Joining CPVC and Steel in a Fire Sprinkler System

As the popularity of CPVC pipe in fire sprinkler systems grows, more installers are dealing with joining plastic piping to steel as part of new construction or retrofits. While BlazeMaster® Pipe and Fittings makes this relatively easy, the process does require installers to follow several safety procedures.

Installers should follow the guidelines for hybrid systems in Chapter 6 of the NFPA 13 handbook, said Lubrizol CPVC Piping Systems Consultant John Pritchard. Because CPVC pipe is not threaded, joining it to threaded steel pipe requires a brass male or female adapter. Brass connectors are best because of brass’s durability, high resistance to corrosion and flexibility, he added.

While the joining is relatively simple and easy, Pritchard warns that installers must be careful with the ancillary products which can be used and the characteristics of the steel pipes.

For example, some types of antimicrobial coatings used on steel pipe can be harmful to CPVC. BlazeMaster Fire Protection Systems recommends that installers check with the manufacturers of the steel pipe and/or the makers of the antimicrobial coating for compatibility with CPVC. Factory Mutual (FM) has modified its nonmetallic (FM 1635) and steel pipe (FM 1630) standards to include testing that demonstrates the chemical compatibility of nonmetallic fire sprinkler pipe with coated steel sprinkler pipe.

Other materials, such as cutting oils, should also be verified for compatibility with CPVC.BlazeMaster Fire Protection Systems recommends that installers check with its FBC™ System Compatible Program to determine the compatibility of ancillary products. The database is also available in an app, which connects directly to the website and allows for easy searching.

Top 6 Quick Tips to Remember

  1. Verify compatibility if pipe has antimicrobial coatings (refer to FM approvals)
  2. Verify compatibility of cutting oils used in prefabrication (refer to FBC system compatibility program or manufacturers recommendations)
  3. Use a Brass threaded by CPVC socket adapter UL listed for use in fire protection systems
  4. Verify compatibility of any thread sealants used to connect the adapter (refer to FBC system compatibility program or manufacturers recommendations)
  5. Use the proper wrenches to secure the adapter to the steel pipe
  6. Do not overtighten the adapter

Following these simple, easy guidelines makes for easy installation of safe and reliable hybrid fire sprinkler systems.

, , , , ,