Fire Resistant Ductwork

Fire Resistant Ductwork
Fire Resistant Ductwork
  • Service enclosures
  • Protected shafts
  • Smoke/ventilation ducts
  • Gas pipes
  • Kitchen extract ducts 
  • Cable protection

DURADUCT® are high impact, fire and blast resistant duct systems made from DURASTEEL® panels, delivering a fit and forget system for the life of the building DURADUCT® is ideal for particularly onerous conditions e.g. where high impact strength is required or for use in aggressive environments, and provides up to 240 minutes fire resistance.

More information available in Chapter 6 of our  Fire Protection Handbook and Technical Data Sheets.  View our Durasteel® videos. 

Certifire Approval - DURADUCT LT® and DURADUCT SMT® - Smoke Control and Fire Resisting Ductwork Systems - No. CF 480

Advantages:

  • Up to 240 minutes fire protection
  • Cellulosic tested 
  • High impact resistance
  • Blast resistant
  • Moisture resistant
  • Promat-trained specialist licensed installers
  • Fit and forget system
  • 40+ year service life
  • Fast installation
  • Site inspection service
  • Certificate of conformity
 
DURADUCT® Fire Resistant ductwork systems: 

  • DURADUCT® LT: a galvanised steel inner duct overboarded with 6.0mm DURASTEEL® and finishing trim angles. An economical fire resisting ductwork solution combining the airflow and wipe down characteristics of standard galvanised steel ductwork with impact and blast benefits of DURASTEEL®.
  • DURADUCT® SMT: formed by fixing 9.5mm, DURASTEEL® panels onto a welded or cleated, prefabricated steel skeletal framework, minimum 3mm thick.  DURADUCT® SMT is tested to provide high levels of blast and fire protection. and is suitable for potentially explosive environments such as electrical transformer and switchgear rooms.
  • DURADUCT® SR: is used together with the DURADUCT® LT and DURADUCT® SMT ranges for connection largely between the main smoke extract system and grilles where fire insulation performance is not required.

These systems remain resistant to firefighters’ hoses, leaving them capable of performing their original function during and after a fire.

 

Ducts Design Considerations

The relative complexity of any ductwork system which is passing through different fire compartments and the relevance of the system’s function in ambient and fire conditions can make the selection of a suitable ductwork system difficult.

To determine the fire resistance of ducts (without the aid of fire dampers) passing through or between compartments, the system should normally be tested or assessed in accordance with BS 476: Part 24: 1987.

Factors for consideration when determining the correct specification to ensure ducts will provide the required fire performance include:

  • Required fire exposure
  • Required fire performance
  • Supporting structure
  • Hanger support
  • Steel ductwork
  • Penetrations through walls and floors
  • Ductwork functions
  • Acoustic performance
  • Thermal insulation
  • Water tolerance
  • Strength and appearance
  • Access requirements (hatches) for inspection

Cable Protection Design Considerations

In the event of a fire it may be vital to the safety of the building occupants that certain electrical systems and services remain functioning until all personnel have escaped. Such systems will therefore require protection from fire for a specified period of time.

The following points are some of the factors which should be considered when determining the correct specification to ensure the cable duct system will provide the required fire performance.

  • Required fire exposure
  • Required fire performance
  • Supporting structure
  • Penetrations through walls and floors
  • Acoustic performance
  • Thermal insulation
  • Water tolerance
  • Strength and appearance
  • Failure temperature of the cable
  • Maximum cable operating temperature


Test Details

Ducts: to determine the fire resistance of ducts (without the aid of fire dampers) passing through or between compartments, the system should normally be tested or assessed in accordance with BS 476: Part 24: 1987. This standard has been written specifically for ventilation ducts, but guidance is also given in the standard on the performance requirements for smoke outlet ducts and kitchen extract ducts.

For any size of duct, the tensile stress in the steel hangers must not exceed the maximum permitted stress for each fire resistance period based on BS 5950: Part 8: 2003. If these stress levels are exceeded then the size of the hanger rods must be increased, the centres of the hangers reduced or the hangers protected. The penetration of the hanger fixings into any concrete soffit should be a minimum of 50mm for 120 minutes ratings or 65mm for 240 minutes ratings.

Service enclosures: For the provision of fire resisting constructions to general building services, 60 to 240 minutes fire rating (integrity with varying periods of insulation), should normally be tested or assessed in accordance with the performance criteria of BS 476: Part 20: 1987.