HTL Responding to Questions About the 2012 Edition of 1403 as it Relates to Fuel Loads.

First, understand that we are not fire protection engineers, and are not qualified to evaluate or predict environments created during live fire training evolutions.  However, Bill Glover has been working on live fire training structures for nearly twenty years, and has served on the National Fire Protection Association’s Technical Committee on Live Fire Training since 2002.

Please note the following warning that is included in our warranty:

WARNING:  Please be advised of a most important basic principle.  Burn rooms that are protected with thermal linings will be generally hotter than rooms that are not lined.  All burn rooms, whether lined or not, will absorb a certain amount of heat (energy) with each evolution.  Therefore, burn rooms get progressively hotter and reflect considerably more radiant energy with each additional evolution. You should experiment with each burn room to develop standard operating procedures that will ensure that fires are monitored and kept under control so that the rooms are not overheated, threatening the safety or life of the firefighters using the room.  HTL assumes no liability for environments and/or conditions created by the user in burn rooms.  System 203 is intended to be used to protect burn rooms that are operated in strict compliance with the National Fire Protection Association’s Publication 1403, Standard on Live Fire Training Evolutions, latest edition.

The 2012 edition of NFPA 1403 provides a process by which the Authority Having Jurisdiction (Owner controlling the use of the structure) can develop safe Standard Operating Procedures by experimenting with the structure as a Burn Sequence Chart is developed in consideration of the specific structure and fuels being used.  We have addressed the intent of this language in the operations and maintenance package provided for your project.  Please review it and let us know if you have questions.

1.  “What is the maximum temperature the fire tiles can reach?” Answer:  You will never get to that temperature using Class A materials in accordance with NFPA 1403.  The tiles can handle continuous temperatures in excess of 2000 degrees F.  When considering maximum temperatures, you should be primarily concerned with the limitations of your PPE.  Note that temperature is only one factor.  Radiant energy is more important, and is not measured by temperature.  See discussion in our website blog.

2. “Does the building dissipate the heat through the tiles?”   Answer:  All materials will absorb a certain amount of energy before radiating most of the energy back into the room.  Since the lining system includes a dense layer of concrete with a barrier of insulation behind, it will radiate energy back into the room faster and longer than the exposed block walls.  However, even block walls will also radiate energy.  All materials will slowly dissipate heat with time; the linings more slowly than unprotected surfaces.

3. “Does it radiate heat from the flame impingement area?”   Answer:  Yes, and from all parts of the room that heat up.

4.  “What is the recommended time length between burns for one burn room?”   Answer:   This is dependent upon many factors.  How much fuel is burned?  What type?  What is the moisture content of the fuel?  How is it arranged?  How much water is used for suppression with each evolution?  What is the ambient temperature, wind, humidity?  A collaboration of NIST, NFPA and UL have been working for years on a research study to answer your question, along with questions about maximum fuel loads and numbers of evolutions that can be conducted in a given room.  It is a complex issue that might not be answered with an acceptable level of certainty, given the number of factors involved, and given that the fire service might have difficulty applying such science in the field.  That is exactly why NFPA 1403 reads as it does today.  The new standard applies a practical, common sense approach to maintaining safe training environments.

5. “Does that time span depend on the temperature reached in that room?”   Answer:  Yes, but it depends more upon how many evolutions have been conducted at what temperature.  The environment of a burn room after the first evolution that achieves ceiling temperatures of 1000 degrees F, is a wholly different environment than that after the sixth 1000 degree evolution.  The room reflects more radiant energy with each successive burn.

6. “Does applying a hose stream to the hot tiles have a negative effect on them?”   Answer:  It is difficult to say “no, there is no effect from the thermal shock associated with hitting a tile that is heated to 1000 degrees with a pressurized hose stream”.  However, the tiles are designed to withstand this thermal shock while delivering years of service.  So, do not be concerned with hitting hot tiles with your hose streams.  We are trying to get 20 years of service out of this lining, and, after nineteen years of experience with our system, we are generally succeeding.

A couple of final comments.

Please see our blog for a discussion about burn racks.  Burn racks are essential to minimize heat conducting through fire brick pavers into the top of structural slabs.  See our learning center for examples of good racks.

Finally, if you have training officers who believe that a live fire training structure will offer the ability to replicate conditions found in actual structure fires, smack them in the head!  Permanent live fire training structures are non-combustible structures.  You cannot develop the realism he is hoping for.  The structure allows you to practice VES, hose line advancement, ladder work, incident command, and some fire suppression.  Do not underestimate the conditions that can be developed. They can be intense, and unsafe.  Indeed, you can create conditions in this structure that you will not see in a house fire because, quite simply, if such conditions existed in a house fire, the house would be gone.

Again, we are not Fire Protection Engineers, and we are not firefighters; so judge our comments accordingly.  However, if you are interested in talking to peers who have similar buildings, go to our Project List where every project is listed, including contact information.  We recommend that you speak with your peers to share experiences and ideas.  http://www.firetrain.com/htl-projects

Thanks for this opportunity to answer your questions.