Process Piping

Process piping is the network of pipe, tube, valves, and fittings that transports the fluids, gases, steam, and process media a manufacturing plant runs on — distinct from plumbing or building services because it carries pressurized, hot, corrosive, or product-contact material under a pressure-piping code. In regulated manufacturing it is designed and installed to ASME B31.3 (Process Piping) and, for hygienic service, ASME BPE (Bioprocessing Equipment), using materials and welding matched to the media. This page is a broad overview of process piping for pharmaceutical, biotech, cosmetic, nutraceutical, and food & beverage manufacturers, and a hub that routes to the specialized services and guides below. Paul Industries designs, fabricates, welds, installs, and validates process piping systems nationwide, with more than 30 years of cGMP/FDA-aware experience.

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What it isThe pipe, tube, valves, and fittings that carry process fluids, gases, and steam through a plant
Governing codesASME B31.3 (process piping) and, for hygienic service, ASME BPE
Materials316L stainless & high-purity tube, carbon steel, and thermoplastics/PVDF for utilities
SystemsProduct, CIP/SIP, WFI/PW, clean steam, gases, and general process & utility piping
ScopeDesign, fabrication, orbital welding, installation, testing, passivation, and validation
CoverageNationwide — shop fabrication plus field installation across the United States

What counts as process piping

Process piping is any piping that participates in a manufacturing process rather than in building services like domestic water, HVAC, or fire protection. It moves raw materials, intermediates, and finished product; delivers utilities such as clean steam, process gases, and high-purity water; and carries cleaning and sterilization media. Because it operates under pressure and temperature and often contacts the product, it is engineered to a pressure-piping code and, in pharma and food plants, to hygienic-design rules. The discipline spans design and stress analysis, material selection, fabrication and welding, installation, examination and testing, and — in regulated plants — documentation and validation. Getting all of those right is what separates a durable, cleanable, code-compliant system from one that rouges, leaks, or fails an audit.

Process piping and ASME B31.3

ASME B31.3 is the process-piping code that governs the safe design, materials, fabrication, examination, and testing of piping in chemical, pharmaceutical, and related plants. It classifies fluid service (for example Normal, Category D, Category M, and high-pressure), and that classification drives allowable materials, design margins, the level of nondestructive examination required, and how the system must be pressure-tested. Almost every process piping system in a manufacturing plant falls under ASME B31.3, whether or not it is also hygienic. For sanitary and high-purity systems, ASME BPE is layered on top of B31.3 to add surface-finish, slope, drainability, and weld-quality requirements — so a pharma product line is typically designed to both codes at once. Designing to B31.3 from the start ensures the system is safe and inspectable; adding BPE ensures it is also cleanable.

Process piping codes and what they govern
ASME B31.3ASME BPE
ScopePressure-piping safety for process plantsHygienic / high-purity design
GovernsDesign, materials, examination, testing, fluid serviceSurface finish, slope, drainability, weld quality
Applies toEssentially all process & utility pipingProduct-contact, WFI/PW, CIP/SIP, clean steam
Pharma useAlways requiredRequired for hygienic systems

Materials used in process piping

Material selection follows the media, the code, and the cleanliness requirement. 316L stainless steel is the workhorse for sanitary and high-purity systems because of its corrosion resistance and cleanability, usually as electropolished tube for product-contact and high-purity water service. Carbon steel and other alloys serve utility and non-contact duties, while thermoplastics such as PVDF, PP, and PVC are used for certain utility, chemical, and high-purity applications where metal is unnecessary or unsuitable. The right choice balances corrosion resistance, temperature and pressure rating, weldability, surface finish, and cost — and in hygienic systems the material and its finish are part of what makes the piping cleanable and drainable.

Fabrication, welding, and installation

How process piping is joined largely determines its quality. Automated orbital welding is the standard for sanitary tube because it produces repeatable, full-penetration, crevice-free welds that resist buildup and are easy to clean and passivate; manual TIG welding covers heavier or non-standard work. Prefabricating spools and skids in a controlled shop improves weld quality and cuts field labor, while field installation sets the system to design slope, alignment, and support for drainability. Systems are then examined, pressure- or hydrostatically tested, and — for stainless sanitary systems — passivated to restore the protective chromium-oxide layer. In regulated plants the whole sequence is documented for qualification.

