Projects

The Hidden Value of High-Quality Ducting in Large Buildings

Paul Bondsfield • January 21, 2026

Why Quality Costs Less in the Long Term

SPIRO Ducting in Fisher & Paykal's Auckland Headquarters


When most people think about HVAC performance, they picture fans, chillers, boilers, and control systems. Hardly anyone thinks about ducting — the invisible network that carries conditioned air through a building. Yet ductwork is one of the most important elements in any major construction project because it determines how efficiently, safely, and effectively that air actually reaches its destination.


In offices, hospitals, stadiums, airports and public infrastructure, ducting isn’t just a commodity. It’s a performance system. And the difference between high-quality ducting and “acceptable” ducting can impact:

  • energy consumption
  • thermal comfort
  • fire safety and smoke control
  • acoustic conditions
  • operating costs over decades


Below, we break down what “high quality” really looks like — and why you should insist on it from your ducting supplier.


Quality Is Defined by Standards


In most major markets, ducting quality isn’t a matter of opinion — it’s defined by established standards. These documents set out everything from metal thickness and joint types to allowable leakage rates and testing methods.

Some of the key standards include:


  • SMACNA HVAC Duct Construction Standards - Worldwide reference for duct construction and sizing.
  • AS 4254 - The Australian/NZ standard governing rigid metal ducting materials, construction and installation.
  • AS 1668 – Australian and NZ standard for the use of ventilation and air conditioning in buildings. Covering mechanical ventilation, ventilation design and performance.
  • AS 1530 – Australian and NZ standard for fire testing building materials, components, and structures


A credible ducting manufacturer can tell you exactly which standard they build to — and show evidence of compliance.

If they can’t, you have a problem.


Airtightness Is Where Money Is Won or Lost


Every duct system leaks a little — but how much matters.

Leakage is measured using airtightness classes (A, B, C, D). In commercial and infrastructure projects, Class C or Class D is commonly targeted because they significantly reduce energy waste. With SPIRO we achieve Class D.


Why does this matter?
Because if 10% of air leaks out of the duct — the system compensates. The fan runs harder, energy consumption rises, and comfort falls -  which over the life of a building can cost hundreds of thousands of dollars.


High-quality ducting isn’t just thicker metal. It’s tight, verified, and tested.

SPIRO Ducting Gasket - Class D Tightness

Materials Are Part of the Story


Quality ducting starts with the right material.

  • For most commercial projects, galvanised sheet steel (commonly G90 / Z275) provides a reliable protective coating against corrosion.
  • For environments with chemicals, fumes, or moisture (labs, hospitals, wastewater facilities), stainless steel (304 or 316) may be required.


The specification should clearly define:

  • coating weight
  • thickness (gauge)
  • yield strength
  • any special internal or external protection


If these elements are vague, costs and risks increase later.


Fire Safety Is Non-Negotiable


Ducting passes through fire-rated barriers, shafts, and risers. Every penetration into a fire zone must be controlled with a tested fire damper or smoke control system.


The safety chain must be intact:

  • the damper must be the correct type
  • installed according to test conditions
  • accessible for maintenance
  • integrated with controls and alarms

High-quality ducting is part of a fire strategy, not an afterthought.

 

Cleanliness Matters More Than Ever


Dust, debris and cutting waste inside ducts can cause poor IAQ (indoor air quality). As standards like TR19 gain traction, more specifiers are requiring ducts to be delivered sealed and cleaned before installation.

It’s a sign of a high-quality manufacturer when they can show you their clean-build process: protective end caps, sealed packaging, controlled factory environments.

 

Why Quality Costs Less in the Long Run


High-quality ducting:

  • saves energy
  • reduces complaints
  • extends equipment life
  • improves safety
  • reduces maintenance costs


Low-quality ducting is a short-term saving with long-term penalties. The duct is expected to last 20–30 years. The small investment in quality up-front will be returned many times over.








