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Boiler codes and design standards provide the basic guidelines for boiler application, design, construction, and operations.
Boilers come in various sizes, shapes, and colors. They are used to generate hot water or steam for process or heating applications. This article will focus on steam generation, as requirements for both types are similar until steam is generated within the drum.
The American Society of Mechanical Engineers (ASME) Boiler Pressure Vessel Code (BPVC), Section I, governs the design, fabrication, installation, and operation of fired pressure vessels (vessels in which steam is generated). The BPVC is one of the two primary references that engineers will require when designing boiler systems. The other is NFPA 85: Code on Boiler Combustion Systems and Hazards. NFPA 85 provides the requirements for the fuel and combustion systems that are used to heat the boiler. Compliance with both codes is required for safe boiler operation. Materials will be briefly reviewed, as their selection is governed by the process fluid and its properties.
A great wealth of knowledge is provided within ASME BPVC Section I. Depending on the boiler type and components, the limits of jurisdiction are defined within Section I and refer to ASME B31.1: Power Piping Code for the remainder of the requirements. The common limits engineers should be aware of are the water inlet and the steam outlet. The incoming water limit for Section I is at the inlet connection of the second isolation valve from the nozzle of the first water component of the boiler. This can either be an economizer or the drum itself. Steam limits vary depending upon the component and ASME BPVC, Section 1 should be reviewed.
NFPA 85 is applicable to boilers with heat inputs of 12.5 MMBtu/h or greater. Another important code in the design and installation of boilers is ASME B31.1. This code is applicable to the piping connecting to the boiler proper that are not under the jurisdiction of ASME BPVC Section I.
The design of boiler systems first requires the engineer to understand the requirements for the unit by understanding the system requirements it will be serving. This would include steam flow, pressure, and temperature requirements necessary to account for system pressure and temperature losses including the anticipated losses up to...