Correction
A May 29 article on Factory Mutual’s new standards for fire-resistant fluids incorrectly reported the flammability classification of phosphate esters. According to Akzo Nobel, phosphate esters will be in the preferred Group 1 class (fluids that are usually unable to stabilize a spray flame), while polyol esters may be Group 2 (less flammable than mineral oil but able to stabilize a spray flame under certain conditions).