Environmental Factors Affecting Human Comfort

Human Comfort
(i)Thermal Comfort
The most commonly used indicator of thermal comfort is air temperature – it is easy to use and most people can relate to it. However, air temperature alone is not an accurate indicator of thermal comfort .It should always be considered in relation to other environmental and personal factors. The six factors affecting thermal comfort are both environmental and personal. These factors may be independent of each other, but together contribute to an employee’s thermal comfort.
Environmental factors:
1. Air temperature
2. Radiant temperature
3. Air velocity
4. Humidity
Personal factors:
1. Clothing Insulation
2. Metabolic heat
Environmental factors
1. Air temperature
This is the temperature of the air surrounding

However, when considering lighting, a number of different factors need to be considered such as color, contrast, glare and so on.
Different activities require different levels of light. In general, the more detailed the task, the greater the light requirement. A process control room should be lit at an illuminance of 300 lux, a corridor or walkway may only require 50 lux, whilst studying an engineering drawing may require 750 lux.
Directional sources of light can bounce off reflective surfaces such as display screens and cause glare. Using blinds, correcting the angle of the source of light and using glare filters can help control this, as can use of e.g. up-lighting. All sources of light have a particular color. Some of these, such as sodium, can make colored text and diagrams difficult to read.
Generally lighting is designed when the workplace is empty and without consideration of the shadows cast by equipment e.g. lighting of yards where trailers and containers may be parked. Pedestrian walkways in these areas should have specific

Artificial lighting is lighting which is man-made, such as fluorescent, tungsten, mercury vapor, sodium vapor, halogen, compact fluorescent, et cetera. It can be turned on and off by a switch. There are also very special types of artificial light for specific purposes such as in-fared heat lamps, ultraviolet lights for plant growth and tanning, et cetera.

Minimum level of illumination
Illumination levels can either be too little or too much light. If there is too little light, employees or the public cannot see well. This could result in an error occurring because a dangerous situation may not be recognized with a corresponding decrease in an individual’s reaction time. Changes in illumination levels interfere with the ability of the eye to adjust quickly enough to permit seeing without error. Examples of changing light levels are the transition from bright outdoor light to dark interiors or from a bright area of a building to a dark one.

Glare
Glare can be defined as the contrast lowering effect of stray light in a visual scene. Glare forms a veil of luminance which reduces the contrast and thus the visibility of a target is decreased. And the sensitivity to glare is amplified as scattering in cornea or lens