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02/07/26

Learn about the most widely adopted air duct manufacturing standards, including TCVN 5687, TCVN 13580, SMACNA, DW/144, and ASHRAE, and understand when each standard should be applied in HVAC projects.

Vietnamese Standards for Air Duct Manufacturing

TCVN 5687:2024 – Ventilation and Air Conditioning Systems – Design Requirements

TCVN 5687:2024 is Vietnam’s national standard governing the design of ventilation and air conditioning (HVAC) systems.

For air duct fabrication, this standard references TCVN 13580:2023 – Ventilation and Air Conditioning Systems – Requirements for Air Duct Fabrication. TCVN 13580 specifies the technical requirements for manufacturing air ducts and accessories, including:

  • Material selection
  • Structural requirements
  • Fabrication methods
  • Dimensional tolerances
  • Workmanship requirements
  • Product quality

Compliance with Vietnamese national standards is mandatory for the acceptance of civil, commercial, and industrial construction projects in Vietnam.

Common International Standards

SMACNA – The World’s Most Widely Used Air Duct Construction Standard

Developed by the Sheet Metal and Air Conditioning Contractors’ National Association (SMACNA) in the United States, the SMACNA HVAC Duct Construction Standards are among the most widely recognized air duct fabrication standards worldwide.

SMACNA is extensively adopted throughout North America, Asia, and many international projects, serving as a key engineering reference for HVAC designers, manufacturers, and contractors.

The standard classifies ductwork according to operating pressure (typically from –10 in.w.g. to +10 in.w.g.) and provides comprehensive guidance on:

  • Sheet metal thickness selection
  • Duct reinforcement
  • Flange and joint construction
  • Supports and hangers
  • Leakage control
  • Structural performance

Many high-rise buildings, factories, airports, hospitals, and data centers in Vietnam reference SMACNA for air duct fabrication and installation.

DW/144 – The UK’s Air Duct Construction Specification

DW/144 is the UK’s leading technical specification for ductwork construction, published by the Building Engineering Services Association (BESA).

The standard provides detailed requirements for the design, fabrication, and installation of HVAC duct systems.

DW/144 places particular emphasis on:

  • Air leakage classifications (Class A, B, C, and D)
  • Minimum sheet metal thickness
  • Reinforcement methods
  • Manufacturing tolerances
  • Joint construction
  • Installation requirements

Unlike SMACNA, DW/144 prescribes more standardized fabrication methods with less flexibility, making it particularly suitable for projects following British or European engineering practices.

ASHRAE

ASHRAE (formerly the American Society of Heating, Refrigerating and Air-Conditioning Engineers) is the world’s leading technical organization dedicated to HVAC&R research, standards development, and engineering guidance.

Unlike SMACNA or DW/144, ASHRAE does not specify how air ducts should be fabricated. Instead, it establishes design criteria and performance requirements for HVAC systems.

These standards provide the engineering basis for calculating ventilation rates, thermal comfort, indoor air quality, and overall HVAC system performance, which subsequently influence air duct sizing and system design.

Among the ASHRAE standards most relevant to air duct system design is:

ASHRAE Standard 62.1 – Ventilation for Acceptable Indoor Air Quality

This standard establishes minimum ventilation requirements to achieve acceptable indoor air quality (IAQ).

Its primary focus includes:

  • Outdoor air ventilation requirements
  • Exhaust air requirements
  • Indoor air quality (IAQ)
  • Ventilation system design
  • System operation and maintenance

ASHRAE 62.1 is one of the most frequently referenced international standards in modern commercial HVAC design.

When Should International Standards Be Applied?

For construction projects in Vietnam, compliance with applicable Vietnamese codes and national standards is mandatory.

However, projects involving international investors, foreign consultants, or multinational contractors often reference additional international standards such as SMACNA, DW/144, or ASHRAE to achieve higher levels of engineering quality, fabrication accuracy, and system performance.

The applicable standards should be determined during the design phase to ensure consistency throughout engineering design, manufacturing, installation, testing, and project acceptance.

REEPRO – A Leading Air Duct System Solution Provider in Vietnam

Depending on project specifications, REEPRO products are manufactured in compliance with Vietnamese national standards as well as internationally recognized standards such as SMACNA and DW/144.
With more than 40 years of manufacturing experience and participation in over 1,300 projects across Vietnam, REEPRO has established itself as a trusted partner in delivering high-quality air duct systems for airports, hospitals, factories, commercial buildings, industrial facilities, and other critical infrastructure projects.
Committed to quality, innovation, and sustainability, REEPRO continues to contribute to the development of modern, safe, and energy-efficient buildings that meet both Vietnamese regulations and international engineering standards.

📌 Note

The information presented in this article is compiled from publicly available references and reflects the standards applicable at the time of publication. For specific projects, designers, consultants, and contractors should consult the latest regulations, applicable standards, and qualified professionals to ensure full technical and legal compliance.