Brass, Stainless Steel and Beyond: A Guide to Liquid Cooling Components
Supporting the Flow: Components Behind the Coolant
As data centres evolve to meet the growing demands of high-performance computing, AI workloads, and dense server configurations, thermal management has become a critical challenge.
Traditional air cooling is being supplemented — and in many cases replaced — by liquid cooling, which offers higher efficiency and precision in heat removal.
While discussions often centre around cold plates, chillers, and immersion fluids, the plumbing and fluid handling components play an equally important role in the reliability and performance of these systems.
One commonly used material in these components is brass — though it's not the only option.
What Is Liquid Cooling?
Liquid cooling removes heat by circulating a coolant (typically water, glycol, or dielectric fluids) in direct contact with heat sources. The two most common approaches are:
Direct-to-chip cooling: Coolant flows through cold plates mounted directly on processors and memory modules.
- Immersion cooling: Servers are fully submerged in non-conductive liquids that absorb heat through direct contact.
Both methods require robust and leak-free systems of fittings, valves, manifolds, and tubing to manage the flow of coolant — which brings material selection into focus.
Material Considerations for Liquid Cooling Components
When selecting materials for fittings, valves, manifolds, and other components in liquid-cooled data centre systems, there’s no one-size-fits-all answer.
Each material comes with trade-offs in corrosion resistance, strength, weight, cost, thermal behaviour, and regulatory compliance. Here's how the most commonly used materials perform in context.
Brass (including Lead-Free Alloys)
Brass is widely used in fluid-handling components thanks to its excellent machinability, dimensional stability, and corrosion resistance, particularly in water-glycol systems. It’s especially well-suited to high-volume, tight-tolerance machining, making it a common choice for precision fittings and connectors.
Modern lead-free brass alloys, such as CW510L and ECO BRASS®, meet growing requirements for RoHS, REACH, and NSF 61 compliance — essential in industries where environmental and human health regulations are a concern. These alloys offer the same mechanical strength and durability as traditional brasses while eliminating the risks associated with lead content.
Brass also has good mechanical strength, natural antimicrobial properties, and a long service life. However, it’s heavier than plastics or aluminium, and in mixed-metal systems, care must be taken to prevent galvanic corrosion.
Its cost is moderate — potentially higher than polymers or aluminium — but offset by its reliability and ease of manufacture.
Stainless Steel
For systems under high pressure, exposed to chemical variation, or where mechanical stress is a concern, stainless steel is a trusted choice. It offers superior corrosion resistance, particularly in more aggressive cooling fluids, and handles mixed-metal contact better than brass or aluminium.
Its strength and durability are excellent, and it’s fully recyclable, making it a good option for long-lifecycle designs. However, stainless steel is significantly harder to machine, especially for complex turned parts, which can increase manufacturing time and cost.
It’s less common in high-volume precision fittings, but ideal for structural or critical components.
High-Performance Plastics (e.g. PEEK, PPS, Nylon)
Plastics are increasingly used in non-load-bearing and secondary coolant system components where lightweight, corrosion resistance, and chemical stability are key. These materials are especially valuable in applications requiring electrical insulation or thermal isolation.
They’re generally easier and cheaper to mould or machine than metals, but may lack the mechanical strength or thread retention needed for pressurised systems.
Their performance can vary widely depending on formulation, and not all polymers meet regulatory or recyclability standards, so careful selection is required.
Aluminium
Aluminium is chosen where weight reduction and cost efficiency are priorities — such as in mobile or rack-mounted cooling modules. It also offers good thermal conductivity, making it useful in components where heat dissipation is required without adding much mass.
That said, aluminium is more prone to corrosion, especially in aqueous systems, and may require protective coatings or anodising to perform reliably over time.
Its machinability is good, but it’s typically reserved for parts where mechanical load is lower or protective measures can be incorporated.
Environmental and Regulatory Considerations
As sustainability commitments and compliance requirements grow more stringent, material selection is no longer guided solely by performance and cost — it’s also shaped by environmental impact and regulatory alignment.
Regulations such as RoHS, REACH, and NSF 61 are pushing manufacturers to eliminate hazardous substances and adopt safer, more sustainable alternatives. This shift is especially relevant in data centre environments, where components often operate near electronics, water-based fluids, or human-accessible infrastructure.
Lead-free materials — particularly modern brass alloys — are increasingly specified to meet these standards, while recyclability is becoming a critical consideration across the board. Metals like brass, stainless steel, and aluminium are attractive not only for their durability, but also for their ability to be fully reclaimed and reused at end of life.
Polymers, although lightweight and chemically resistant, present a more complex picture. Their environmental credentials depend heavily on formulation, processing methods, and local recycling capabilities — which can vary widely.
In short, materials are now being judged not just by how they perform during operation, but also by how they are sourced, processed, and retired. For data centre cooling systems designed to last and scale responsibly, these considerations are becoming as important as technical fit.
Making Informed Material Choices
Liquid cooling continues to reshape how data centres manage thermal loads, and the success of these systems depends on choosing the right components — made from the right materials.
Each material discussed — from brass and stainless steel to aluminium and advanced polymers — brings a unique balance of mechanical properties, processability, and design trade-offs.
The ideal solution often lies not in a single choice, but in a strategic combination of materials selected to meet performance, compliance, and sustainability goals.
A system-level approach — one that accounts for thermal dynamics, regulatory requirements, lifecycle impact, and cost — gives engineers and procurement teams the best chance of building cooling systems that are efficient, scalable, and built to last.
