Applications & Engineering

This question comes up frequently from offshore, marine, and desalination customers, and the honest answer is: it depends on the application within the marine environment — and standard brass is wrong for most of them.

Direct seawater service — no. Standard CW617N — and in time even CW602N DZR brass — is attacked in continuous seawater contact. Chloride concentration in seawater (≈19,000 mg/L) is orders of magnitude above the dezincification threshold. For structural fittings in direct seawater contact, the material choices are: gunmetal (CC491K, 85/5/5/5 Cu-Sn-Pb-Zn) — excellent marine performance; cupro-nickel (90/10 or 70/30) — the standard for marine heat exchangers and pipework; or 316 stainless steel for non-galvanic-compatible assemblies.

Marine deck and above-waterline fittings: Salt-air corrosion is less severe than immersion. CW602N DZR with appropriate surface protection handles this well. The brass parts we machine are regularly specified for marine deck fittings, fresh-water systems aboard vessels and shore-power (non-fluid) applications where brass is the standard. Desalination plant instrument connections (brine side, above operating temperature): Specify gunmetal or duplex stainless. Desalination post-treatment (fresh water distribution): Brass fittings per the relevant dimensional and alloy standard are generally appropriate — confirm certification requirements (WRAS, NSF 61, or equivalent) with your end customer at RFQ.

Always disclose the exact application environment to us at RFQ — "marine" covers a huge range of conditions and the right material for a fresh water system on a yacht is different from the right material for a seawater cooling circuit.

UK potable water specification has a clear hierarchy, and if you follow it, you won't have problems. If you deviate from it, the consequences range from a failed building control inspection to a product liability claim.

Material: Dezincification-resistant brass (CW602N to EN 12165) for hot water and wherever the water is aggressive to brass — soft, low-alkalinity or chloride-rich supplies. Under the Water Supply (Water Fittings) Regulations 1999, any concealed water fitting that is not a terminal fitting must be made of gunmetal or another dezincification-resistant material, so DZR brass is the norm for buried and built-in fittings, and many specifiers require it throughout for whole-system consistency. Standard CW617N is used in accessible positions where the water is not aggressive. Certification: every fitting must comply with Regulation 4 of the Water Fittings Regulations. WRAS approval is the most widely requested evidence of that compliance (KIWA KUKreg4 and NSF REG4 are alternatives); the non-metallic materials in a fitting are tested to BS 6920. A fitting without such evidence can be rejected by the water company's inspectors. Thread standard: BSPP (ISO 228, G-thread) for UK plumbing — not NPT. Dimensional standard for compression fittings: EN 1254-2 for copper tube, EN 1254-3 for plastic pipe. Valve pressure rating: PN16 minimum for most building services applications; PN40 for commercial and heating applications. Lead: the Regulations prohibit materials that contaminate the water. CW602N is a leaded DZR brass (Pb 1.7–2.8%) that is widely used and accepted for this service; where a lead-free alloy is required, specify CW724R. Buy approved fittings from a supplier who holds the approval for the finished product. Note: Brassland does not currently hold WRAS certification — confirm this requirement at RFQ so the appropriate approved supply chain can be arranged.

Compressed air is one of brass fitting's strongest application domains — and it's also one where under-specification creates serious workplace safety risks. Here is the engineering picture.

Brass (CW617N) is appropriate for compressed air systems from 0°C to 80°C operating temperature, at working pressures up to 25–40 bar (depending on fitting size and design) for standard industrial supply pressure ranges of 6–10 bar. This covers the vast majority of factory compressed air systems worldwide. The material isn't usually the constraint — the installation quality is.

