Healthy Indoor Environment

 

Why do we build Houses? The simple answer is comfort, without buildings we would be living outdoors which isn't so pleasant in the cold winter months. Whilst we are staying indoors we also look for comfortable spaces and there are six key factors that contribute to a healthy and comfortable environment. Human comfort is essential for a healthy well being and lifestyle. 

1. Thermal Comfort
2. Air quality and movement
3. Light
4. Sound
5. Electromagnetic fields
6. Ambience

Thermal Comfort:
Even though the Temperature outdoors is constantly changing the indoor temperature should be maintained at a steady level. Generally 18-20 degrees Celsius is comfortable for most people.

Air Quality and movement:
A constant supply of fresh clean air (with a humidity level between 35% and 55%) must be provided. There must be no draughts or air movement that would have a cooling effect on the people indoors.

Light:
The light levels outdoors varies from 10000 to 25000 lux on a typical overcast day. 150 to 300 lux is appropriate in most areas of a typical home.

Sound:
30 Decibels to 70 Decibels is comfortable for most people. Noise pollution from outdoors must be excluded.

Electromagnetic Fields:
All electrical devices produce an electromagnetic field. these fields may be harmful. There are some EU countries that are adapting standards to indicate safe levels of exposure to these fields.

Ambience:
This is achieved by using materials and furnishing to give a room warmth and comfort. it is essential to create a positive, healthy indoor environment,.





There is a number of factors that influence thermal comfort. These include Air temperature, Radiant temperature, Relative humidity, Air Velocity, Activity rate and Clothing level.


Air Temperature: The temperature of the room.
Radiant Temperature: The combined temperature of the surfaces in a room.
Relative humidity: The moisture content of the air.
Air Velocity: The speed at which the air in a room is moving.
Activity Rate: What the person is doing (eg; Sitting, dancing).
Clothing Level: The type and number of layers of clothing being worn.


Activity within a home can contribute to thermal comfort. The rate of heat emission depends upon the individual metabolic rate and upon the surface area of each person. the average rate of heat emission decreases with age. The output from adult females is about 85% that of males



Air Quality
- Carbon Monoxide - Colorless, odorless, tasteless, highly toxic (Above 0.67% can be fatal). It is produced by burning fossil fuels (eg: gas boilers). 
- Nitrogen based gases in high concentrations causes lung cancer. 
- Formaldehyde vapors - Impairment of the eyes and upper respiratory tract.
- Radon - Radioactive particles adhere to dust particles in the air and are inhaled. This causes lung cancer. The level should not exceed 200Bq/m.

Carbon Dioxide - Colorless, odorless at low concentrations, has a sharp acidic odor at higher concentration. Humans are the main indoor source of carbon dioxide - the more occupants in a given sealed indoor space, the more quickly CO2 level will increase and oxygen levels will decrease. High levels indoors may cause occupants to grow drowsy, get headaches, or function at lower activity levels. Outdoors air has approximately 0.35 - 0.4%. Carbon dioxide indoor air should not exceed 1.0%


















Comments

Post a Comment

Popular posts from this blog

Passivhaus Design Principles

Image
There are 2 fundamental approaches to building design. Active and Passive Design. Active design is burning fossil fuels such as coal, oil and gas to provide comfortable living space. By burning these fossil fuels it provides the home with artificial light and heat to maintain a comfortable living environment. this has a major impact on the environment as it releases emissions within the atmosphere.  There is now a bigger push to increase a more suitable environment and by achieving this, there is more emphasis and passive design. Passive design is effectively solar gain which maximizes the heat from the sun and provides natural light into the home. this reduces the amount of energy used within a home and reduces the running cost. The necessary need for solar panels installed within the home is to take the heat from the sun and provide hot water in the home all year round. Orientation:   It is effectively designing a building that is facing the sun with large glazed windows to ...
Read more

Water Supply

Image
For my house I have went for an indirect cold water supply system as it can reserve the supply of water if mains fail. There is constant pressure on all taps, except the kitchen tap and there is also an overflow fitting fitted to storage tank to prevent water damage due to overflow.  The indirect cold water supply system directs the mains water coming into the house in two directions, one up to a storage tank or the cistern in the attic and the other to the kitchen tap. It is fed off to individual appliances from the cistern. The only outlet coming directly from the mains is the kitchen tap. This tap is the source of clean drinking water for the household. The tap is also the only high-pressure outlet in the system.  I have chosen the indirect hot water supply because it reduces stress on boiler due to regulated temperatures. There is no build up of limescale as the same water is being reused and radiators can be connected to the system. The indirect system is much more common...
Read more