A procurement-ready guide for waterworks, irrigation, industrial PVF, and fire protection teams
Pipe fittings can look “interchangeable” on a packing list—until a crew is waiting on site, the bolt pattern doesn’t match, the gasket material isn’t compatible, or the project submittal gets rejected. For buyers and project engineers across the United States, the fastest path to fewer RFIs and change orders is aligning three things early: application (what you’re moving and where), standard (what the spec calls for), and connection method (how it will be installed and maintained).
Below is a practical framework used by procurement teams, MRO managers, and project engineers to source pipe fittings with fewer surprises—especially when projects involve multiple trades (waterworks + industrial + fire protection) or when material must be export-ready.
1) Start with the “service” (what the system is doing)
Before selecting elbows, tees, reducers, couplings, valves, or flanges, confirm the system category. In distribution environments like IFW Supply supports—waterworks & irrigation, industrial PVF, and fire protection—the same nominal size can have different outside diameters, joining methods, and standard requirements.
Quick checklist to confirm service:
• Media: potable water, reclaimed water, irrigation water, glycol, air, steam, chemicals, etc.
• Pressure class / design pressure (and any surge considerations)
• Temperature range (ambient vs hot service) and exposure (UV, buried, coastal, chemical)
• Installation environment: buried, aboveground, mechanical room, hazardous location, marine, etc.
• Governing spec: municipal standards, ASME piping code, NFPA system requirements, or owner standards
• Media: potable water, reclaimed water, irrigation water, glycol, air, steam, chemicals, etc.
• Pressure class / design pressure (and any surge considerations)
• Temperature range (ambient vs hot service) and exposure (UV, buried, coastal, chemical)
• Installation environment: buried, aboveground, mechanical room, hazardous location, marine, etc.
• Governing spec: municipal standards, ASME piping code, NFPA system requirements, or owner standards
2) Match the standard to the application (don’t “mix families”)
“Pipe fittings” is a broad category. The key is selecting fittings that belong to the same sizing system and standard family as the pipe and the project spec.
| System | Common pipe/fitting “family” | Typical connections | Where it shows up |
|---|---|---|---|
| Waterworks | PVC pressure pipe standards and CIOD/IPS sizing | Gasketed bell & spigot, mechanical joint, flanged adaptors, restrained couplings | Municipal mains, pump stations, meter vaults |
| Irrigation | PVC, HDPE, and agricultural/landscape fitting systems | Solvent weld, gasketed, compression, barbed, clamp | Pivots, turf/parks, farms, drip and pumping skids |
| Industrial PVF | Steel/stainless pipe schedules and ASME/ANSI dimensional systems | Threaded, socket weld, butt weld, flanged, grooved | Power, refining, food processing, geothermal, facilities |
| Fire protection | Steel pipe with fittings approved/listed for fire systems | Grooved couplings, threaded, flanged, welded (where allowed) | Sprinkler risers, standpipes, fire pumps, special hazards |
Example (waterworks PVC pressure pipe): AWWA C900-22 covers PVC pressure pipe and fabricated fittings across a wide size range and includes CIOD and IPS outside diameter systems with pressure classes spanning 80 psi to 305 psi. (store.awwa.org)
3) Use schedules and dimensions correctly (what “Schedule 40” really means)
In industrial and many fire protection applications, steel pipe is selected by NPS and schedule (wall thickness series). A frequent sourcing issue: people assume schedule changes outside diameter. In reality, for a given NPS, the outside diameter stays the same while wall thickness increases as schedule increases. (engineeringtoolbox.com)
Why procurement cares: If your pipe wall changes, your mating components can change too—thread engagement, groove dimensions, weight, hanger loads, and sometimes even valve end requirements. Getting the schedule wrong can cascade into rework and return freight.
For stainless pipe dimensions, ASME notes the separate schedule naming (e.g., “10S/40S/80S”) used to differentiate stainless schedules from carbon steel schedule thickness series. (asme.org)
4) Material selection: a practical approach for buyers
Procurement teams usually have to balance cost, lead time, and compliance. Here’s a straightforward way to reduce risk:
Step 1: Confirm whether the spec calls for waterworks pressure pipe (often PVC/DI-related systems) vs industrial PVF (ASME piping). Mixing these is where OD and connection problems appear.
Step 2: Determine if the service is high temperature. For carbon steel pipe, ASTM A106 is commonly referenced for higher-temperature service compared with general-purpose ASTM A53, with differences in chemistry (including silicon minimum in A106) that support elevated-temperature performance. (cortecsteel.com)
Step 3: Confirm connection method (threaded vs grooved vs welded vs flanged) and ensure each fitting is ordered with the correct end prep.