What matters in compressed air applications: Pressure rating: Specify fittings rated to at least 1.5× your maximum supply pressure. A system running at 10 bar needs fittings rated to at least 15 bar. Brass threaded fittings for compressed air are typically rated PN25–PN40 depending on size and geometry — the rating of a specific fitting is set and validated by whoever owns its design; we machine the components to your drawing and do not rate them. Filtration: Compressor oil carry-over degrades PTFE seats and seals over time. Specify oil-resistant elastomers (NBR as minimum, FKM for oil-injected rotary screw systems) for any fittings with elastomeric seals. Thread sealant: Loose PTFE tape fragments entering a pneumatic actuator or solenoid valve is a common cause of system failure. Specify a liquid thread sealant rated for pneumatic service on threaded joints.

HVAC refrigerant applications have very specific material requirements, and the wrong specification creates equipment failures and refrigerant leaks — which carry both safety and regulatory consequences under F-Gas regulations in Europe.

Refrigerant-grade copper fittings (Cu-DHP, C12200/CW024A) are the industry standard for refrigerant pipework in air conditioning and heat pump systems. The reason: Cu-DHP is phosphorus-deoxidised copper (0.015–0.040% P), so it can be brazed without hydrogen embrittlement, and the ACR tube standard sets internal-cleanliness requirements that keep moisture and debris out of the refrigerant circuit. Standard CW024A copper tube and fittings to EN 12735 (ACR tube) are specified for refrigerant applications globally.

Brass fittings in refrigerant systems: brass is used for service valves, Schrader valve cores, pressure gauge connections, and safety relief valve bodies — components where the refrigerant contact is intermittent or the geometry requires machined brass. These must be compatible with the specific refrigerant (R410A, R32, R22, R134a etc.) and with the POE or mineral oil in the system. We machine brass bodies, flare fittings to SAE J513 and Schrader-type valve bodies to drawing; we do not assemble, test or rate finished service valves.

For R32 systems specifically: R32 runs slightly above R410A — the saturation pressure at 65°C is about 43 bar against about 41.5 bar — and both are far above older low-pressure refrigerants. Every component must be rated for the design pressure stated by the equipment manufacturer; verify this whenever components are carried over from an older design — a common oversight in field retrofits.

Yes — brass can be used in hydrogen systems. Copper and its alloys — brass, bronze and copper-nickel — are rated compatible with gaseous and liquid hydrogen (NASA NSS 1740.16, Table A5.1), and oxygen-free copper is relatively unaffected by high-pressure hydrogen.

There are two limitations. Avoid copper that contains oxygen (such as Cu-ETP, C11000): hydrogen embrittles it. And take the pressure class from the standard that governs your system — it results from the fitting design and is confirmed in qualification by the system manufacturer. 300-series stainless steel is the usual choice for gaseous-hydrogen piping.

For hydrogen blending into natural gas networks, acceptance of existing fittings is decided by the gas safety body of your market — this is an active area of regulatory development. Brassland machines the components to your drawing. See our guide to brass in hydrogen applications.

High-rise commercial building plumbing has a specific set of engineering demands that you don't encounter in residential work — and specifying for it requires understanding the pressure zones, the regulatory framework, and the maintenance realities.

Pressure: In buildings above 10 storeys, the base-of-riser pressure typically exceeds 16 bar — sometimes reaching 25 bar before pressure-reducing valves. Specify fittings rated to PN40 as standard throughout. Don't accept PN25 fittings at the bottom of a tall building — the transient pressure during pump starts can exceed steady-state significantly. Material: DZR brass for potable water systems — leaded CW602N where the market accepts it, lead-free CW724R where a drinking-water lead limit applies (European positive list, US 0.25 %, Australia) — required in the UK for concealed fittings and good practice wherever the water is aggressive. For UK potable water, fittings must comply with Regulation 4 (WRAS approval is the usual evidence); Brassland holds no product approvals — confirm this at RFQ. For Middle East high-rise: consider that aggressive desalinated water with low mineral content can accelerate certain corrosion mechanisms differently from European water chemistry. DZR brass is the correct material choice (lead-free CW724R where a drinking-water lead limit applies); confirm specific water chemistry with the local water authority and specify accordingly. Dezincification risk is heightened in desalinated water at elevated temperature. Valve selection: For building services isolation, full-bore ball valves in DN15 to DN50 (PN40) with lockable handles. For pressure control: use reduced-bore ball valves only where flow coefficient (Cv) allows — don't restrict flow unnecessarily in commercial systems. Legionella prevention: System design must support regular thermal flushing. Specify fittings with no dead legs — T-junctions rather than blind-end branch connections wherever possible.

