PREFABRICATED ELEMENTS USED IN FAÇADES

The concept of building components to be assembled off site and shipped onto the project ready to final placement is known as prefabrication, so we can say that prefabricated façades are made by panels which are manufactured in a warehouse and the dropped off at the site just in time to be put in place. These panels could be structural or not, in fact, prefabricated façades are defined as: “An outer covering of a building in which the outer walls are non-structural, but merely keep out the weather”.

Prefabricated façades are an alternative to other traditional enclosures due to their quick installation, but also for its

–          Resistance to support their panels own weight, wind pressure and temperatures .

–          Stability.

–          Weather barrier, they must be carefully designed in order to make a waterproof and windproof façade.

–          Achieve a good comfort indoors.

–          Fire prevention.

There are lots of different classifications based on different properties of prefabricated façades, but we will focus on a structural point of view. There are two main groups:

– Lightweight façades, which are not fixed directly to structural elements of the building,. It is necessary to add some auxiliary structure between panels and columns or other structural element which has to support the façade.

Auxiliary structure could be made by stainless steel, aluminum even wood, although last one is uncommon.

Lots of factors contribute to the failure of these façades, some more harmful than others. Joints are totally related with each other, if one doesn’t work as it should damage the others. However the most common cause of failure is related with corrosion of structural elements.

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– Heavyweight façades, which are the opposite, these are fixed directly to building structure, they don’t need auxiliary support.

Usually are compound by concrete panels, which are thicker and heavier than the previous.

These panels could combine structural and architectural requirements in a huge range of possibilities.

Environmental factors are which contribute most to the failure of façades. Moisture could be the responsible of lots of damages because it contributes to anchor deterioration. Another cause could be produced mixing the effect of water, low temperatures and cracks.

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According to all this, when we need to choose a type of prefabricated façades, we need to fix the specifications of our building, in order to select a type of panels, and then try to choose the option that will support better the conditions at which the building will be exposed.

Lizama Velázquez, Sara.

Give New Life to Old Bottle Waste

The SodaBIB Project is a recent invention by Architect Farzana Gandhi and a group of her very own students at New York Institute of Technology located in Manhattan, NY. This invention organizes any type of used plastic bottles to form a new concept of roof membrane; this is design to help people create shelter from waste.

SodaBIB

A new type of pallet was design to be able to fit standard plastic bottles, this pallet breaks into different types of brackets, the brackets then form a new kind of roofs. The bottle and cup is safely secured onto the bracket allowing for 100% recycle process.

SodaBIB it’s an exceptional recycling idea, it enables people to create cheap shelter from waste. This new concept allows for natural ventilation and light. Unlike corrugated metal roofs, the translucent empty plastic bottles absorb all the heat. The bottles also create gaps for natural ventilation.

The SodaBIB features a strong pallet made out of multiple layer of a special designed material which is stacked to maximize weather resistance. The layers are offset allowing anyone to take the whole roof apart with their own hands, so that each layer can be connected to the other layers somewhere else. The patter formed by this layers is very strong because they nest within each other, this helps the layers buttress each other and prevents bending in any direction.

This type of roof is best suited for disaster relief areas or as permanent houses for developing countries where they are constantly shifting between strong rain and over-heating.

Everything and more about this wonderful initiative can be found at http://sodabib.org/

Are tall buildings really sustainable?

Tall buildings are certainly one of the most important pieces in urban centers. For the past 10 years, many cities around the world have been involved in the development of tall building projects, a competition for the tallest building, the most innovative design, the most sustainable, etc. All cases have embraced environmental approaches to a lesser or greater degree.  There are those that believe that the concentration of population through high-density (therefore reducing transport costs and urban / sub-urban spread) combined with the economies of scale of building tall, make typology an inherently sustainable option, on the other hand others believe that embodied energies involved in construction at height, make them inherently anti-environmental.

According to this debate, several issues should be considered in the evaluation cases “for” and “against” tall building. (Fig. 1)

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(Fig. 1)

According to Wood, A (2008), after a rise of environmental conscience in tall building design, several design principles have to be considered for the new sustainable skyscraper, simply based on a response to climate; an aesthetic based on sustainability.

Design Principles:

  1. Variation with height. Building should not be monolithic vertical extrusions on an efficient floor plan.
  2. New programmes. Increase the usefulness of the typology in sustainable cities of the future. Tall buildings have the versatility to accommodate uses other than the standard office, residential, hotel or small retail and leisure functions.
  3. Communal space. More open, communal, recreational spaces need to be introduced into tall buildings, rather than insistence on the maximum financial return.
  4. Envelope Opacity. Tall buildings should be designed with more envelope opacity, not as all-glass transparent boxes. Usefulness of daylight has to be taken more into consideration.
  5. Vegetation. Vegetation should become an important part of the material palette for tall buildings, both internally and externally.

