Lecture_1_(82724)_-_Indoor_Air_Quality.pdf

Lecture 1 (8/27/24) - Indoor Air Quality Owner R Ryan Tags Notes 1. Lecture - 8/27/24 a. EPA established in December 1970 by Richard Nixon in response to...

Lecture 1 (8/27/24) - Indoor Air Quality Owner R Ryan Tags Notes 1. Lecture - 8/27/24 a. EPA established in December 1970 by Richard Nixon in response to pollution i. indoor air quality is an aspect of EPA oversight 1. legionnaire’s disease a. a serious type of pneumonia caused by the Legionella bacteria. It's transmitted by breathing in contaminated water droplets or aerosols b. example: cooling towers in a hotel were ejecting bacteria out of the towers and people were exposed to it and died i. bacteria can be found in water systems, hot tubs, respiratory devices, soil and compost, evaporative condensers, cooling towers, and humidifiers ii. mission is to protect human health and the environment b. What is Indoor Air Quality? i. comfort level of indoor air based on 1. temperature 2. humidity 3. airflow 4. contaminant levels (particles and chemicals) a. Sources of Indoor Air Quality Contaminants Lecture 1 (8/27/24) - Indoor Air Quality 1  i. Asbestos ii. Biological Pollutants (molds, viruses, bacteria) iii. Carbon Monoxide (CO) iv. Formaldehyde/Pressed Wood Products v. Lead (Pb) vi. Nitrogen Dioxide (NO2) vii. Pesticides viii. Radon (Rn) ix. Indoor Particulate Matter x. Secondhand Smoke/ Environmental Tobacco Smoke xi. Stoves and Heaters xii. Fireplaces and Chimneys xiii. Volatile Organic Compounds (VOCs) ii. populations affected 1. young 2. elderly 3. chronically ill (especially those with respiratory or cardiovascular diseases) iii. Characteristics 1. Good IAQ is when the indoor air of a building is free of harmful amounts of chemicals and particles, and the temperature and humidity of the air is comfortable. 2. Poor IAQ can occur when the indoor air temperature, humidity, chemicals, or contaminants rise to harmful or uncomfortable levels. 3. Poor IAQ affects the health of building occupants and can lead to serious health problems as more time is spent in the undesirable air. Lecture 1 (8/27/24) - Indoor Air Quality 2  a. People who are exposed to indoor air pollutants for the longest periods are most susceptible to the effects of indoor air pollution. Within this group, the most highly susceptible populations to poor IAQ include the young, the elderly, and the chronically ill, especially those suffering from respiratory or cardiovascular diseases. c. Pollutant Stratification i. pollutants can aggregate at different levels of the room/space d. How to Improve Indoor Air Quality i. Source Control ii. Improved Ventilation iii. Air cleaners/Filtration e. ASHRAE 62.1 i. Goal 1. specify minimum ventilation rates to minimize the risk of adverse health effects for building occupants ii. Scope 1. Applies to all commercial, institutional, and residential buildings (excl. low-rise buildings) iii. Concepts 1. sets minimum outdoor air intake rates based on the occupancy and floor area of the space 2. sets outdoor airflow, effective air distribution and mixing, and contaminant controls (concentration limits for CO2 and VOCs) 3. provides guidance on HVAC system design and ductwork or air handling 4. guidance on maintenance and operations 1. Ventilation Rate Procedure: Lecture 1 (8/27/24) - Indoor Air Quality 3  Minimum Outdoor Airflow Rates: The ventilation rates are generally given in cubic feet per minute (CFM) per person or per square foot, depending on the space type. Office Spaces: 5 CFM per person + 0.06 CFM per square foot of floor area. Conference Rooms: 5 CFM per person + 0.06 CFM per square foot of floor area. Classrooms: 10 CFM per person + 0.12 CFM per square foot of floor area. Retail Spaces: 7.5 CFM per person + 0.12 CFM per square foot of floor area. Theaters and Auditoriums: 5 CFM per person + 0.06 CFM per square foot of floor area. These rates ensure that sufficient outdoor air is provided to dilute indoor air contaminants. 2. Carbon Dioxide (CO2) Limits: ASHRAE 62.1 uses CO2 levels as a rough indicator of adequate ventilation. The guideline suggests that indoor CO2 concentrations should not exceed outdoor levels by more than 700 parts per million (ppm). Typical outdoor CO2 levels are about 400 ppm, so the indoor CO2 concentration should ideally be below 1,100 ppm to indicate adequate ventilation. 3. Contaminant Limits: The standard does not specify limits for every possible indoor air contaminant, but it references limits provided by other standards, such Lecture 1 (8/27/24) - Indoor Air Quality 4  as those from the U.S. Environmental Protection Agency (EPA) and the Occupational Safety and Health Administration (OSHA). Volatile Organic Compounds (VOCs): The specific limits for individual VOCs like formaldehyde are not directly specified in ASHRAE 62.1 but are often referenced from other health-based guidelines. 4. Air Changes per Hour (ACH): ASHRAE 62.1 does not prescribe ACH directly but provides ventilation rates that translate into ACH based on the volume of the space and the outdoor air supply. For example, typical office environments might achieve 4-6 ACH, depending on the ventilation design and occupancy. 5. Humidity Control: ASHRAE 62.1 recommends maintaining indoor relative humidity (RH) between 30% and 60% to minimize the growth of mold and dust mites, which are common biological contaminants. 6. Air Cleaning: ASHRAE 62.1 suggests using filters with a minimum efficiency reporting value (MERV) of 6 to 8 for general building ventilation systems. For spaces with higher contaminant loads, higher MERV ratings (e.g., MERV 13 or higher) may be recommended. 