Only company in the Middle-East with lightest smoke-extract duct tested under full time-temperature curve for 120min

Airmaster Fire Rated Ductwork Performance Criteria

Duct A fulfils the criteria for the following times shown below:

Type of ductStabilityIntegrityInsulation
Ventilation duct129 Minutes129 Minutes129 Minutes
Smoke Outlet Duct129 Minutes129 Minutes129 Minutes
Kitchen Extract Duct129 Minutes129 Minutes60 Minutes

Duct B fulfils the criteria for the following times shown below:

Type of ductStabilityIntegrityInsulation
Ventilation duct129 Minutes129 Minutes129 Minutes
Smoke Outlet Duct120 Minutes129 Minutes129 Minutes
Kitchen Extract Duct129 Minutes129 Minutes129 Minutes
insulated fire rated duct


  • Tested under full time-temperature curve
  • Fully complied to BS476:24 for 60 min & 120 minutes
  • Tested for Stability , Integrity & Insulation criteria
  • Savings on installation and labor cost due to Light weight construction
  • Environment friendly Superwool® Low Biopersistent Fibres (LBP) insulation
  • Aesthetically appealing

Fundamental Characteristics of Fire Rated Ductwork

Fire rated ductwork usually needs to pass through compartment walls or floors that will have a prescribed fire resistance period in terms of the load bearing capacity, integrity and insulation criteria, for durations of 30 to 240 minutes. It is a requirement that where these compartment walls/floors are penetrated by HVAC ducts or other building services, the fire performance criteria for the penetrated wall or floor are maintained, such that fire in one compartment may not spread to other areas. So, the fire resisting duct needs to maintain i.e., not compromise the fire resistance of the wall or floor through which it penetrates. The performance of a fire resisting duct which penetrates a fire resisting/separating element requires careful consideration by specifiers and controlling authorities. The standard periods of stability and integrity should in all cases be at least equal to those required for the penetrated element of construction.

The methods followed for the fire resistance of walls and floors penetrated by ventilation ducts in building regulatory requirements and under the guidance of BS 9999:

Method 1

Protection using Fire Dampers

Method 2

Protection using Fire Resisting Enclosures

Method 3

Protection using Fire Resisting Ductwork

It is most important to choose the most suitable fire resisting ductwork system for its intended application area to ensure that the ductwork fire performance meets the requirements of the relevant application.

Standard Time-Temperature curve

Airmaster Fire Rated Ductwork

Air Master was established in the year 1987 in the United Arab Emirates. Since then it has been known to be the pioneers in the field of manufacturing of air-distribution and air-control products like HVAC Air ducts, Splitter damper, Grilles, Diffusers, Louvers and Dampers. Having a successful startup of “Sheet Metal Ducting” in 2017, Air Master has now come up with a new product in line with the existing fire safety products – Fire Rated Ductwork.

“AIR MASTER” fire rated ductwork (AMFRD) is a non-coated type galvanized steel sheet met-al ductwork, tested in accordance with BS 476 part 24 and International standards in inter-nationally accredited laboratories. It is manufactured by specialized technical team using computerized state-of-the-art sheet metal duct manufacturing machines.

Air Master Fire Rated Ductwork is designed in a such a way that it is easy to install, light in weight and cost effective for the contractors, fulfilling stringent criteria of international codes of fire safety in buildings.

Successful testing and assessments are done for the duct size range up to 6000 millimeters in compliance with BS 476 part 24 and ISO 6944-1985 at internationally accredited Applus+ Laboratories at Barcelona, Spain.

Tested in horizontal as well as vertical orientation separately under cellulosic (standard time Vs. temperature curve) fire conditions and successfully achieved over 120 minutes of fire resistance for integrity and stability of

  • Duct A (Fire Outside the ductwork)
  • Duct B (Fire Inside the ductwork).

A global product assessment and certification of the fire resistance performance for ventilation and smoke extraction ducts is being done by Applus+ Laboratories

Complied with

  • BS476-24:1987
  • ISO 6944-1985
  • BS 9999


  • Mechanical Ventilation System
  • Car Park Smoke Extraction System
  • Dual Ventilation / Smoke Extraction System
  • Stairwell Pressurization System
  • Kitchen Extraction System


  • AMFRD-01A (without insulation)
  • AMFRD-01B (without insulation)
  • AMFRD-02A (with insulation)
  • AMFRD-02B (with insulation)
  • AMFRD-3A (with insulation)
  • AMFRD-3B (with insulation)


Duct A

fire outside ductwork

Duct B

fire inside ductwork

Fire Ducts for Ventilation

Air Master Fire Rated Ductwork helps maintain pressurization systems and ensures compartmentation. The integrity of the duct and its ability to function must be maintained in the event of a fire. The Ductwork is a non-coated system, suitable for installation in multi-compartment, single compartment, stud wall, solid wall, and aerated concrete floors. A comprehensive set of support systems is provided. Penetration seals guidance is provided with detailed drawings.

Smoke Extract Duct

Smoke is recognized as the major killer during fire outbreaks. It can spread quickly to nearby buildings that are quite remote from the original flash, threatening life and damaging property. Stairwells and elevator shafts frequently become smoke logged, blocking evacuation routes and preventing firefighters and other rescue teams from doing their critical jobs. Air Master Smoke Extract ductwork is a key element of a fire strategy, by safely channeling smoke out of the building.

