ASTM E2535-07(2013)

5.1 This guide is intended for use by entities involved in the handling of UNP in occupational settings. This guide covers handling principles and techniques that may be applied, as appropriate, to the variety of UNP materials and handling settings. These settings include research and development activities, material manufacturing, and material use and processing. This guide may also be used by entities that receive materials or articles containing or comprising nanoscale particles fixed upon or within a matrix (that is, bound nanoscale particles), but whose own processes or use may reasonably be expected to cause such particles to become unbound.

1.1 This guide describes actions that could be taken by the user to minimize human exposures to unbound, engineered nanoscale particles (UNP) in research, manufacturing, laboratory and other occupational settings where UNP may reasonably be expected to be present. It is intended to provide guidance for controlling such exposures as a cautionary measure where neither relevant exposure standards nor definitive hazard and exposure information exist.

1.2 General Guidance—This guide is applicable to occupational settings where UNP may reasonably be expected to be present. Operations across those settings will vary widely in the particular aspects relevant to nanoscale particle exposure control. UNP represent a vast variety of physical and chemical characteristics (for example, morphology, mass, dimension, chemical composition, settling velocities, surface area, surface chemistry) and circumstances of use. Given the range of physical and chemical characteristics presented by the various UNP, the diversity of occupational settings and the uneven empirical knowledge of and experience with handling UNP materials, the purpose of this guide is to offer general guidance on exposure minimization approaches for UNP based upon a consensus of viewpoints, but not to establish a standard practice nor to recommend a definite course of action to follow in all cases.

1.3 Applicable Where Robust Risk Information Does Not Exist—This guide assumes the absence of scientifically sound risk assessment information relevant to the particular UNP involved. Where sound risk assessment information exists, or comes to exist, any exposure control measures should be designed based on that information, and not premised on this guide. Such measures may be more or less stringent than those suggested by this guide.

1.4 Materials Within Scope—This guide pertains to unbound engineered nanoscale particles or their respirable agglomerates or aggregates thereof. Relevant nanoscale particle types include, for example, intentionally produced fullerenes, nanotubes, nanowires, nanoropes, nanoribbons, quantum dots, nanoscale metal oxides, and other engineered nanoscale particles. Respirable particles are those having an aerodynamic equivalent diameter (AED) less than or equal to 10 µm (10 000 nm) or those particles small enough to be collected with a respirable sampler (1-3).² The AED describes the behavior of an airborne particle and is dependent upon the particle density, shape, and size—for instance, a particle with a spherical shape, smooth surface, density of 1.0 g/cc and a physical diameter of 4 µm would have an AED of 4 µm, whereas a particle with a spherical shape, smooth surface, density of 11.35 g/cc and a physical diameter of 4 µm would have an AED of 14 µm and would therefore be of a nonrespirable size. Respirable fibers are those having physical diameters less than or equal to 3 µm (3000 nm) or those fibers small enough to be collected with a thoracic sampler 1.5 Materials Beyond Scope: