As metal heats up, it will expand. The design of B-vent is such that the bottom end of the inner liner is free to lengthen as the aluminum gets hotter. The vent system is designed to expand without restriction. Since the aluminum liner will expand more than twice as much as the steel outer, if the expansion is restricted in anyway, noise will occur.
To keep your vent systems noise free, use these best practices at the time of installation:
- Do NOT use sheet metal screws at lock joints.
Screws that touch or penetrate the inner liner will cause noise. The use of screws are only permissible where mentioned in the manufacturers’ installation instructions.
- Appropriately support pipe and offsets.
Inadequate support or supports that “slip” may allow the expansion that occurs at the connection to rub.
- Use factory built supports, firestops, and components.
By using system specified supports, you ensure appropriate clearance to combustibles and product engagement. Field fabricated components may interact with the system in an unintended way.
A source of noise will reverberate through the entire vent system. Once a problem occurs, it may be difficult to pin point and correct. By following these best practices, your customers will enjoy safe, noise free venting from their appliances!