Our Certificates











Fire-rated ducts




Frequently Asked Questions about Fire Rated Ducts

Duct used for the distribution or extraction of air and designed to provide a degree of fire resistance

Duct used for the extraction of smoke in case of fire and designed to provide a degree of fire resistance 

  • Normal Ducts:
    No protection against fire and doesn’t prevent fire spread.
    Lighter construction, not fit for fire resistant application.
    Tested for air leakage only (if deemed necessary)
  • Fire Rated Ducts :
    Restricts fire spread from Outside and Inside duct up to certain time.
    Stronger and more rigid than normal ductwork.
    Tested for different international standards for fire resistance (BS, EN, ASTM, UL etc)
  • Stability: Ducts and supports are intact
  • Integrity: Ducts are free of cracks and holes
  • Insulation: Limit temperature on Insulation surface
  • Kitchen Extraction: Limit the fire inside the duct
  • Smoke Extract: Limit the reduction in cross section
  • BS 476-24
  • EN 1366-1,-8,-9
  • EN 13501-4
  • ISO 6944
  • ASTM E2816-12

Standard fire tests to which specimens of constructions are subject to, are based on the Cellulosic time/temperature curve, as defined in various national standards, e.g. ISO 834, BS 476: part 20, DIN 4102, AS 1530, etc.

This curve is based on the burning rate of the materials found in general building materials and contents.

1049 º C

Type A: Fire Outside (generally for applies ventilation ducts)

Type B: Fire Inside (extraction ducts)

In any building/premises both these conditions are possible in the event of fire


Sometimes contractors wrap normal ventilation ducts with Rockwool or non-combustible insulation of any thickness/density. This is absolutely wrong and is considered detrimental to building safety. If the ductwork loses stability / integrity, Insulation will fail as it will move with the collapse of ducts.

It is very important to understand that ‘We can have an Integrity-Stability rating without Insulation rating, but NOT an Insulation rating without Integrity-Stability’

Insulation is totally dependent upon the ductwork maintaining its integrity and stability.

Overall, it’s the system (DUCT + INSUALTION) that works. It delivers the highest possible protection against fire. Therefore, it is important for an Insulated Fire rated duct to be tested and certified as a single system.

NO Any additional services connected to fire ductwork supports may add unknown load bearing factors, which in case of fire may impact the stability of the ductwork just when it is needed most. Ductwork Installations have to be strictly in compliant with manufacturers certified performance specifications.

 Coated Ducts :

  • Special paint/coating applied on to the steel ducts
  • Lighter in construction
  • Limited temperature exposure 400oC Max (for Insulated)
  • For Stability & Integrity full std. TT curve exposure

 Non-coated Ducts :

  • Bare steel ducts with relatively heavier construction (GI/MS/SS finish) 
  • Exposed to full Standard time-temperature curve (for both Insulated and Uninsulated)

Ducts coated with Fire Resistant paint may not completely qualify as Fire Rated Duct.

Coated ducts can qualify for Stability & Integrity criteria when exposed to full time-temperature curve however it does not qualify for insulation criteria.

Insulation criteria for coated ducts is limited to maximum 400º C temperature only.


It has to be as tested and certified as a single system. Insulation and installation method will be recommended by certified manufacturers based on the assessment approvals from testing and certification body.

Ducts have to be supported strictly as per manufacturers specifications and installation guidelines. Support system assessment must be based on test performance.

Wall penetration design is exactly as per test conditions. Manufacturers’ will provide necessary training and guidelines to install it.

During the event of fire, smoke removal process results in potential risk of flashover or thermal radiation feedback. This will ignite nearby combustible materials or gases in adjacent transporting areas spontaneously due to higher temperatures. By insulating smoke extraction ducts, we are limiting the risk by preventing flashovers which may be caused while transporting hot gases from the place of fire to the atmosphere. Any kind of secondary fire can be encountered by firefighters easily due to removal of hot gases from the place of fire.
No. Not if it passes through dedicated shafts which are fire rated with insulation. Otherwise, it is highly recommended to be insulated.
Yes, it has to be. It is the system that has to work. Stability, Integrity and Insulation have to be tested together as a system. Smoke extract ductwork is an emergency system and insulation will be able to control the exhaust temperatures. However this had to be proven in a fire test.
Not necessary. On the roof, the smoke extract ductwork terminates to the atmosphere, and the flashover risk no longer exists generally. However, if there is a proximity of certain services and equipment mounted on the roof, then it is recommended.


The primary function of smoke duct is to carry hot gases from the place of fire out in to the atmosphere. A fire damper will close and prevent smoke extraction functions.

Kitchen extract ductwork poses a specific risk due to the presence of combustible grease lining (cooking oil fumes become grease) inside the ductwork. When ductwork passes through multiple compartments, there is a risk from a fire in a compartment outside the kitchen. This can cause the grease inside the duct to ignite and spread fire inside the ducts throughout the building.


Insulation on the ducts in the kitchen provide no protection. A fire in a commercial kitchen will be subject to the kitchen suppression systems and compartmentation structure.


Fire dampers are used to maintain compartmentation in the event of fire, to restrict spread of fire from one location to another to prevent migration of fire through the building.
Due to the presence of grease inside the ducts, fire dampers become inoperable. Hence, they offer no protection against fire and damage.

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