Solar thermal systems are a demanding application that punishes poor specification choices — because the operating conditions are extreme and maintenance access is typically difficult once installed.

Temperature: The collector circuit in a flat-plate or evacuated tube system can reach stagnation temperatures of 150–200°C when there's no flow (pump failure, power cut). Standard PTFE seats start to creep above about 150°C, so for the collector circuit valve makers use glass-filled PTFE seats, which extend the range toward 200°C — we machine the brass valve components; seat selection and the valve's temperature rating are the valve manufacturer's. On the heat exchanger secondary side (domestic hot water), standard PTFE is fine — temperatures stay below 80°C. Fluid: The primary circuit uses inhibited propylene glycol (typically 35–45% concentration) as antifreeze and corrosion protection. Brass is compatible with propylene glycol at normal concentrations. However, glycol that is not maintained — where inhibitor degrades — becomes acidic and attacks brass aggressively. Specify that the system owner maintains annual glycol pH checks (target pH 8–9); acidic glycol (pH below 7) is a copper alloy corrosion accelerant. Pressure: Solar circuits typically run at 2–4 bar working pressure with a safety valve at 6–8 bar. PN10 fittings are technically sufficient, but we recommend PN16 minimum for the collector circuit given the pressure transients during pump start against a hot, partially steam-flashed header. Connection type: Compression fittings on copper ACR tube for the collector circuit — no push-fit. Thermal cycling at 150°C is beyond the design range of standard push-fit thermoplastic grab-rings.

Food and beverage is a sector where material selection has public health and regulatory consequences — and the answer is nuanced by application, fluid contact type, and the specific regulatory framework of your market.

Brass in direct contact with food or beverages: Generally not recommended and often not permitted by food safety regulations. Standard brass (CW617N) contains lead as a machining aid — even at low levels, lead migration into food products or beverages is a regulatory and public health issue. In the EU, materials in contact with food are governed by EC 1935/2004 and specific material regulations (there is no EU-wide measure specifically for metals; the Council of Europe technical guide on metals and alloys in food contact, with its specific release limits, and national rules such as those of France and Italy are the usual references). In the UK, the Food Contact Materials Regulations apply. For most regulatory frameworks, lead-containing metals in direct contact with food must demonstrate migration below specific thresholds — that has to be shown by migration testing of the finished part, also for low-lead alloys, and the testing and documentation are the responsibility of the company placing the product on the market.

Where brass is clearly appropriate in food processing: Pneumatic control systems (compressed air, not in contact with product), clean utility systems (steam, cooling water, glycol) that don't contact product, general plant infrastructure (equipment mounting, machine frame connections). Where you should use stainless or approved plastics: Any wetted surface in direct product contact, CIP (clean-in-place) circuits where caustic soda (NaOH) is used for cleaning — caustic is very aggressive to brass at concentration. Aluminium components (6061, 6063) for dry compressed-air lines in food plants are machined to drawing, with anodising on request.

District energy systems — where hot or chilled glycol-water mixture is circulated over long distances at elevated temperature and pressure — place specific demands on fittings that general industrial products don't always address.