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October 30, 2025
Christchurch, New Zealand We were honoured to provide the precision-engineered ductwork solutions for Te Kaha, a landmark multi-use arena designed to revitalise Christchurch’s sporting and cultural heart. Our systems support the complex HVAC infrastructure required for a venue that accommodates tens of thousands of spectators, while meeting stringent expectations around natural ventilation, indoor air quality and resilience. By integrating our high-performance air-ducting within a mechanically-efficient, future-focused building envelope, our contribution helps deliver a world-class facility that stands for durability, sustainability and community pride.
October 30, 2025
Auckland, New Zealand We were pleased to supply the air-ducting systems for the new headquarters-style facility of Orams Marine in Auckland. Located in the heart of the marine precinct, this advanced multi‐storey building complements the company’s world-class superyacht refit yard and mixed-use marine village, featuring open offices, workshops and service zones designed to support high-value marine activity. Our precision-engineered ductwork helps deliver high‐quality indoor air across varied areas—from office floors to workshop bays—while aligning with the site’s robust industrial needs and high-performance building goals.
October 30, 2025
Auckland, New Zealand We were proud to supply the air-ducting systems for Fonterra Co-operative Group’s new global headquarters in Auckland. This seven-storey, 16,000 m² building consolidates staff from multiple sites into a high-performance workplace defined by open floor plates, a central atrium and world-class sustainability features. With fully electric heating, rainwater harvesting, a high-efficiency thermal envelope and an advanced ventilation strategy, our ductwork plays a key role in achieving the building’s 5-Green Star base-build rating and readying it for even higher targets. By integrating our precision-manufactured duct systems seamlessly into the fit-out and services architecture, we supported the building’s flexible activity-based work zones and the company’s ambition for a future-proof, low-carbon and people-centric headquarters.
October 30, 2025
Auckland, New Zealand Express Sheetmetals was proud to supply the air-ducting systems for Fisher & Paykal’s new global headquarters — a landmark development that brings together the company’s people, innovation, and production under one roof. Designed for collaboration and sustainability, the building combines open, flexible workspaces with advanced mechanical systems to ensure a healthy and efficient environment. Our precision-engineered ducting supports the complex airflow requirements across office, research, and production areas, contributing to the project’s high-performance, low-carbon objectives and helping create a workplace that truly reflects Fisher & Paykal’s forward-thinking ethos.
February 23, 2020
The chic and modern addition to the University of Auckland, B507 Park West Development - Grafton campus, boasts a value of $100m+, spans 19,500m², and has five occupied levels and includes a carpark, acoustic booths, teaching spaces, clinics and offices. Express was subcontracted to Numecon Contracting to deliver the job within a tight timeframe, beginning in October 2018 and going through to February 2020. “Establishing consistent and clear communications has ensured all aspects of this job were completed with minimum fuss and maximum accuracy. The job was modelled and provided in Revit 3D and which enabled a simple and accurate translation to manufacturing requirements. This and the timely release of high-quality mechanical drawings from Numecon via Aconnex really improved the ability to plan and manufacture this project in support of the site program and ensure manufacturing was completed accurately - first time - to very high standards”, Mike Arcari – Director Production, Express Sheetmetals. Numecon notes that Express excels in responding to site demands in a timely manner, their QA and quality of install are top notch, and their can-do attitude is greatly appreciated. According to Paul O’Callaghan, Director of Numecon Contracting, Express takes the initiative to use innovative technology that significantly improves accuracy and therefore efficiency. “It was a relatively simple space-restricted project, but it had to be done fast, and the accuracy had to be there”, explains Paul. On Express, Paul had this to say, “They are a good company. They have good systems and good people.” On their relationship, “It’s construction. You’re in people's faces. You’re building things. You’re under pressure to deliver. But at the end of the day, they have the right people.” “I liken it to an old Māori proverb that goes like this: ‘He aha te mea nui o tea o? He tangata, he tangata, he tangata. It translates to: ‘It is the people, it is the people, it is the people.’ And this explains Express Sheetmetals to a tee”, Paul finishes. “Working in an environment where there was fantastic alignment and communication between the head contractor, the Numecon team, and ourselves has made this project a pleasure to complete. With stability in the build program, completeness of design and very strong on-site management of the mechanical aspects of the project, we were able to place additional emphasis on quality to ensure we met the very highest of customer expectations” , Sander Dales – Director Operations.
October 9, 2019
Elegant, spacious, luxury living at its best; Waterford Retirement Village crossed the spectrum of the HVAC industry, bringing a variety of HVAC elements into one complex. This stunning project in Hobsonville Point, completed in October 2019, is looked upon as a village within a village; whether independent or community living is desired, it’s got something for everyone. Comprising 30+ apartments and a community lodge with a restaurant/café, bar, wellness centre, private theatre and library, and a heated swimming pool & spa and gym complex, Waterford certainly delivers. Each apartment has a standalone ventilation and air conditioning system, and all common areas are fully ventilated and air conditioned using a highly energy-efficient Mitsubishi Electric VRF air conditioning system. The swimming pool area is also fully ventilated with exposed ducting and heated with space radiant wall-mounted hot water heaters in addition to the underfloor heating. The Basement carpark is fully ventilated with a mechanical extract system to add to the mix. According to Grant Brosnan, Project Manager for Air Mark Services Ltd (Mechanical Contractor), “There was a lot of diversity and different aspects to this job. It was like a whole lot of jobs intermingled into one project; roof work, louvres on outside walls, fully welded kitchen extracts, and exposed pool ducting, etc.” “The major benefit of using Express Sheetmetals on a job of this nature is the two facets of their business: supply and manufacture of ductwork and the installation.” The convenience of the full service is what sets Express Sheetmetals apart, as is one of the biggest in Auckland, providing both product and installation. “It really takes the workload and pressure off us, and is part of what makes Express Sheetmetals a good go-to company.” Grant credits Express Sheetmetals for taking constructive criticism, sorting out any issues swiftly, and their direct communication. “Sander is very good at smoothing over any issues if there are any. To be fair, over the whole project, we never had a major one”, he explains. “Successful completion of this project came down to a comprehensive joint team effort between Air Mark Services Ltd and Express Sheetmetals, as we worked through a significant number of emerging architectural details and requirements throughout the project duration. That kind of teamwork highlights the value of a close partnership, and means all parties can share their best ideas and experiences when working through construction challenges on the project” , Sander Dales – Director Operations, Express Sheetmetals. This project is similar to another retirement village Express completed for Air Mark Services Ltd, a few years ago, Greenwich Gardens – a similar project but at scale, with over 250 apartments. “I must say Express put into their machinery and development of their products the most than any other company I know; money, time and quality. Most of their machinery comes from Switzerland, and the quality of their ducting and so forth is probably one of the best that I have seen in my career. We have used thousands of their particular rubber seal products that alleviate the need to apply duct sealant around the duct. Very impressive”, closes Grant.
May 8, 2015
The multi-million dollar, 17-hectare design and build for the Wiri Prison in South Auckland was an example of a project that combined sheer scale and significant complexity. With 9 different subcontractor companies on that job, effective collaboration was key to the efficient onsite operation. The melding of trades from electrical, ductwork, commissioning, pipework, air conditioning and more meant a concerted team effort was required. Fletcher Construction was the prime contractor on the job, with Aquaheat NZ Ltd providing the building maintenance services. According to the Aquaheat Management Team, "The design was all low storey and rather straightforward. The challenge was the scale; that amount of buildings ail happening at the same time plus the size of the site." There were 32 buildings in total, of which a round half a dozen were small in the ductwork context. At least 20 buildings housed significant ductwork; 3 big house blacks (each 2 storey with over 900 cells each), residents' buildings, which were all low security, kitchen and laundry (a lot of ductwork within), and health, education and administration buildings were also huge buildings containing large volumes of ductwork. Express Sheetmetals did the manufacture and installation on the Wiri Prison job and had at least a 30-strong team working onsite. This showcased their ability to deliver on sizable-scale projects efficiently and with professionalism. Express Sheetmetals are very passionate about what they do!" exclaims David Houghton, Project Manager, Aquaheat NZ Ltd, when asked about Express Sheetmetals and the service they provide. "The word "passion" definitely comes to mind. It's the way they are, and because of that, they do a really good job."
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