LP-Gas odorants must not exceed what fraction of the lower limit of combustibility?

The correct answer is that LP-Gas odorants must not exceed 1/5 of the lower limit of combustibility. This guideline is crucial for safety as it ensures that the odorants added to LP-Gas—typically a mercaptan compound to impart a sulfur-like smell—are at a level that allows for effective leak detection without compromising the fuel's combustibility.

Maintaining the concentration of odorants below this threshold is important because it helps prevent any potential interference with the gas's combustion characteristics. If the odorant concentration were too high, it could potentially alter the gas's burning properties, leading to unsafe conditions. The 1/5 limit is an industry standard that helps ensure both safety and practicality in using LP-Gas while providing a reliable means for detecting leaks quickly and effectively.