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 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.

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.

Standards & compliance

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.