What is the primary difference between a high-pressure boiler and a low-pressure boiler?

The primary difference between a high-pressure boiler and a low-pressure boiler is indeed based on the operational pressure. High-pressure boilers are defined as those that operate above 15 psi, while low-pressure boilers are designed to function at pressures of 15 psi or below. This classification is important because it has implications for design, safety regulations, operating procedures, and maintenance requirements.

Operating at higher pressures typically means that high-pressure boilers must be constructed with more robust materials and include more sophisticated safety features to handle the increased stress and risks associated with these levels. In contrast, low-pressure boilers generally have simpler designs and may not require the same stringent safety measures, which can make them easier to operate and maintain.

Options regarding maintenance differences, size, or efficiency do not capture the fundamental distinction defined by the pressure thresholds, thus highlighting the critical nature of pressure in determining the category of the boiler. Understanding this difference is essential for anyone preparing for a boiler licensing exam, as it underscores the safety implications and regulatory requirements associated with the operation of these types of boilers.