BASIC PRINCIPLES IN OCCUPATIONAL HYGIENE 职业卫生基本原则 Day 4 第4天

15 - THERMAL ENVIROMENT 15-热环境

THERMAL ENVIROMENT 热环境 In order to function effectively we need to maintain our bodies at a constant temperature within 36.5 - 37.5 oC. 为了能让身体正常运行，我们需要确保体温恒定在36.5 - 37.5℃。 Temperature regulation centres in our brain are sensitive to small changes of blood temperature and also get feed back from sensory nerves at the skin. 我们的大脑是一个温度调节中心，对体温的微小变化都很敏感，还能获得皮肤感觉神经的反馈。 Our brains then use this information to adjust our bodies responses to heat. 我们的大脑会根据反馈的信息调节身体，适应热环境。

HEAT 高温 Physiological responses to heat 对高温的生理反应 Blood vessels in skin expand 皮肤血管扩张 Pulse rate increases 脉搏加快 Increases blood to the surface of the body 体表血液增加 Sweating also increases heat loss due to latent heat of evaporation. 出汗也会散热，因为汗液会蒸发。 In very hot conditions, sweating offers greatest potential for regulating body temperature. 如酷热环境，出汗是调节体温的最有效方式。 Possible adverse effects of exposure to excessive heat include; 接触高温可能的副作用包括： Fatigue 疲劳 Behavioural modification 行为变化 Reduced concentration 集中度不高 Heat cramps due to salt loss 因体内盐分减少，可能出现中暑性痉挛。 Fainting heat exhaustion 中暑昏厥 Heat stroke 中暑

COLD 低温 Physiological responses to cold 对高温的生理反应 Blood vessels in skin contract 皮肤中血管紧缩 Heat flow to the body surface is reduced 皮肤表面热流减少 Heat production is increased by physical activity and shivering. 因活动和发抖会增加产热 No physiological acclimatisation to cold 生理水土不服 Possible adverse effects to excessive cold include; 接触低温可能的副作用包括： lassitude/listlessness, 精神不振/萎靡 chilblains, 冻疮 frost bite 冻伤 hypothermia. 低体温

Psychological Responses to the Thermal Environment 对热环境的心理反应 People will often modify the way they work depending on the thermal environment. 人们会根据热环境条件改变其工作方式 Modify their local work environment 调节其工作环境 moving to a more comfortable area, 转移到更加舒适的区域 changing clothes, 换衣服 increasing or decreasing ventilation 增加或减少通气量 Performance and efficiency can also be affected by adverse thermal conditions. 热环境不当可能会影响绩效和效率。

Heat Transfer from the Body 体内传热 Six parameters that may be taken into account: 应考虑如下六个参数： S = M ‑ W + C + R + K ‑ E Where: S = Storage, which in the long term must equal 0 M = Metabolism W = External work done C = Convection R = Radiation K = Conduction E = Evaporation 其中： S = 存储，如长期存储，则该数值为零 M = 代谢 W = 完成的对外工作 C = 对流 R = 辐射 K = 传导 E = 蒸发

Factors Influencing Heat Balance 影响热平衡的因素 1 Work rate (i.e. activity or metabolic rate) 工作率（即活动或代谢率） Person 人 2 Clothing 服装 3 Air temperature 空气温度 Environment 环境 4 Radiant temperature 辐射温度 5 Air Velocity 空气流速 6 Humidity (moisture) conditions 湿度（水分）条件

Metabolic Rate 代谢率 Activity 活动 Metabolic Rate (W/m2 body surface) Sleeping 睡觉 43 Resting 休息 47 Sitting 坐 60 Standing 站 70 Slow Walk (2.5 kph) 慢走(2.5 kph) 107 Walking (5 kph) 正常走(5 kph) 154 Running ( 16 kph) 跑步（16 kph) 600 Sprinting (25 kph) 短跑 (25 kph) 2370

Personal Insulation 防烫伤隔热 Clothing 服装 Clo Value 克罗值 Naked 裸体 Shorts 穿短袖 0.1 Light summer clothes 穿夏装 0.5 Typical indoor clothes 穿家居服 1.0 Heavy suit 穿厚外套 1.5 Polar clothing 穿极地服装 3-4 Practical maximum 穿很多衣服（实际最大量） 5

THERMAL ENVIROMENT 热环境 Dry Bulb Temperature 干球温度 Mean Radiant Temperature 平均辐射热 Air Velocity 空气流速 Personal monitoring. 个人监测

Heat Stress Indices 热应力指数 Various workers have devised indices to combine some of them into a single figure to which a standard could be applied. Some of these include: 各类工人都已制定了指数，即，可以将其与标准应用环境相互融合的指数。其中包括： Wet Bulb Globe Temperature: A simple index calculated after measuring the dry bulb, natural wet bulb and globe temperatures. 暑热压力指数：测量干球、自然湿球和黑球温度后计算的简单指数。 HSI (Heat Stress Index): Calculated using a range of environmental measurements as well as work rate. HSI（热应力指数）：使用各类环境测量数值和工作速率计算的指数。 P4SR (Predicted Four Hour Sweat Rate): Calculated from charts and used to assess physiological limits. P4SR（预测4小时出汗率）：根据图表计算的指数，用于评估生理极限。

Thermal Comfort 热舒适 Very subjective and people will feel differently about what is the ‘ideal’ thermal environment. 热舒适因人而异，非常主观，不同的人对理想的热环境有不同的感觉。 Much less extreme conditions than thermal stress. 极端条件比热应力少很多。 Indices have also been generated in an attempt to measure thermal comfort. 在尝试测量热舒适时产生的指数。

Controlling the Thermal Environment 控制热环境

Specific Environmental Problems 具体的环境问题 High radiant components 高辐射器件

Specific Environmental Problems 具体的环境问题 High humidity conditions 高湿度条件

Specific Environmental Problems 具体的环境问题 Hot dry conditions 极干环境