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Component psi Running − Water meter (displacement) 2.5 64.5 − Service friction (1" copper, 18.8 gpm) 8.8 55.7 Residual pressure at building entry 55.7 − Critical fixture requirement (flush-tank WC, §604.3) 20.0 35.7 Pressure available for interior distribution 35.7 psi ✓ No elevation head is carried. The site and service run are essentially flat, and the governing fixture is the at-grade flush-tank water closet (20 psi). The highest fixtures — 2nd-floor office lavatories, 13 ft above entry, requiring only 8 psi — remain non-governing even with their ~5.6 psi static lift (8 + 5.6 = 13.6 < 20 psi). Static pressure (72 psi) is below the 80 psi §604.8 threshold, so no PRV is required; 35.7 psi remains for interior piping friction after the critical fixture — ample for a building of this size, confirmed at the plumbing permit stage. 8. Fire Suppression Determination Automatic fire-sprinkler protection is not required for this building. This has been confirmed based on the occupancy classification, the building area and height remaining within the limits permitted for non-sprinklered construction, and the fire-resistance-rated separations incorporated in the design. Accordingly, no fire-protection flow is added and the service is sized for domestic demand only — a material factor in the adequacy of the 1" service. Any future introduction of a fire-suppression requirement would require re-evaluation (Section 10). 9. Conclusion The existing 1" copper domestic water service is adequate for the proposed building addition under its non- coincident daytime/evening pattern of use: ● Design demand: 18.8 gpm — velocity 7.31 ft/s, within the 8 ft/s ceiling. ● Residual at building: 55.7 psi, leaving 35.7 psi for interior distribution after the critical fixture — ample. ● No PRV required (static 72 < 80 psi); no booster; no backflow assembly; no fire-protection demand; simultaneous use of both groups is not possible. 10. Recommendation — Future Service Upsizing The 1" service is adequate for present conditions but carries little reserve (91% of its velocity ceiling at design demand). The following would render it inadequate and should trigger upsizing: ● Simultaneous (rather than alternating) use of both occupancy groups. ● Change of tenant or occupancy, added fixtures, or conversion from flush tanks to flushometer valves. ● Increased brewery production or overlapping fill demand, added irrigation, or any future fire-suppression requirement. Upsizing is recommended as a programmed future capital improvement, undertaken when funding is available and ideally coordinated with street/main work, a tenant fit-out, or re-occupancy. Service size (copper) Velocity @ 24.9 gpm* Capacity @ 8 ft/s Headroom vs. present 1" (existing) 9.7 ft/s (over) ~20 gpm Occupancy managed 1½" 4.5 ft/s ~44 gpm Simultaneous use OK 2" 2.6 ft/s ~77 gpm long-term growth + fire option * full simultaneous demand (reference). A 1½" service carries full simultaneous demand comfortably (4.5 ft/s); a 2" service adds reserve for future fixtures, irrigation, brewery growth, or a future fire service. If the service trench or building entry is disturbed under this project, an oversized sleeve/entry penetration now materially reduces the future upsizing cost. 11. Assumptions, Limitations & Certification ● Existing service (1" Type L copper), developed length, available/static pressures (67/72 psi), and meter loss (2.5 psi) are per the Engineer's project data and field information; a purveyor pressure-availability letter is recommended for the record. Page 42 of 84