# Performance Specification Gap in Division 33 Utilities submittals

> Source: https://deviationcheck.com/divisions/33-utilities/performance-specification-gap/

A measurable performance property in the submittal (rating, capacity, tolerance, efficiency) does not meet what the spec requires.

## What to look for in Division 33 Utilities

Key performance parameters in utility submittals:
- **Water pipe pressure class and material:**
  - Ductile iron pipe (DIP): Class 52 is minimum for most water mains; verify class vs working pressure + surge; AWWA C151
  - PVC pressure pipe: C900 (4-12") or C905 (14"+), pressure class 150, 200, or 235; lower class than spec is a blocker
  - HDPE water main: DR (dimension ratio) rating determines pressure rating; DR 11 = 160 psi, DR 13.5 = 128 psi
- **Sewer pipe SDR (standard dimension ratio):**
  - PVC gravity sewer: SDR 26 (pipe stiffness 115 psi per ASTM D2412) or SDR 35 (pipe stiffness 46 psi); SDR 35 is weaker and only acceptable at shallower depths
  - Specify which SDR is required and verify submitted product matches
- **Reinforced concrete pipe (RCP) class:**
  - Classes III, IV, and V correspond to increasing wall thickness and 3-edge bearing strength
  - Class III is minimum for most culverts; higher traffic or deeper burial requires Class IV or V
- **Storm HDPE pipe corrugation profile** - affects ring stiffness (ADS N-12 SB vs HP Storm); spec may require smooth interior for hydraulic capacity
- **Manhole wall thickness and reinforcing** per ASTM C478 for 48" diameter; custom sizes require engineered drawings
- **Trench backfill compaction** requirement (% of ASTM D1557 Proctor) - typically 95% in paved areas, 90% in unpaved; lower compaction causes pavement settlement
- **Pipe bedding gradation** (Class B, C, or D per ASTM D2321) - affects pipe deflection under load
- **Hydraulic capacity** - Manning's n coefficient and pipe internal diameter must match hydraulic design; smooth interior HDPE has n = 0.012, corrugated has n = 0.024
- **Fire hydrant rated working pressure** and flow test GPM - must match fire flow design
- **Gate valve Cv (flow coefficient)** and operating pressure rating vs system design

## Severity

Default grade: Blocker. Always a Blocker when the gap touches life-safety or structural performance.