If you are more interested in this matter, here is the link for the complete research paper, where you can find several sustainable and non-sustainable tall buildings designs examples,

Paper title: Green or Grey? The Aesthetics of Tall Building Sustainability

Author: Wood, A.

http://www.ctbuh.org/LinkClick.aspx?fileticket=CTrwCEw%2FXyw%3D&tabid=141&language=en-GB

Lack of knowledge about building science cost Norway billions per year.

Moist and mold growth have for several decades been the largest problems on existing buildings in Norway. Not surprisingly, considering the country’s rough climate and large seasonal temperature variations. A high amount of old buildings also contributes to the problem. Old buildings tend to be poorly ventilated and not have adequately heating. Considering that 70% of Norwegian buildings are more than 40 years old [1] the widespread problem of moist damages should not surprise anyone.

More surprising however, is the extent of moisture problems in new buildings. It is expected that one out of two new buildings in Norway will experience problems with moisture and mold. Despite increased focus on these problems, damages still occur due to poor craftsmanship and lack of knowledge. The leading building research organization in Norway, Byggforsk, claims that lack of knowledge in the field of building physics is one of the biggest challenges in the Norwegian construction industry [2].

The cost of construction errors and defects on new buildings nationwide is about 2.3 billion dollars annually [3]. The number may not seem that big. In fact a study reveals that the 2 billion dollars is the same amount that the US spent on the war in Afghanistan, per week! [4] But if you take the size of the country into account the numbers become more frightening. 2.3 billion dollars equals to 10% of all investment costs in the Norwegian construction industry. Out of all registered defects 76% relates to moist and mold. That means that the cost of registered repairs due to moist problems every year is 7.6% the cost of all new buildings in Norway.

Lack of knowledge is said to be the number one reason for these types of damages. With such high annual costs of reparation it is safe to say that educating more people within the field of building physics and building science would be a good investment.

[1] Statistics Norway (2013)

[2] Mauren, A. (2005) Moist in buildings costs billions. http://www.aftenposten.no/bolig/article984354.ece#.Uht4zBukpCZ

[3] SINTEF Byggforsk (2003) Construction errors results in major costs. http://tjenester.byggforsk.no/prosjekter/klima2000/portals/0/02-07.pdf

[4] Terkel, A. (2011) The War In Afghanistan: How Much Are You Paying? http://www.huffingtonpost.com/2011/04/18/afghanistan-war-cost_n_850293.html

Boralpure Smog-Eating Tile

yingzhang201308

Air pollution is an undisputed problem in the U.S. Air pollution can cause health problems, by inhaling particles, such as reactive chemicals like ozone, and biological materials like pollens. Air quality is a serious, increasing concern in the United States. The American Lung Association recently reported that more than 175 million Americans (roughly 58 percent) are often exposed to pollution levels too dangerous to breathe. What is worse, The World Health Organization estimates 2.4 million people die annually world wide of causes attributable to air pollution.

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Boralpure Smog-Eating Tile, one of The 10 Most Innovative Tech Products of 2011, is invented for protecting the environment. Using some creative chemistry, Boral Roofing has turned a standard building material into a formidable weapon—not just against sun and rain, but also air pollution. . When exposed to sunlight it speeds up oxidization reducing nitrogen oxide, which can be generated from fossil fuel burning…

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Styrofoam, Concrete and Going Green

The differences in building techniques and priorities in a society where people are concerned about renewable resources and the responsible use thereof, such as in USA, as opposed to the cheapest way to build without any thought about the ecological footprint was something that was interested in from the very first day I got to USA. Coming from a country where wood frames are almost non-existent and even residential buildings are built from the ground up using mortar, bricks and concrete, I was very much interested in the differences in mentality behind the construction and design here in the US.

Going green and conserving energy as well as reducing the ecological footprint are a necessary part of today’s design mentality as everyone in the society is willing to play their role in helping out mother nature, be it through recycling or going paperless at the office and schools, or more relevantly to our field finding ways to be more environmentally responsible.

One technique that caught my eye in this regard and interested me quite a bit was the use of Insulating Concrete Forms, or ICF for short as opposed to the norm of using wooden frames. Wood frame buildings seemed like a strange choice to me as an architectural engineer from Pakistan, where concrete is used even for residential buildings.  Wood frame buildings contribute to the diminishing of our forests. Homes that are built with this technique are more susceptible to mold infestation and fire control can be a real issue with these homes. The new technology of insulated concrete form uses premade Styrofoam walls that fit together like pieces of a puzzle. The walls are erected by assembling the forms and stacking them together. There are two layers, an outer and an inner layer and the layers are re-enforced with steel on the inside of the two layers. Concrete is then added to the inside, between the two layers, making a concrete sandwich enclosed by Styrofoam. These walls are not only superior in strength to the wood frame alternative, but they result in better sound attenuation, better fire resistance, and a key advantage called the “thermal mass advantage”. Thermal mass advantage can decrease energy costs in one year by up to 70% by slowing down the flow of energy through the wall due to the concrete core of the insulated concrete form. Wood frame buildings are becoming outdated and for good reason.

