NADCA members have signed a Code of Ethics stating they will do everything possible to protect the consumer and follow ACR, the NADCA Standard, for cleaning to the best of their ability. Air duct cleaning companies must meet strict requirements to become a NADCA member. Among those requirements, all NADCA members must have a certified Air System Cleaning Specialist (ASCS) on staff who has taken and passed the NADCA certification examination. Passing the exam demonstrates extensive knowledge in HVAC design and cleaning methodologies. ASCSs are also required to further their industry education by attending seminars in order to maintain their NADCA certification status.