Final answer:
The statement is true; building codes typically require railings for stairs with four or more risers or over 30 inches in vertical height to ensure safety.
Step-by-step explanation:
The statement '4 or more risers on stairs or 30" in vertical height you need a railing' is generally true. Building codes, such as those found in the International Building Code (IBC) or local jurisdiction standards, often specify that stairs with at least four risers or having more than 30 inches of vertical height require handrails to ensure the safety of individuals using the stairs. These requirements can vary by region and intended use, but they serve the important purpose of preventing falls and injuries. Therefore, as a rule of thumb for safety and compliance, a railing should be installed in these circumstances.
For example, in a commercial building or public space, building codes typically require railings for any stairs that exceed a certain height or have a certain number of risers. These requirements may vary depending on local regulations and the purpose of the building.
In residential buildings, such as homes, the specific requirements for railings may be different. However, it is always important to prioritize safety and consider adding a railing if there are multiple risers or a significant vertical height.