Fire Ratings, Codes and Safety: A Comprehensive Guide

Navigating Fire Safety: Essential Knowledge for Building Professionals

We’ve all encountered fire ratings, but the terminology, regulations and guidelines surrounding them can be challenging to navigate. At Metallic, we believe it’s vitally important to comprehend why they exist, what they actually signify, how they’re developed and how to implement them properly. This knowledge enhances safety for everyone – and our structures. When properly installed, fire-rated materials and assemblies can delay or even prevent the spread of a fire. This creates valuable time to evacuate people from the building before flames consume it or the structure gives way.

Fire Behavior Fundamentals

If you’ve built or observed a campfire, you already possess some understanding of how different materials burn. You’ve witnessed lightweight, dry material ignite and burn rapidly, allowing flames to spread. You’ve likely also observed that damp, green or thicker pieces of wood require much more time to burn. And if you’ve ever thrown an aluminum can into the fire, you’ve seen that it doesn’t burn at all.

Fire ratings and tests systematically formalize these principles and more, enabling us as builders to ensure our structures can withstand, halt or contain fires when they ignite.

Terminology and Definitions

While certain materials are fireproof, no building – not even one constructed entirely of metal – is completely fireproof. Fire resistance refers to the ability of specific materials to endure heat and fire without igniting themselves. Fire ratings, however, are the outcomes of tests where materials and assemblies (some being fire-resistant) were subjected to fire conditions. These tests evaluate various construction elements, including beams, floors, columns, walls and roofs. These ratings indicate how long and how effectively these materials and systems maintain their structural integrity when exposed to fire, typically rated between one and four hours.

Regulatory Organizations and Standards

The terminology and abbreviations in the fire rating field can be perplexing due to the multiple organizations that establish ratings, tests and standards:

Testing & Code Development Bodies

Underwriters Laboratories (UL)

American Society for Testing and Materials (ASTM)

International Building Code (IBC)

UL and ASTM meticulously test materials and assemblies under various conditions to determine their fire resistance rating. These findings inform the development of codes by the IBC as well as local building regulations.

Industry Guidance and Enforcement Groups

International Code Council (ICC)

Metal Building Manufacturer’s Association (MBMA)

To help builders, designers, architects and engineers understand and comply with the codes established by ASTM and UL, the ICC and MBMA provide guidelines and recommendations.

Comprehensive Fire Protection Strategy

Effectively preventing, managing or containing fires depends on several different systems. First, detection systems such as smoke and fire alarms enable building occupants and emergency responders to react quickly. Second, compartmentalization systems contain the fire, preventing rapid spread throughout the building. These may include fire doors and fire-resistant walls and assemblies. Third, suppression systems including sprinklers, hose systems, and non-water-based fire suppression/extinguishing mechanisms work to extinguish the fire or slow its progression until firefighting personnel arrive. The designation “fire-protected” encompasses all these aspects.

Requirements for such systems, along with fire-rated building materials and assemblies, vary based on several factors. What is the intended occupancy of the building? Fire resistance requirements for a warehouse will be considerably less stringent than those for an office complex or residential building with higher occupancy. Building height is another crucial factor, as is the proximity to adjacent structures or property boundaries. Building material selection is also a key consideration.

Metal Construction Benefits

Similar to the campfire example mentioned earlier, fires that erupt in wooden structures – where the building material itself is combustible – encounter few barriers to rapid spread. Metal buildings, however, possess an inherent advantage. Cold-formed steel, unlike alternative building materials, does not burn. It doesn’t ignite, fuel the flames, or facilitate their spread. Consequently, steel framing is classified by the IBC as a noncombustible material. During a structural fire, it significantly outlasts wood framing, light-gauge steel framing, and other construction systems.

Constructing with steel and metal components can greatly simplify compliance with fire codes. In building categories such as retail, office and education, regulations permit a much larger unprotected or non-fire rated area than in wooden structures – frequently 50% or more. Sprinkler installations are optional for typical single-story metal buildings, and most metal structures don’t require fire protection on the structural framing. An additional benefit is that many insurance providers offer substantial discounts for steel buildings.

Safety Considerations

However, this doesn’t mean metal buildings are impervious to fire. Extreme temperatures can weaken steel until structural failure occurs – but this requires temperatures exceeding 1,500°F. To safeguard occupants against eventual collapse, metal buildings may still need fire rating on specific walls that separate different occupancies, are in close proximity to neighboring properties, or are essential for life-saving exit corridors.

Fire-Resistant Solutions

Beyond using noncombustible materials for construction, there are additional options for enhancing fire protection in your buildings. Fire-resistant protection comes in various forms, including coatings, gypsum board, spray-applied fire-resistant materials (SFRMs) and metal track with intumescent tape.

However, with these products and any fire rating system, strict adherence to application or installation requirements is absolutely essential. They underwent testing under very specific conditions. Altering any aspect – such as leaving small gaps in an assembly, failing to thoroughly clean surfaces before applying fire-resistant products, or utilizing materials that weren’t included in the tested system – creates potential points of failure that could result in casualties. Always ensure you understand and follow these requirements precisely – and verify your work thoroughly.

Planning and Implementation

Incorporating fire-rated assemblies and products into construction projects is as diverse and complex as the countless different buildings that exist. ASTM and UL simply cannot test every possibility, component combination or newly conceived assembly. The optimal approach is early and thorough planning. Engineers can ensure continuity of assemblies and joints, verify that increased structural loads from fire protection and sprinkler systems can be supported, and prepare for details such as cable trays, ducts, pipes and other penetrations with fire-resistant solutions like intumescent firestop material – which expands when heated to fill voids and contain flames.

We hope this guide helps clarify and untangle some of the confusion surrounding fire ratings. At Metallic, we consider understanding fire codes to be critically important. For additional information, refer to the Fire Resistance Design Guide for Metal Building Systems, published by MBMA, which is regarded as the comprehensive source for fire protection information. Or, for personalized assistance, connect with a Metallic representative.