Test chambers formaldehyde emissions

Standard practice for the determination of VOCs (excluding formaldehyde) emissions from wood-based panels using small environmental chambers under defined test conditions... 

ISO DIS 16000-3 determination of formaldehyde ISO DIS 16000-6 indoor air and emission test chamber air - determination of VOCs active sampling on Tenax TA, thermal desorption and gas chromatography MSD/FID... 

Product tests. Clearly, the best product test is full-scale testing of finished panels under actual use conditions. This has been done (27,38) but is expensive, because several full-sized panels of each product must be pre-conditioned at constant temperature and humidity for at least a week. The next best approach is to test product samples in air chambers under standardized conditions. A summary of such methods is contained in Table I. A very large effort has been made over the last three decades world-wide to develop quick, reliable and meaningful product tests. Wittmann (16), Zartl (20), Plath (17), Verbestel (1, Neusser (21,22), Roffael (25), HUD, the U.S. Forest Products Industry (39,40), many standaraization organizations (41-43) and others have published many viable methods, but the testing involves a combination of complex factors and there is simply no single test that fulfills everybody s specific needs. Table I list some of the currently accepted test methods for formaldehyde emission from particleboard, plywood and medium density fiberboard. 

Manufactured Home Construction and Safety Standard, Air Chamber Test Method for Certification and Qualification of Formaldehyde Emission Levels," U.S. Code of Federal Regulations, Vol. 24, Part 3280.406, (U.S. Department of Housing and Urban Development), and F eral Register, Vol. 48, pg 37136-37195, 1983. 

Large Scale Test Method for Determining Formaldehyde Emission from Wood Products Air Chamber Method, FTM-2" National Particleboard Assocaiton, Hardwood Plywood Association, U.S. Department of Housing and Urban Development, Federal Register, 1982, 48, 37169. 

National Particleboard Association, Hardwood Plywood Manufacturers Association, October 10, 1983. Large scale test method for determining formaldehyde emissions from wood products, large chamber method, FTM 2, Reston, VA. 

Since Nestler s review was published, some additional information on formaldehyde emissions from phenolic panels has appeared in the literature. Information obtained using dynamic test chambers is summarized in Table I. Perforator and two-hour desiccator data are summarized in Table II. 

Large-Scale Test Method For Determining Formaldehyde Emissions From Wood Products — Large Chamber Method, FTM 2-1983 National Particleboard Association Gaithersburg, MD, 1983. 

The measurement of formaldehyde release from wood products Involves the collection of formaldehyde vapor in the test chamber using a suitable absorbing solution and then analyzing the formaldehyde collected. For many years, formaldehyde emission measurements were carried out using the desiccator test sampling method due to... 

These test chambers can be incorporated to the enzymatic methods for formaldehyde determination. Formaldehyde emissions of a product, or mix of products, to the ambient air can be collected in distilled water or 1% sodium bisulfite as the absorbing solution. After collection, formaldehyde samples are analyzed as described above. In the mobile home simulator test method (2J, double or triple impingers, which are placed in series, should be used in order to collect all of the formaldehyde vapor. The test conditions should simulate the actual environment. Several factors such as temperature and relative humidity of the system including the specimens and background of formaldehyde in the test chamber, affect the precision and accuracy of the results. It has been shown that a 7 C change in temperature doubles the emission level (L). The temperature of the test chamber should be... 

Formaldehyde as a pollutant in the indoor air is usually connected with the use of formaldehyde based resins in e.g. building materials and in furniture. This article presents measurements of the formaldehyde emission from various products containing urea-formaldehyde (UF) or phenol-formaldehyde (PF) resins. The emission from all test objects have been measured in a ventilated test chamber at the standardized testing atmosphere 23 C, 50 % RH according to the International Organization for Standardization (ISO). The emission from woodbased panels and other materials have been measured at a loading factor of 1.0 m /m and at an air change rate of 1.0 h . ... 

In Denmark, Finland, Norway, Sweden and in West Germany the content of formaldehyde in woodbased panels are regulated by perforator values. In Denmark and West Germany these rules furthermore are based upon requirements of the formaldehyde emission to the air in ventilated test chambers. The regulations in Sweden include at the moment only UF-bonded particle boards. The boards should not exceed a perforatorvalue of 40 mg free formaldehyde per 100 gram dry board. 

In the future the Swedish formaldehyde rules may include other UF-bonded products as MDF-boards and the requirements also may be formulated as emission rates. On the behalf of the National Board of Physical Planning and Building, the Swedish National Testing Institute has performed a study on the emission from products bonded with formaldehyde based resin. The measurements have been performed in a ventilated test chamber at standardized climate in agreement within the work of the European Organization for Standardization, CEN. 16 West European countries are represented in CEN. 

The GEM method is based upon the assumption that the size and shape of the testing chamber does not influence the emission. During the testing the formaldehyde concentration in the chamber will rise and stabilize at a steady state concentration. At constant climate the steady-state concentration or emission rate from the test object depends on the relation between the loading factor and the air change rate. Good air circulation in the chamber is also essential ( ). 

