The humidex is a gauge of our body temperature. It is a parameter that the general people can use to convey how they feel about the combined effects of warm temperatures and humidity. Similar to how the comparable chill temperature, or ""wind chill factor,"" indicates how chilly people feel, it provides a value that expresses how hot people feel. Humidex ratings are used by Environment Canada to alert the public to potentially uncomfortable heat and humidity conditions. Table 1 the Humidex Range Amount of comfort 20 to 29 in comfort a little pain 30-39 Avoid exerting yourself above 45 as it is harmful and can result in heat stroke. Source: Weather dangers during the summer. Administration of Canada
What role does humidity play?
The body makes an effort to keep its interior temperature at 37 °C at all times. Sweating is a natural cooling mechanism for the body in hot temperatures. Sweat does not evaporate as quickly as the humidity or moisture content of the air rises. When the relative humidity reaches roughly 90%, sweat evaporation ends completely. In these conditions, the body temperature increases and could lead to disease.
What are the risks associated with working in warm environments?
There are various frequent ailments brought on by the heat. More harsh than others are some. Heat rash, often known as prickly heat, develops when clogged sweat glands swell up. The body's capacity to sweat and tolerate heat is decreased by this uncomfortable rash. Heat cramps are excruciating muscle spasms. The muscles that are used for work are most vulnerable. The body's inability to replenish lost bodily salts is what leads to the spasms, which typically follow periods of intense perspiration. When working in hot surroundings, the body loses a lot of fluid through sweating, which leads to heat exhaustion. The skin turns damp and cold. Sweating a lot, feeling weak, queasy, nauseous, and having headaches are other symptoms. The most serious condition, heat stroke, necessitates urgent medical care. The body temperature rises dramatically and can potentially surpass 41 C. It is possible to lose consciousness completely or partially. Sweating is not a reliable indicator of heat stress because there are two types of heat stroke: ""classical,"" in which there is little to no sweating (common in children, the elderly, and people with chronic illnesses), and ""exertional,"" in which the body temperature rises as a result of strenuous activity and sweating is typically present.
Can humidex be used in workplaces to monitor situations that could lead to heat-related illnesses?
Weather forecasters use a tool called Humidex to communicate the consequences of high humidity and warm temperatures to the general public. In addition to ambient temperature and humidity, there are various workplace variables that affect heat-related disorders. Additional factors to consider include job load, radiant heat sources, wind speed or air movement, and a person's physical condition. The humidex may be used as a sign of discomfort brought on by work-related heat exposure in certain office settings. For instance, humidex may be helpful when humidity is high but work load, wind speed, and radiant heat sources are not considerably increasing the heat burden. The typical type of workplace where humidex could be employed is an office. Utilizing the real measurements of the temperature and relative humidity made at the workplace is crucial. The workplace's actual conditions could be very different from what the Weather Service reports.
How am I able to define the humidex?
The chart below can be used to calculate the humidex rating if you know the temperature and relative humidity. The humidex rating is 41, for instance, if the temperature is 30 °C and the relative humidity is 70 %. Exercise should be avoided at this level since it is seen as one of ""severe discomfort."" For information on humidex in relation to temperature and humidity, go to the Government of Canada's humidex table. According to the Government of Canada, a Humidex rating over 40 is considered to be exceptionally high. You should avoid engaging in any unnecessary physical exertion under these circumstances. Depending on your age, health, physical condition, clothing choice, and other weather circumstances, you should scale back or adjust some outdoor exercises if the reading is in the mid to high 30s. If working outside is absolutely necessary, make sure to stay hydrated and take frequent pauses to rest. There is a significant danger of heat stroke and sunstroke in hot, humid weather.
How should one interpret humidex?
The relationship between comfort and humidex is arbitrary. Individual differences are significant. When using the humidex rating, workplaces must exercise caution. A high humidex rating can be used as a signal to more accurately evaluate working conditions. Please refer to the fact sheets on: OSH Answers for further details. Temperature Coniditions - Hot Hot Environments - Control Measures Hot Environments - Health Effects and First Aid The Occupational Health Clinics for Ontario Workers Inc. (OHCOW) created a humidex-based response plan that translated the TLVs® WBGTs into humidex values and developed recommended responses for each humidex range. Given that most businesses find using the WBGT to be difficult and expensive, this strategy was created as a tool to assist workplaces. While technically there is no way to directly compare WBGT and humidex values, this humidex response plan provides an additional guideline that uses information that is easily available to most employers. OHCOW notes, """"in the translation process some simplifications and assumptions have been made, therefore, the plan may not be applicable in all circumstances and/or workplaces (follow steps 1 through 5 to ensure the humidex plan is appropriate for your workplace)"""" which is available on their website at Source: Occupational Health Clinics for Ontario Workers (OHCOW) - Humidex Based Heat Response Plan. See Table 2 for details. Notes: These humidex levels are for unacclimatized workers performing moderate physical activity. The ACGIH specifies an action limit and a TLV® to prevent workers' body temperature from exceeding 38°C (38.5°C for acclimatized workers). Below the action limit (Humidex 1 for work of moderate physical activity) most workers will not experience heat stress. Most healthy, well-hydrated, acclimatized workers not on medications will be able to tolerate heat stress up to the TLV®. (Humidex 2 for moderate physical activity). Between Humidex 1 and Humidex 2, general heat stress controls are needed and above Humidex 2 job-specific controls are needed. Table 2 Recommended Actions Based on the Humidex Reading IMPORTANT: Consult with the OHCOW material for interpretation and use of this chart. ALWAYS follow steps 1 to 5 as listed on the OHCOW web site. Also see the Humidex-based Heat Stress Calculator.
What index should workplaces use to monitor conditions that may result in heat-related illness?
Occupational (Industrial) hygienists recommend using the Wet Bulb Globe Temperature (WBGT) index to measure workplace conditions. This method closely relates to the human body's response to heat. The WBGT measurement takes into account air temperature, air movement, radiant heat and humidity. There are direct-reading WBGT meters. These are also called """"heat-stress indicators,"""" commercially available. The WBGT measurements can then be related to the physical demands of the job. Only qualified professionals, whether they be in-house staff, consultants, or from the local occupational health and safety regulatory agency, should perform the measurement. Direct comparison between WBGT and humidex is not possible--there are no conversion tables or mathematical formulas to do such conversions. However, one can estimate WBGT and humidex for a given ambient air temperature and humidity when radiant heat sources (hot and cold surfaces) are absent and air movement is less than 0.5 m/sec. (100 feet per minute). Under these conditions the globe temperature equals room temperature and the natural wet bulb temperature (on the WBGT apparatus) is approximately 2°F (1.1°C) higher than the wet bulb temperature measured using a psychrometer. Standard charts are available to determine wet bulb temperature from given air temperature and relative humidity values. For indoor or outdoor conditions with no direct sunlight, WBGT is calculated by using the following formula: WBGT = 0.3 x globe temperature + 0.7 x natural wet bulb temperature"""