Industries and systems served

Process piping underpins nearly every regulated manufacturing sector. In pharmaceutical and biotech plants it carries product, buffers, media, WFI and Purified Water, clean steam, and CIP/SIP media; in cosmetics and nutraceuticals it handles compounding, transfer, and utility duties; in food & beverage it moves product under 3-A sanitary standards. A single facility usually needs several distinct systems, each with its own materials, code requirements, and cleanliness expectations, and building them under one contractor keeps material traceability, weld records, and slope documentation consistent across the plant.

Explore process piping services & guides

This pillar links down to the specialized pages that go deeper on each part of process piping — the sanitary capability, hiring a contractor, high-purity water filtration, and the underlying concepts.

Sanitary Process Piping (ASME BPE)Our hygienic process-piping capability — electropolished 316L tube, orbital welding, and drainable, dead-leg-free design to ASME BPE.Read → Process Piping ContractorHiring a contractor: design, shop fabrication, orbital welding, field installation, testing, and validation under one accountable team.Read → High-Purity Water FiltrationThe filtration inside PW and WFI systems the piping feeds — RO, ultrafiltration, and 0.2-µm sterilizing and endotoxin filters.Read → Guide: How to Choose a ContractorWhat to look for when hiring — code experience, self-performed welding, documentation, and single-source accountability.Read → Guide: Sanitary Piping & ASME BPEWhat makes piping “sanitary,” and how ASME BPE governs surface finish, slope, drainability, and weld quality.Read → Guide: What Is Orbital Welding?How automated orbital welding produces the repeatable, crevice-free welds that hygienic process piping depends on.Read →

Standards & compliance

ASME B31.3 (Process Piping)
The pressure-piping code governing safe design, materials, fabrication, examination, and testing of process and utility piping.
ASME BPE (Bioprocessing Equipment)
Adds hygienic-design, surface-finish, slope, and weld-quality requirements for product-contact and high-purity piping.
3-A Sanitary Standards
Sanitary design criteria widely applied in food, dairy, and beverage processing.
cGMP / 21 CFR 211
FDA current Good Manufacturing Practice requirements the installed system must support.

Why manufacturers work with Paul Industries

We are a single-source process piping partner: design support, shop fabrication, orbital welding, field installation, testing, passivation, and validation under one accountable team. That reduces the coordination gaps common on multi-vendor jobs and keeps material traceability and weld documentation consistent from spool to turnover. Whether you need a new system, an expansion, or a retrofit into a live plant, we scope the work to the code and cleanliness your product requires and provide capability statements, weld and material documentation, and validation deliverables on request.

