The symbol depicted, a circle with a solid dot in its center, is the standard graphical representation for a public fire hydrant as viewed in a plan drawing. This symbol is defined within NFPA 170, Standard for Fire Safety and Emergency Symbols, which provides a common set of symbols for use in architectural, engineering, and insurance diagrams to ensure clear and consistent communication regarding fire safety features and equipment locations.

B. Riser: A fire protection riser is typically symbolized by a vertical line intersecting a horizontal line, often with a circle at the base indicating its location.

C. Floor drain: A floor drain is a plumbing fixture, and its symbol is commonly a circle containing the letters "FD" or a circle with crosshairs inside.

D. Utility meter: Symbols for utility meters, such as a water meter, are distinct and often represented by a bowtie shape on the supply line or a circle with "WM".

1. NFPA 170, Standard for Fire Safety and Emergency Symbols, 2021 Edition, Chapter 5, "Symbols for Use in Architectural and Engineering Drawings and Insurance Diagrams," Table 5.5.1, "Water Supply and Distribution Symbols." The symbol for "Public Fire Hydrant (in plan)" is explicitly shown as a circle with a solid dot in the center.

2. SFPE, The SFPE Handbook of Fire Protection Engineering, 5th Edition, Appendix C, "Units, Conversion Factors, and Symbols," Section C.3, "Symbols." This section directs users to NFPA 170 for a comprehensive list of standard fire protection symbols used on drawings.

3. Oklahoma State University, Fire Protection Publications, Plans Review for Fire and Life Safety, 1st Edition, Chapter 3, "Reading Plans and Specifications," Figure 3.10, "NFPA 170 Water Supply Symbols." This educational material reproduces the NFPA 170 symbol for a public fire hydrant.