Flange shields are used on which type of systems?

• A. Dry air systems
• B. Flammable systems above 20 psi
• C. Non-pressurized lines
• D. Cryogenic systems

Answer: (B)

Flange shields are protective barriers placed around flange connections that carry flammable fluids or gases when the system is pressurized beyond a certain level. The risk of a dangerous flame jet from a flange leak increases as pressure rises, so the shield helps direct that potential jet away from people and critical equipment and can help contain the leak. That’s why they’re used on flammable systems above a threshold like 20 psi. Dry air systems aren’t flammable, non-pressurized lines don’t produce a jet from a leak, and cryogenic systems require other protections, so flange shields are specifically tied to flammable, pressurized services.