Houses Are a Potential Source of Physical Hazard; for Example, Injury from Fire Scalds

ENV500

STUDY GUIDE

1. The Residential Environment

1.1Introduction

Housing is meant to address basic human needs for shelter and security by providing protection against climatic condition (excessive heat and cold) and unwanted intrusions from insects, rodents, and environmental nuisances, including noise, which may be harmful for health and well-being.

Houses are a potential source of physical hazard; for example, injury from fire scalds sharp edges, and structural collapse of the building. Houses can also provoke climate hazard (notably too cool or too hot ambient indoor temperature). The houses can also harbor biological hazards (from molds and pest species), as well as chemical hazard (indoors smoke from cooking fire or tobacco).

In addition, houses can be the locus of infectious disease hazards (stemming from inadequate food storage and exposure to vector organisms like mosquito). To basic human activities, defecation and cooking produce potentially health-endangering waste products. When human excreta are not completely remove from the household environment and isolated from drinking water supplies, a high risk of diarrhea and other waterborne diseases ensues.

Housing provision is probably the most contentious issue which the local plan has to address. On the one hand there is the requirement to meet the future housing needs of the local population. On the other hand, there is widespread concern over the use of “fresh” land for building, the loss of open spaces and so call “town cramming”. Housing also plays a special role in the social and political dialogue in most societies. It is a major component in creating stable and healthy communities and is often the largest single household expense.

When providing for new housing the council has to have full regard to national, regional and structure plan guidance. However, in arriving at the pattern of development, the council has also had regard to many other factors including local demographic trends, the performance of the local housing market and the likely contribution from other housing provider in additional to private companies building for sale.

1.2Social-psychological and physical requirements for health, welfare and comfort.

The internal housing environment, which consists of thermal comfort, lighting, ventilation, plumbing and so forth, effects the physical, emotional and mental states of the occupants. An individual needs to be protected against the element of heat, cold, disease, insects and harmful chemical.

People need to know that when they arrive home they can leave the pressure of society behind them, can relax in safety an comfort, and than can face the challengers of society again.

1.2.1Thermal comfort

The CDC housing code states that the temperature should be at least 200Cat a distance of 18 inchesabove the floor level. If person need the higher temperature, because of age or physical condition, 240Cis required.

What is Thermal Comfort

Creating a thermally comfortable environment is one of the most important parameters to be considered when designing buildings. Thermal Comfort is defined as: "That condition of mind which expresses satisfaction with the thermal environment".

Thermal environments are considered together with other factors such as air quality, light and noise level, when we evaluate our working environment. If we do not feel the everyday working environment satisfactory, our working performance will inevitably suffer, as thermal comfort has an impact on our work efficiency.

Parameters influencing Thermal Comfort

The Thermal Comfort Equation derived by P.O.Fanger combines the effect of 6 parameters:

• Metabolism [MET]
• Clothing level [Clo]
• Air Temperature
• Mean Radiant Temperature
• Air Velocity
• Humidity

The four physical parameters, the Air Temperature and Mean Radiant Temperature can be combined into the Operative Temperatureorthe Air Temperature, the Mean Radiant Temperature and the Air Velocity can be combined into the Equivalent Temperature.

Metabolic rate estimation

The metabolism is the energy released in by oxidation processes in the human body which depends on the muscular activity. Normally, all muscle activity is converted to heat in the body, but during hard physical work this ration may drop to 75%. For instance when walking up-hill, where the energy is stored in the body at potential energy.

Traditionally, metabolism is measured in Met (1MET=58 W/m² of body surface). A normal adult has a surface of 1.7 m², and a person in thermal comfort with an activity level of 1 Met will thus have a heat loss of approximately 100 W. When evaluating the metabolic rate, it is important it is important to use an average of the activity the person has performed within the last hour.

Clothing level estimation

Clothing reduces the body's heat loss. Therefore, clothing is classified according to its insulation value. The unit normally used for measuring clothing's insulation is the Clo unit. The more technical unit is m²°C/W is also used frequently (1 Clo = 0.155 m²°C/W).

The Clo scale is designed so that a naked person has a Clo value of 0.0 and someone wearing a typical business suit has a Clo value of 1.0. Some normal Clo values are shown in the figure. The Clo value can be calculated if the persons dress and the Clo values for the individual garments are known, by simply adding the Clo values together. Appendix D contains a list of clothing items and their corresponding Clo values.

Obtaining the Clo value through calculation normally gives a sufficient accuracy. If exact values are required, it is better to measure the Clo value using a heated mannequin dummy. When calculating Clo values, it is important to remember that upholstered seats, car seats and beds reduce the heat loss from the body too, and therefore, these must be included in the overall calculation.

