Measuring Temperature in Emission Testing Micro-chambers
Dustin G. Poppendieck, Edwin Guillermo, Havishk Tripathi
ASTM subcommittee D22.05 on Indoor Air is working to finalize WK40293: Standard Test Method for Estimating Chemical Emissions from Spray Polyurethane Foam (SPF) Insulation Using Micro-Scale Environmental Test Chambers. One issue in WK40293 is determining the best method to accurately measure the temperature in the micro-chambers. Properly characterizing micro-chamber temperature is vital to get comparable emission data. Three methods to determining micro-chamber temperature with a thermocouple were investigated using two micro-chamber systems: 1) placing the thermocouple in the airspace of a micro-chamber, 2) taping the thermocouple to the bottom of the air filled micro-chamber, 3) placing the thermocouple in a micro-chamber filled 50 % to 75 % with water. The results show that air measurements are dependent upon the depth of the thermocouple placement, as both micro-chamber systems are stratified. Taping the thermocouple to the bottom of the micro-chamber resulted in average values that were similar to a water filled micro-chamber for one system but not the other. Data from both the air and tape methods had 1° C to 2 °C temperature cycles in one of the systems, but not the other. The water method consistently resulted in temperature data with the smallest standard deviation. As a result of this research the authors propose new prescriptive and performance metric text for temperature measurement requirements in ASTM WK40293.