For CO2 systems, ASTM A120 and ordinary cast-iron pipe shall not be used.

For CO2 systems, ASTM A120 and ordinary cast-iron pipe shall not be used.

• A. False
• B. True
• C. Only for certain installations
• D. They are allowed for certain systems

Answer: (B)

In CO2 extinguishing systems, piping must be designed and rated for high-pressure gas service and be resistant to brittle failure. Ordinary cast-iron pipe is prone to brittle fracture and corrosion under the conditions typical of CO2 flooding, and ASTM A120 is a standard for cast-iron soil pipe rather than pressure-rated pipe for gas service. These materials do not provide the appropriate pressure ratings, joint designs, or reliability required for CO2 systems, so they shall not be used.

In CO2 extinguishing systems, piping must be designed and rated for high-pressure gas service and be resistant to brittle failure. Ordinary cast-iron pipe is prone to brittle fracture and corrosion under the conditions typical of CO2 flooding, and ASTM A120 is a standard for cast-iron soil pipe rather than pressure-rated pipe for gas service. These materials do not provide the appropriate pressure ratings, joint designs, or reliability required for CO2 systems, so they shall not be used.