Mean Radiant Temperature (MRT)

Mean radiant temperature, which has the same importance as air temperature in thermal comfort is defined asthe uniform surface temperature of an imaginary black enclosure in which an occupant would exchange the same amount of radiant heat as in the actual non-uniform space.

(ASHRAE STANDARD, 1995:4) The depiction above points up that in an actual room, the temperature of every surface usually is slightly different compared with an imaginary room where each surface has exactly the same temperature. It is worth noting that mean radiant temperature is the temperature when the radiation transfer for “an occupant” not for the other entities in actual room equals the one in an imaginary enclosure.MRT can be ascertained basically in two ways:

• By calculation which is dependent on surface temperatures of all areas in a space and the location of a person.
• Directly measured by GT (globe temperature).

The mean radiant temperature is the area-weighted average of all the surface temperatures in a room, and is affected by the position of the person in relation to the various surfaces.The larger the surface area and the closer to the person, so it will have more influence to an occupant’s MRT. Furthermore for different positions in a space, the value of MRT will be changed, and there will be a corresponding air temperature for the requirement of thermal comfort. This depends on several other factors but in general for every 1 degree F that the MRT drops, the air temperature must be raised about 1.4 degrees F to achieve comfort conditions. In addition, comfort can be affected by radiant asymmetry, and people are especially sensitive to warm ceilings (10 °C radiant asymmetry from a warm ceiling can give rise to 20% comfort dissatisfaction).

Values to be measured

When measuring the thermal indoor climate, it is important to remember that man does not feel the room temperature, he feels the heat loss from the body. The parameters that must be measured are those which affect the energy loss, namely: Air Temperature, Mean Radiant Temperature, Air Velocity and Humidity. The influence of these parameters on energy loss is not equal and it is not sufficient to measure only one of them.

One of these parameters, the Mean Radiant Temperature, requires a more detailed explanation. The Mean Radiant Temperature of an environment is defined as that uniform temperature of an imaginary black enclosure which would result in the same heat loss by radiation from the person as the actual non-uniform enclosure.

Measuring the temperature of all surfaces in the room is very time consuming, and even more time consuming is the calculation of the corresponding angle factors. That is why the use of the Mean Radiant Temperature is avoided and the Operative Temperature or Equivalent Temperature is used instead.

1.2.2Lighting

According The Uniform Building By Law, every habitable rooms must have window and fix opening facing outdoors and the window area must be at least 10% of the total floor area of the room. For the fix opening, total opening area must be at least 5% of the total area of the room.

1.2.3Plumbing

In the house, the piping of water service should be as short as possible, and elbows and bends should be reduced to maintain water pressure. The water line to the house should be at least 4 feet below the soil to prevent the contamination. Valves are usually located outside the building so that the building supply may be turned off when it is necessary for service the building.

1.2.4Ventilation

Theusually minimum requirements for the natural ventilation are 10% window area.Poor ventilation contributes to both damp and increases in indoor air pollutant levels from domestic heating and cooking appliances, furniture and building materials. Poor ventilationalso has been associated with increased relative humidity, increased levels of house dust mite, poor lung function and increased respiratory symptoms.

1.2.5Space requirement

The space area for the first habitable room must be not less than11squaremetres. The second habitable room must be not less than9.3 sq metresand all other rooms must be not less 6.5 square metres in area. Every bathroom and toilet room must comply with housing code and rules on adequate ventilation.

1.2.6Water supply

All housing required the adequate quantities of running water be provided for a dwelling. This generally means 1gal/min of running water per each fixture in the house.

1.2.7Kitchen facilities

All kitchen facilities must contain sink, cabinet or shelves, stoves and refrigerator. The sink must be large enough for the kitchen use and not a small hand-washing sink. Because the kitchen sink is used in the preparation of food and the cleaning of dishes, utensils and equipments. The stoves must be adequately built, install and maintained to avoid electrical, fire or carbon monoxide accidents.

1.2.8Fire safety and personal security

All dwellings should have at least to means of egress leading to safe. Individuals should not have to exit through someone else’s dwelling unit. The entrance doors in a multiple dwelling should be equipped with a device that allows the occupants of the unit to see a person at the door without fully opening the door.

1.3Housing, the environment and health status

The WHO definition states that health is not merely the absence of disease and infirmity but astate of optimal physical, mental, and social wellbeing. This definition is idealistic but has the merit of not focusing on illness and disease, which have often been considered as either a temporary or permanent impairment to health or a malfunction of a single or several constituents of the human body. Given that the WHO definition of health includes social well-being, then the most common interpretations of health ought to be enlarged. The WHO also states that the enjoyment of the highest attainable standard of health is one of the fundamental rights of every human being without distinction of race, religion, political, economic, or social condition.

