Metal Pipe Fittings, Flanges, and Unions: BLS PPI Quick-Reference
Estimators pricing commercial plumbing, mechanical runs, fire protection, and industrial piping packages face continuous shifts in component manufacturing costs. Tracking producer price benchmarks provides objective verification when evaluating supplier quotes or negotiating subcontracts. This reference guide outlines federal Producer Price Index (PPI) movements for metal pipe fittings, flanges, and unions through late 2026.
Series Overview: BLS Series WPU114903
The federal benchmark for these manufactured piping components is published under the U.S. Bureau of Labor Statistics PPI commodity data series WPU114903, officially titled Machinery and equipment-Metal pipe fittings, flanges, and unions. Key parameters for this dataset include:
- Index Base Period: December 1982 = 100.
- Adjustment Status: The figures are not seasonally adjusted, meaning they capture unadjusted market price movements.
- Revision Window: Recent monthly figures are preliminary and subject to monthly revisions by the agency for four months following initial release.
Key Pricing Benchmarks: Current Levels vs. Historical Baselines
In September 2026, the index reached a level of 562.4 (raw value 562.356). This represents the highest monthly value recorded across the entire data window from January 2017 to September 2026, sitting at +0.0% versus that historic high. In contrast, the lowest monthly value within this historical window occurred in May 2017, when the index registered 284.8 (raw 284.800).
Comparing the September 2026 benchmark against prior historical periods highlights substantial upward movement across multiple timelines:
- One Year Earlier: The index stood at 532.2 (raw 532.165) in September 2025, reflecting a 1-year change of +5.7% to the latest reading.
- Two Years Earlier: In September 2024, the index was 499.1 (raw 499.101), resulting in a 2-year increase of +12.7%.
- Five Years Earlier: In September 2021, the index measured 402.1 (raw 402.054), showing a 5-year rise of +39.9%.
- Pre-Pandemic Baseline: In January 2020, the index sat at 329.9 (raw 329.900), representing an overall expansion of +70.5% through September 2026.
| Benchmark Period | Index Value | Raw Value | Change to Latest (Sep 2026) |
|---|---|---|---|
| September 2026 (Latest / Window High) | 562.4 | 562.356 | +0.0% |
| September 2025 (One Year Earlier) | 532.2 | 532.165 | +5.7% |
| September 2021 (Five Years Earlier) | 402.1 | 402.054 | +39.9% |
| January 2020 (Pre-Pandemic) | 329.9 | 329.900 | +70.5% |
| May 2017 (Window Low) | 284.8 | 284.800 | — |
Recent Monthly Momentum: The 13-Month Trajectory
Examining month-by-month changes reveals how pricing behaved over the most recent 13-month stretch from late 2025 into late 2026. After registering 532.2 in September 2025, the index leveled off at 535.6 across four consecutive months: October 2025, November 2025, December 2025, and January 2026.
Modest upward increments resumed in early 2026, starting at 535.7 in February 2026, advancing to 538.2 in March 2026, 541.1 in April 2026, and 544.0 in May 2026. The index settled at 544.3 for both June 2026 and July 2026 before accelerating to 551.4 in August 2026. Between August 2026 and September 2026, the index recorded a month-over-month increase of +2.0%, reaching 562.4.
Annual Averages from 2017 Through 2026
Longer-term bidding strategies require understanding annual average price plateaus. The computed annual averages demonstrate steady, multi-year appreciation across the metal fittings sector:
- 2017: 292.2
- 2018: 309.2
- 2019: 318.9
- 2020: 333.0
- 2021: 391.6
- 2022: 458.1
- 2023: 480.3
- 2024: 493.5
- 2025: 517.9
- 2026 (January–September only): 544.1
Applying Fitting and Flange Trends to Construction Proposals
Piping bids on large commercial projects often experience prolonged gaps between initial submission, contract award, and actual material buyout. Subcontractors and general contractors can protect their estimates by referencing official price movements:
- Structure Formal Adjustment Terms: Tie long-term piping supply packages to established market metrics by drafting clear price escalation clauses that explicitly name series WPU114903 as the reference baseline.
- Support Change Negotiations: When project delays or scope revisions push procurement past initial quotation windows, use verified government index shifts when pricing change orders to justify updated supplier quotes.
- Account for Revision Periods: Because the Bureau of Labor Statistics treats the most recent four months as preliminary, contracts referencing recent monthly figures should define whether billing reconciliations use preliminary data or wait for finalized numbers.
Sources
Data referenced in this guide is sourced directly from the U.S. Bureau of Labor Statistics PPI Commodity Data Series WPU114903.
Published October 31, 2026. No affiliate links on this page. Facts come from the sources linked above; check them for updates.