46 CFR §53.01-3

1. (a)Heating boilers must be designed, constructed, inspected, tested, and stamped in accordance with Section IV of the ASME BPVC (incorporated by reference; see § 53.01-1) as limited, modified, or replaced by specific requirements in this part. The provisions in the appendices to Section IV of the ASME BPVC are adopted and must be followed when the requirements in Section IV make them mandatory. For general information, table 1 to § 53.01-3(a) lists the various paragraphs in Section IV of the ASME BPVC that are limited, modified, or replaced by regulations in this part.
2. (b)References to the ASME BPVC, such as paragraph HG-307, indicate:
   1. (1)H = Section IV of the ASME BPVC.
   2. (2)G = Part containing general requirements.
   3. (3)3 = Article in part.
   4. (4)307 = Paragraph within Article 3.
3. (c)When a paragraph or a section of the regulations in this part relates to Section IV of the ASME BPVC, the relationship with the code will be shown immediately following the heading of the section or at the beginning of the paragraph, as follows:
   1. (1)(Modifies H__.) This indicates that the material in H__ is generally applicable but is being altered, amplified, or augmented.
   2. (2)(Replaces H__.) This indicates that H__ does not apply.
   3. (3)(Reproduces H__.) This indicates that H__ is being identically reproduced for convenience, not for emphasis.