Perforator test emission

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. 

Because the utility test showed that the tramp material exit from the bed, a perforated "draw-down" cone, became clogged, EPI designed an on-line bed changeout system, which continually pulls the bottom layer of sand and wire out of the bed, cleanses it, and returns it.14 Emission results of the pilot test burning 100 percent tires are shown in Table 2-1.14... 

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. 

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. 

While the perforator method also can be used for production control of MDF-boards it is questionable weather the method is feasable for plywood and other laminated wood panels. The two tested UF-bonded plywood boards e.g. although equal perforator values shows large difference in emission. 

This raises doubts about the reliability of predicting formaldehyde emission by using the perforator. However, on the other hand, each group of products corresponds to a given adhesive. This means that for a given adhesive a constant relationship exists between the perforator rate and the emission, as has been already demonstrated in earlier studies. Thus, this relation varies from one adhesive to another. Nevertheless, it will be necessary to carry out further tests in order to confirm that point. 

At this point of the study it is not possible to improve our knowledge of the emission trends with this method. However, given that the formaldehyde emission from a particleboard must decrease with time, we decided to measure this effect. Two sets of experiments were carried out parallel to each other for one year at 23 L and 65% RH, 80% RH, or 30% RH. The boards were tested at regular intervals by both the perforator method and the gas flow... 

To this aim, the three configurations of residenhal heating devices whose combustion test results are presented in previous figures have been analyzed with respect to particle emissions two combustion heads equipped with premixed burners differentiated by metallic mat and perforated cylindrical heads and one equipped with a blue diffusive flame consisting in a five-tube injector where blue flames of gaseous hydrocarbons can be stabilized. The three flames have been characterized by in-situ optical diagnostics for the identification of the flame structures and the formation of particulate matter, whereas particle emission has been determined by scanning mobility particle sizer (SMPS) and spectroscopic characterization of sampled material. 

The formaldehyde emission test on the plywood panels was carried out according to the specification prescribed in European norm EN-210, by the perforator method [26]. 

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