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Thermal Building Codes for developing countries.
Why not better than developed countries?
by Hakan Falk at Energy Saving Now. (energysavingnow.com)
Introduction.
Building codes are the most important tools to control safety and quality of building constructions. In many developing countries and emerging economies, there are building codes and regulations. If it does not exist, it is always used construction codes for larger buildings anyway. The main purposes of building codes are to ensure that the building are dimensioned to hold up and to last for a long period, with a minimum suitability standards for the purpose of their use. Building codes are also used for defining contracts and what is to be regarded as proper fulfillment of design and construction work.
Each code in a building code (normally represented by letters and numbers), is description of data values, calculation methods, specific construction, model construction, rules, etc.. They can be of mandatory or recommendation kind and will be a well known and defined subject/object. By using building codes, a lot of costs, misunderstandings and conflicts are avoided. Building codes are normally divided in chapters, depending of the subject areas they address i.e. load dimensioning, humidity insulation, thermal insulation, acoustic insulation, etc..
In this article I will aim at suggesting an outline for a Thermal Building Code suitable for developing countries. I will also discuss the element in it as it is modelled after the Swedish Building Code, which at the moment is the only one who considers surface temperatures. To understand the full complexity of energy efficiency in buildings, one must also understand how the human body interacts with its environment. Please look at,
Make it comfortable for real People
to understand how the human body system works.
It is considerable energy savings that can be done with an adequate Thermal Building Code and climate control system, in some cases up to 70% savings compared to traditional Building Codes and practices in developed countries. This will give necessary efficiencies, needed to an efficient use of biofuels, sun and wind energy. It is absolutely necessary to pave the way out of poverty traps.
Insulation standards.
Insulation standards are maybe the first important element one should look at when it comes to thermal insulation. It is many other things and some of them possible to complement with in existing buildings. As an sample of energy saving effects, we can look at the following EU investigation and suggestion,
EU commission suggest common building code for thermal insulation.
It is very important that a developing country have a Thermal Building Standard, before any substantial growth of its economic activities. Any rise in human standards always involve an almost boom in building activities and if clear energy saving measures are not in place, it creates a large and long term commitment of energy resources. Climate is almost indifferent, since if it have low demand of heating it will have a high demand of cooling and will in both cases need thermal insulation. It is very few spots in our world that have a constant and perfect climate for humans.
EU is working on establishing the Danish Thermal Building code, identical to the Swedish prior 1978, to be a minimum directive for EU member countries. We belive that this also is a very applicable minimum goal for developing countries.
- Base insulation.
Base insulation of 10 to 20 cm special mineral wool protected by ventilated base and humidity barrier.
- Wall insulation.
Wall insulation is corresponding to 10 cm mineral wool.
- Ceiling insulation.
Ceiling or roof insulation is corresponding to 20 cm of mineral wool.
- Cost of insulation.
The real cost for insulation is very low, when introduced in new constructions. The cost of insulation material is low and are normally possible to produce locally. The aim for the developing country would be to control the modern building constructions for offices and apartments, who normally are dependent on use of energy. For one family or low building structures, it is very interesting projects and experiences from straw bale houses and alike, that are modern application of traditional building techniques. Each developing country have probably interesting traditional buildings and should try to explore and develop this.
- Window standards.
Minimum double glassed insulation or so called insulation window. The general recommendation is to use glasses of different thickness, this will at the same time improve acoustic insulation. As thermal insulation the largest benefit from 2 or 3 glass windows is coming from the higher surface temperature on the inner glass, not necessarly the modest gain in insulation value.
Open vs. closed constructions.
In building constructions the principles often falls in the category of open or close construction. This term is describing if the air and humidity is allowed to pass through the construction or not, this is important for the effectiveness of the thermal insulation. Many old historical buildings have been destroyed by "renovations" that failed to respect the basic principles of the original construction.
- Open constructions.
