A study by the Fire Protection Research Association, “Thermal Capacity of Fire Fighter Protective Clothing,” shed new light on the issue of stored energy in 2008:

This laboratory based study shows that the Stored Energy Test (SET) method provides information not provided by any other protective performance test method currently incorporated in NFPA 1971 Standard on Protective Ensembles for Structural Fire Fighting and Proximity Fire Fighting. It supports a hypothesis that sub-flashover burn injuries may occur as the result of two different heat transmission mechanisms, or combination of two thermal phenomena. Tests conducted on moisture preconditioned materials exposed for 1.5 and 2.0 minutes to 0.2 cal/cm2sec radiant heat, predict burns mainly from transmitted thermal energy. For these conditions, the SET functions essentially as a Radiant Protective Performance (RPP) test for moist samples with attached trim or reinforcements. For 1.0 minute radiant heat exposure followed by contact compression, SET performance is more noticeably influenced by thermal energy discharged from the heated turnout materials. Both phenomena could contribute to the burn hazard, depending on the specifics of the heat exposure and other conditions of use. In both scenarios, the presence of non-porous reflective trim or non porous reinforcements reduces test performance when these materials are attached to the outer surface of a turnout composites consisting of a thermal liner, outer shell and a breathable moisture barrier.

This study and others have led to the upcoming changes in the 2012 edition of the NFPA 1971 standard. In its first rendition, the new stored energy requirement will only apply to the garment sleeves. The imposed criteria requires manufacturers to make changes to how trim bands are applied and investigate alternative materials or construction methods for addressing any exterior reinforcements on coat sleeves. LION Connects provided an update on the 2012 edition in August:

Stored energy test addition

–   This test evaluates the stored and transmitted heat energy in a turnout composite underneath a reinforcement material.
–  This requirement will apply to coat sleeves with additional layers attached (excluding cuffs and items smaller than 1”). For example: visibility markings, elbow reinforcements, sleeve patches and logos, etc.
–  The reinforced area is tested on a base composite with the additional layers attached. The composite is exposed to a heat source (stored energy) and then compressed (transmitted energy). Passing performance is > 130 seconds time to 2^nd degree burn.

LION has been aware of the benefits of ventilating reflective trim bands and has offered LION’s Ventilated Trim for several years. Ventilated trim provides breathability to a traditionally impermeable component of your turnout gear. Moisture can collect between the reflective trim and the outer shell of your turnout. Ventilated Trim is perforated with 0.8 mm holes (114 per square inch) to provide a conduit  for the release of vapor that can occur when moisture is heated and the trim compressed.

If you still aren’t sold on the importance of stored energy, consider this quick video demonstration LION created to help visualize the effect of ventilation: