Final answer:
Certification of modular homes is conducted according to national or regional building codes, such as the International Residential Code (IRC). They must follow local building codes and are inspected by local building authorities, differentiating them from the HUD Standard for manufactured housing.
Step-by-step explanation:
The certification that governs modular homes is typically carried out according to national or regional building codes. In the United States, this is often overseen by state and local building departments, and the standards that apply are the same as those for traditional on-site construction. The relevant standards may include the International Building Code (IBC), International Residential Code (IRC), or specific state codes such as the California Building Standards Code. Additionally, the Department of Housing and Urban Development (HUD) has established a national code for manufactured housing, which is sometimes confused with modular homes. However, modular homes are not subject to the HUD Standard, but instead must be constructed in accordance with the local building codes of their intended location. It's also important to note that modular homes must be installed on a permanent foundation and pass inspections by local building authorities.