How to Design a Home or Building with Good and Healthy Air Quality
Fox Blocks insulated concrete form (ICF) wall system enables a home or building to provide a home or building with healthy and good air quality. The easy to install Fox Blocks resist moisture and air and lack toxins, all of which diminish indoor air quality
We spend more than 90 percent of our time indoors, which makes designing for good air quality essential to our health, productivity, and cognitive function. The design of a building or home to achieve a healthy indoor environment must address the air tightness of the building envelope and the ability to control moisture, pollutants, and indoor air quality (IAQ). Also, the envelopes design must control the thermal transfer with improved energy efficiency and air handling equipment to provide the best IAQ.
The Benefits of Designing for Superior Air-Quality
Designing a home or building with excellent air quality ensures a healthy and safe indoor environment. It also can improve workers' productivity and student's test scores.
- Good air-quality lessens employee sick days. Buildings with good air-quality report 9-20 percent less respiratory diseases, 18-25 percent fewer asthma and allergies issues, and 20-50 percent fewer non-specific health and discomfort problems than buildings with poor air quality.
- A 2014 study supported by United Technologies found that cognitive function test scores doubled in indoor environments with improved indoor environmental quality, including air quality.
- Employees with an outside view perform 10 to 25 percent better on mental health and memory recall tests and work 6 to 12 percent faster than workers in rooms without windows.
5 Vital Design Components for Ensuring Healthy and Good Air Quality
1. Good and Healthy Air-Quality Requires Moisture-Resistant Design
A moisture resistant and airtight design must include elements that prevent moisture and air from infiltrating the walls. For energy-efficiency, the design must also include continuous insulation (CI) in accordance with ASHRAE 90.1 and 2018 IECC. CI involves wrapping all structural members with a layer of insulation to increase the effective R-value and eliminate thermal bridges and condensation.
When correctly applied, CI produces moisture-resistant, airtight, and energy-efficient homes and buildings. Unfortunately, water and air can still invade even the most precise and tightly constructed wall.
Typical ways that air and moisture infiltrate a wall system include:
- bulk wind-driven rain that pushes its way into a wall system
- poor air sealing of the building envelope
- vapor diffusion, condensation
- moisture generated by the occupants
- moisture particles transported by airflow into a wall system, and failure of the HVAC to remove moisture.
If any of the infiltrated moisture becomes trapped in the interior of the walls, it can form unhealthy mold and degrade the air quality of the home or building. Therefore, for good air quality, the design must also include a means for moisture that infiltrates the walls to evaporate or be removed.
Managing Moisture Within Wood-Frame Structures for Good Air Quality
Preventing moisture accumulation in the wall system of a wood-framed building challenges builders, because effective techniques that prevent moisture from entering a wall cavity may also stop the moisture from leaving the wall cavity. To avoid a build-up of moisture in the walls of a wood-frame building, builders must apply a permeable air and moisture barrier so that water trapped within the wall system can escape.
How Fox Blocks ICFs Ensure Superior Moisture Control and Air Quality
Builders can avoid the moisture issues that plague wood construction by using easy to install Fox Blocks insulated concrete forms (ICFs).
- They exceed ASHRAE/ANSI 90.1 energy code requirements for CI with an R-value of 23 - features that ensure an airtight building envelope with better performance than wood-frame construction.
- They also provide excellent, built-in moisture resistance. Fox Blocks ICFs provide a solid continuous monolithic concrete wall system with a perm rating below 1.0. These features control moisture infiltration and stop the growth of unhealthy mold that can diminish the air quality of a home or building.
2. The Foundation of a Healthy Home or Building
Air that flows through the foundation can contain more moisture than that generated from all the structure's occupants. In addition, when the soil below the foundation becomes saturated, water may flow into a home or building through cracks or pores in the foundation by capillary action or gravity. Water may also diffuse through the uncracked sections of concrete block foundations. Therefore, the design of a home or building must include proper drainage and sealed foundations.
3. Designing with Low-Toxicity Building Products
Designing for good air quality can reduce, if not eliminate, the adverse health effects of toxic indoor pollutants.
Wood-frame buildings may contain chemicals, adhesives, and volatile organic compounds (VOC). If present, these toxins diminish the air quality of a home or building. Specifically, VOC emissions can cause nose, eye, and throat irritations, headaches, nausea, and damage to the kidney, liver, and central nervous system.
Fortunately, Fox Blocks provides a healthier choice over wood for ensuring good air quality - Fox Blocks contain little to no VOC.
4. Radon-Resistant Construction Techniques
Designing for good air quality must include radon-resistance, since exposure to radon can cause lung cancer. For radon-resistant design, builders can use everyday materials and straightforward techniques:
- Place a 4-inch layer of clean, coarse gravel under the foundation - this allows the soil gases, including radon, to move freely below the house.
- The layering of plastic sheeting or a vapor retarder on top of the gravel can prevent soil gases from entering the house.
- To vent radon and other soil gases to the outside, run a 3- or 4-inch solid PVC Schedule 40 pipe vertically from the gravel layer through the house’s conditioned space and roof.
- Builders should seal all cracks, openings, and crevice in the concrete foundation floor and walls with polyurethane caulk to stop radon and other soil gases from entering the home or building.
- For added measure, install an electrical junction box (outlet) in the attic for use with a vent fan.
5. Ventilation Improves Air Quality
Ventilation lowers the concentration of indoor air pollutants by maximizing the amount of outdoor air coming indoors. This outdoor air must be temperature controlled, conditioned to remove moisture.
For high-performance airtight homes and buildings, to control and improve IAQ, rather than opening windows, the installation of an energy-efficient heat recovery ventilator (HRV or ERV)is recommended. Along with ceiling fans, specifically designed exhaust fans in the bathrooms and kitchens to remove moisture and contaminants.
An HVR filters the indoor and mixes it with conditioned exterior fresh air to control the IAQ.
In addition, bathrooms and kitchens should include exhaust fans to remove contaminants directly from those areas. For new homes, the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) recommends a ventilation rate of 0.35 air changes per hour.
Designing structures with good air quality not only protects the health of the occupants but can also improve productivity and performance. The essential features of the design include moisture-resistance, eliminating exposure to toxic materials, and proper ventilation. Moisture-resistant and toxin-free Fox Blocks achieve two of these basic requirements.
Please contact Fox Blocks for more tips on designing homes and buildings with good and healthy air quality.