BREATHE BRICKS FOR SUSTAINABLE AND ENERGY EFFICIENT HOUSING

Introduction

Nowadays air pollution has become a huge problem at some cities which tends for causes such as global warming, heat island effect. The countries closer to equator have inherited the problem of hotter climates. They receive comparatively lesser rainfall. Many of them are developing countries including Sri Lanka. As a result, buildings that help to reduce this problem are all the range. In past few years though, designers and architects have started to move beyond simply reducing building’s emissions and started to work with techniques that actually remove pollutants from the air. However, in most incidents, these new technologies have been effecting air, chemically or physically by comes into contact with them. 

What if buildings could work a little more like a vacuum cleaner? What if they could take a more effective role in pulling in pollutants from the sky? This was exactly the concept of inspiration behind the developing of Breathing Brick.

Breathe Brick is a masonry system which is designed and constructed to constitute and be a part of ventilation system of buildings. It filters polluted outdoor air so that it becomes healthy enough to bring directly into occupied spaces. It acts as a pollution absorbing brick where the design is very similar to a vacuum. The pollution vacuums in bricks were developed by assistant professor Carmen Treadle at Cal Poly College of Architecture and Environmental design. The brief brick sucks pollutants in the air and releases filtered air. The innovative material is designed to be a part of a building standard violation system. In short, it is a technology that can be easily applied to the current construction process by performing wind tunnel tests.

Product / Material

The Breathing Brick is designed to form a part of a building’s regular ventilation system, with a doubled-layered facade of the specialist bricks on the outside, complemented by a standard internal layer providing insulation. At the center of the Breathing Brick’s function is cyclone filtration, an idea borrowed from modern vacuum cleaners, which separates out the heavy pollutant particles from the air and drops them into a removable hopper at the base of the wall.

The system is composed of two key parts: Concrete bricks and Recycled plastic coupler. 

1. Concrete Bricks

Breathe Brick unit is a structural masonry component within which is embedded with a cyclone filter. The concrete brick is featured with a faceted surface which helps to direct airflow into the system, and a separate cavity for inserting steel structure. The brick is designed in a way that it can be replaced some exterior.

2. Recycled Plastic Coupler

It helps to create a path from outside into the brick’s hollow center and to align bricks.

It has a two layer facade system with the specialist bricks on the outside and standard insulation on the inside in the center is a cyclone filtration system that separates out the heavy air particles from the air and collects them in a removable hopper.

How “Breathe Brick” Wall Operates?

By the help of the faceted surface of the Breathe Brick, the air outside the structure is directed into rectangular inlet ports. The air that comes into the system is spinned by cyclone filter winnowing out particles.

The cyclone filter is cast directly into the concrete form. The filtered air that passes into the cavity of the double-Wythe wall system could then supply an HVAC system or an adjacent interior space directly. (Breathe Bricks – Operation Mechanism, Applications, Advantages (online))

The Breathing Brick can function with both mechanical and passive ventilation systems, as the brick simply delivers filtered air into the wall plenum; this air can be delivered to the building interior through mechanical equipment or through trickle vents driven by passive systems such as stack ventilation.

Importance as a sustainable product

• Cheap.

• Sustainable.

   Breathe Brick is a clever way of taking the heavy particulates out of the air as a byproduct of making a building

• Environmentally friendly.

• Low Embodied Energy.

• Ease of handling and construction.

• Low Carbon construction. (using of natural construction material)

• Lightweight. (Technique for modification of breathe brick)   

 By replacing sand in concrete by EPS, the brick can be formed into a lightweight brick. Discussed further under Physical properties of Breathe Brick.

• Help to improve thermal comfort.

• Energy efficient.  Since it operates without electricity and makes part of ventilation system. It works with pressure and temperature differentials

• Passively filter outdoor air prior to introduction to an indoor environment.

• Can operate through existing HVAC system or passive as independent system.

• The design of breath bricks can be configured in a wall with window and the cooling system as well.

• It was proven that the system can filter 30% fine particle pollutants and 100% course particles such as dust.

In wind tunnel tests, the system was found to filter 30% of fine aggregates such as airborne pollutants and 100% of course aggregates such as dust. As the entire system is relatively expansive, the Trudell posits the Breathing Brick is a way to lower the pollution level in developing countries, where rapid expansion of industry and less stringent environmental regulations often cause problems. (Rory Stott, www.archdaily.com)

Applications

• Breathe Brick is optimal for one or two story structures in areas with poor air quality.

• It can be used to construct exterior walls (plenum or courtyard, sound walls along freeways, school playground enclosures)

• It is specifically designed for regions with elevated outdoor particulate matter.

Physical properties of Breathe Brick

“Breathing Walls” concept is an innovative construction procedure that can help improve thermal comfort in houses utilizing local materials.

Breathe brick is made up of concrete and plastic couplers made from recycled plastic. The concrete part can be made out of user’s choice. As a technique the brick can be constructed to have light weighted characteristic.  By the introduction of expanded Polystyrene (EPS) which is a replacement for sand, the brick is lightweight and contains various properties of strength and water absorption. EPS has been frequently used in construction industry in production of lightweight building materials such as wall panel and lightweight concrete blocks. Replacement of sand by EPS is based on volume. The replacement percentage of EPS was 0%, 20%, 30%, 40% and 50%. 

Based on experimented results, the density and compressive strength of the brick was decreased as the percentage of the replacement increased. Meanwhile for water absorption properties, it was found that water absorption of the brick was decreased as the percentage of EPS increased. However the properties obtained have been satisfied the requirement where the brick density for lightweight should be less than 1680kg/m3. The strength of load bearing and non-load bearing brick is 11.7MPa and 3.45MPa for each individual unit. Meanwhile, for water absorption, the percentage of water absorption of brick should be less than 12%. From researches it was found that replacement of sand by EPS give significant impact towards strength and water absorption performance of concrete. 

Unfortunately the strength is limited to one or two story buildings. The strength limitation is the major weakness in lightweight breathing brick. But it is more suitable for houses in Sri Lanka.

E. Dilmi D.Z. Abeysekera

Department of Civil Engineering

University of Sri Jayewardenepura  

REFERENCES

• Admin, (17 December  2017), Breathe Brick (online) [Accessed on 25/09/2019],Available at : http://transmaterial.net/breathe-brick

• Madeh Izat Hamakareem, Breathe Bricks – Operation Mechanism, Applications, Advantages (online) [Accessed on 24/09/2019], Available at: https://theconstructor.org/building/breathe-bricks/29216/

• Rory Stott, (12 August  2015), This Innovative Brick Sucks Pollution From the Air Like a Vacuum Cleaner (online) [Accessed on 25 September 2019],Available at: https://www.archdaily.com/771767/this-innovative-brick-sucks-pollution-fromthe-air-like-a-vacuum-cleaner

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