Not really, in most circumstances. When it comes to the allowed range of temperatures at work, especially when working outdoors, legislation is not always clear. Legislation occasionally specifies a range of allowable temperatures for particular situations. Some jurisdictions have formally adopted the Threshold Limit Values® (TLVs®) for heat stress published by the American Conference of Governmental Industrial Hygienists (ACGIH) as occupational exposure limits, while other jurisdictions utilize the TLVs® as guidelines. For a list of laws from each jurisdiction, see OSH Answers Temperature Conditions - Legislation. This document focuses on tasks performed in warm environments. For further information on how to work in different settings, please visit the OSH Answers Temperature Conditions - Cold, Thermal Comfort For Office Work, and Humidex Rating and Work.
What are the heat stroke red flags?
Heat stroke is the biggest health and safety risk in a very hot setting. If treatment is not found right away, heat stroke can be fatal. Other heat-related ailments include heat exhaustion and fainting (syncope), which are not lethal but can impair a person's ability to work. The capacity of coworkers to recognize symptoms in others and seek medical attention is crucial to the survival of heat stroke victims because they are unable to recognize the symptoms when they are happening to themselves. The warning indications of heat stroke can include complaints of sudden and extreme weariness, nausea, lightheadedness, dizziness, and may or may not include sweating. Symptoms can vary from person to person. When a coworker exhibits unusual irritation, lethargy, or flu-like symptoms, or if they appear confused or disoriented (including euphoria), they should be transferred to a cool area and should get medical attention right once. Please visit our OSH Answers documents on Hot Environments - Health Effects and First Aid for additional details.
Why are there no temperature restrictions in the rules?
The temperature is only one of several variables that affect the occupational exposure limits or guidelines for exposure to high temperatures. These other elements include: the relative humidity exposure to heat sources like the sun the volume of air moving Task demands, such as how physically demanding the work is, whether the employee has adapted or not to the work load, the working environment, and the attire worn at work (including protective clothing) What is the work-rest schedule (% time working vs. % time taking a break)?
Exist any broad criteria for temperature?
Yes. Thermal comfort limits and occupational exposure limits are the two types of exposure limits that are frequently utilized. Workplace exposure restrictions are there to safeguard industrial workers from heat-related illnesses. The TLVs® for Heat Stress issued by the ACGIH are typically used by occupational health and safety jurisdictions for non-office workplace conditions. As previously indicated, certain Canadian jurisdictions have made use of these TLVs as occupational exposure limits, while others utilize them as suggestions to reduce workplace heat stress. The WBGT (wet bulb globe temperature) limit values are expressed in degrees Celsius (°C). The WBGT unit considers environmental elements like air temperature, humidity, and air movement that affect how hot people perceive things to be. When calculating the WBGT in specific workplace circumstances, solar load (heat from radiant sources) is also taken into account. The measurement should only be carried out by qualified professionals, whether they are internal workers, consultants, or members of the regional occupational health and safety authorities. The OSH Answers publication Working in Hot Environments - Control Measures has more details about WBGT. Office workers must adhere to thermal comfort guidelines to maintain quality and productivity. Check out the OSHAnswers. For additional information on interior temperatures, see Thermal Comfort for Office Work.
What are the exposure restrictions for performing work in warm conditions?
Recommendations for screening criteria for heat stress exposure for employees are provided in the ACGIH publication 2017 TLVs® and BEIs® (or the most recent booklet) (Table 1). For additional information on these screening criteria, categories of job demands, directions for limiting heat stress, and heat stress management, reference the publications 2017 TLVs® and BEIs® (or most recent) and Documentation of TLVs® and BEIs®. Table 1 ACGIH Screening Criteria for Heat Stress Exposure (WBGT values in °C for 8 hours of labor, five days a week, including traditional breaks) Work Distribution in a Work/Rest Cycle TLV® Action Capacity Low Moderate High Extremely Heavy Lightweight Heavy Really hefty 75-100% 31.0 28.0 — — 28.0 25.0 — — 50-75% 31.0 29.0 27.5 — 28.5 26.0 24.0 — 25-50% 32.0 30.0 29.0 28.0 29.5 27.0 25.5 24.5 0-25% 32.5 31.5 30.5 30.0 30.0 29.0 28.0 27.0 Notes: The table is designed as a screening tool to determine whether a potential case of heat stress exists. According to ACGIH, this table offers greater protection than either the TLV® or Action Limit. The values do not intend to impose work and recovery periods because they are more protective. assumes a 5-day workweek with 8-hour workdays and standard breaks. TLVs assume that workers exposed to these conditions are adequately hydrated, are not taking medication, are wearing lightweight clothing, and are in generally good health. See the TLV® booklet for more guidance notes and documentation. Various workload examples: Rest - sitting Light work - sitting or standing to control machines; performing light hand or arm work (e.g., using a table saw); occasional walking; driving Moderate work - sustained moderate hand and arm work; light pushing or pulling; walking at a moderate pace; or moderate arm, leg, and trunk work. Heavy work – intense arm and trunk work; pick and shovel work, digging, carrying, pushing/pulling heavy loads; walking at fast pace Very Heavy - very intense activity at fast to maximum pace Adapted from: 2017 TLVs® and BEIs® - Threshold Limit Values for Chemical Substances and Physical Agents and Biological Exposure Indices. Cincinnati: American Conference of Governmental Industrial Hygienists (ACGIH), 2017, p.238.
What about humidex?
The weather broadcast service of Environment Canada uses the humidex scale to inform the public about hot weather conditions. The humidex scale quantifies human discomfort due to perceived heat taking into account the effect of air temperature and relative humidity. For a given temperature, the humidex increases as the relative humidity (moisture content) of the air becomes higher. Please see the OSH Answers Humidex Rating and Work for more information.
What should be done when it is very hot and/or humid?
Employers have a duty to take every reasonable precaution to ensure the workplace is safe for the worker. This duty includes taking effective measures to protect workers from heat stress disorders if it is not reasonably practicable to control indoor conditions adequately, or where work is done outdoors. Certain steps can be taken to reduce discomfort. These include: using fans or air conditioning wearing light, loose fitting clothing taking more frequent rest breaks drinking cold beverages (ones that do not have caffeine or alcohol) allowing flexibility to permit less physically demanding activities during peak temperature periods. using screens or umbrellas to create shade. More information about ways to control heat stress is available in the OSH Answers document Hot Environments - Control Measures.
Where can I find more information?
Please see the following OSH Answers documents: Temperature Conditions - Cold Temperature Conditions - Legislation Hot Environments - Health Effects and First Aid Hot Environments - Control Measures Humidex Rating and Work Thermal Comfort for Office Work"""