Currently, widely available three-dimensional (3D) printers are very popular with the public. Previous research has shown that these printers can emit ultrafine particles (UFPs) and volatile organic compounds (VOCs). Several studies have examined the emissivity of filaments from 3D printing, except glycol modified polyethylene terephthalate (PETG) and styrene free co-polyester (NGEN) filaments. The aim of this study was to evaluate UFP and VOC emissions when printing using a commonly available 3D printer (ORIGINAL PRUSA i3 MK2 printer) using PETG and NGEN. The concentrations of UFPs were determined via measurements of particle number concentration and size distribution. A thermal analysis was carried out to ascertain whether signs of fiber decomposition would occur at printing temperatures. The total amount of VOCs was determined using a photoionization detector, and qualitatively analyzed via gas chromatography-mass spectrometry. The total particle concentrations were 3.88 × 1010 particles for PETG and 6.01 × 109 particles for NGEN. VOCs at very low concentrations were detected in both filaments, namely ethylbenzene, toluene, and xylene. In addition, styrene was identified in PETG. On the basis of our results, we recommend conducting additional measurements, to more accurately quantify personal exposure to both UFPs and VOCs, focusing on longer exposure as it can be a source of potential cancer risk.
This article presents the results of experimental determination of temperature fi eld and heat fl ux density in a fl ashover container used for the training of fi refi ghters. Experimental measurements were carried out in a chamber No. 1 of a fi refi ghting trainer of Fire and Rescue Service of the Czech Republic at Zbiroh. The article describes the design and equipment of this chamber, used method of measurement and test procedure. Measured values of temperature fi eld and heat fl ux density are stated and discussed. In conclusion, recommendations for further measurements in this chamber aimed at acquiring other fi ndings concerning thermal loads on fi refi ghters in the course of training are presented.
The contribution presents two basic variants of fire compartmentation. A conservative standard design is confronted with an atypical design supported by the mathematical modelling of temperature field. In both the cases, the required level of safety is ensured. The atypical design in this case enables the use of more available and economically profitable products ensuring the fire safety of the structure.
— Volatile organic compounds (VOCs) are among the most common pollutants released into the air in the petrochemical and chemical industries. The article deals with removing VOCs while producing plastic granules containing approx. 80% polypropylene and polyethene, together with other additives. In this sector, the simplifying factor is that it deals with only one volatile pollutant, total organic carbon TOC, regardless of the specific materials from which the VOC emission originates. The permissible pollution level indicates a TOC emission limit of 50 mg ∙ m-3 for this production. During operation, emissions are extracted from the machinery to a stationary source. It is a fabric filter where the air is cleaned through a layer of diatomaceous earth. To determine if the above limit is not exceeded, measurements showed that the TOC limits are significantly higher (82.9 mg m-3 ). Therefore, tests were carried out using a mixture of activated carbon and diatomaceous earth. The results showed that activated carbon significantly reduced TOC concentrations to 8.4 mg m-3 . Keywords— Activated carbon, diatomaceous earth, polymers, stationary source, total organic carbon, TOC, volatile organic compounds, VOC.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.