The concentration in air that should not be exceeded during any part of the working exposure. Ceiling limits may supplement other limits or stand alone. Developed by the American Conference of Governmental Industrial Hygienists (ACGIH).
Notice: The AIChE website is undergoing an ecommerce system upgrade to better serve you. Until Wednesday, December 11 at 9:00 AM EST you will not be able to reliably purchase or renew any AIChE products or services through the website... Learn more