You send us your isometric drawings. We handle everything else—spool design, material procurement, cutting, fitting, welding, inspection, coating, and coordinated delivery to your site. AGI Fabricators provides full-service custom pipe spool fabrication under one roof, so you get a single point of accountability instead of juggling multiple vendors across every phase of the project. We have been fabricating metal since 1893, and our pipe spool fabrication services bring that same depth of experience to every flange, every weld, and every spool that ships from our 182,500-square-foot facility. Your spools arrive built to spec, fully documented, and ready to install.
What We Build: Pipe Spools Engineered for Your System
A pipe spool is a prefabricated section of a piping system—cut pipe lengths joined with flanges, fittings, and valves into a single transportable assembly built to the exact dimensions on your isometric spool drawings. When it arrives on-site, installation is a matter of bolting pre-fitted sections together rather than fabricating from raw pipe and fittings at elevation.
AGI fabricates spools with the full range of components your system requires: straight pipe sections, elbows, tees, reducers, concentric and eccentric couplings, weld neck and slip-on flanges, blind flanges, valves, and branch connections including weld-o-lets and sock-o-lets. Every spool part is staged, tagged, and tracked from the moment raw material enters our shop until the completed assembly ships to your site. The result is a piping system that goes together the way the engineering intended—without field improvisation.
How We Do It: Our Pipe Spool Fabrication Process
Spool Design and Engineering
Every project starts with engineering. Our team works from your spool drawings, P&IDs and isometric drawings using AutoCAD REVIT to generate detailed spool drawings with precise dimensions, weld locations, material callouts, flange orientations, and a complete bill of materials.
Clash detection during the engineering review phase catches routing conflicts before we cut a single pipe. Digital twin models let us simulate the fit of every spool within the larger system, verifying that fabrication will proceed without rework-inducing surprises at installation. Approved drawings are then released to our shop floor.
Material Selection and Traceability
We select materials based on the service conditions your spools will face—temperature range, operating pressure, and corrosion environment. Carbon steel covers the majority of general process piping. Stainless steel grades 304 and 316 serve corrosive or sanitary applications. Alloy steel grades such as A335 chrome-moly handle high-temperature service in power generation and refinery settings. For specialized service, we source duplex and super duplex stainless steels, copper-nickel alloys, and other non-ferrous materials matched to your project requirements.
Every piece of pipe, fitting, and flange entering our facility carries full material traceability—heat numbers, mill certificates, and compliance documentation verified against ASTM and ASME standards. You should not have to chase paperwork to prove your piping meets code. We handle that from day one.
Precision Cutting and Fit-Up
Pipe is cut to length on a CNC plasma pipe profiler, or band saws, with ends beveled to the weld preparation geometry specified in the approved welding procedure specification. This precision machinery work ensures tight tolerances from the first step of spool production.
Fit-up is the critical alignment step where pipe sections, fittings, and flanges are positioned per drawing tolerances and tack-welded to hold alignment before full welding begins. Our fitters use levels, squares, and laser alignment tools to ensure each spool assembly meets dimensional requirements—because a spool that does not fit in the field means costly rework on your schedule, not ours.
Welding
Our certified welders execute every joint according to approved welding procedure specifications. Root passes use GTAW (TIG) for full-penetration quality. Fill and cap passes use GTAW (TIG), GMAW (MIG), FCAW (Flux-Core) or SMAW (Stick) depending on material, wall thickness, and your project specifications. Weld maps track each joint from tack to final pass, and welders on the floor hold current certifications under ASME Section IX.
Quality Inspection and Testing
Quality control follows a structured inspection sequence at every stage. Visual inspection and dimensional checks against spool drawings verify fit, alignment, and weld appearance. Non-destructive testing then confirms weld integrity: radiographic testing (RT), ultrasonic testing (UT), magnetic particle inspection (MPI), and dye penetrant testing (PT)—selected based on the governing code and weld criticality for your project.
Hydrostatic or pneumatic pressure testing per ASME B31.3 confirms that each spool can safely handle its rated operating pressure. High-alloy or thick-wall spools requiring post-weld stress-relief heat treatment receive it before testing. All results are documented in weld logs, NDT reports, and material test reports that travel with the spool through delivery and installation. When your inspector reviews the package, the documentation is complete.
Surface Treatment, Coating, and Delivery
After fabrication and testing and when customer required, spools receive surface preparation and protective coatings tailored to their service environment. Blast cleaning to SSPC-SP6 or SP10 standards removes mill scale and prepares the surface for coating adhesion. Protective coating systems—primer, epoxy, polyurethane topcoats—are selected based on corrosion exposure: buried service, submerged conditions, chemical contact, or high-humidity outdoor environments.
Each completed spool receives identification marking and tagging per your project specifications, including spool number, line number, material grade, and installation orientation. We package to protect flanges, valve internals, and coated surfaces during transport—and we coordinate logistics so spools ship in installation sequence, matching your construction schedule. Your site keeps moving without laydown yard congestion.
Why Shop Fabrication Outperforms Field Welding
Our shop gives us repeatable control over every variable that affects weld quality—position, access, shielding gas coverage, preheat temperature, and interpass control. Defect rates drop significantly compared to field welding, where wind, rain, awkward positioning, and limited inspection access make rework a frequent and expensive problem.
The biggest schedule advantage is parallelism. We fabricate your spools in our shop while civil and structural work continues on your site. Field labor and equipment mobilization costs drop because spools arrive ready to install—crews bolt flanges and complete a small number of tie-in welds rather than building piping systems from raw components. Weather-independent production in our 182,500-square-foot facility eliminates the schedule risk that plagues outdoor field work.
Industries We Serve
Oil and gas: Refinery process piping, offshore platform systems, and LNG facilities depend on prefabricated spool assemblies to meet aggressive construction schedules. We build the spools that keep these projects on track.
Power generation: Boiler piping systems, main steam lines, feedwater systems, and cooling water circuits—high-temperature, high-pressure applications that demand rigorous fabrication standards and the right alloy selection.
Chemical and petrochemical: Corrosion-resistant spools for reactor feed lines, acid transfer piping, and solvent distribution networks built from stainless, duplex, and specialty alloys.
Water and wastewater: Large-diameter spools for treatment plant piping and distribution pipelines.
Pharmaceutical and food processing: Sanitary stainless steel piping with orbital-welded joints and polished internal surfaces. Across every one of these industries, we deliver spools that meet the specific code, material, and quality requirements your project demands.
Standards and Certifications
AGI Fabricators holds current ASME and AWS certifications. Our pipe spool fabrication operates under ASME B31.3 (Process Piping) and ASME B31.1 (Power Piping). Welder qualifications comply with ASME Section IX and AWS D1.1. Oil and gas pipeline work follows API 1104. Material properties and testing comply with ASTM standards. Every weld, every material, and every test traces back to the governing code—because compliance is not optional, and neither is documentation.
Getting Custom Pipe Spools Is Easier Than You Think
You send us your spool drawings, P&IDs or isometric drawings. We handle the rest—spool design, material procurement, fabrication, NDT inspection, coating, tagging, and logistics coordination through delivery. One source, one point of accountability, no coordination overhead from juggling multiple vendors. Whether you need a handful of custom spools for a plant retrofit or hundreds of production spools for a greenfield build, our 182,500-square-foot facility and experienced fabrication team have the capacity to deliver on your schedule.
We have been doing this since 1893. We would love to help with your next project.