Health is defined by the author of this specialissue as a condition or state of human beingsresulting from the interrelations between humansand their biological, chemical, economic, physical,and social environment. All components of the residential environment should be compatible with the basic needs of the residents and their full functional activity, including reproduction over a long period. Health is the result of both;

(a) The direct pathological effects of chemicals, several biological agents, and radiation; and

(b) The influence of physical, psychological, and social dimensions of daily life, including housing, transport, and other characteristics of metropolitan areas.

Theseconstituents of the daily lives of individuals are represented in terms of their health status in Fig. 1.For example, improved access to medical services is a common characteristic of urban neighborhoodsbut is rare in rural areas.

pertinent for the field of housing and health because the environmental and social conditions in specific residential environments have an impact on human relations, induce stress, and can have a positive or negative impact on the health status of groups and individuals. Given the multiple factors that influence health shown in Fig. 1, the necessity of using interdisciplinary approaches to studying the health of a population in precise residential neighborhoods should be evident.

Fig. 1: The multiple influences of health status

1.3.1 Health and the housing Environment

There are approximately 5.3 million crowed substandard dwelling in the UnitedState, with 4 million in such poor condition that they cannot be refurbished without major repairs. There are 92,200 deaths and million of injuries due to unintentional events each year. The leading cause of death is motor vehicles, followed by fires, falls, drowning and poisoning. The cost is over USD500 billion a year.

In many areas, houses are abandoned because it is chapter to leave them than to repair them or pay the property taxes. As a result, house become dilapidated, vandalized, and eventually places where young children, teenagers and adults get into serious trouble.

Not only are such buildings aesthetically unpleasant, but they also become dumping places for garbage, trash and other junk, breeding places for mosquito, roaches, mice and rats. They also become the meeting place for alcoholics, drug addicts and criminals.

1.3.2 Human illness

Environmentally related diseases are more prevalent in poor housing than in better housing. Congested between the house can lead to the increased upper respiratory diseases because of close contact with the contaminated individuals.

Diseases caused by salmonella, staphylococcus and streptococcus may be found in the housing environment. Other diseases can be cause by intestinal roundworms, hookworms, Aspegillus, Blastocystis, etc.

Ventilation is an important part of stress or the stress reduction factor within shelter. The use of mechanical may be good or bed, and if fresh air is added instead of reticulating inside air, than home ventilation may be good. In reticulated air, as many as 100 identifiable contaminants have been found. These include pesticides, cleaners, bacterial contaminants and viral contaminants.

The thermal environment helps reduce or increase stress, depending on the combination of temperature and relative humidity present and the velocity of the air. Proper temperature within the home should range from 20 to 240C with relative humidity raging from 20 to 60% .Temperatures or relative humidity above these levels tend to cause discomfort.

2.URBANIZATION AND URBAN GROWTH

Urbanization is a phenomenon characterized by an increasing higher proportion of urban population compared to the total population. This trend is influenced by various factors including:

• Rural-urban migration
• Natural population growth in the urban area
• Socio economic status, and
• The economic development of the country

In addition to an increase in the proportion of urban population, the urbanization process is also characterized by change of economic activity from agriculture non-agriculture, a change of population distribution characterized by uneven distribution, greater concentration and higher densities in certain region, and the change from traditional to modern society.

2.1Trend of Urbanization

Urbanization in Malaysiastarted with the growth of straits settlements of Penang, Malacca and Singapore and the mining town of Ipoh and Kuala Lumpur during British Colonial rule. The early growth of towns in Peninsular of Malaysia was not the result of industrialization as experienced in western countries, but rather was owing to the growth of an economic based on the extraction of tin and growth of rubber plantation during the colonial period.

2.2Neighborhoods and their effect on housing

The neighborhood is the area comprising all the public facilities and condition required by the average of family for their comfort and existence. Residents of a neighborhood share service, recreational facilities, and generally an elementary school and shopping area.

Neighborhood community facilities include educational, social, cultural, and recreational and shopping centre; utilities and services include water, light, fuel, sewage, waste disposal, fire and polis protection, and road maintenance.

2.3Side selection and the neighborhood environment

When developing a new neighborhood, it is essential to consider the land-use trend for the area; the presumed availability of transportation, public utilities, school and the legal controls place on the area by the local government body.

Site selection for the neighborhood is extremely important. The existing neighborhood may have to change, be razed or develop to meet proper neighborhood and housing standard. The new neighborhood should avoid the problem of existing neighborhood by locating on proper site.

In site selection, competent professional should determine the geology of the land, the type of soil, and the type of weather condition. We also should consider whether disturbing condition such as superhighway, heavy industry, or animal’sfarmisnearby, and whether the site is in a flood plain.

Water supply and sewage disposal are important key to site selection. It is also necessary to determine the method of removal and disposal of solid waste. Telephone service must also be planned for new site.