1. in a Controlled Chamber
Effects of Temperature on the Emission Rate of Formaldehyde from Medium Density Fiberboard
in a Controlled Chamber
William Swankie, Yehia Hammad Sc.D.
University of South Florida
Research Question
Is the rate of emission of formaldehyde from Medium Density Fiberboard (MDF) related to temperature, resulting in increased airborne concentrations?
Methods
A 0.53 m3 Plexiglas chamber equipped with one inlet and two outlets was used for the experiment. North Multi-Gas/Vapors/P100 Respirator cartridges were epoxied to the inlet and outlet so that air would be filtered as it entered and exited the chamber. The outlets were connected to a calibrated Escort ELF air pump operating at 1.0 liters per minute which was changed daily. A background test was first conducted to measure residual formaldehyde in the Plexiglas box using Assay Technology 571 Aldehyde Monitors. One monitor was placed in the inlet and one in each exit port for a total of 3 samples and retrieved 72 hours after sampling began. After the background test, the Plexiglas chamber was placed inside a heat stress chamber where temperature could be controlled. Five equal pieces of MDF were cut from one panel to create a total surface area of 4.49 m2. Two 1” pieces of MDF were epoxied to the bottom of each panel to create an air channel. The three inner perimeter edges of one of the panels surface was also lined with Sponge Window Seal to create a better seal inside the Plexiglas chamber. The panels were placed in a staggered order to force air to travel across all exposed surface area. Four temperatures were measured which include: 26.1, 29.3, 34.1, 38.9 ᵒC. At each temperature, a 48 hour acclimation period was conducted to allow the Plexiglas chamber to reach a steady state formaldehyde concentration. Three samples were then taken repeating the methods used in the background test. In total, 20 samples were taken and analyzed by Assay Technology.
Results
Average Temperature
(ᵒC)
Average Concentration (ppm)
Standard Deviation
(ppm)
Average Emission Factor (µg/m2-h)
Standard Deviation (µg/m2-h)
26.1
0.52
0.035
8.81
0.590
29.3
0.74
0.015
12.36
0.250
34.1
1.20
0.000
19.90
38.9
1.59
0.330
25.58
5.215
Background
Formaldehyde is a colorless, odorless gas that is found naturally in the environment. It is a popular additive in many consumer products including composite wood products. Composite wood products are engineered wood panels produced from pressing pieces, chips, particles, or fibers of wood together at high temperatures held together with a bonding agent. This bonding agent is often a formaldehyde containing resin which has the potential to off gas over time.
Conclusion
As temperature increases, the amount of formaldehyde emitted from Medium Density Fiberboard also increases. This results in a higher concentration of airborne formaldehyde where the panels are present.
Acknowledgements
This project was a success thanks to the continuing support of:
University of South Florida
Yehia Hammad, Sc.D.
Steve Mlynarek, Ph.D.
John Smyth, Ph.D.
Foday Jaward, Ph.D.
National Institute of Health and Safety
Sunshine Education & Research Center
Molli Hayworth
Correlation Information
Average Concentration
Average Emission Factor
Linear R2
0.9983
0.9954
Linear R
0.9991
0.9977
Linear Regression Equation
Y = x – 1.712
Y = x – 26.52