A common misconception is that one piece of material is the same as the other! Unfortunately that is not the case, it is important to understand that these products are made up of chemical compositions that are specifically fabricated to give an end result that is fit for a specific purpose. It is therefore logical to see that they will also perform differently when under stress.
It is also critical to remember that because a system is tested, it does not mean another will perform in the same manner, keeping that in mind, it is important to recognise that our method of fabrication may not be same for another alternative. It is why we are adamant that all our systems are independently tested to meet your system requirements.
At Ductus, we have done just that and will guarantee our systems. We also believe that it is our duty to keep you updated with the latest information in duct construction. On this page will find the requirements for meeting the AS/NZ standards for steel duct. We also want to make it easy for you meet the required thermal outlines. If you require further assistance, please do not hesitate to contact us.
Definitions
All boards are not the same and therefore not all testing can be transferrable from one system to another. Hence the fabrication manual cannot be used.
…three critical documents are referenced in this guide:
– National Construction Code Building Code of Australia,
– Volume 1, Rigid ductwork standard AS 4254.2,
– Insulation standard AS/NZS 4859.1
1.5.10 Duct—a component part of an air-handling system, intended for the passage of
air from one part of an air-handling system to another. (See also definition of ‘plenum’).
1.5.36 Plenum—an air compartment or chamber, intended for the passage of air, to
which one or more ducts may be connected and which forms part of an air-handling
system.
This year Ductus has held its second Iso Duct Fabrication Course. We do this to ensure all practices are maintained to the highest of quality, it also means that regardless of where you get your ALP ductwork in the region, it is constructed to the same high standards that we expect, giving peace of mind to the contractor, developer and specifier that its done right from the get go! Check out the video below! Don’t forget to hit the follow button for some big announcements coming up.

Protected: NCC2019 Volume Three
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Protected: NCC2019 Volume Two
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Protected: NCC2019 Volume One
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Protected: NCC2019 BCA Guide
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Protected: Natspec
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Climate Zones
Australia has a varied climate, leading to different locations around the country having different heating and cooling requirements. To account for these differences the energy efficiency Deemed-to-Satisfy Provisions vary from location to location and for simplicity, locations with approximately similar climates have been combined into eight climate zones.
The following provides a brief description of each NCC climate zone:
Climate zone 1 – High humidity summer, warm winter
Climate zone 2 – Warm humid summer, mild winter
Climate zone 3 – Hot dry summer, warm winter
Climate zone 4 – Hot dry summer, cool winter
Climate zone 5 – Warm temperate
Climate zone 6 – Mild temperate
Climate zone 7 – Cool temperate
Climate zone 8 – Alpine
These eight climate zones are illustrated in the form of a climate zone map which was created using Bureau of Meteorology climatic data with two supplementary zones added to accommodate an additional temperate zone and alpine area. The climate zone boundaries are also aligned with local government areas and are therefore subject to change from time to time.
Australia is a varied climate with different locations requiring different heating and cooling needs. Accounting for these variations in climate, the Energy Efficiency Deemed-To-Satisfy has, for simplicity, allocated locations that are approximations of one another in terms of what their general climates are like. As a result, there are eight climate zones, described briefly below.
Climate Zone 1: Warm winters and high-humidity summers
Climate Zone 2: Mild winters and warm, humid summers
Climate Zone 3: Warm winters and hot, dry summers
Climate Zone 4: Cool Winters and hot, dry summers
Climate Zone 5: Warm in temperature
Climate Zone 6: Mild in temperature
Climate Zone 7: Cool in temperature
Climate Zone 8: Alpine
These zones are illustrated below in a series of diagrams that have been sanctioned by the Bureau of Meteorology. Two additional zones have been added to account for alpine and temperate areas. The eight zone-boundaries are subject to changes over time as they are (in some cases) aligned with local government. The map is relevant to the State of Victoria.
Australia has a varied climate, leading to different locations around the country having different heating and cooling requirements. To account for these differences the energy efficiency Deemed-to-Satisfy Provisions vary from location to location and for simplicity, locations with approximately similar climates have been combined into eight climate zones.