Procurement tip: If the spec references a temperature threshold or the line is steam/hot process, treat “A53 vs A106” as a deliberate decision—not a substitution. When in doubt, ask for the line list and the governing code notes (B31.1/B31.3, project general notes, etc.).
5) “Installability” matters: choose fittings that make maintenance easier
Even when materials match the spec, installability is where budgets are won or lost. When you’re selecting pipe fittings for MRO work or project installs, evaluate:
| Decision point | What to verify on the PO/submittal | Why it prevents rework |
|---|---|---|
| End connections | Thread type, groove spec, weld end prep, flange drilling pattern | Mismatched ends are one of the most common field-stoppers |
| Pressure class / DR / schedule | DR and pressure class for PVC, schedule series for steel | Ensures rated performance and correct fit with mating parts |
| Gaskets & seals | Elastomer type and compatibility (water, chemicals, temperature) | Avoids swelling, leaks, and early failure |
| Approvals/listings (fire) | Verify the required listings/approvals for the system | Keeps inspections smooth and avoids failed acceptance tests |
Did you know? Quick facts that help buyers avoid common pitfalls
For steel pipe, a higher schedule means thicker wall—and smaller inside diameter—while outside diameter remains constant for a given size. (engineeringtoolbox.com)
AWWA C900-22 covers PVC pressure pipe and fabricated fittings across broad sizes and includes CIOD and IPS sizing options with defined pressure classes. (store.awwa.org)
ASTM A106 vs A53 is more than a naming preference—A106’s chemistry requirements (including silicon minimums) are commonly cited as a reason it’s used for higher-temperature applications. (cortecsteel.com)
6) United States sourcing reality: standardization + logistics wins
In the United States, multi-site buyers often manage consistent product standards across multiple markets. That usually means:
• Standardized submittals across sites (same fitting family, same end connections)
• Approved alternates defined up front (so procurement can react to lead times)
• Export-ready documentation when equipment ships globally (packing, labeling, inspection coordination)
IFW Supply supports contractors, distributors, and end users with fire protection, waterworks & irrigation, industrial, and safety products—and can assist with cross-referencing and logistics planning when specs are complex or timelines are tight.
Ready to source pipe fittings with fewer RFIs and faster approvals?
Send your spec, line list, or takeoff and we’ll help confirm the fitting family, end connections, pressure class/schedule, and documentation needs—especially when your order spans waterworks, industrial PVF, and fire protection requirements.
FAQ: Pipe fittings sourcing and specification
Are “pipe fittings” the same across waterworks, industrial, and fire protection?
Not always. These systems often use different standards, sizing conventions, and joining methods. Start by identifying the governing spec and the pipe family (PVC waterworks vs steel PVF vs listed fire protection components), then match fittings and end connections to that family.
What does AWWA C900 cover?
AWWA C900-22 provides minimum manufacturing, verification, and marking requirements for PVC pressure pipe and fabricated fittings, and it covers CIOD and IPS outside diameter systems with multiple pressure classes. (store.awwa.org)
Does Schedule 80 pipe have a bigger outside diameter than Schedule 40?
For steel pipe in a given NPS, the outside diameter remains the same; the wall thickness increases as schedule increases, reducing the inside diameter. (engineeringtoolbox.com)
When does ASTM A106 matter versus ASTM A53?
When service conditions involve higher temperatures or the project spec explicitly requires it. Differences in chemistry requirements (including silicon minimums) are commonly cited for A106’s suitability in higher-temperature applications compared with general-purpose A53. (cortecsteel.com)
What should I include when requesting a quote for pipe fittings?
Include: size and quantity, material (and grade), schedule/DR/pressure class, end connections (threaded/grooved/butt weld/flanged), governing spec, media/temperature/pressure, and any documentation needs (certs, marking, export packing). This reduces back-and-forth and speeds approvals.
Glossary (helpful terms for pipe fittings)
NPS (Nominal Pipe Size): A sizing designation for pipe; for many sizes it does not equal the actual outside diameter.
Schedule (Sch): A wall-thickness series used for many steel pipe systems; higher schedule typically means thicker wall and smaller inside diameter for the same NPS. (engineeringtoolbox.com)
CIOD / IPS: Common outside-diameter sizing systems used in waterworks PVC standards; CIOD aligns to cast/ductile iron sizing, IPS aligns to iron pipe size conventions. (store.awwa.org)
PVF: Pipe, valves, and fittings—an industrial procurement category that typically includes dimensional standards, end connections, and material specifications.