Is it true that a listed expansion chamber must be provided where an anti-freeze system connects to a wet pipe system with a backflow prevention device?

The statement is indeed true. When an anti-freeze system connects to a wet pipe system that includes a backflow prevention device, it is required to have a listed expansion chamber. This requirement exists because anti-freeze solutions can expand when heated, and without an expansion chamber, this expansion can create excess pressure within the system, potentially leading to damage or failure of components.

The inclusion of a listed expansion chamber helps accommodate this expansion safely, ensuring the integrity of the piping system and all associated fittings during temperature fluctuations. This is particularly crucial in preventing the potential for leaks or failure points that can occur when such systems are subjected to pressure beyond their designed limits.

Furthermore, the requirement for an expansion chamber addresses both safety and compliance with standards, ensuring that the anti-freeze system operates effectively alongside the wet pipe system. While local codes can sometimes specify additional requirements or adaptations, the necessity of an expansion chamber in this scenario provides a critical safeguard against operational issues.