The following provides a brief description of each NCC climate zone:
Climate zone 1 – High humidity summer, warm winter
Climate zone 2 – Warm humid summer, mild winter
Climate zone 3 – Hot dry summer, warm winter
Climate zone 4 – Hot dry summer, cool winter
Climate zone 5 – Warm temperate
Climate zone 6 – Mild temperate
Climate zone 7 – Cool temperate
Climate zone 8 – Alpine
These eight climate zones are illustrated in the form of a climate zone map which was created using Bureau of Meteorology climatic data with two supplementary zones added to accommodate an additional temperate zone and alpine area. The climate zone boundaries are also aligned with local government areas and are therefore subject to change from time to time.
This Climate Zone Map is relevant to the New South Wales and Australian Capital Territory regions.
Australia has a varied climate, leading to different locations around the country having different heating and cooling requirements. To account for these differences the energy efficiency Deemed-to-Satisfy Provisions vary from location to location and for simplicity, locations with approximately similar climates have been combined into eight climate zones.
The following provides a brief description of each NCC climate zone:
Climate zone 1 – High humidity summer, warm winter
Climate zone 2 – Warm humid summer, mild winter
Climate zone 3 – Hot dry summer, warm winter
Climate zone 4 – Hot dry summer, cool winter
Climate zone 5 – Warm temperate
Climate zone 6 – Mild temperate
Climate zone 7 – Cool temperate
Climate zone 8 – Alpine
These eight climate zones are illustrated in the form of a climate zone map which was created using Bureau of Meteorology climatic data with two supplementary zones added to accommodate an additional temperate zone and alpine area. The climate zone boundaries are also aligned with local government areas and are therefore subject to change from time to time.
This Climate Zone Map is relevant to the Queensland region.
Australia has a varied climate, leading to different locations around the country having different heating and cooling requirements. To account for these differences the energy efficiency Deemed-to-Satisfy Provisions vary from location to location and for simplicity, locations with approximately similar climates have been combined into eight climate zones.
The following provides a brief description of each NCC climate zone:
Climate zone 1 – High humidity summer, warm winter
Climate zone 2 – Warm humid summer, mild winter
Climate zone 3 – Hot dry summer, warm winter
Climate zone 4 – Hot dry summer, cool winter
Climate zone 5 – Warm temperate
Climate zone 6 – Mild temperate
Climate zone 7 – Cool temperate
Climate zone 8 – Alpine
These eight climate zones are illustrated in the form of a climate zone map which was created using Bureau of Meteorology climatic data with two supplementary zones added to accommodate an additional temperate zone and alpine area. The climate zone boundaries are also aligned with local government areas and are therefore subject to change from time to time.
This Climate Zone Map is relevant to the Western Australia region.
Australia has a varied climate, leading to different locations around the country having different heating and cooling requirements. To account for these differences the energy efficiency Deemed-to-Satisfy Provisions vary from location to location and for simplicity, locations with approximately similar climates have been combined into eight climate zones.
The following provides a brief description of each NCC climate zone:
- Climate zone 1 – High humidity summer, warm winter
- Climate zone 2 – Warm humid summer, mild winter
- Climate zone 3 – Hot dry summer, warm winter
- Climate zone 4 – Hot dry summer, cool winter
- Climate zone 5 – Warm temperate
- Climate zone 6 – Mild temperate
- Climate zone 7 – Cool temperate
- Climate zone 8 – Alpine
These eight climate zones are illustrated in the form of a climate zone map which was created using Bureau of Meteorology climatic data with two supplementary zones added to accommodate an additional temperate zone and alpine area. The climate zone boundaries are also aligned with local government areas and are therefore subject to change from time to time.
This Climate Zone Map is relevant to the South Australia region.
Australia has a varied climate, leading to different locations around the country having different heating and cooling requirements. To account for these differences the energy efficiency Deemed-to-Satisfy Provisions vary from location to location and for simplicity, locations with approximately similar climates have been combined into eight climate zones.
