ISO Construction Types Explained

Understanding the six ISO construction types is crucial when working on construction projects of any size. This classification system, established by the Insurance Services Office (ISO), helps standardize the evaluation of building construction for insurance purposes.

In this article, we will break down the different ISO construction types to help you understand their differences and practical applications.

ISO 1 – Frame (Combustible Walls and/or Roof)

ISO 1 construction features combustible materials in the walls and/or roof. Typical materials include timber framing, insulation, and shake shingles. These buildings have exterior walls, roofs, or decks that can burn, requiring additional fire protection measures. This type of construction is common in residential homes and apartment buildings.

ISO 2 – Joisted Masonry (JM) (Non-Combustible Masonry Walls with Wood Frame Roof)

ISO 2, or Joisted Masonry, combines non-combustible masonry walls with a combustible wood frame roof. Exterior walls are typically made of brick veneer, concrete block, or similar masonry materials. However, the roof is usually supported by wood joists. This construction type provides better fire resistance than ISO 1, but the combustible roof elements still pose a fire risk.

ISO 3 – Non-Combustible (NC)

ISO 3 buildings are constructed with non-combustible materials throughout. Both the walls and roof must be made of metal, gypsum, or concrete block. This type of construction significantly minimizes fire risks. Common in commercial and industrial buildings, ISO 3 structures often feature metal roofing and a steel frame for increased fire-resistive properties.

ISO 4 – Masonry Non-Combustible (MNC)

ISO 4, or masonry Non-Combustible construction, includes buildings with exterior walls of masonry materials and non-combustible roofs. ISO 4 construction further enhances fire resistance compared to ISO 3 by incorporating more robust exterior wall materials. Materials like brick, concrete block, and heavy steel ensure a higher fire-resistance rating.

ISO 5 – Modified or Semi-Fire Resistive (MFR or SFR)

ISO 5 buildings, known as modified or Semi-Fire-Resistant, are typically mid-rise office buildings that incorporate additional fire-resistive elements beyond standard masonry or non-combustible materials. These structures are often framed with heavy steel and utilize various fire-resistant construction materials like precast concrete panels and BUR roofs (-BUR (built up roof with gravel or modified bitumen).

ISO 6 – Fire Resistive (FR)

ISO 6, or Fire Resistive construction, represents the highest level of fire resistance in the ISO classification system and is typically used in high-rise commercial buildings, condos, and parking garages. These structures are designed and constructed using materials and techniques that can withstand fire for extended periods. All floors must be cast in place concrete with a minimum thickness of 4″, and all exposed steel must be fireproofed to meet the required minimum 2-hour fire rating.

Leveraging Autodesk Tools for ISO Construction Standards

Autodesk tools like Revit and AutoCAD can significantly enhance the productivity and accuracy of designing buildings that meet ISO construction standards. These tools allow architects and engineers to create detailed models with precise specifications for non-combustible materials, fire-resistive construction, and load-bearing components.

Revit

Revit is a powerful building information modeling (BIM) software that enables the creation of comprehensive 3D models. It supports the integration of all elements required for ISO construction types, allowing you to specify materials like concrete block, steel frame, and brick veneer with precision. Some of Revit’s practical applications include:

• Material Specification: You can detail every component, from non-combustible exterior walls to fire-resistive roofing materials, ensuring compliance with ISO standards.
• Fire-Resistive Construction: Revit’s advanced modeling capabilities enable you to simulate fire-resistive properties of materials, helping you design buildings that meet fire protection requirements.
• Load-Bearing Analysis: The software supports structural analysis, allowing you to model and test load-bearing components, ensuring they meet the necessary safety and ISO compliance standards.
• Collaboration: Revit’s cloud collaboration features enable multiple stakeholders to work on the same model simultaneously, ensuring that all design aspects adhere to ISO construction standards from the outset of the project.

AutoCAD

AutoCAD is the gold standard for precision drafting tools. Its ease of use and ability to integrate into other Autodesk programs make it ideal for creating detailed construction plans that specify fire-resistive materials and non-combustible construction techniques. AutoCAD facilitates:

• Precision Drafting: AutoCAD allows for the meticulous drafting of building components, ensuring every detail is accurate and adheres to ISO standards. This includes the specification of non-combustible materials such as metal roofing and gypsum.
• Detailed Documentation: The software’s robust documentation capabilities help create comprehensive construction documents detailing fire-retardant materials and techniques. These documents are essential for building code compliance and insurance purposes.
• Customization and Automation: AutoCAD supports customization through programming interfaces like AutoLISP, allowing for the automation of repetitive tasks and creating custom tools tailored to ISO construction standards.
• Integration with Revit: AutoCAD can seamlessly integrate with Revit, allowing for the import and export of data between the two platforms. This ensures that detailed 2D plans align perfectly with the 3D models, providing a cohesive design process.

Take Your ISO Compliance to The Next Level

Understanding ISO construction types is essential for designing safe, standard-compliant buildings. By leveraging advanced tools like Autodesk Revit and AutoCAD, construction professionals can ensure their designs adhere to the highest fire protection and structural integrity standards. Whether you’re working on a residential project with a wood frame design or a high-rise with heavy steel and precast concrete, recognizing these ISO classifications will enhance your ability to create resilient, fire-resistant structures. If you’re interested in implementing AutoCAD or Revit into your daily workflow, we encourage you to check Autodesk AEC Collection, where you can find these and other leading tools in one comprehensive package.