Glycol compatibility: Inhibited propylene glycol (IPG) at 25–50% concentration is compatible with brass (CW617N and CW602N) at temperatures up to 120°C. The inhibitor package matters — phosphate/molybdate-inhibited glycol is benign to copper alloys. Uninhibited or degraded glycol is not. Specify to your system operator that glycol must be maintained at pH 7.5–9.0 and inhibitor concentration must be tested annually. This is not over-caution — degraded glycol turns acidic, and acidic glycol attacks copper alloys. Pressure: District heating primary circuits typically operate at 6–16 bar and temperatures of 70–130°C (for medium-temperature DH) or 150–180°C (high-temperature DH). For high-temperature DH, brass has marginal temperature headroom — above roughly 200°C brass itself is the limiting factor — and primary circuits normally use flanged valves rather than compression or push-fit joints. Size range: District energy primary connections are typically DN40 to DN100 and larger — mostly flanged steel, ductile-iron or stainless valves, which are outside Brassland's scope. We machine brass components from bar up to Ø150 mm to your drawing — typically the smaller fittings, valve internals and instrument connections of a substation. Thermal insulation: Specify fittings with extended stems for insulated pipework — the handwheel must be accessible through the insulation.

Medical gas systems are the most unforgiving application a machined component can end up in — because a component failure in oxygen, nitrous oxide, or vacuum systems doesn't result in a process upset. It results in a patient harm event. We take this application category more seriously than any other.

Regulatory framework: In the UK, medical gas pipeline systems (MGPS) are governed by HTM 02-01 (Health Technical Memorandum). In Europe, EN ISO 7396 series applies. In the USA, NFPA 99 governs healthcare facility gas systems. These are not voluntary standards — they are mandatory design specifications for hospital projects, and non-compliance creates both regulatory and criminal liability for the specifier.

Material requirements: Oxygen service demands materials with zero oil or grease contamination — any organic contamination in the presence of high-pressure oxygen creates a combustion risk. Components for oxygen service have to be cleaned and degreased to an oxygen-cleanliness specification — ASTM G93 is the usual reference — and sealed in clean bags immediately afterwards. Brassland does not run a certified oxygen-cleaning line: we machine the copper and brass components to drawing and can degrease and bag them to an agreed specification, while oxygen cleaning and its verification are carried out by the system manufacturer or a specialist cleaner. Standard industrial fittings are not appropriate regardless of material — the cleaning protocol is what creates oxygen-grade components, not just the alloy. For anaesthetic gases (nitrous oxide, CO₂): degreased copper tube (EN 13348) and fittings are standard, to the cleanliness requirements of the pipeline standard that applies. Marking: medical gas components and pipelines must be identified for the gas service they are intended for; the marking scheme is defined by the pipeline standard and applied by the system manufacturer. We can engrave or laser-mark part numbers and identification to your drawing.

Fire suppression systems are a life-safety application and the specification requirements are non-negotiable — not best-practice guidelines. Get this wrong and you're in the territory of building regulation failure and insurance voidance.

In the UK, fire sprinkler systems are designed to BS EN 12845 (fixed firefighting systems) and BS 9251 (residential sprinklers). In the USA, NFPA 13 governs commercial sprinkler systems, NFPA 13R for residential. In Europe, EN 12845 is the reference. Each standard specifies approved materials, pressure ratings, and listed/approved component requirements. Not all brass fittings are approved for fire suppression — you must use products listed by an approved body (UL listed for USA, LPC/FM approved for UK commercial).

Brassland does not currently hold UL listing or FM approval. Grooved-end and threaded brass fittings for fire suppression must be sourced from a UL-listed and FM-approved supplier — this is a mandatory certification requirement, not a preference. If you require machined brass components to a specific drawing for a fire suppression assembly where the UL/FM listing is held at the assembly level by your customer, we can machine to your drawing — confirm the approval structure at RFQ. For residential sprinkler systems where copper compression fittings on branch lines are used, BS EN 1254-compliant fittings may be appropriate — confirm with your sprinkler system designer. Brass is appropriate for branch lines and head connections; steel and ductile iron are typically specified for mains.

One critical operational point: never use thread sealant paste on fire sprinkler fittings unless it is specifically listed/approved for the application. PTFE tape is acceptable on tapered threads per most standards. Some LPCB-approved systems specify listed sealants only — follow the system designer's specification, not a general plumber's preference.