Air Date: 7-15-2011| Episode: 213
Lew founded Mason-Grant in 1986 as a technical research and development consultancy. ..
Lew founded Mason-Grant in 1986 as a technical research and development consultancy. Through his writing, speaking and training, Lew specializes in explaining complex issues especially those related to moisture — to professionals and laypersons in understandable, accessible ways. It’s hard to believe Lew last joined us almost 4 years ago and we are looking forward to his return with an update on what’s new in IEQ, disaster restoration and building science. We are particularly interested in Lew’s thoughts about the Indoor Air 2011 conference where it seemed he was everywhere asking probing questions plus giving a well received presentation.
Lew Harriman, Mason-Grant Consulting
Expert moisture consultant Lew Harriman was our guest on today’s episode of IAQradio. Lew, a presenter at Indoor Air 2011, discussed both his impressions and takeaways from Indoor Air 2011 with IAQradio listeners.
· Indoor Air 2011, was truly a collaborative international event that featured new research and new information rather than rehashing the old.
· Craig Venter, PhD’s Metagenomic research results. The human body contains 20,000 unique human genes and 10,000,000 microbial genes. Over 1,000 distinct organisms found in our mouths. Microbial diversity in the environment is far greater than we knew before very recent metagenomic research (last two years).
· Kathleen Kreiss, MD’s 3-part negative health predictor based on NIOSH workplace health investigations. When water stains, odors and visible mold growth are all present at the same time, the building is more likely to have produced negative health effects for occupants. This “3-part predictor” has proven a more reliable indicator of potential health problems than fungal sampling or moisture content measurements.
· Synergistic effect of moisture + fungi, bacteria and viruses.
· David Miller, PhD. Molds produce different flavors of beta glucans when fungi propagate on outdoor materials versus indoor building materials. “Triple helix” D-beta glucan is produced when certain fungi digest building materials, but not when those same fungi digest outdoor vegetation. The triple-helix version has a known path to negative health effects, including causation of asthma.
· Jordan Peccia, Ph.D. at Yale University- Aspergillus fumigatus produces different metabolites when grown at different temperatures, The metabolites produced at 60 F – 70 F are most troublesome. Lew’s takeaway was ductwork downstream from cooling coils may need even more attention than we’ve already been giving it when designing HVAC systems, and in building maintenance programs.
· Pawel Wargocki, Ph.D research into health effects of elevated levels of CO2 in stuffy classrooms. In rooms with poor IAQ, occupants’ breathing rate and breathing volume decreases, resulting in the backup of CO2 in their bloodstreams. Over time, this buildup results in slight acidosis, in turn causing drowsiness and headaches. Our technical director Dieter Weyel, Ph.D disagrees with what Lew described as Dr. Wargocki’s results, commenting that exhaled breath contains 5,000 PPM of CO2. Therefore an extra 500 or 1,500 ppm in the indoor environment is not likely to have any significant effect on the amount of CO2 in the bloodstream.
· We understand causation better than before. We understand pathways better than before. This will influence regulations, occupant behavior, and building design.
· Avoiding IAQ problems through building design. Designing and constructing buildings without guttering to keep water away from the foundation and with “persistent ornamental dampness” (aka ornamental water features within buildings) increases the risk of IAQ problems.
· Lew’s presentation at Indoor Air 2011 focused on “the geography of moisture in buildings.” How moisture varies over time. Materials which get wet and don’t dry out are a concern. Relative humidity is very misleading when measured in the air, rather than at the surface of materials. Investigators will learn more about the geography of moisture within a building by monitoring surface temperatures and dew points than by tracking RH. Keeping track of dew point, and comparing it with surface temperatures will help locate identify potential areas of condensation.
• Ventilation air flow rates were the first topic of discussion at ASHRAE in 1896 and are still being vigorously debated today.
• Lew opines that building ventilation should be variable. Varying ventilation rates within buildings can improve IAQ and save energy. There is an energy penalty for ventilation and a corresponding energy saving potential when less ventilation is required (when fewer people are in the building).
• Advised listeners of a recent story on NPR radio. “As number of foreclosed houses grows, so does mold” http://www.npr.org/2011/07/13/137629788/as-number-of-foreclosed-homes-grows-so-does-mold.
Lew is a master of explaining complicated concepts to those of us who are far less knowledgeable. Lew was well organized and well prepared for his interview on IAQradio and we want to thank him again for taking time out of his busy schedule to join us on IAQ Radio.