The following provides a brief description of each NCC climate zone:
- Climate zone 1 – High humidity summer, warm winter
- Climate zone 2 – Warm humid summer, mild winter
- Climate zone 3 – Hot dry summer, warm winter
- Climate zone 4 – Hot dry summer, cool winter
- Climate zone 5 – Warm temperate
- Climate zone 6 – Mild temperate
- Climate zone 7 – Cool temperate
- Climate zone 8 – Alpine
These eight climate zones are illustrated in the form of a climate zone map which was created using Bureau of Meteorology climatic data with two supplementary zones added to accommodate an additional temperate zone and alpine area. The climate zone boundaries are also aligned with local government areas and are therefore subject to change from time to time.
This Climate Zone Map is relevant to the Tasmania region.
Australia has a varied climate, leading to different locations around the country having different heating and cooling requirements. To account for these differences the energy efficiency Deemed-to-Satisfy Provisions vary from location to location and for simplicity, locations with approximately similar climates have been combined into eight climate zones.
The following provides a brief description of each NCC climate zone:
- Climate zone 1 – High humidity summer, warm winter
- Climate zone 2 – Warm humid summer, mild winter
- Climate zone 3 – Hot dry summer, warm winter
- Climate zone 4 – Hot dry summer, cool winter
- Climate zone 5 – Warm temperate
- Climate zone 6 – Mild temperate
- Climate zone 7 – Cool temperate
- Climate zone 8 – Alpine
These eight climate zones are illustrated in the form of a climate zone map which was created using Bureau of Meteorology climatic data with two supplementary zones added to accommodate an additional temperate zone and alpine area. The climate zone boundaries are also aligned with local government areas and are therefore subject to change from time to time.
This Climate Zone Map is relevant to the Northern Territory region.
NCC Compliance
Reference: NCC BCA Vol. 1, Specification J5.2-3
Under Section J, ductwork and fittings, used for heating and cooling, must be insulated to the levels detailed in the following table – Mimimum Material R-value and must comply with AS/NZS 4859.1.
Reference: NCC BCA Vol. 1, Specification C1.10-5 referencing AS 4254.2, Section 2.1.2
Rigid ductwork must comply with the following fire hazard properties as set out in AS 4254.2 (see Table 2 Minimum Fire Hazard Properties). These requirements apply to both bulk insulation used to lag rigid ductwork and to pre-insulated ductwork systems.
Reference: NCC BCA Vol. 1, Specification J5.2-2 referencing AS 4254.2, Section 2.2.4
Rigid ductwork systems must be sealed against air leakage in accordance with AS 4254.2 for the static pressure in the system (see the following table).
The above requirements do not apply to ductwork and fittings located within the only or last room that is served by the system.
Reference: NCC BCA Vol. 1, Specification A2.2
There are a number of ways a manufacturer or supplier can show that a ductwork system meets a Performance Requirement or a Deemed-to-Satisfy Provisionof the NCC. Subject to the fire safety requirements detailed in the Fire Performance section, suitability can be demonstrated with any one of the following:
- A report issued by a Registered Testing Authority (refer to definition below), showing that the material or form of construction has been submitted to the tests listed in the report, and setting out the results of those tests and any other relevant information that demonstrates its suitability for use in the building.
- A current Certificate of Conformity or a current Certificate of Accreditation.
- A certificate from a professional engineer or other appropriately qualified person which –
- certifies that a material, design, or form of construction complies with the requirements of the BCA; and
- sets out the basis on which it is given and the extent to which relevant specifications, rules, codes or practice or other publications have been relied upon.
- A current certificate issued by a product certification body that has been accredited by the Joint Accreditation System of Australia and New Zealand (JAS-ANZ).
- Any other form of documentary evidence that correctly describes the properties and performance of the material or form of construction and adequately demonstrates its suitability for use in the building.
Where calculations are performed, compliance with the ABCB protocol can be demonstrated with any one of the following:
- A certificate from a professional engineer or other appropriately qualified person which –
- certifies that the calculation method complies with a relevant ABCB protocol; and
- sets out the basis on which it is given and the extent to which relevant specifications, rules, codes or practice or other publications have been relied upon.
- Any other form of documentary evidence that correctly describes how the calculation method complies with a relevant ABCB protocol.
The NCC requires that any documentary evidence that is submitted must be a complete copy of the original.
1 Scope
Intent
To clarify that Specification J5.2b provides the required performance of ductwork insulation and sealing.
