| Boiler Type | Fuel | Gross Efficiency (HHV) | Net Efficiency (LHV) | |-------------|------|----------------|----------------| | Large utility (pulverized coal) | Bituminous coal | 82–87% | 87–92% | | Industrial water-tube | Natural gas | 80–84% | 89–93% | | Fire-tube | #2 oil | 78–83% | 85–88% | | Package boiler | Natural gas | 79–82% | 88–91% |
The document commonly referred to as ASME PTC 4.1.pdf is the outdated version of the standard. The original ASME PTC 4.1-1964 (Reaffirmed 1973, 1991) was titled "Steam Generating Units" (often called the "Heat Loss Method"). This was officially replaced by ASME PTC 4-1998 and later by ASME PTC 4-2008 (currently in effect, reaffirmed 2022). However, PTC 4.1 remains widely used in legacy systems, training, and industrial calculations because it is simpler and many older boilers were designed around it. 1. Purpose and Scope of ASME PTC 4.1 The purpose of ASME PTC 4.1 is to provide a standardized, reproducible test code for determining the efficiency and performance of a steam generator (boiler) under defined operating conditions. Asme Ptc 4.1.pdf BEST