scope:

INTRODUCTION

The purpose of these recommended guidelines is to promote safety in the use of power boilers. These guidelines are intended for use by those directly responsible for operating, maintaining, and inspecting power boilers.

With respect to the application of these guidelines, a power boiler is a pressure vessel constructed in compliance with Section I in which steam is generated for use external to the boiler at a pressure exceeding 15 psig (100 kPa) due to the application of heat. This heat may be derived from the combustion of fuel (solids, liquids, or gases), from the hot waste gases of other chemical reactions, or from the application of electrical energy. The term power boiler in this Section includes stationary, portable, and traction types, but does not include locomotive and high temperature water boilers (Section I), nuclear power plant boilers (Section III), heating boilers (Section IV), miniature boilers (Section I), pressure vessels (Section VIII), or marine boilers.

These guidelines apply to the boiler proper and to pipe connections up to and including the valve or valves as required by the Code. Superheaters, reheaters, economizers, or other pressure parts connected directly to the boiler without intervening valves should be considered as part of the boiler. Guidelines are also provided for operation of auxiliary equipment and appliances that affect the safe and reliable operation of power boilers.

Previous editions of these guidelines covered the full range of power boilers from small capacity, low pressure, and low temperature to once-through units. Specific references to the once-through units have been deleted. Emphasis has been placed on industrial-type boilers because of their extensive use.

The difficulty in formulating a set of guidelines that may be applied to all sites and types of plants is recognized; therefore, it may be advisable to depart from them in specific cases. Manufacturer's operating instructions should always be adhered to. Other recommended procedures such as National Fire Protection Association's Codes covering prevention of furnace explosions are suggested for additional guidance.