Fire-Resistance Ratings For Control Areas

As the number of laboratory fit out projects has increased over the years, one requirement in particular has stood out as commonly being overlooked, yet remains one of the most critical when determining the feasibility of a project: the floor rating requirement for control areas. The building code requires that floor assemblies of control areas and all supporting construction extending down to the foundation of the building have a 2-hour fire-resistance rating. Numerous laboratory fit out projects have been proposed in buildings with 1-hour or non-rated floor construction, leading to unanticipated complications that potentially have a major impact on the overall feasibility of the project.

Part of the confusion stems from the fire-resistance ratings specified in Table 414.2.2 of the IBC. For Levels 1-3 above grade plane, the required fire-resistance rating for fire barriers is shown to be 1 hour. Further, there is a footnote indicating that the fire-resistance rating is to be applied to fire barriers and horizontal assemblies to provide separation from other portions of the building. However, as noted in the IBC commentary, these ratings are not intended to apply to floor construction, but rather to the walls of the control area and the horizontal assembly above the control area. The required rating of the floor construction is specified in Section 414.2.4, which states that “the floor assembly of the control area and the construction supporting the floor of the control area shall have a fire-resistance rating of not less than 2 hours.”

Are there any exceptions?

The building code does allow control areas to have 1-hour floor construction and supporting construction in cases where all of the following criteria are met:

  • The building is Type IIA, IIIA, or VA construction (all of which require 1-hour floor assemblies)
  • The building is three or fewer stories above grade plane; and
  • The building is equipped throughout with an automatic sprinkler system in accordance with NFPA 13.

What options are available?

If a laboratory fit out is proposed within a building that does not have the required 2-hour floor construction, there are a few options available, including but not limited to:

  • Utilizing a multi-story control area approach in cases where lower chemical quantities are needed. For multi-tenant buildings, the feasibility of this option depends on the other tenants within the building, as a multi-story control area is shared among building occupants and is often dependent on the lease agreement.
  • Limiting the location of chemical usage within a building (e.g. on the first floor only) such that control areas are not needed on the upper levels.
  • Rating the floor assembly and supporting construction to provide the required 2-hour rating. This can be the entire floor or a small portion of the floor to be used as centralized chemical storage.
  • Constructing a High-Hazard Group H occupancy to accommodate larger quantities of chemicals.

If you have any questions or would like assistance with applying these options to a project, please do not hesitate to contact us.


Application of any information provided, for any use, is at the reader’s risk and without liability to Code Red Consultants. Code Red Consultants does not warrant the accuracy of any information contained in this blog as applicable codes and standards change over time. The application, enforcement and interpretation of codes and standards may vary between Authorities Having Jurisdiction and for this reason, registered design professionals should be consulted to determine the appropriate application of codes and standards to a specific scope of work.