Plumbing Takeoff for a 1,200-Student K-12 School by F&K

## Project Context This walkthrough demonstrates a typical plumbing estimating methodology for a new K-12 campus in a public school district. The example scenario is a 1,200-student, approximately 185,000 SF campus in the Dallas-Fort Worth metroplex. School plumbing is a specialized discipline. Unlike commercial office buildings, K-12 facilities have high fixture density concentrated in a small number of locations — restrooms, locker rooms, kitchens, and labs — all subject to IPC occupancy-based minimums and ADA requirements. ## Estimating Objectives A typical engagement involves an independent plumbing takeoff for a mechanical subcontractor preparing a bid. Common objectives include: - Validating fixture counts against IPC Section 403 minimums - Identifying ADA compliance requirements that affect rough-in dimensions - Correctly sizing grease interceptors for commercial kitchen operations - Applying prevailing wage labor burdens where applicable ## Typical Challenges ### 1. Fixture Unit Analysis The IPC Section 403 mandates minimum fixture counts based on occupant load. The engineer's fixture schedule must be cross-referenced against IPC minimums — they are not always the same. A typical discrepancy pattern: | Space | IPC Min | Architect's Schedule | Common Finding | |:---|:---:|:---:|:---:| | Student Restrooms | 12 WC + 12 Lav | 14 WC + 14 Lav | Usually adequate | | Gymnasium Locker Room | 8 shower + 6 WC | 8 shower + 4 WC | Missing 2 WCs | | Kitchen Handwashing | 1 per 5 staff | Varies | Often undersized | Gymnasium locker rooms frequently have fewer water closets than the IPC minimum for the calculated occupant load. Kitchens often lack the minimum handwashing sinks mandated by state food establishment rules (such as the Texas TFER Chapter 228). Pre-bid RFIs to the EOR can resolve these before bid day — but only if the discrepancy is identified during estimation. ### 2. ADA Compliance Beyond Grab Bars ADA compliance in school restrooms extends beyond accessible stall dimensions. Every accessible fixture has plumbing implications: - **Water closet height:** ADA requires 17"–19" seat height vs. standard 15". ADA-compliant elongated WCs use different rough-in dimensions (14" vs. 12"), affecting waste rough-in locations in slab-on-grade construction. - **Lavatory pipe insulation:** Exposed supply and drain pipes must be insulated per ADA Section 606.6 to prevent contact burns for wheelchair users with limited sensation. This is a quantifiable line item that non-specialist estimators frequently miss. - **Drinking fountain bi-level units:** IBC Section 1109.5 requires one accessible and one standard-height unit per fountain location. Single-height units in the schedule may need to be upgraded to bi-level combination units. ### 3. Grease Interceptor Sizing For a school serving 1,000+ meals per day, a grease interceptor is mandatory for any foodservice operation discharging to the public sewer. Sizing follows a three-step calculation per ASPE/PDI G101: 1. **Fixture units draining through the interceptor** — pot sinks, pre-rinse spray stations, floor drains, and dishwasher 2. **Flow rate calculation** — typically 2 GPM per DFU peak factor 3. **Interceptor sizing** — per PDI G101, matched to peak flow A common error is specifying a smaller interceptor than the actual fixture loading requires. The corrected unit represents a change order avoided — the differential between an undersized and correctly sized unit is typically several thousand dollars. ### 4. Prevailing Wage Calculations For public school projects in certain districts, prevailing wage schedules may apply. Even in open-shop states like Texas, some school districts adopt local wage policies for facilities contracts above a threshold. A common risk is using state average open-shop rates instead of the actual prevailing wage schedule. The difference in burdened journeyman rates can represent a significant understatement on estimated labor hours — potentially thousands of dollars per project. ## Applicable Codes & Standards - **IPC Section 403** — Fixture count minimums by occupancy - **ADA Standards for Accessible Design** — Fixture accessibility requirements - **IBC Section 1109.5** — Drinking fountain accessibility - **ASPE/PDI G101** — Grease interceptor sizing standard - **Texas TFER Chapter 228** — Food establishment plumbing requirements - **Davis-Bacon Act** (federally funded) or local prevailing wage schedules ## Software Workflow | Software | Purpose | |:---|:---| | PlanSwift | Plumbing quantity takeoff from PDF plans | | Bluebeam Revu | Plan markup and ADA compliance verification | | RSMeans Online | Localized labor rate reference | ## Common Estimating Risks | Risk Area | Typical Impact | Mitigation | |:---|:---:|:---| | Missing WCs in locker rooms | Code violation, permit denial | Cross-reference IPC minimums against schedule | | ADA pipe insulation omitted | Change order, $3k–$5k | Quantify all exposed lavatory piping | | Undersized grease interceptor | $8k–$12k change order | Size per ASPE/PDI G101 calculation | | Prevailing wage understatement | $5k–$10k labor loss | Use actual district wage schedule, not state averages | ## Lessons Learned 1. **IPC minimums are minimums.** The architect's schedule may not meet them — always cross-reference. 2. **ADA compliance is quantifiable.** It is not just grab bars — it affects rough-in dimensions, pipe insulation, and fixture selection. 3. **Grease interceptor sizing is math, not guessing.** The three-step ASPE calculation prevents mid-construction corrections. 4. **Prevailing wage data matters.** Using the wrong rate basis can erase projected profit on labor. ## How F&K Applies This Process F&K Estimatings applies this systematic fixture-by-fixture, code-by-code approach to every institutional plumbing estimate. The methodology documented in this walkthrough — IPC validation, ADA compliance checking, grease interceptor sizing, and prevailing wage calculation — is standard process for every K-12, healthcare, and civic facility we estimate. --- *This walkthrough is an educational sample based on representative institutional estimating practices. Figures are illustrative and rounded for clarity. Specific project details are generalized to protect confidentiality.*

Plumbing Takeoff for a 1,200-Student K-12 School by F&K

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