Alkaline Earth Silicate Wool (AES Wool)

See the AES-section for more information.

Alumino Silicate Glass Wool (ASW)

See the ASW-section for more information.

Biopersistence

The property of remaining in tissue for some period. MMMF have low biopersistence compared with most natural mineral fibres, recent developments have ensured that manufacturers concentrate on the development of materials with very low biopersistence.

Crystallization

In the case of amorphous HTIWs crystallization or devitrification reduces resiliency and mechanical strength of the products. Heated above 900°C the amorphous wools become more brittle and more dust is formed accordingly. Various crystalline phases can be formed like mullite enstatite, wollastonite and cristobalite. Crystalline phases produced when heating polycrystalline wools at high temperature (1400 °C - 1600 °C) are mullite (main phase) and corundum (secondary phase).
Crystalline silica is not formed upon heating of PCW.

Diameter

While this may seem a simple concept the diameter of fibres in wools is complex and often wrongly reported. "Nominal diameters"(without further definition) are often provided but rarely provide a meaningful description of any property of the wool. Wools contain fibres with a wide range of diameters; if these are to be measured in any type of microscope the wool must usually be ground, milled or broken up in some other way. When this is done the thin fibres break more easily than thick ones. This also happens when working with wools so that for any fibres in workplace dusts length and diameter are correlated, finer diameter fibres tend to be shorter than coarser fibres. If the diameter of a number of fibres is measured and a simple mean diameter calculated then this figure will depend on how many thin fibres are created and this on the way the fibres have been handled.

Therefore to obtain a meaningful and reproductible measure of fibre diameter, independent of the preparation, the so called “length weighted geometric mean diameter  (LWGMD)” of the wool concept has been devised. As the diameters usually vary so that their logarithms are normally distributed then the geometric mean should be used, here 50% of the total length of fibres present will be less than the LWGM. This value is also close to the median diameter. The vast majority of man-made fibres are fairly coarse with most fibres with LWGMD well above 1 µm.

Dose

The amount of dust able to reach the lungs during a certain period of time . It is usually expressed in F/ml*year or F/ml*month.

See the Health & Safety-Section for more information.

Emission-relevant fibres

Emission-relevant fibres are fibrous dusts that can be found in industrial applications and processes or released from products during processing.

EU Directive 97/69/EC

A directive concerning the hazard classification, and e labelling, of Man made vitreous (silicate) fibres. It doesn’t deal  with risk. It exonerates thick fibres and then divides the rest into two groups at a 18% alkaline and alkaline earth oxides weight composition boundary. Those containing more than 18% are called mineral wools and may be exonerated from classification and labelling if certain bioassays guarantee either their low biopersistence or lack of pathogenicity (see Nota Q). The terms (Mineral wools, refractory ceramic fibres) used in this directive are descriptions not definitions in that refractory ceramic fibres are themselves mineral wools.

Exposure

Specifically in this context the measure of airborne  fibrous dust  or other material , that can reach the deep lung in persons (or animals in case of bioassays). This shouldn’t be confused with airborne fibre concentration often evaluated according to the WHO EURO definition of fibres.

See the Exposure Limit Values-section for more information.

Fibre

A small object longer than its width; material scientists normally call objects fibres when their length is more than 10 times their width (that is their aspect ratio is 10). Occupational hygienists begin at aspect ratios of 3 or 5. To be useful in most applications fibres must have aspect ratios very much more than this. Exposures in the air are to fibres either lofted from dust or broken from articles. Animal Experiments therefore concentrate on using shortened fibres samples with size distributions similar to those in workplace air. (See also WHO-Fibre)

Fibrous dusts

Fibrous dusts are dusts released from products that contain emission-relevant fibres. In order to harmonise optical fibre counting, the World Health Organisation has normalised fibre dust size. In order to evaluate the workplace concentration only airborne fibres with a diameter less than 3 µm, a length greater than 5 µm and an aspect ratio L/D greater than 3 shall be considered. Beside differences in their chemical composition, synthetic MMMFs generally have parallel edges in contrast with some other ubiquitous fibres shaped particles.

GHS

The Globally Harmonized System of Classification and Labelling of Chemicals or GHS is an internationally agreed upon system set to replace the various different classification and labeling standards used in different countries. (See also Wikipedia)

High-Temperature Insulation Wool (HTIW)

See the HTIW-section for more information.

Labelling

In the past classification and labelling of hazardous substance and preparations had to be done following Directive 67/548/EEC and 1999/45/EEC. In order to harmonise the classification and labelling regulation the European Union has decided to adapt the Global Harmonised System (GHS) proposed by the United Nations. As a consequence a new Regulation (EC) No 1272/2008 has been published aiming at replacing the former above listed Directives. Substances and mixtures will have to be labelled according to the European regulation GHS/CLP-rules.

In addition to the labelling of classified substances, ECFIA members are voluntarily labelling articles made of these classified substances including handling advices for the users.

See the Classification & Labelling-section for more information.

Length

Another simple variable that conceals necessary complexity (c.f. diameter). The length of fibres in wools is highly variable ranging from a few micrometers up to some centimetres. When fibres are handled any airborne dust includes non-fibrous particles and fibres with lengths up to some tens of mm.

Man Made Vitreous Fibres (MMVF)

The super class of materials including all the glassy fibres such as rockwool , glass wool, slagwool, AES and ASW/RCFS-wools. This term has been used in ways to exclude ASW/RCF´s, there is no formal justification for this usage. The European Union added the term (silicate) in Directive EU/97/69 to identify a subset of these fibres. Inorganic man made mineral fibres are recognized and differentitated from other fibrous particles by parallel edges.

Man Made Vitreous Wools (MMVW)

Conglomerates made from MMVFs are called MMVWs.

Nota Q

A note stating the conditions that may be used in Europe to exonerate some man-made vitreous (silicate) fibres from classification as carcinogens under Directive EU/97/69 (q.v.).

OEL

Occupational Exposure Limit. Any of several (TLV, PEL, MEL, etc) exposure levels set by regulators to control worker exposure.

Pleural plaques

Non-malignant inflammatory condition of the pleural surface detected on chest x-rays and even more prevalent if looked for at post mortem. Plaques are common in the general public and are not usually associated with any ill health therefore sometimes described as a sign of asbestos exposure.

Polycrystalline Wool (PCW)

See the PCW-section for more information.

REACH (Reach, Evaluation, Authorization and Restriction of Chemicals)

REACH is a European Union Regulation of 18 December 2006. REACH addresses the production and use of chemical substances, and their potential impacts on both human health and the environment. REACH entered into force in June 2007, with a phased implementation over the next decade. (See also ECHA-website)

Refractory Ceramic Fibres (RCF)

See the ASW-section for more information.

Respirable

Capable of reaching the deep lung when inhaled.

Vitreous, Glassy Fibres

Vitreous fibres are  not crystalline fibres. They have no cleavage planes and when handled they break transversely and do not cleave into thinner fibres.

WHO-Fibres

Different studies have used different rules for counting fibers in air. The WHO counts fibres as particles with lengths >5 μm, widths <3 μm, and aspect ratios ≥3:1.

Wool

Wool is the term used to describe an unordered mass of fibres of different lengths and diameters (EN 1094-1).