Evaluation of HVAC Systems Following A Structure Fire

Claims involving structural fires pose many unique challenges. The origin of visible soot and char, as well as the extent of damage and need for specialized remediation techniques, means that claim professionals, among others, be informed on the most current consensus standards. HETI Horizons is pleased to publish this article, prepared by the Indoor Air Quality Association (IAQA) and the Indoor Environmental Standards Organization (IESO), on a new standard to evaluate HVAC systems following a structure fire.

IESO/RIA Standard 6001

IESO, in conjunction with a subcommittee from the Restoration Industry Association (RIA), began developing this standard – Evaluation of Heating, Ventilation and Air Conditioning (HVAC) Interior Surfaces to Determine the Presence of Fire-Related Particulate as a Result of a Fire in a Structure – in early 2009 in an effort to address whether or not fire-related residues had been deposited on HVAC interior surfaces. It was completed in 2011 and accredited as an ANSI-recognized standard in early 2012.

The standard was not created to determine what materials have been burned in a fire or what deposited on the surface of the HVAC system. It uses char and soot as indicators of fire-related particulate because both are byproducts of most fires. Ash is not included in the standard because structure fires do not produce enough to be utilized as an indicator of residue.

Char is the primary indicator in determining if residue from a fire has been deposited on a HVAC interior surface and generally consists of fragments of combusted material typically greater than one micron in size and irregular in shape. These physical characteristics allow char fragments to be identified by a trained microscopist using appropriate optical microscopy methods.

Soot is also used as indicator because it can be easily identified if the sample is appropriately collected and analyzed. Because individual soot particles are sub-micron in size, surfaces may look visibly clean. However, when wiped, the clustered clumps may darken the surface of the wipe. Analysis of the wipe sample(s) by a trained microscopist using appropriate optical microscopy methods is necessary to confirm that the darkened wipe has collected soot and not dirt or other particles that could be mistaken for fire residue.

Components of the Standard

The standard contains different sections that address specific issues encountered as part of the investigation, including:

  • Health and safety – Evaluation personnel must comply with applicable federal, state, and local requirements to protect employees and building occupants.
  • Investigator qualifications – The standard can be implemented by an individual or team of professionals who are knowledgeable about HVAC/mechanical systems and the various components comprising the system; are familiar with construction materials; and understand air distribution and pollutant pathways.
  • Inspection & sampling locations – Defines the inspection and sampling process; identifies what the inspection and sampling protocol will entail, and how it should be documented; and indicates how sampling should be conducted in systems of various sizes and configurations.
  • Sampling protocols – Outlines the sampling procedures and protocols; lists how porous and non-porous surfaces should be sampled, exceptions for sampling, and sampling materials; and reinforces the importance of maintaining the chain of custody for the samples.
  • Laboratory analysis – Microscopist reviewing the samples must be trained or have experience in identifying   morphological characteristics of carbon particles, as well as partially-combusted material utilizing optical microscopy techniques. The screening method in the standard is designed to detect the presence of fire residue as indicated by the presence of char and soot particles using light microscopy techniques such as stereo, PLM and DF illumination. It inherently assumes that the overwhelming majority of char and soot particles observed originated from the fire. The method is not designed to provide identification of  individual char particles or to determine their origin.
  • Inspection & sampling report – Provides a brief description of what should be included in the report delivered to the client.
  • Other information – The standard also includes sections on terminology, references and samples of field reports and sample ID forms.

Further information on IESO/RIA Standard 6001 can be found at

www.restorationindustry.org and www.ieso.org.

HETI…Your Resource for EHS Services

HETI’s staff continually reviews new and proposed standards and regulations to make sure we have current knowledge of environmental health & safety (EHS) issues that may impact our clients. An RIA committee is currently in the process of developing a standard that will address whether or not a structure has been impacted by a fire. In addition, work on structure restoration and contents restoration standards will begin in early summer 2013. We will report on these, as  appropriate, as part of our commitment to assisting our clients with a comprehensive range of EHS support services.