Four Materials Every Hydrogen Plant Engineer Needs to Understand
The UK's hydrogen pipeline is real and it is moving quickly. Twenty-seven green hydrogen projects were shortlisted under HAR2 in April 2025, with HAR3 and HAR4 to follow. Every one of those projects has a process pipework specification to write. If you are the engineer writing it, the material selection decisions you make now will determine whether that plant runs reliably for its full design life or becomes a maintenance problem within the first operating year.
Here is a plain-language guide to the four thermoplastic materials that do the real work on a hydrogen production site, and where each one belongs.
Polypropylene: the internal workhorse
Alkaline electrolysis uses a KOH solution of typically 20 to 30 per cent by weight, at operating temperatures of 70 to 80°C. PP is the standard choice for internal KOH distribution within the electrolysis plant at these concentrations and temperatures. It handles alkalis, inorganic acids and salt solutions well. It is cost-effective, widely available, and well understood. The AGRU industrial PP piping range, which IPS stocks, is designed for precisely these chemical duties. Know the limit: PP is not the right material for highly concentrated alkalis at elevated temperature, or for aromatic and chlorinated solvents. When conditions push beyond that boundary, the next material takes over.
PVDF: for aggressive chemical duties and high purity
PVDF handles what PP cannot. It is resistant to most inorganic acids and bases, aliphatic and aromatic hydrocarbons, organic acids, alcohols and halogenated solvents. Safe working temperatures run from -40°C to +140°C. It is non-toxic and suited to high-purity applications. On a hydrogen plant, PVDF is the correct choice for concentrated acid or alkali circuits, chemical dosing lines and, in its UHP form, for the ultrapure water circuits that PEM electrolysis demands. AGRU's PURAD PVDF-UHP piping system is manufactured under ISO Class 5 cleanroom conditions with minimal leach-out, which is exactly what a PEM process running at very low ion concentration requires. IPS stocks AGRU PVDF systems and holds the welding equipment for sale or hire.
ECTFE: when PVDF meets its limits
For the most aggressive chemical duties, particularly where concentrated alkali at high temperature is involved, ECTFE offers even better chemical resistance than PVDF, with particularly strong performance in alkaline solutions. It is highly impact-resistant and maintains its properties over a wide temperature range. On a large alkaline electrolyser plant operating at next-generation process temperatures approaching 120°C, ECTFE becomes the informed specifier's choice for the most demanding circuits.
PE100: for bulk water and large diameter
Every electrolysis process needs water, and significant volumes of it. Large-diameter PE100 pipework handles feed water, cooling water and process water transport reliably. AGRU XL large-diameter PE piping is designed for exactly this duty, jointed by butt fusion and electrofusion to proven standards. For coastal electrolyser sites, where feed water may be drawn from desalination plant, large-diameter PE is the standard specification.
Valves matter as much as pipe
A correctly specified pipe run let down by an under-specified valve is still a liability. For KOH service, chemical dosing and any line carrying corrosive or toxic media, the valve must provide zero fugitive emissions. SwissFluid fully lined ball valves and butterfly valves carry maintenance-free stem seals compliant with TA Luft VDI 2440 and ISO 15848-1, rated leak-free across the full operating range. Liner options in PTFE, PVDF and PFA match the duty. These credentials belong in the specification from the start, not added as a value-engineering afterthought.
For closed sampling duties on process lines, SwissFluid sampling systems provide zero-stem-leakage, no-dead-space sampling from corrosive and aggressive media, compliant with EN ISO 15848-1 and TA Luft. That means representative samples and zero operator exposure risk.
One more thing: stock and delivery
A hydrogen project on a government-backed revenue support contract has a programme. Delays have consequences that are measured in real money. IPS holds large UK stocks across the AGRU PP, PVDF and PE ranges, with next day delivery available and technical support to back the specification. Getting the material right is half the job. Having it on site when the programme needs it is the other half.
If you are specifying a hydrogen plant and want to discuss material selection in detail, book a call with one of our sales engineers. We will work through the duty conditions with you and make sure the spec is right before it reaches procurement.
