Building Assessments
A typical indoor air quality building investigation involves several steps.- review building history
- conduct visual inspection
- test for contaminants
- interpret results
- prepare report with recommendations
1. Review Building History
The first stage of an IAQ investigation is to review the building’s history. This will involve:- interviews with building management, building occupants, and contractors.
- a review of relevant documents such as maintenance records, and architectural and mechanical drawings.
Sometimes it is difficult to determine if health symptoms are building-related or if they are caused by stress or psychological factors. A useful rule of thumb is to suspect a building-related cause if one or more of the following are true:
|
2. Conduct Visual Inspection
The purpose of the visual inspection is to look for clues that might explain the problem. Items to include in the inspection:- the outdoor environment for contaminant sources
- ventilation equipment
- the building envelope (roof, walls, foundations)
- equipment in the indoor spaces
- areas in the building identified in the interviews as problems
The problem may be obvious after the visual inspection. If not, testing might be needed.
3. Test for Contaminants
Contaminants in the indoor environment include airborne particulates, noxious gases, radon, volatile organic compounds and contaminants of biological origin. Contaminants may be generated indoors or brought in from outside.Other parameters such as temperature, relative humidity, and carbon dioxide may also be tested to provide an assessment of the heating, ventilation and air conditioning equipment.
A list of health symptoms reported by the building’s occupants and information gathered during the visual inspection may point to a particular contaminant. This information can be used to determine testing methodology. A hypothesis is formed at this point and testing is done to either confirm or disprove the hypothesis.
The following table outlines health symptoms associated with various indoor contaminants.
| Disease | Symtoms | Causes |
|---|---|---|
| Rhinitis and Sinusitis | Stuffy/runny nose, post-nasal drip | Moulds, volatile organic compounds, allergens |
| Asthma | Coughing, wheezing, chest tightness | Moulds, volatile organic compounds, allergens, nitrogen dioxide |
| Hypersensitivity Pneumonitis | Cough, weakness, fever | Moulds, moisture |
| Organic dust toxic syndrome | Cough, chest tightness, fever | Gram-negative bacteria |
| Contact dermatitis (allergic) | Dry skin, itching, scaling skin, rash | Moulds, laser toners |
| Eye irritation | Eye itching, irritation, dryness | Low relative humidity, volatile organic compounds, particulates, nitrogen dioxide |
| Nasal irritation | Stuffy, congested nose, rhinitis | Low relative humidity, volatile organic compounds, particulates |
| Central nervous system symptoms | Headache, fatigue, irritability, difficulty concentrating | Volatile organic compounds, noise, lighting, stress, carbon monoxide, moulds |
| Legionnaires’ disease | Pneumonic illness | Bacteria from contaminated water (shower heads, water faucets, humidifiers, hot water heaters) |
4. Interpret Results
Once measurements of indoor air parameters are obtained and the laboratory reports their findings, IAQm will compile the data and interpret the results. IAQm will address any deficiencies by recommending actions that will bring about solutions.A scope of work may be generated.
A health risk assessment may be formulated.
5. Report with Recommendations
IAQm will generate a detailed report based on the building assessment. It will include:- a description of the building
- methodology of the investigation
- results from the building history, visual inspection, and testing
- recommendations for making improvements and preventing the problem from recurring
Remediation
Remediation can sometimes be simple, however most IAQ investigations involve complex remediation action involving the removal of contaminant sources, adjustments to the heating ventilating and air conditioning systems, and repair of the building envelop.There are several basic remediation methods:
- source management
- activity management
- design intervention
- dilution
- cleaning
Source Management (removal or modification)
The permanent way to eliminate a contaminant is to remove the contaminant from the environment. This can be done with some types of contaminants and should be done when the contaminants cause serious harm to humans or the environment. Such materials as paints, finishes, manufactured wood products, plastics, and cleaning agents almost always have satisfactory substitutes. Encapsulation is a source control method that involves coating materials, or otherwise interfering with the materials’ ability to off-gas pollutants.Activity Management
Activity management is the process of ensuring that a building is used for the activities that it was designed to accommodate, and making appropriate alterations when activities change. Usually, the building and the spaces within are designed to handle the pollutants generated by the activities expected to be performed there. When activities change pollutant concentrations may increase to harmful levels unless changes are also made to the layout or ventilation system.Design Intervention
Design intervention is a proactive pollution control method. It requires creative, informed individuals who, through a conscious effort, endeavor to build indoor environments that are healthy, functional and sustainable. Design intervention involves thinking about indoor air quality during the design stage, anticipating potential problems, and designing architectural details and building mechanical systems that will prevent problems from arising. Examples of design intervention include adequate and appropriate ventilation systems; hard, flat surfaces that are easy to clean; and specifying building materials that do not off-gas.Dilution
Dilution of pollutants in buildings is achieved through ventilation. Quantities of outdoor air are increased in the building to reduce the concentration of the indoor pollutant. Ventilation is not ideal and has little effect on the control of biological contaminants. Source control should always be considered before dilution.Cleaning
Cleaning is the process of removing pollutants from the environment and putting them in their proper place of disposal. Cleaning should not only be used as a reactive pollutant control method, but also as a method of prevention. Care must be taken to use non-toxic cleaning solutions to avoid contributing additional chemicals into the indoor environment.Portable vacuum cleaners expel small particles through their exhaust, which become suspended in the air causing a risk to human health. Vacuum cleaners equipped with a HEPA filter (High Efficiency Particulate Air Filter) or central vacuum cleaners vented to the outside are better alternatives.
Air filtration is a way of cleaning the air of particulates and gases. There are essentially three types of air filter technologies: impingement, electronic and adsorption. Impingement and electronic air filters remove particles from the air while adsorption filters remove gases from the air. There is a wide variety of impingement and electronic air filters on the market ranging in efficiency from 5% to 99.97%. Filters greater than 30% efficient may require additional fans to compensate for the increased static pressures.
Special Remediation Considerations for Fungi
General strategies for fungal contamination remediation:- eliminate conditions that promote fungi amplification (eliminate source of water and moisture)
- provide protective clothing and equipment for clean-up personnel
- clean non-porous materials (concrete, metal, ceramic) with a detergent
- remove porous contaminated materials (wood, gypsum board, carpet)
- clean adjacent walls, floors, fixtures and furnishings
- maintain a dust-free environment
- dispose of contaminated materials properly (materials contaminated with toxic fungi must be placed in plastic bags and taken to an appropriate waste site)
Isolate the work area with plastic sheeting and use negative pressure if the contaminated area is larger than 100 square feet (10 feet by 10 feet) or if there are toxigenic fungi present.
| IAQm does not advocate the use of antimicrobials at any time during the remediation process. Antimicrobials kill the fungi to prevent it from growing and reproducing. Contractors like to use antimicrobials because they increase the chances that the clearance test will be passed when there are fewer airborne spores. However, even dead fungi retain their allergenic and toxigenic properties. IAQm supports the complete removal of contaminated porous building materials and using a detergent to clean hard surfaces. The longer porous building materials remain wet, the more likely toxins will be associated with the mould contamination. If a water leak is allowed to persist or with repeated wetting events, mould will continue to grow. Eventually the different types of mould colonies, which start out as tiny spots, completely cover the wet substrate. As the available food source is used up, the types of fungi capable of producing toxins will do so in order to obtain a competitive advantage for the same food source. |
Top