Diisocyanates threshold limit values

The 2003 ACGIH threshold limit value-time-weighted average (TLV-TWA) for toluene-2,4-diisocyanate is 0.005 ppm (0.036mg/m ) with a short-term excursion limit (STEL) of 0.02 ppm (0.14mg/m ). 

ACGIH Ibluene-2,4-Diisocyanate. Documentation of the Threshold Limit Values and Biological Exposure Indices, 7tb ed, 6pp. Cincinnati, OH, American Conference of Governmental Industrial Hygienists, 2001... 

The American Conference of Governmental Industrial Hygienists (ACGIH) (1997) has recommended 0.036 mg/m as the 8-h time-weighted average threshold limit value for occupational exposures to 2,4-toluene diisocyanate in workplace air. Similar values have been used as standards or guidelines for 2,4- or 2,6-toluene diisocyanates in several countries. In some other countries, values ranging from 0.04 to 0.14 mg/m for mixed isomers have been used (International Labour Office, 1991). 

The American Conference of Governmental Industrial Hygienists threshold limit value for toluene diisocyanate is 0.005 ppm. The reference exposure level for toluene diisocyanate is 0.01 ppb. 

Volatile isocyanates, such as TDI and hexamethylene diisocyanate, are irritants to the eyes, nose and throat. Higher molecular weight polyisocyanates for paints therefore should contain very low levels of these isocyanates, so that the isocyanate content of the air around them remains below the threshold limit value (see p. 124). Even if they contain only low levels of volatile isocyanates, precautions must be taken to prevent inhalation of spray droplets containing unreacted isocyanates (either excellent extraction of overspray in the spray booth, or the wearing of fresh air hoods by those in the vicinity). The uncured liquid finishes can also be skin irritants. 

THRESHOLD LIMIT VALUES (TLV) FOR SOME COMMONLY USED DIISOCYANATES... 

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