In ventilation ductwork systems, the proper distribution of air between different spaces is of high importance. The spiral duct tee provides the possibility for airflow to divide from a main path into two sub-paths. This connection is widely used in main ventilation lines, risers, and ceiling branches.
The principled design of the tee ensures that the airflow is guided to different branches in a balanced manner without severe pressure drop.

Applications of Spiral Duct Tees

Tees are used in various parts of the ventilation system, including:

• Branching from the main duct
• Distributing air to multiple different spaces
• Connecting risers to sub-branches
• Designing complex ventilation networks
• Managing air flow rate in different paths

In large projects, the correct selection of the tee plays an important role in the overall performance of the system.

Types of Spiral Duct Tees

Spiral duct tees are divided into different types based on angle and structure:

45-Degree Tee
In this type, the sub-branch separates from the main path at a 45-degree angle.
Advantages:

• Lower pressure drop
• Smoother airflow
• Suitable for professional and low-noise systems

90-Degree Tee
In this model, the branch is created perpendicular to the main path.
Applications:

• Confined spaces
• Short paths
• Projects with execution limitations

Introduction to Reducing Tees

In many projects, the diameter of the main duct is not the same as the branch duct. In such conditions, a spiral duct reducing tee is used. This connection provides the possibility of changing the duct size in addition to creating a branch.
Reducing tees play an important role in:

• Controlling air flow rate
• Balancing pressure
• Preventing sudden flow drop

Advantages of Using Reducing Tees

Using standard reducing tees offers numerous benefits:

• Uniform air distribution between branches
• Reduced system pressure drop
• Reduced noise caused by airflow
• Compatibility with system engineering design
• Reduced fan energy consumption

In professional ventilation designs, using a reducing tee instead of several separate connections is cost-effective both technically and economically.

Material and Composition of Spiral Duct Tees

Tees and reducing tees are usually manufactured from the following materials:

• Galvanized steel sheet (most common option)
• Stainless steel sheet (for special environments)
• Aluminum sheet (in lightweight projects)

Galvanized sheet is the first choice for most projects due to its high resistance to corrosion, long durability, and suitable price.

Impact of Tee Design on System Performance

Non-principled tee design can cause:

• Severe pressure drop
• Unbalanced air distribution
• Increased energy consumption
• Creation of annoying noise in the duct

Conversely, standard spiral tees with engineered design guide the airflow in a controlled and uniform manner.

Important Considerations in Choosing Tees and Reducing Tees

To choose these fittings appropriately, attention must be paid to the following:

• Main and branch duct diameters
• Branch angle
• Type of tee (standard or reducing)
• Installation space
• Project usage type
• Manufacturing quality and sealing

Specialized consultation before purchase can prevent execution problems and additional costs.

Application of Tees in Different Projects

Tees and reducing tees are used in diverse projects:

• Residential buildings
• Office and commercial complexes
• Hospitals and medical centers
• Factories and industrial sheds
• Large halls and shopping centers

In all these projects, the correct choice of tee has a direct impact on air ventilation quality.

Conclusion

The spiral duct tee and reducing tees are key components of HVAC systems responsible for branching and principled distribution of airflow. Using standard and high-quality tees increases system efficiency, reduces pressure drop, and improves overall ventilation performance. Kian Fan professionally meets the needs of different ventilation projects by offering various types of spiral duct tees and reducing tees.