Methyl isocyanate liquid and vapor permeation through selected respirator diaphragms and chemical protective clothing.
Berardinelli SP; Moyer ES
Am Ind Hyg Assoc J 1987 Apr; 48(4):324-329
Tests were conducted to determine the ability to withstand permeation by liquid methyl-isocyanate (624839) of 22 chemical protective clothing materials and in regulator diaphragms from four different closed circuit, positive pressure self contained breathing apparatuses. The chemical protective clothing materials that exhibited the longest methyl-isocyanate breakthrough times were an MSA aluminum laminate and a Chem Fab Teflon Nomex laminate. The aluminum laminate, however, cracked when flexed. Breakthrough times for most flexed materials were very much shorter than for unflexed materials. Flexing did not affect breakthrough time of one specimen of Teflon Nomex laminate. While no garment material was deemed capable of affording workers adequate protection for at least 1 hour, the Chem Fab laminate was considered the least permeable by liquid methyl-isocyanate. Results of the tests of liquid methyl- isocyanate permeability upon respirator diaphragms indicated that penetration at high concentrations would occur within 2 minutes of direct contact with the material. The authors recommend that total encapsulating suits with the respirator on the inside should be worn by personnel who may come into contact with methyl-isocyanate in either vapor or liquid form during emergency response operations.
NIOSH-Author; Protective-clothing; Chemical-industry-workers; Respirators; Body-protection; Respiratory-protection; Personal-protective-equipment
American Industrial Hygiene Association Journal