Formaldehyde emission was measured at 23 C and 50 % RH in a ventilated test chamber of 1.0 m, the testing climate recommended by the Intemational Organization of Standardization (ISO) (. ... 

Furnishing. The formaldehyde level in a room at actual conditions depends on several factors, and is not an arithmetical sum of various sources (10), (11). In order to estimate the contribution of formaldehyde emission from single pieces of furniture the test objects have been exposed in area to air volume proportions to which they can be found in a small room or a kitchen. The assumption that the formaldehyde level in the chamber and in the actual room is the same, is based on a theoretical model originally developed for particle boards (4). At constant climate the emission from a test object is determined of the relation between the loading factor and the air change rate. 

The U.S.Department for Housing and Urban Development s rule 3280.308 established formaldehyde emission standards for particleboard and hardwood plywood paneling used in mobile homes. These standards took effect February 11, 1985. The certification program under this rule requires each manufacturer to develop a quality control in-plant testing program that relates to tests conducted in a large scale environmental chamber. 

Newton, L. "Formaldehyde Emissions from Wood Products Correlating Environmental Chamber Levels to Secondary Laboratory Tests" International Particleboard Symposium No. 16 Washington State University, Pullman, 1982. 

Black, M.S. "Correlation Of Wood Product Formaldehyde Emission Rates As Determined Using A Large Scale Test Chamber, Small Scale Test Chamber, and Formaldehyde Surface Emission Monitor" Georgia Institute of Technology, April 18, 1985. 

Air chamber test, material standards for formaldehyde emission, 224... 

EC-European Commission (1989) Formaldehyde Emission from Wood Based Materials Guideline for the Determination of Steady State Concentrations in Test Chambers. Indoor Air Quality and its Impact on Man. Report No. 2, Luxembourg. 

It is a known fact that many freshly printed books and journals have strong odor. In a particularly severe case, school children complained that they were irritated when they touched a schoolbook with a PVC cover. To find out the reasons, the book was conditioned for 24h and put into a 23.5-1 chamber with open pages at T = 23 °C, RH = 45% and N = 1.0h"1. Sampling was performed after 24h and 48h. As shown in Table 15.3, very high emissions of aromatic hydrocarbons, glycols and other compounds were observed. In addition, a chamber test carried out on issue 4/96 of Indoor Air journal showed that it had an unpleasant smell. The main components detected in the chamber air were formaldehyde (335 (tg/m3), hexanal (15 xg/m3), toluene (123 ( Lg/tn3) and aliphatic hydrocarbons (>C10) (100—150 (xg/ m3). Higher aliphatic aldehydes (C7-C11) appeared in concentrations <10 tg/rn3. 

A limited number of sink effect studies have been conducted in full-sized environments. Tichenor et al. [20] showed the effect of sinks on indoor concentrations of total VOCs in a test house from the use of a wood stain. Sparks et al. [50] reported on test house studies of several indoor VOC sources (i.e., p-dichlorobenzene moth cakes, clothes dry-cleaned with perchloroethylene, and aerosol perchloroethylene spot remover) and they were compared with computer model simulations. These test house studies indicated that small-chamber-derived sink parameters and kj) may not be applicable to full-scale, complex environments. The re-emission rate (kj) appeared to be much slower in the test house. This result was also reported by other investigators in a later study [51]. New estimates of and were provided,including estimates of fca (or deposition velocity) based on the diffusivity of the VOC molecule [50]. In a test house study reported by Guo et al. [52], ethylbenzene vapor was injected at a constant rate for 72 h to load the sinks. Re-emissions from the sinks were determined over a 50-day period using a mass-balance approach. When compared with concentrations that would have occurred by simple dilution without sinks, the indoor concentrations of ethylbenzene were almost 300 times higher after 2 days and 7 times higher after 50 days. Studies of building bake-out have also included sink evaluations. Offermann et al. [53] reported that formaldehyde and VOC levels were reduced only temporarily by bake-out. They hypothesized that the sinks were depleted by the bake-out and then returned to equilibrium after the post-bake-out ventilation period. Finally, a test house study of latex paint emissions and sink effects again showed that... 

The incidence of perceptible formaldehyde in homes, offices and schools has caused widespread uncertainty about the safety of living with formaldehyde. This uncertainty was enhanced by the large scale installation of urea formaldehyde foam insulation (UFFI) because a substantial part of this material was made from small scale resin batches prepared under questionable quality control conditions, and was installed by unskilled operators (10). The only reliable way to avoid such uncertainty is to know the emission rate of products and develop a design standard that allows prediction of indoor air levels. The first and most important step in this direction was achieved with the development and implementation of material emission standards. As indicated above, Japan led the field in 1974 with the introduction of the 24-hr desiccator test (6), FESYP followed with the formulation of the perforator test, the gas analysis method, and later with the introduction of air chambers (5). In the U.S. the FTM-1 (32) production test and the FTM-2 air chamber test (33) have made possible the implementation of a HUD standard for mobile homes (8) that is already implemented in some 90% of the UF wood production (35), regardless of product use. 

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