In order to avoid damages or malfunctions, please follow the instructions below carefully when installing or using the DUCT.

Conditions for usage

  1. As FLEXIBLE-DUCT is a duct for air conditioning, do not use it for any other purposes. Otherwise, the product may be damaged or deteriorated and causes to lose functionality.
  2. Do not use this product at any environment that could be exposed to rain, wind, ultra-violet or heat outside of the duct as it may trigger a corrosion or condensation of rail equipment. For the ducts with heat insulation, thy may get a negative impact of temperature, humidity, etc. depending on the usage environment, and could be a cause to accelerate material deterioration and lose functionality.
  3. In case of using the ducts at an exposed environment (i.e. no roof or outside of facilities), there could be a deterioration faster than the using in inside of facilities.
  4. Do not use in following, but not limited to, conditions to prevent damage or deterioration of AIR SOX:
    ・ Any environment with heat, acids, alkalis, salt or smoke dust.
    ・ Any environment with flowing metal powder or chemicals.
    ・ Any environment with extremely high humidity.
    ・ Hot springs.
    ・ Offshore environment.
  5. Do not mix the inflowing air with liquids, chemical, gases or anything that are not for air conditioning purpose to air.
  6. Do not use if the inner tube is getting moldy or the internal glass wools is remarkably wet.
  7. Please use the ducts with lower pressure than the acceptance range mentioned in the catalogue. (The acceptance range is a value for ambient temperature and air.)
  8. The acceptance range of negative pressure listed in the catalogue is to prevent the ducts being crushed.
  9. The recommended wind speed is less or equal to the inside wind speed 10m/s. Do not use the product at velocity exceeding the operating range.
  10. Please use the duct within the temperature range described in the catalogue.
  11. In case of bending the duct to install them, (e.g. mounting positions at both ends are 180°), please keep the start and end of the duct straight at least for the same length as its diameter and bend them no less than minimum bending radius.
  12. The FLEXIBLE-DUCT is excellent in flexibility but not good in maintaining its original shape so shapes or how it looks like could be different by the lot or conditions of your construction. For instance, it could have waviness and deflection by its own weight. For this reason, please consider about sufficient safety factors when you calculate the pressure loss. (Pressure loss increases as the number of bending points increases.)
  13. Do not use the duct with any conditions that gives continuous vibrations that could give negative effects to its functionalities.
  14. Do not use the in any places where there is a possibility of damages such as external force repeatedly loaded by external factors.
  15. Keep your fingers and face away from the edge of the metal duct as the edges are sharp and there is a risk of injury depending on the use.
  16. In case of installing flexible metal ducts, please pay attention to a distance from anything made of different metal in order to avoid rust or corrosion.
  17. When using SEMI-FLEX FE and METALO-FLEX FA, please be careful with the plated coating not to be removed or peel off.
  18. Due to its structure of the duct, for some materials you may see the two pieces connected but this does not give any negative influence on product quality.
  19. The specifications and contents of the catalogues could be changed without prior notice.

Transportation, Storage and Unpacking:

  1. Storage of FLEXIBLE DUCTS must be done with free from water, dust, rain, wind, or direct sunlight.
  2. Please be careful not to deform the ducts when storing. Please also be careful not to put anything other than the same duct on them.
  3. Please be careful not to scratch the product with cutter, knife or scissors when opening duct from containers/packages.
  4. Make sure to wear protective equipment (safety shoes, goggles, gloves, etc.) and pay close attention to people and objects during moving and transporting the duct.
  5. Please be careful not to give any damages to the ducts before use especially during transportation. Do not drag the Duct as the helix, covering, or materials can be damaged.


  1. This product is basically designed for exhausting air. Please check and confirm if the ducts are really appropriate in your environment before you implement them.
  2. During the installation, please wear protective equipment (safety shoes, goggles, gloves, etc.) and pay close attention to people and objects around you.
  3. Please be careful not to damage the cover filters of ducts when installing as it may give a negative impact to its function.
  4. In case of ducts damaged before use, do not try fixing it with tape or other method.
  5. Do not make any changes or modification to the ducts by yourself as the product may be damaged or lose functionality.
  6. Please follow the instruction manual when connecting the duct to air conditioning equipment.
  7. When using the flexible duct with heat insulation, the outer diameter (jacket material) will expand within a range of approximately 1 to 5%.
    As the duct may vibrate or move when in they are in use or the air conditioner is turned on/off; please make sure there are nothing around the duct as it may damage the duct itself or the anything around it.
  8. When hanging a duct from a ceiling, please use a dedicated hanging strap and make sure that the hanging distance will be less than 1.0m.
  9. Do not climb on, slap, drop, or apply any physical damages to the duct.
  10. Do not deform the ducts before or during installation.
  11. If you have a welding job somewhere close to the ducts, please be sure to protect ducts by a fire-proof sheets or something to avoid the ducts being damaged by welding sparks.
  12. Keep your fingers and face away from the edge of duct as the helix parts at the end of duct are sharp and there is a risk of injury depending on the use.
    In case of adjusting the length, please provide filings to remove burrs of the edge to prevent injuries. Please wear protective equipment (safety shoes, goggles, gloves, work clothing, etc.) when cutting the duct.
  13. Make sure the duct is mounted properly to the ceiling to prevent them falling on people.

Product Warranty:

  • Although the usage conditions are listed as above as a reference, it is very difficult to expect the exact product lifecycle of FLEXIBLE-DUCT as it depends on the environment they are used at.
    For this reason, FLEXIBLE-DUCT is not set for a certain time period for product warranty.
    Depending on the operating environment and conditions, the product may not be suitable. Therefore, when you are considering to implement the duct, please consider and evaluate the suitability of the product under actual operating conditions.


OHTSUKA Co., Ltd. provide disclaimer from legal liability from malfunction or damages caused by, but not limited to, the followings.

  1. End users not following the instructions of our catalogue (such as target environment, acceptable pressure, minimum bending radius, storage conditions, installation manuals, etc.) or the cautions above.
  2. The product is used or installed in an environment where deterioration, deterioration, or deformation is expected to occur.
  3. Any modifications to the products by third parties.
  4. Failures of parts or materials of third parties are used.
  5. Artificial mistakes caused during transportation or installation.
  6. Duct used in improper ways or in environments where deterioration, chemical damage or corrosion, are expected (e.g. extremely low or high temperature, highly humid, exposed to ultraviolet rays, etc.)
  7. Failures of air conditioners or machines the ducts are connected.
  8. Deformation or reforming of the end user's facility, such as due to natural disaster, aging degradation, constructions at other areas, etc..
  9. End users or buyers not informing damage and defects found when the ducts are delivered and implemented.
  10. Any malfunctions or damages happened in the same product but purchased from original manufacturers or other distributors.
  11. Any malfunctions or damages caused that could not have foreseen by technical knowledge at the time of product delivery.
  12. Any act of god (natural disaster, typhoon, earthquake, lightning strike, flood, etc.).
  13. Any consequence of human neglects.
  14. Any damages by animals such as dogs, cats, birds, rodents, or bugs.
  15. Any force majeure such as riots and terrorist activities.
  16. Any other malfunctions or damage that does not obviously lead to our fault.