HEALTH AND SAFETY
Ciceri de Mondel S.r.l., in pursuing its customer focused vision of limiting the health and safety risks involved in using its products, commissioned a reputable Services Company, specialised in chemical, commodity and environmental related analyses, to assess pollutant air dispersion when processing thermoplastic polymer filaments with a 3D printer (thermo extrusion).
These brief comments are a simple introduction to the research report (see report for analytical aspects) used by those not “professionally” involved in this field.
Tests and relative environmental samples were carried out during processing with ABS, HIPS and PMMA polymers, using two FDM technology 3D printers, in areas comparable to residential spaces or for office use and in “extreme” aeration conditions (with closed doors and windows and without forced air exchange and localised exhaust systems).
These analyses focused on determining the air concentration of the following main components and substances those involved in this specific processing may be exposed to: inhalable dust, volatile organic solvents, butandiene, acrylonitrile, formaldehyde and methyl methacrylate.
Reference was made to accredited standards and national and international recommendations for analysis methods and risk assessment. In particular, reference was made to the ACGIH (American Conference of Governmental Industrial Hygienists) list of so-called TLVs (threshold limit values) for the assessment methods, adopted in Italy with ACGIH’s authorisation from the AIDII (Italian Association of Industrial Hygienists). These are the time weighted average concentration limit values of a chemical agent in the air within a worker’s breathing area, referred to a “typical” working day of 8 hours (TWAA), and/or short-term exposure of 15 minutes (STEL) or lastly, in certain cases, indicate the concentration that must not be exceeded during any moment of exposure (Ceiling).
By "threshold limit values" ACGIH means the "environmental concentrations that nearly all workers can be exposed to, day after day, throughout their life without suffering any detrimental effects". Therefore, these limits represent parameters under which there should be no harmful effects to an exposed worker’s health. However, due to significant differences in individual sensitivity, a small percentage of workers, in these conditions, could experience discomfort or find that existing illnesses worsen or even occupational diseases appear. Therefore, the concept of tolerable limit is that of “reference value” that does not guarantee absolute safety but a good level of safety for the majority of individuals.
The environmental monitoring results showed risk indexes way below the reference limit values for all substances investigated.
However, if it is true that these reference values (TLV) are to be intended as a prerogative for working environments and applicable to adult healthy subjects exposed to these values for 8 hours a day and 5 days a week, and therefore should in no way be used for other environments (for example domestic environments or atmospheric pollution in general), it should be noted that the risk indexes resulting from the ratio between the measured concentrations and relative TLVs are always at very low levels, even 10 or 100 times lower than the alarm thresholds.
Taking the pollutant formaldehyde as an example, the concentration values noted during 3D printer processing are below the limit recommended by the Italian regulations on living environments (note 1) and are very similar to data found in scientific literature referring to average concentration values recorded during indoor air quality research carried out in homes in Italian metropolitan areas.
Ciceri de Mondel however suggests to aerate rooms where FILO ALFA filaments are used.
All analytics data are available here.
Note 1: Cf. Ministry for Health circular no. 57 of 22 June 1983 "Uses of formaldehyde-Risks linked with possible methods of use" indicating a maximum exposure limit of 0.1 ppm (0.124 mg/m3) in experimental and temporary living environments. Decree of 10 October 2008 "Provisions aimed at regulating the emission of formaldehyde from wood based panels and articles made with them in living environments" confirmed said value.