Materials of construction means the materials from which process equipment is built - the vessel itself, its pipework, valves, seals and gaskets. In chemical manufacturing this is a compatibility question rather than an engineering detail, because the wrong material can be attacked by the product, and the product contaminated by the equipment.
Stainless steel is the general-purpose choice, handling a wide range of chemistry at reasonable cost. It is vulnerable to strong acids and to chlorides, which can cause pitting and stress corrosion. Where that is a problem, glass-lined steel offers excellent chemical resistance at the expense of thermal shock sensitivity and vulnerability to mechanical damage. Specialist alloys, plastics and lined systems cover cases neither handles well.
Two failure modes matter. Corrosion damages the plant, which is expensive and eventually dangerous. Contamination affects the product, as material picked up from the equipment - metal ions, most commonly - enters the batch, which can be unacceptable in high-purity applications regardless of whether the vessel itself is harmed.
Seals and gaskets deserve specific attention because they are frequently overlooked. An elastomer that swells or degrades in your solvent will fail long before the vessel does. Ask about materials of construction throughout the system, not just the vessel - see corrosive chemical processing.
Send the manufacturer your safety data sheets early and ask them to confirm compatibility across the whole system - vessel, pipework, pump, seals and gaskets. Compatibility problems found at this stage are a conversation; found during a trial batch they are a lost batch.
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Last reviewed: August 2026. Regulation and guidance change — verify anything you rely on against the primary source. Tell us if something here is out of date.
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