The Humidex plan is a simplified way of protecting workers from heat stress which is based on the 2007 ACGIH Heat Stress TLV ® (Threshold Limit Value ®) which uses wet bulb globe temperatures (WBGT) to estimate heat strain. Humidex Based Heat Response Plan www.ohcow.on.ca Humidex Based Heat Stress Calculator www.ohcow.on.ca