7. Natural Ventilation Requirements: Openable areas (e.g., windows) should be at least 4% of the net occupiable floor area to allow sufficient natural ventilation. Natural ventilation should be used only in spaces where outdoor air quality is acceptable and where it can meet the required ventilation rates. ASHRAE 62.2 focused on residential buildings, and specifically low-rise buildings Lecture 1 (8/27/24) - Indoor Air Quality 5  Detailed Summary of ASHRAE 62.2: 1. Purpose and Scope: Purpose: The main goal of ASHRAE 62.2 is to define the minimum ventilation rates and other measures to achieve acceptable indoor air quality in residential buildings. The standard aims to reduce the risk of adverse health effects associated with poor indoor air quality. Scope: The standard applies to low-rise residential buildings, which include single-family homes, duplexes, and multifamily buildings up to three stories. It covers both new constructions and existing buildings. 2. Ventilation Requirements: Whole-Building Ventilation: ASHRAE 62.2 establishes the minimum continuous ventilation rates for the entire home. The required ventilation rate is determined based on the square footage of the home and the number of bedrooms. Ventilation Rate Formula: The formula used is Qtotal=0.03×Afloor+7.5×(Nbr+1), where: Qtotal=0.03×Afloor+7.5×(Nbr+1)Q_{\text{total}} = 0.03 \times A_{\text{floor}} + 7.5 \times (N_{\text{br}} + 1) QtotalQ_{\text{total}}Qtotal = total ventilation rate in cubic feet per minute (CFM) AfloorA_{\text{floor}}Afloor = floor area in square feet NbrN_{\text{br}}Nbr = number of bedrooms For example, a 2,000 square foot home with three bedrooms would require a minimum ventilation rate of 0.03×2000+7.5×(3+1)=60+30=90 CFM. 0.03×2000+7.5×(3+1)=60+30=900.03 \times 2000 + 7.5 \times (3+1) = 60 + 30 = 90 Local Exhaust Ventilation: Lecture 1 (8/27/24) - Indoor Air Quality 6  The standard also sets minimum exhaust ventilation requirements for specific rooms, such as kitchens and bathrooms, where moisture and pollutants are generated. Kitchen Exhaust: At least 100 CFM intermittent or 5 air changes per hour continuous. Bathroom Exhaust: At least 50 CFM intermittent or 20 CFM continuous. Natural Ventilation: Natural ventilation is allowed but must be designed to meet the same minimum requirements as mechanical ventilation systems. Openable windows or other openings must provide sufficient ventilation based on the building's design and location. 3. System Design Requirements: Air Inlets and Outlets: The standard requires that outdoor air inlets be located away from sources of contaminants, such as exhaust vents, combustion appliance outlets, or areas with high pollutant levels (e.g., garages). Air outlets should be positioned to effectively remove indoor air contaminants. Filtration: ASHRAE 62.2 recommends the use of air filters with a minimum efficiency reporting value (MERV) of 6 or higher in HVAC systems to reduce the amount of particulate matter entering the home. 4. Air Cleaning and Source Control: Source Control: The standard emphasizes controlling sources of indoor air pollution, such as volatile organic compounds (VOCs), moisture, and combustion by-products. This includes proper installation and Lecture 1 (8/27/24) - Indoor Air Quality 7  maintenance of appliances, adequate sealing of combustion areas, and proper venting of exhaust gases. Air Cleaning: While not a requirement, the standard acknowledges that air cleaning devices, such as high-efficiency particulate air (HEPA) filters or electronic air cleaners, can be used to supplement ventilation systems, especially in areas with high outdoor pollution levels. 5. Special Considerations: Multifamily Buildings: ASHRAE 62.2 includes specific provisions for multifamily buildings to address common issues such as air leakage between units, shared ventilation systems, and the need for additional ventilation in certain areas like corridors and lobbies. Unvented Combustion Appliances: The standard discourages the use of unvented combustion appliances (e.g., space heaters) due to the risk of carbon monoxide (CO) buildup. If used, these appliances must meet strict emission limits. 6. Commissioning and Maintenance: System Verification: The standard requires that ventilation systems be properly installed and verified to ensure they meet the required ventilation rates and operate effectively. Maintenance: Homeowners or building operators are encouraged to maintain ventilation systems regularly, including changing filters, inspecting ductwork, and ensuring that exhaust fans are functioning properly. 7. Energy Considerations: Lecture 1 (8/27/24) - Indoor Air Quality 8  Energy Efficiency: While the primary focus of ASHRAE 62.2 is on IAQ, the standard also considers energy efficiency. Ventilation systems should be designed and operated to minimize energy use while still meeting IAQ requirements. Heat Recovery Ventilation (HRV) and Energy Recovery Ventilation (ERV): The use of HRV or ERV systems is recommended to improve energy efficiency by recovering heat or energy from exhausted air and using it to condition incoming outdoor air. 1. IAQ Investigations a. Info that could be helpful in investigations i. General office conditions: 1. Housekeeping 2. How often is the office vacuumed? 3. How often are carpets and drapes shampooed? 4. How often are floors waxed? 5. Are there any visible signs of dust? 6. Have pesticides been applied recently? 7. Is there any evidence of moisture intrusion into the building? ii. Air quality in the office: 1. Odor 2. Dry 3. Humid 4. Dusty 5. Warm 6. Cool Lecture 1 (8/27/24) - Indoor Air Quality 9  7. Drafts 8. Temperature fluctuation 9. Within office 10. Between office 11. Between floors iii. Any recent changes in: 1. Workspace 2. General office 3. Building 2. Class Notes and Links IAQ Notes and Class Notes 08272024.docx https://www.epa.gov/indoor-air-quality-iaq/introduction-indoor-air-quality Lecture 1 (8/27/24) - Indoor Air Quality 10