Details on the Evaluation of Volatile Organic Compound (VOC) Source Control Measures for Advanced
Relocatable Classrooms (RCs)
Year-one efforts for this task can be broken down into several broad project categories as follows:
Identify existing relocatable classroom (RC) materials that potentially emit toxic or odorous volatile organic compounds
(VOCs), and identify practical alternative materials with lower emissions for testing in high-performance commercial building
system (HPCBS) RCs.
Working with American Modular Systems (AMS), we obtained a set of samples of all major materials that are exposed in the
interiors of the basic RCs ordered by the school districts. We also obtained from various vendors a set of 17 types of
alternative materials expected to have lower aldehyde and VOC emissions. The materials included standard and alternative
carpet systems, resilient flooring, tackable wall panels, and ceiling panels. Test specimens were conditioned for 10 days
at typical indoor conditions and then exposed for 96 hours in small-scale environmental chambers prior to the collection of
chamber air samples. These samples were analyzed for formaldehyde, acetaldehyde, and a broad range of VOCs including compounds
that are regulated in California as Toxic Air Contaminants (TACs) and which have chronic non-cancer Reference Exposure Levels
(RELs) established by the California Office of Environmental Health Hazard Assessment.
The detailed
results of this testing are presented in a July 18, 2001 deliverable to the California Energy Commission (CEC). In summary, the
following materials were selected for replacement because of the potential that reduced indoor concentrations of selected VOCs
would result: fiberglass ceiling panel, vinyl-covered fiberboard tackable wall panel, and olefin-fiber broadloom carpet bonded
to plywood with solvent-free full-spread adhesive. The following materials were selected as replacements, respectively, for the
above materials: mineral-fiber ceiling panel, Teflon-coated vinyl-covered fiberboard tackable wall panel, and Nylon 6,6 fiber,
olefin hardback carpet bonded to plywood with adhesive tape.
The conclusions of the VOC emissions testing of the RC materials can be summarized in the following observations:
- Tested carpet systems were not major sources of compounds of concern.
- Glue-down carpet systems can substantially reduce emissions of formaldehyde and other contaminants from plywood
subfloor.
- Use of ceiling panels with nondetectable emissions of formaldehyde is predicted to substantially reduce indoor
formaldehyde concentrations.
- Use of Teflon-coated vinyl wall fabric is predicted to reduce indoor concentrations of TACs, acetaldehyde, phenol,
Di(ethylene glycol)butyl ether (DEGBE) or 2-(2-butoxyethoxy)ethanol), vinyl acetate & 1,2,4-trimethylbenzene.
- Formaldehyde and acetaldehyde concentrations in ventilated classrooms with alternate materials may still exceed their
RELs of 2 and 5 parts per billion (ppb), respectively, depending on actual heating, ventilation, and air conditioning (HVAC)
supply airflow rates.
- No substantial odor problems are expected when HVAC systems are operating as recommended by the manufacturer and/or in
compliance with the American Society of Heating, Refrigeration, and Air Conditioning Engineers (ASHRAE) 62-1999 standard of
15 ft3 per person fresh outdoor air.
Design and begin construction of an energy and indoor environmental quality (IEQ) monitoring and data collection package for
the HPCBS RCs
The IEQ monitoring equipment to be used in the RCs is described in the Element 6 scope of work. Real-time IEQ parameters to be
monitored include indoor and outdoor airborne particle size (0.3 to 10 micrometers) and count, carbon dioxide, temperature,
relative humidity (RH) and noise level. Real-time data are to be collected by a central data acquisition system (CDAQS). Each
school is to have a single CDAQS that will collect data for both RCs.
Selected toxic and odorous VOCs and formaldehyde and acetaldehyde are to be sampled during school-day-long periods on a weekly
basis and subsequently quantified at LBNL using standard laboratory techniques.
Two ASHRAE thermal comfort (TC) carts were designed for the study. These carts contain low-range air velocity probes and RH, air
temperature, and radiant temperature probes. All information will be measured at three standard heights. - All data will be
collected and stored on an onboard microcomputer. The carts are designed to look similar to a standard classroom audiovisual
cart. They will be placed at predetermined locations in the RCs during a single school day each week.
RC energy monitoring will include individual monitoring of all electrical loads, e.g., standard HVAC system, indirect/direct
evaporative cooler (IDEC) and heating system, plug loads, lighting. Natural gas use will be monitored in real time as well.
HVAC supply, return, and exhaust temperatures and RH will be monitored. Hydronic heat pump cycling will also be monitored. A
weather station to monitor wind speed and direction, outdoor temperature, and RH will also be connected to the CDAQS. Door and
window opening events will be monitored continuously.
The CDAQS and air quality instrumentation are to be housed in a special indoor cabinet in one of the two RCs at each school. The
second RC is to have a similar cabinet that houses its own air quality instruments (particles, CO2 and will be
connected to the CDAQS in the other RC. Metal enclosures connected by conduit through the RC wall to the indoor cabinets are to
be mounted on the outside wall of each RC. These enclosures will house pumps for collecting VOC and aldehyde samples as well as
computer interface components so the CDAQS can be accessed during school hours without disrupting the class inside the RC.
As of this writing all of the equipment and materials for the above monitoring systems have been purchased. Instrument testing,
CDAQS construction, and TC cart construction projects are well under way. Two summer students are assisting in calibration and
verification of the instruments.
Construct four HPCBS RCs for study in school settings in Year 2. Construct two of the RCs using selected low-VOC alternative
interior materials
School district facility managers and architects approved all modifications to the standard RC designs placed at AMS by the two
school districts. These plans were thoroughly inspected by AMS during several meetings with LBNL and Davis Energy Group staff.
All alternate materials were purchased and supplied to AMS. Construction of the RCs began in July and was completed August 20,
2001. LBNL staff were in attendance during most of the RC construction process.
Contact:
Michael Apte, Lawrence Berkeley National Laboratory (LBNL), (510) 486-4669
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