Why is a guard required at heights of more than 30 inches?

A guard is required at heights of more than 30 inches primarily to prevent falls and to comply with building codes. Falls from elevated surfaces can result in serious injuries or fatalities, which is why having guardrails or similar protective measures in place is crucial for safety. The requirement for guards is a standard part of safety regulations to mitigate the risks associated with working or moving at height.

Additionally, building codes are designed with safety in mind, setting standards that contractors must adhere to in order to ensure public safety. By having a guard in place, builders not only enhance user safety but also fulfill legal obligations established in these codes.

The combination of maintaining safety and adhering to regulatory requirements underscores the importance of this measure, rather than seeking aesthetic improvements or other less critical reasons. Thus, the correct answer encompasses both the need to prevent falls and the requirement to comply with building standards.