Subject: Construction Air Quality
Doing it right the first time: Controlling air quality during construction can dramatically increase project efficiency while delivering the highest quality finished product to building ownership.
The FACT is there are existing codes and guidelines for construction projects that provide recommendations for air quality environment during construction:
06 40 00 Architectural Woodwork (Temperature: N/A, Relative Humidity: (43-70%)
09 21 16 Gypsum Board (Temperature: 13-21°C, Relative Humidity: <55%)
09 65 14 Resilient Rubber Sheet Flooring (Temperature: >21°C, Relative Humidity: <75%)
09 65 17 Resilient Sheet Safety Flooring (Temperature: >20°C, Relative Humidity: <75%)
09 65 19 Resilient Strip Flooring (Temperature: ≥21°C, Relative Humidity: <75%)
09 65 30 Resilient Base (Temperature: >20°C, Relative Humidity: Per Manufacturer’s Requirements) 09 66 23 Epoxy Seamless Flooring (Temperature: >20°C, Relative Humidity: <75%)
09 68 13 Carpet Tile (Temperature: Per Manufacturer, Relative Humidity: <75%)
The requirements of modern construction and industrial processes, as well as more stringent indoor air quality (IAQ) standards, have resulted in an increased demand for effective control of both industrial and commercial indoor spaces. ASHRAE Standard 62-1989, for instance, states, “Relative humidity in habitable spaces preferably should be maintained between 30% and 60%… to minimize the growth of allergenic and pathogenic organisms.” (Section 5.11).
There are high-efficiency temporary equipment systems available on the market to control all aspects of indoor air quality.
There are numerous advantages to using construction-grade temporary systems to control temperature, humidity, and quality. A specific, tailored strategy needs to be established based on project details and location.
The benchmark for the perfection of IAQ control goals should be based on the specifications of permanent building systems. The design should be sufficient enough to maintain constant control, with minimal fluctuations, and as closely match the temperature and humidity conditions that the permanent building system will produce upon construction and building completion.
Our real-life experiences and testing translate into techniques that are field-proven with data to support their value in the field. We have proven numerous benefits that are possible to have improved product quality during the construction phase. These improvement areas include reducing casework and millwork rejected from the site, increasing schedule efficiency by reducing drying times for drywall taping and other curing products, mitigated shrinkage and expansion problems for drywall and flooring. From staff productivity to air quality after owner occupancy, all areas of the project benefit in a positive manner.
The below techniques have been tested and proven successful with the recent completion of multiple test pilot projects. Optimal curing environments ensured the construction schedule remained intact, building deficiencies were very low, and it was noted that staff productivity was increased through good air quality on location.
Temporary Heating Systems
Temporary Cooling Systems
IAQ Strategy for Vancouver is entirely different from Toronto, the fact is if you review regional weather history across Canada, you won’t find a single area that is room temperature and 35%-50% humidity, at any time of the year.
Step one of any project is to review our regional ambient conditions vs. our desired goal.
Ambient conditions can not be 100% predicted, however, their normal range is well documented in most areas and regions.
We can implement a program at a regional level to control all of these factors:
By controlling the construction environment in line with permanent building specifications, building materials cure in a proper manner, changes in humidity and temperature during the curing process resulting in the expansion and contraction of building materials, which can result in deficiencies in the finishing process. High-end finishes such as millwork, flooring; wood products can be highly affected by temperature and humidity swings.
Air quality is equally essential; hospitals have documented that infection control during the construction process is necessary to reduce the risk of infection to patients after project completion. HEPA filters can be utilized to create negative air barriers in line with CSA Z319 specifications, either to protect active areas of the hospitals that need to be remodelled or to filter exhaust air to hospital add-ons.
Excellent practice with HEPA filters is to attach them to ductwork during the entire construction process, because air is filtered to 99.997% there is no risk of contamination. This circulates filtered air Which would drastically reduce the amount of time needed for duct cleaning at the end of the project. This also helped air distribution throughout the structure as filtered air was distributed through the permanent ducting system.
It should be noted that forced mechanical ventilation has positive effects on IAQ. By forcing a portion of outside air we can maintain a positive pressure within the control area, this translates into increased surface temperatures, high air quality, and better air movement within the structure.