ Condensate Drain)

  • Saves thousands of dollars or more by preventing ice-and-corrosion-related damage
  • Preassembled drum drip assembly saves time when installing preaction- or dry-pipe fire sprinkler systems
  • Prevents potential leaks by combining standard bell reducers and condensate nipple into a single steel component
  • Features UL-listed and FM-approved valves and fittings
  • Shipped from locations throughout the U.S. for fast arrival times
  • Buy with PayPal or our one-step checkout

Which fire protection systems is this drum drip assembly designed for?

Drum drips—also known as low-point drains, condensate drains, or auxiliary drains—are installed where water trapped in fire protection piping can't get to the main drain. This device features a single-piece condensate barrel and two 1" valves, making it suitable for:

  • Dry or preaction fire sprinkler systems
  • Sections of trapped piping that can hold more than 5 gallons of water (see NFPA 13, section

The barrel included with this drum drip has a total capacity of 0.1875 gallons. When installed and used properly, this device allows water or condensation to drip out of the pipes above, reducing corrosion and freeze-related damage.

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Do I need an additional "auxiliary drain" sign to comply with NFPA 13?

Yes. Add an NFPA-compliant "auxiliary drain" sign—or corrosion-resistant sign chain—to this drum drip by selecting it from the options at the top of this page. For more information on NFPA 13's requirements for valve signs, see section (2019 edition).

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What's the advantage of the Model DD-1 drum drip?

Known also as a Williag™ condensate drain, the Model DD-1 eliminates potential leaks by reducing the total number of threaded components. Standard drum drips feature two bell reducers, along with a 2" x 12" nipple, to store condensation. The DD-1 replaces these components with a single "condensate barrel" made from electric-resistance-welded steel tubing.

In addition, this drum drip assembly is designed to:

  • Comply with NFPA 13 and NFPA 25's requirements for auxiliary drains
  • Make operation easy with UL-listed and FM-approved high-quality brass ball valves
  • Withstand corrosion and wear
  • Arrive fully assembled, eliminating the need for fabrication in the field

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How do I use this NFPA 13 auxiliary drain?

Don't open both valves at once—and re-open the top valve after each use. A fully-open drum drip assembly will release pressurized air trapped in a dry or preaction system, causing it the system to activate (and fill pipes with water). Forgetting to open the top (inlet) valve after use will prevent water from draining out of the pipes above, leaving the system vulnerable to corrosion and ice.

To remove trapped water with this drum drip, simply:

  • Close the upper valve
  • Place a drum or bucket beneath the auxiliary drain
  • Open the lower valve
  • Allow water to drip out
  • Close the lower valve and open the upper valve
  • Repeat these steps until little or no fluid is discharged

For dry-pipe systems, NFPA 25 recommends operating this sprinkler drum drip:

  • On a daily basis after a dry system operates
  • Daily as temperatures approach freezing
  • According to your facility's maintenance program

The frequency of inspections may be reduced if little or no water discharges when operating the valve.

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QRFS Part NumberAvailabilityShips From
TYADDD-1Usually ships within 48 hoursVirginia
Shipping Weight
6.5 lbs.


Overall HeightWidthLength
24" (61.5 cm)3" (7.6 cm)

2-1/2" (6.4 cm)


Ball ValvesValve Turning RadiusCondensate Barrel
1" MNPT x FNPT - Brass2-1/2" (6.4 cm)ASTM A513 Electric-Resistance-Welded Steel
Square Head Plug
1" MNPT - Steel

Fire Protection Specs

Compatible SystemsTrapped Piping GallonageValve Listings/Approvals
Dry and Preaction Fire Sprinkler SystemsDesigned for Sections Holding More Than 5 GallonsUL, FM
Tyco Part Number

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Williag is a registered trademark of The Williag Company.

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