Clause 1(a) clarifies that Specification J5.2b contains the required performance for the insulation and sealing of ductwork and fittings, where the ductwork is part of an air-conditioning system.
Clause 1(b) outlines that for the purposes of this Specification, ‘fittings’ includes passive or static components of a ductwork system and excludes active components of a ductwork system such as those used in an air-handling unit.
This means passive or static components of a ductwork system must meet the requirements of this Specification and may include items such as plenums, bends, branches, transitions, reducers, offsets, spigots, cushion heads, attenuators and fixed air balance dampers.
Active components of a ductwork system are exempt from the insulation and sealing requirements of this Specification. This exemption recognises that there are practical difficulties applying insulation to components that move or where access is regularly required.
Active components may include Variable Air Volume (VAV) boxes, electric duct heaters, actuated volume control dampers, access panels and doors, fire and smoke dampers, fans or humidifiers.
As 4254.2 ductwork for air-handling systems in buildings, part 2: rigid duct
Reference: AS 4254.2, Section 1.8
Fire testing on insulation, facing material and rigid ductwork material must be performed by a Registered Testing Authority. Samples submitted for testing must be identical to the manufactured product. The test certificates must include the following minimum product data:
- Manufacturer’s name or registered trademark and product name.
- Thickness, R-value, density of insulation and all flame retardants used.
- Nominal grammage (g/m2) of facing or lining material and all flame retardants used.
- For facings and lining materials of a composite nature that are bonded together with fire-retardant adhesives, the adhesive type, all flame retardants used in the adhesive and the weight of adhesive applied (g/m2).
Any alternative materials, designs, methods of assembly, and procedures that do not comply with specific requirements of this Standard, or are not mentioned in it, would need to be assessed by the appropriate regulatory authority.
Reference: AS 4254.2, Section 2.2.4
In addition to the air leakage limitations detailed in the previous Ductwork Sealing (Air Leakage) section, AS 4254.2 requires that a minimum of 10% of each duct system, longitudinal seams length and total circumferential joints length shall be tested, inclusive of floor distribution, riser and plant room duct, and of each seam, joint and sealing construction type.
The Standard requires records to be kept of each test result, inclusive of seam, circumferential joint and sealant type and length, calculated section operating pressure, test pressure and air leakage.
Reference: AS 4254.2, Section 2.3
In relation to rectangular duct reinforcement, AS 4254.2 details a wide range of construction and reinforcement specifications which can be referenced unless specified otherwise. The standard conveys details around minimum joint reinforcement, joint types and joint ratings, types of intermediate reinforcements, longitudinal seams and seam locations, tie rod details and rectangular duct construction.
Reference: AS 4254.2, Section 2.6
As with rectangular duct reinforcement requirements, AS 4254.2 similarly details specific requirements for hangers and support systems for both strap-and-rod systems and wire rope suspension systems.
Reference: AS 4254.2, Section 4.1.1
The deflection of the sheet sections of ducting shall not exceed the following:
Reference: AS 4254.2, Section 4.1.2
The maximum deflection shall be 6.0 mm at maximum operating pressure.
Reference: AS 4254.2, Section 4.1.3
Longitudinal seams shall not deform or fail at 150% of maximum operating pressure.
Reference: AS 4254.2, Section 4.1.4
Transverse joints shall not fail at 150% of maximum operating pressure.
Where transverse joints act as reinforcing members, deflection shall be 6.0 mm at maximum operating pressure.
Reference: AS 4254.2, Section 4.1.5
A duct section between adjacent hangers shall be capable of carrying its own weight and resist external loads for which it is constructed.



Compliance to the NCC Deemed to Satisfy Note: important acceptance Evidence of Suitably Performance Requirement in product quality thermal Perform fire requirement leakage pressure irrection fabrication.
We are able to show Deemed to Satisfy by past installations globally, EN standards, Middle Eastern Standards, Australian standards New Zealand standard Different climate/enviroments Training installers and Fabricators
Registered Test Authority NATA testing as per duct stanards in Australia.
Certificate of Accredited (accronum) by a professional engineer Stipulating (iii) – (A) and (B) by providing his 65 pg report.
Fire is met as stipulated in AS425.2