Dryer Vent Upgrade & Installation - San Francisco, CA

## Fire-Safe Dryer Vent Upgrade in San Francisco Our team completed a comprehensive dryer vent system upgrade for a residential property in San Francisco, addressing critical safety violations that posed significant fire and health risks. The existing installation featured a 9-foot Mylar transition duct—a prohibited flexible material that violates IRC M1502.4.1 requirements for smooth interior finish metal duct construction. ## Code-Compliant Installation with UL-Listed Materials We removed the dangerous Mylar flex duct and installed a proper fire-rated system using UL 2158A-listed semi-rigid metal transition ductwork. The new installation features both 8-foot and 4-inch DryerFlex components, ensuring compliance with IRC M1502.4.3 transition duct requirements while maintaining the minimum 4-inch diameter specified in M1502.4.1. All duct joints were secured with metal tape and proper mechanical fasteners per M1601.4.1 standards. ## Professional Duct Installation & Safety Verification The complete duct installation and repair work included proper male-into-female joint orientation in the direction of airflow, with all connections secured using minimum 3 sheet metal screws per joint as required by IRC M1502.4.2. This upgrade eliminates the fire hazard associated with prohibited duct materials, which cannot withstand dryer exhaust temperatures that can exceed 200°F and are prone to melting, sagging, and trapping lint at dangerous levels. ## Results: Enhanced Safety and Performance The new fire-rated metal duct system provides smooth airflow, significantly reduces lint accumulation compared to the ribbed interior of the old flex duct, and ensures long-term safety compliance. This San Francisco homeowner can now operate their dryer with confidence, knowing their exhaust system meets all current building codes and manufacturer specifications for safe, efficient operation.