For those interested in ICF the following resources might be useful.

http://www.spokanehomebuilders.org/insulated_concrete_forms.html

http://en.wikipedia.org/wiki/Insulating_concrete_form

Particulate Matter and Health Implications

WHY WE SHOULD BE INTERESTED IN THE QUALITY OF OUR AIR?

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The choice to follow through on more sustainable building methods and practices often clashes with economic, material and labor variables which are the forefront issues for most clients. I believe that if the implications that sustainable building had on human health and lifestyle were brought to the attention of mainstream Americana that it would be the ultimate deciding factor in the design of building systems.

COMPARATIVE STUDY OF  AIRBORNE PARTICLES

In order to better understand how particulate matter that is found both naturally and man made begins to interact with the human respiratory system it is important to break down these pollutants by size. The diagram below breaks down micro items found from the environment, man made emissions, the human body, materials, and biological organisms.

particle_size_diagramSeveral points of interest from this diagram:

  1. Volatile Organic Compounds [VOCs] are the smallest in scale and are comparable to the wavelength of X-rays
  2. Keep note of the Human Body items in blue to begin to understand how these particulates interact with various parts of the body
  3. The initials AC represent Activated Carbon, a filtration material which utilizes a wide variety of pore sizes and surface area to trap particles

SIZE CLASSIFICATION

Particulate matter cannot be seen by the naked eye, they can be soil or liquid forms. The coarse/ bigger particles are between 2.5 and 10 micrometers, these particles are called PM10. The fine/small particles are smaller than 2.5 micrometers and are called PM2.5. PM10 particles can stay suspended in the air for minutes or hours whereas PM2.5 particles can stay suspended for days to weeks. The lightness of the PM2.5 particles allows them to stay in the air longer and travel farther, up to hundreds of miles, than PM10 particles.

PM10 HEALTH EFFECTS

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The coarse particles can be detrimental to human health and are classified as inhalable particles. Inhalability is the fraction of the suspended material in ambient air that actually enters the noise or mouth and deposits on the respiratory tract. It is a function of the particles aerodynamic size, flow rate, wind speed and direction [See the following equation].

I = 0.50 (1 + e ^(-0.06d)

for PM10, d= 10 um and I = 0.770

The health effects that come from inhaling these particles which include pollen, sand, silt and dust, just to name a few, range from minor to severe health effects. PM5 particles enter into the bronchial tubes and upper lungs, leading to more severe problems. These health implications include ENT irritation, headaches, dizziness, fatigue, asthma, and emphysema.

PM2.5 HEALTH EFFECTS

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The adverse health effects of PM2.5 is more severe than PM10 and can lead to chronic and fatal incidents. The reason for this is that the smaller particles can enter the blood stream and respiratory system. Respirablity is the particles that are inhaled which enter the gas exchange region of the lungs. The equation for calculating respirability is a function of the cumulative log normal function [See following equation].

R= 1 [1-F(x)]

x= ln (d/4.25)/ ln 1.5

for PM2.5, d=2.5 and R = 0.83

The health effects that come from PM2.5 particles range from ENT irritation, coughing to more severe chronic bronchitis, heart strain, pneumonia, lung cancer, heart disease, vascular inflammation, atherosclerosis and heart attacks. PM0.5 is the most prevalent size which enters indoor air due to infiltration. Exceedances of the PM2.5 standard causes up to 15,000 premature deaths globally.

WHY IS THIS IMPORTANT

It is critical to bring to light how pollutants in the air impact the health of people. When making design decisions for building systems, the most important criteria is how material selection and proper ventilation strategies affects the individuals who are directly and indirectly engaged with the building. The rising rate of ailments in the American population, such as asthma, cannot be ignored or deemed less important than any other variable which affects building design decisions.

Essentially, in order to sell our ‘product’ of sustainable building systems, the problems that arise from poor case studies must be humanized. To draw parallels between building systems and an individual person is the first step towards allowing people to understand the issue and prioritize it as a critical issue in their lives. With proper understanding of the importance of good air quality we can then analyze just how to develop systems which improve the air quality of the built environment.

Sources:

  1. http://www.h2odistributors.com/chart-particle-sizes.asp
  2. http://www.whatman.com/PRODTeonPTFEMembranes.aspx
  3. http://www.coheadquarters.com/PennLibr/MyPhysiology/lect0p/lect0.03.htm
  4. http://www.pottiaceae.com/imagenes/pdf/P6.pdf
  5. http://www.circulatory-system.com/blood-vascular-system/
  6. http://www.gulink.osd.mil/appendix_d.pdf
  7. http://www.gulflink.osd.mil/appendix_d.pdf
  8. http://www.tsi.com/uploadedFiles/Product_Information/Literature/Application_Notes/ITI-050.pdf