Frequently asked questions

What does Paul Industries include in a process piping project?
Paul Industries handles the full scope: system design and isometrics, shop and field fabrication, orbital welding, passivation, pressure testing, slope verification, and IQ/OQ/PQ validation. As a single-source contractor it owns every phase, so one accountable party delivers a documented, weld-mapped, turnkey system. Call 201-450-8280.
What materials are used for cGMP process piping?
Most sanitary process piping uses 316L stainless steel for product-contact surfaces because of its corrosion resistance and low carbon content for cleaner welds. Higher-purity or aggressive-media systems may use AL-6XN, PVDF, or PTFE-lined pipe. Material selection depends on the fluid, temperature, and cleaning chemistry involved.
What surface finish does product-contact process piping require?
ASME BPE specifies mechanically polished interior finishes commonly at 20 Ra microinch or better, sometimes electropolished to 15 Ra or lower. A smooth, crevice-free surface prevents bacterial adhesion and biofilm, and supports effective cleaning and drainability in hygienic systems.
How is process piping different from plumbing?
Plumbing delivers potable and waste water to code for building services. Process piping conveys production fluids, gases, and chemicals between equipment and is engineered for pressure, temperature, purity, and cleanability. Sanitary process piping adds ASME BPE surface finishes, orbital welds, and full material traceability that plumbing never requires.
Why does process piping need to be sloped?
Slope lets systems fully drain, preventing pooled liquid that harbors microbial growth or dilutes the next batch. ASME BPE typically calls for a minimum gravity slope, often around 1/8 inch per foot, verified after installation. Paul Industries checks slope during fabrication and field fit-up to guarantee drainability.
What is orbital welding and why is it used?
Orbital welding uses a computer-controlled rotating tungsten electrode to make consistent, full-penetration girth welds on tubing. It produces repeatable, smooth internal beads with minimal discoloration, which is essential for hygienic process piping. Each weld is logged and can be tied to a weld map for validation documentation.
How do you document a process piping installation?
Documentation includes weld logs and weld maps, welder and machine qualifications, material test reports, slope and pressure-test records, passivation certificates, and IQ/OQ/PQ protocols. This turnover package proves the system was built to specification and supports FDA and cGMP audits. Paul Industries compiles it as part of every project.
Can Paul Industries handle process piping nationwide?
Yes. Paul Industries fabricates at its Kilmarnock, Virginia shop and mobilizes field crews to all 50 states. Skidded and pre-fabricated spools reduce on-site time, and traveling orbital-welding teams deliver consistent quality regardless of location. Call 201-450-8280 to discuss your site.
What industries rely on sanitary process piping?
Pharmaceutical, biotech, biopharma, medical-device, cosmetic, nutraceutical, and food and beverage manufacturers all use sanitary process piping. Any operation with cGMP purity requirements, clean utilities, or product-contact fluid transfer needs hygienic piping built and documented to ASME BPE.
How long does a process piping installation take?
Timelines depend on system size, weld count, site access, and validation scope. A small utility loop can take a few weeks; a full facility distribution system runs several months. Shop pre-fabrication of spools shortens field time and shutdown windows significantly.
What is passivation in process piping?
Passivation is a chemical treatment, using citric or nitric acid to ASTM A967 or A380, that removes free iron and enriches the chromium-oxide layer on stainless steel. This restores corrosion resistance after fabrication and welding, protecting purity. Paul Industries passivates and documents systems as part of turnover.
Do you provide validation for process piping?
Yes. Paul Industries performs commissioning and validation including IQ, OQ, and PQ, plus supporting slope, pressure, riboflavin, and passivation verification. Because the same contractor designs and installs the system, validation aligns directly with the as-built documentation, simplifying audits.
What causes process piping systems to fail inspection?
Common failures include insufficient slope with dead legs, weld discoloration or incomplete penetration, surface finish above spec, missing material traceability, incomplete passivation, and gaps in weld or test documentation. Paul Industries controls each of these through orbital welding, verified slope, and full turnover records.
Should I hire separate design, fabrication, and install firms?
Splitting work across firms creates coordination gaps and finger-pointing when problems arise. A single-source contractor like Paul Industries owns design, fabrication, installation, and validation, so one party is accountable for the finished, documented system. That reduces schedule risk and audit exposure.
How do I start a process piping project with Paul Industries?
Share your process requirements, drawings, media, and site details, and Paul Industries scopes design, fabrication, and installation with a validation plan. With 30-plus years of cGMP experience nationwide, it can walk your site or review P&IDs to begin. Call 201-450-8280.
What is process piping?
Process piping is the pipe, tube, valves, and fittings that carry process fluids, gases, steam, and product through a manufacturing plant — distinct from plumbing or building services. It is designed and installed to a pressure-piping code (ASME B31.3) and, for hygienic service, to ASME BPE.
What is ASME B31.3 process piping?
ASME B31.3 is the Process Piping code that governs the safe design, materials, fabrication, examination, and testing of piping in chemical, pharmaceutical, and related plants. It classifies fluid service and sets the design margins, examination, and pressure-testing each system requires. Almost all process piping falls under B31.3, with ASME BPE layered on for hygienic systems.
What is the difference between B31.3 and ASME BPE?
ASME B31.3 governs pressure-piping safety and applies to essentially all process piping. ASME BPE adds hygienic-design requirements — surface finish, slope, drainability, and weld quality — for product-contact and high-purity systems. Pharma and biotech lines are usually designed to both at once.
What materials is process piping made from?
316L stainless steel, often electropolished, is standard for sanitary and high-purity systems; carbon steel and other alloys serve utility duties; and thermoplastics like PVDF and PP suit certain chemical and high-purity utility applications. Selection follows the media, code, temperature, pressure, and cleanliness requirement.
Do you handle design through validation?
Yes. Paul Industries provides single-source process piping — design, shop fabrication, orbital welding, field installation, testing, passivation, and IQ/OQ/PQ validation — for manufacturers nationwide, with full documentation for cGMP and code compliance.
Related capabilities

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How much does process piping cost per linear foot and per weld?

Industrial process piping spans a wide cost range because material selection and code category do most of the work in setting the price. The figures below are typical installed costs for field work in an operating plant in the United States, including labour, supports and standard examination.