Open constructions are constructions that allows a significant movement of air and humidity trough it. Often the construction is dependent on the possibility of having humidity in it and to dry it by air movement. When applying insulation (or even paint), it is important to either maintain the open construction or change it to a closed one. It is easy to make mistakes, with humidity damages and/or fungus in the construction. A sample of open construction is the traditional brick house, single or double wall, without thermal insulation.
- Closed constructions.
Closed constructions are constructions that prohibit air and humidity to pass through the construction. This is often achieved by having a humidity barrier in the construction, often also a wind breaker and internal ventilation in the wall, to remove humidity. Closed constructions are often used in Wooden houses or for special purpose spaces, like computer rooms, laboratories, etc. Closed constructions are generally much more energy efficient, often preferred in cold climates, than open constructions and are the predominant constructions in Sweden. For closed constructions, it is necessary to allow for controlled ventilation of the building space.
Heavy vs. light constructions.
Thermal storage is a very important factor, but often neglected, for building constructions. The most common method is to heat or chill a space based on air temperatures and with narrow limits. This with total disregard to storage / emission from the thermal storage and the surface temperatures. The result is quite large energy waste from the attempt to fight the constructions influence, instead of incorporate and utilize the capacity. In heavy constructions like bricks or concrete, the effect can be very substantial, but light constructions like wood are less influenced.
Comfort criteria.
The normal comfort criteria described in Building Codes are air temperatures, describing only 24% of the human body system of sensation. The most correct are the Effective Temperature used as base for the Swedish Building Code, which covers 74% of the human body sensation.
- Surface temperatures.
The human body system is more sensitive to radiation/emission and with a reasonable balance, the air temperature and the large energy losses can be kept down with a lower air temperature. To benefit from this, the 1978 Swedish Building Code prescribes minimum 18 degree Celsius surface temperatures inside on outer walls. One effect of this was also that windows went from double glass to triple glass.
- Room temperatures.
One effect of the introduction of surface temperatures in the Building Code was that dimensioning room temperatures could be lowered from 21 degree Celsius to 18 degree Celsius, a potential energy saving of around 25% to 30%. The major effect of this changes in the Building Codes, will be obvious around year 2015.
- Humidity and ventilation control.
During the last 50 years the predominant Swedish constructions have gone from open constructions to closed constructions. By the control of humidity, ventilation and air movements through the construction, the energy losses can be kept to a minimum. The major effect of this and the enhanced 1978 insulation standard, will also be obvious around 2015.
Dimensioning temperatures.
Dimensioning temperatures are a common method of sizing HVAC systems for building constructtions, as a sample of its use see,
The history of dimensioning temperatures for Stockholm, Sweden.
It is a valuable tool in managing the inadequate calculation metods and over dimensioning of HVAC systems.
Suggested outline for Thermal Building Codes.
For a developing country it can be extremely valuable to introduce Thermal Building Codes and biofuels as soon as possible. Almost every improvement in the countries economy will be followed by higher living standards and this is strongly connected to rise in building activities and automobiles.
- Insulation. (Mandatory)
It is very little to gain on a few centimeter more or less insulation, we are therefore suggesting the earlier described EU implementation as a resonable and effective middle way.
- Construction. (Recommendations)
Depending of the climate zone, it should be considered to introduce closed construction methods.
- Surface temperatures. (Recommendations)
This is a very efficient way to acheive savings, but might be too complicated for the engineering resources in a developing country and should therefore be a recommendation.
- Dimensioning temperatures. (Recommendations/Mandatory)
This is a very important part, since it is almost the only way to avoid over dimensioned and wasteful HVAC systems.
- HVAC design and systems. (Recommendations)
This can be prefered radiator types and placement for heating,
RADIATOR MESS, Radiators Use and Design.
Preferred type of systems and energy used etc.
Conclusion.
If the boom in buildings and purchase of cars is not controlled from an energy consumption angle, the continuation of development could bring some serious hangovers. One sample is Spain that during the last 20 years had a strong boom without Thermal Building Codes and now face the difficulty of a very unbalanced need of energy resources. A house in Spain consume around three times more energy than a house in Sweden, after climate corrections are done. In absloute terms, the house in Spain consumes slightly more than the house in Sweden.
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