Final answer:
An inspector is not required to enter a crawl space if the opening is less than 18 inches in width or height, according to industry standards such as those from the American Society of Home Inspectors.
Step-by-step explanation:
The question asked pertains to home inspection standards and what conditions would lead an inspector not to enter a crawl space. According to the American Society of Home Inspectors (ASHI) and similar industry standards, an inspector is not required to enter areas that are not readily accessible or where entry could cause damage to the property or pose a hazard to the inspector. Typically, a crawl space with an opening less than 18 inches in width or height is considered not readily accessible. Inspectors also may avoid entering crawl spaces if the space is waterlogged, heavily obstructed, or if there are other hazardous conditions such as exposed wiring or unstable flooring.