Material and serviceTypical installed costWhat drives it
Carbon steel utility, 2 in to 6 in$45 to $110 per linear ftSimple welds, minimal examination, widely available material
Carbon steel large bore, 8 in and above$130 to $320 per linear ftHandling, rigging and support design begin to dominate
Stainless 304 or 316 process, 2 in to 6 in$95 to $220 per linear ftMaterial cost, purge requirements, slower deposition rate
Jacketed piping for heating or cooling$180 to $450 per linear ftTwo pipe systems in one; jacket closures and expansion are the cost
Alloy piping such as duplex or nickel alloy$250 to $700 per linear ftMaterial price and tightly restricted welding parameters
Code weld with non-destructive examination$60 to $180 per weldRadiographic or dye penetrant scope set by the B31.3 fluid service category
Pipe supports, guides and spring hangers$400 to $2,500 eachSpring and constant-effort supports on hot lines are a major line item
Hydrostatic testing and turnover documentationAdds 5 to 12 percentTest package structure, material traceability, as-built drawings

The largest single swing factor is the ASME B31.3 fluid service category, because it sets how many welds are examined and by what method. Moving a system from Category D to Normal Fluid Service, or from Normal Fluid Service to Category M, changes the examination scope for every joint in the system, not only for the line that triggered the reclassification. That is a design-stage decision carrying a construction-stage price tag.

Inspection, testing and code questions buyers ask before awarding piping work

How often does process piping need to be inspected?
ASME B31.3 governs how piping is designed, fabricated, examined and tested, but it does not set in-service inspection intervals. Those come from the owner’s mechanical integrity programme, and in refining and chemical plants they are usually written against API 570, which assigns intervals by piping class and by the consequence of a leak. Under that framework thickness measurement on higher-consequence lines typically falls on a five year cycle or half the remaining life, whichever is shorter, with external visual inspection more frequent than that. Injection points, dead legs, soil-to-air interfaces and lines subject to corrosion under insulation are inspected more often than straight runs because that is where wall loss concentrates. For a plant with no formal programme, the practical point is that intervals should be driven by measured corrosion rate, not by a default number.
What happens if a pressure test fails?
A failed hydrostatic or pneumatic test stops acceptance of that test package until the cause is found, corrected and the full test repeated. Re-testing only the repaired joint is not acceptable, because the point of the test is to prove the system as a whole. Most failures are not welds. Flange joints that were not tightened in the correct pattern, gaskets damaged during assembly, valve packing, threaded connections and test blinds account for the majority. When a weld does fail it is cut out and re-welded rather than seal welded over, and the repair is re-examined at the original acceptance level. Under ASME B31.3 the hydrostatic test pressure is normally 1.5 times design pressure, and a failure at that point is a good outcome, because the alternative is finding the defect with process fluid in the line.
What does ASME B31.3 Normal Fluid Service mean?
Normal Fluid Service is the default category in ASME B31.3, covering piping that falls into none of the special categories. The code sorts services into Category D, which is non-flammable, non-toxic service below 150 psig and 366 degrees F and carries the lightest requirements; Normal Fluid Service, which is everything ordinary; Category M, for fluids so toxic that a single exposure could cause serious irreversible harm; High Pressure service; and Elevated Temperature service. The category drives the examination requirement. Normal Fluid Service calls for five percent random radiographic or equivalent examination of welds, Category D allows visual examination only, and Category M imposes far more extensive examination plus a sensitive leak test. Getting the category wrong at design stage is expensive, because it changes the inspection scope for the entire system rather than one line.
What are the alternatives to welded process piping?
Flanged construction is the usual alternative where lines must come apart for maintenance or cleaning, at the cost of a potential leak path at every joint and considerably more space. Grooved mechanical couplings install quickly and tolerate limited movement, which makes them common on fire protection, chilled water and utility service, though they are generally unsuitable for hygienic or high-purity duty. Threaded connections remain acceptable on small bore low-pressure service but are excluded from most process applications above modest sizes and pressures. For corrosive service, lined pipe, a carbon steel shell with a fluoropolymer or elastomer liner, avoids the cost of solid alloy, and thermoplastic systems in PVC, CPVC or HDPE are standard for chemical drains and low-pressure water. Selection is driven by corrosion, temperature and whether the line will ever need to be dismantled.
Who are the best process piping contractors?
The differentiator is whether the contractor can carry code responsibility, not just make welds. Ask to see welding procedure specifications and procedure qualification records covering the actual material and thickness range on your job, continuity records proving each welder is current, and how non-destructive examination is scheduled and by whom. Ask how they build and track test packages, because on a plant of any size the test package structure determines whether the job finishes on schedule. Ask what their plan is for tie-ins to live systems and for working around an operating plant, since that is usually the real constraint rather than the pipe itself. Paul Industries delivers design support, fabrication, field installation, examination coordination, pressure testing and turnover documentation under one contract nationwide.