A recent multi-state market analysis has revealed that industry standard horizontal HVAC fire-rated duct assemblies are not in compliance with requirements of the International Building Code (IBC).

Widely used in multi-story and commercial structures of all types, horizontal HVAC fire-rated duct assemblies serve a basic purpose: to manage hot gases for a period of time during a fire so occupants and first responders are safe. Specifically, these fire-rated duct systems must be rated for two hours or more.

This non-compliance situation, which is pervasive in multi-story and commercial buildings throughout the United States, has clear implications for the life safety of building occupants and first responders, to say nothing of the potential liability of specifiers, designers, contractors and code officials. Perhaps even more dangerous than non-compliance is that the current practice of using non-compliant insulation for horizontal duct systems not only masks the problem, but also accelerates system failure by causing the system to retain heat and fail more rapidly. Accordingly, without code-compliant smoke evacuation systems, the lives of occupants and first responders are in peril.

To further drill down into the problem, non-compliance with IBC involves projects that use either ceramic fiber duct-wrap or drywall assemblies in horizontal applications. For the most part, the industry has been focusing on the mechanical code and ignoring important provisions of the IBC that relate to fire-rated HVAC assemblies. To cite chapter and verse: Non-compliance with the symmetry and continuity requirements of fire-rated duct assemblies in IBC chapter 7 and 9 eliminate important fire protections that the IBC codes intend.Systems must be tested in fire inside and outside conditions in both the vertical and horizontal configurations.

The IBC Is a Prescription, Not a Suggestion

When the IBC is applied to ceramic fiber duct-wrap or drywall assemblies in horizontal applications, the code is not a theory or a suggestion for design specification. The IBC clearly defines prescriptive practices that are required for new construction. Moreover, the IBC is a distillation of best practices based on lessons learned from past building failures. But the codes are only as effective as code officials understanding and enforcing code provisions, as has been made painfully clear in the recent failure of effective enforcement in the London high-rise fire.

Reasons for Non-compliance

The broad non-compliance of horizontal field assembled ceramic fiber duct-wrap or drywall ventilation assemblies arises from lack of enforcement of codes, which in turn arises from lack of awareness of key IBC provisions. States such as Florida, Massachusetts and New Jersey have already either agreed with, or taken official notice of, the need for enforcement of IBC rules that are on the books today, and several have written bulletins and “declaratory statements” in support of proper enforcement; more states will follow.

With a careful reading of the IBC, it’s clear that the use of non-compliant drywall assemblies arises from field use of untested configurations. Code-compliant vertical installations cannot simply be turned horizontally and remain compliant. According to the Gypsum Association, “the system must be built as tested.”

Ceramic insulation non-compliance is simpler: It is not tested under fire inside conditions as required by symmetry and continuity provisions in the code.

The reality is that professionals in the field—designers, specifiers and contractors—are choosing duct systems without understanding code requirements for tested materials and assemblies. Meanwhile, “grandfathering” past practice for jobs under contract but not yet installed sounds like a comfortable path. But in the face of new information, and recent examples in London and Honolulu, is this responsible and safe?

Addressing non-compliance starts with education, and moves to immediate enforcement of the IBC; otherwise dangers remain real, and liability all too great.