Question: One of our customers asked us the following.  “Using NFPA 1402 & NFPA 1403 as guides, we are trying to determine, as the administrative authority, what types of “containers” are acceptable for use when conducting live fire training evolutions. Additionally, we would like some clarification as to whom would be considered “another competent professional as determined by the AHJ” when considering who may inspect containers used for live fire training.  These are some issues that we are seeing while conducting our site visits. Specifically, we need to know what types of containers would not be acceptable (i.e., rail cars?).”

Our response might be of interest to other AHJs.  Keep in mind, this is only our opinion, NOT a formal NFPA interpretation.

It really is a tough question. 

NFPA does not have specific language that dictates what does or does not constitute an acceptable containerized structure.  Keep in mind that 1402 is merely a guide that is offering ideas.  1403 is a standard with shall language.  1403 does distinguish between permanent and acquired structures.  For permanent structures, the standard addresses what shall be considered when inspecting the burn facility on a daily, annual, five year and ten year basis.  However, it does not distinguish between a conventionally constructed permanent structure and a containerized structure.

Containerized structures should meet all of the building code requirements that a conventional structure must satisfy.  This is not so hard when it comes to space planning, but it is a real challenge to ensure that design compensates for all loads.  Those loads are dead, live, wind and even seismic.  All of those loads need to be transferred through the structure to a properly designed foundation.  Attachment to the foundation needs to be adequate to resist wind and seismic activity (earthquakes).

Engineers who are not familiar with fire training environments might fail to address stresses from expansion and contraction of structural materials.  Those numbers are huge and, if not addressed, the structure fails.

Each structural element should be calculated to ensure it is not compromised when openings (doors and windows) are cut through, by specifying adequate reinforcing to allow the member to continue to transfer the stresses imposed.  This seems very simple, but I believe it is complex.  These are questions to be considered by designers and code officials.

Assuming all of these things are properly designed when the facility is erected, the inspections conducted by the AHJ, and the engineers retained by the AHJ, should evaluate a containerized structure in the same manner as it would any structure.  The inspection should address any safety issues that might exist with respect to emergency means of egress, railings, stairs, openings, shutters, etc.  It should record any deficiencies such as corrosion, deflection, compromised structural connections (bolted or welded), etc.  The same engineer should then be retained to prepare repair documents providing details and specifications for corrective work.  Daily inspections should be looking for hazards related to clear means of egress, damaged shutter assemblies and shutter hardware, presence of improperly stored fuels, trip or fall hazards, etc.

Regarding the “who” question: This has been a point of contention in the technical committee meetings.  So the final language is, in my opinion, kind of loose.  Reference appendix A.6.2.7 for more information.  However, even with the clarifying appendix language, your question is still valid.  “Who is a “another competent professional”?

Some AHJs complain about having to spend money on “licensed professional engineers with live fire training structure experience and expertise”.  So they insisted that we add “or by another competent professional as determined by the AHJ”.  This opens the door to much subjectivity when it comes to the meaning of “competent”.  Nevertheless, understand that 1403.7.2.5, 1403.7.2.6, and 1403.7.2.7 are all dealing with “structural integrity”.  The alternative to the licensed P.E. with experience, is a competent “professional”.  My opinion is that this means a professional with structural competence.  That translates to at least a Structural Engineer.  The part about “with live fire training structure experience and expertise” is in the air for the AHJ’s discretion.

I have been dealing with burn buildings for over twenty-years.  I believe these structures present unique concerns and loads that should be addressed by someone with experience.  Too frequently, we encounter good engineers who struggle with the special challenges associated with live fire training structures.  This inexperience can cause serious problems.

Finally, please remember that the engineer who inspects the structure for structural integrity is not inspecting the structure to certify it as a safe structure for the fire loads you build.  He is not a fire protection engineer.  He is a structural engineer.  It is incumbent upon the fire service to experiment with the structure to develop safe SOPs.  Then it is critical that the safety and ignition officers inspect every fire load and burn room before conducting each evolution to ensure compliance with the SOP.  In the end, those are the most important inspections.  Is the room safe? Is the room overheated?  Are we adhering to the SOP?  Critical.

Thanks and let me know if you have more questions.