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Manual Manufacturing Chemists’ Association, Inc. Tolylene Di isocyanate
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Specific Gravity (25°C./15.5°C.) 1.22 1.22 1.22
Specific Heat (77-167°F.) 0.375 BTU/lb./°F.
Vapor Density (Air = 1) 6.0 6.0 6.0

Vapor Pressure at 20°C __________________ Approx. 0.01mm Approx. 0.01mm Approx. 0.01mm
Viscosity at 50°C 1.45 centistokes
Threshold Limit (Max. average atmospheric
concentration for 8 hr. working day with­
out injury to health.) 0.1 ppm. or 0.7 mg. per cu. m.

3. HAZARDS

3.1 HEALTH HAZARDS in the air. No one will voluntarily stay in a high
concentration of vapor. However, at the tentative
Tolylenc diisocyanate is an irritating substance in threshold limit value (0.1 ppm. or 0.7 mg. per cu.
either its liquid or vapor form. On contact with the m.) for prolonged exposure, it is difficult to detect
skin or eyes it produces irritation and if not removed the compound by odor or immediate sensory effects.
immediately may cause burns. Inhalation of the This low level has been set to avoid delayed irritation
vapor may be injurious to the lungs. The vapor is or possible difficulty in breathing.
capable of producing difficult and labored breathing
in some individuals.
3.2 FIRE AND EXPLOSION HAZARDS
3.1.1 Warning Properties
Its characteristic odor and strong irritating effect Due to its high flash point tolylene diisocyanate
on the eyes and upper respiratory passages are warn­ does not constitute a severe fire hazard. (See Sec­
ings of the presence of tolylene diisocyanate vapors tion 6.) o

4. ENGINEERING CONTROL OF HAZARDS

4.1 BUILDING DESIGN fating to workers and cause them to abandon the
area. Provisions should be made to make possible
4.1.1 Buildings in which tol’ylene diisocyanate the addition or removal of materials without open­
is handled or stored should be well ventilated and ing the equipment.
be of fire-resistive construction. 4.2.2 Whenever it is found necessary to open
4.1.2 Equipment should be installed in such the equipment, adequate ventilation should be avail­
fashion that a worker’s path to the nearest exit able to immediately remove any vapors that may be
clear and unobstructed. * present.
4.1.3 Not less than two means of exit should 4.2.3 Solid or residual materials that are removed
be provided from each separate room or building from the process should be thoroughly decontami­
in which tolylene diisocyanate is stored, handled nated of tolylene diisocyanate vapors.
or used. No portion of such a room or building 4.2.4 Open containers or partially opened con­
should be further than 75 feet from the nearest tainers of tolylene diisocyanate should not be left
exit. Additional exits should be provided depending standing in working areas. Points at which con­
upon the number of persons in the building. (See tainers must be opened should be adequately venti­
NFPA “Building Exits Code.”) lated.
4.1.4 All exit doors should open out in the
direction of travel and should be provided with 4.3 VENTILATION
panic hardware. 4.3.1 Good ventilation is essential in rooms or
areas where tolylene diisocyanate is handled. Al­
4.2 EQUIPMENT DESIGN though the material is not highly toxic, its vapor is
highly irritating to personnel.
4.2.1 Totally enclosed systems should be used
for processes where tolylene diisocyanate is a raw 4.3.2 Exhaust Hoods
material. This is necessary because the escape A hood type ventilation unit should be situated
of tolylene diisocyanate vapors would be highly irri- K O over equipment where tolylene diisocyanate vapors