Arch 432

Indoor Air Quality (IAQ)

Attendance

The dust mite creates the second most allergic reactions, second only to pollen. What part of the dust mite is the cause of the reaction?

A. Shed skinsB. CorpsesC. DroppingsD. Regurgitated foodE. Eggs

Good Morning Arch 432 students

How are you this fine morning.

Respirable Particles

• #1 allergen in homes is the dust mite– How best to

mitigate dust mites in your bed?

Respirable Particles

• Dust mite (insect) populations decrease below 50% RH

• Dust mites die below 40% RH

Terms

• Indoor Air Quality (IAQ)

• Bioeffluents• Dilution• Filtration• Source

capture/elimination• Friable• Allergen• Pathogen

• Sick Building Syndrome (SBS)

• Building Related Illness (BRI)

• Environmental Tobacco Smoke (ETS)

• Volatile Organic Compound (VOC)– Formaldehyde

What You Need to Know

• Be conversant in the various codes and standards relative to healthy indoor environments

• Know how to design and construct healthy buildings

What You Need To Be Able To Do

• Identify and avoid dangerous conditions

• Select the appropriate strategy to ensure a “healthy” environment

Filters

• When it comes to HVAC systems found in residential construction, they are sized mostly by a rule-of-thumb calculation based on outdated information and performance specification using high, medium, and low guesses (LaLiberte, 2011.)

Filters

• Central air system where a filter system is used, most filters are designed to filter the air entering the furnace chamber and protect it from dust (EPA, 2008; EPA, 2009).

• Their purpose is not solely to benefit human health. The minimum efficiency reporting value (MERV) for these flat filters is 1 to 4.

Filters

• ASHRAE Standard 62.1 2010 requires a minimum filter requirement of a MERV 6.

• The International Mechanical Code IMC-2009 does not state a minimum MERV value for filters (Mudarri, 2010).

Filters

• MERV ratings (from 11 to 16), pre-filters and their effectiveness on dust, pollens, emission particles before entering a ventilation system

• Higher MERV rated filters would increase air volume and air pressure

Sick Building Syndrome

“Exists when a significant percentage (e.g., more than 20%) of the occupants complain during a two week period of a set of symptoms, including headaches, fatigue, nausea, eye irritation, and throat irritation, that are alleviated by leaving the building, and are not known to be caused by specific contaminants.”

ASHRAE Standard 62.1-2004

Sources of IAQ Problems

• Vapors and gases• Chemicals • Respirable particles• Mold, fungus and viruses

Vapors and Gasses

• VOCs– Formaldehyde– Cleaning supplies– Chlorine

• Bio-effluents– Human odors– Organic odors

• ETS– CO2

– CO

• Ozone/smog

Chemicals

IAQ and health is a very new area of scientific explorationFlame retardants & Electronic devices

polycyclic aromatic hydrocarbons (PAHs)

Polychlorobiphenyls (PCBs)

Polycyclic Aromatic Hydrocarbons (PAH)

• PAHs are found naturally & can also be man-made. In their purest form, PAHs are solid and range in appearance from colorless to white or pale yellow/green. PAHs are created when products like coal, oil, gas, and garbage are burned but the burning process is not complete.

Polychlorobiphenyls (PCBs)

• PCBs were used in hundreds of industrial and commercial applications including electrical, heat transfer, and hydraulic equipment; as plasticizers in paints, plastics, and rubber products; in pigments, dyes, and carbonless copy paper; and many other industrial applications.

• PBDEs are not chemically bound to plastics, foam, fabrics, or other products in which they are used, making them more likely to leach out of these products. Despite the United States having phased out the manufacture and import of penta- and octaBDE in 2004, their component congeners are being detected in humans and the environment.

Polybrominated Diphenyl Ethers

PBDEs (cont.)

• Some reports indicate that levels are increasing. One potential source is imported articles to which these compounds have been added. Another is the possible breakdown of decaBDE in the environment to more toxic and bioaccumulative PBDE congeners.

Respirable Particles

• Asbestos• Cyanide• Dust mite

droppings • Others?

One Example

Bacteria, Viruses & Mold

• Legionella• Viruses

– High or low RH

• Mold

Mold• Over 64,000

different types of fungi

• A few are toxic• Considered a

“growth industry” for both remediation contractors and the legal profession

Conditions Needed for Mold Growth

• One viable spore• An acceptable

temperature range

• A usable food source

• Adequate moisture in the food source

Failure Analysis

• Prof. Kirk’s one-of-a-kind, surefire process guaranteed to result in a mind-numbing law suit.

More Mold

More Mold

More Mold

Strategies Addressing IAQ Concerns

• Source Elimination/ Capture

• Filtration• Dilution

Source Elimination Strategy

“If there is a pile of manure in a space, do not try to remove the odor by ventilation.

Max Van Pettenkofer (1848)

Remove the pile of manure.”

Design Criteria for Capture

• Walls to deck above and sealed

• Independent exhaust

• No return or recirculation air

• Negative air pressure

Source Elimination/Capture

• Smoking Rooms• Janitors Closets• Photocopying

rooms• Bathrooms• Locker rooms• Kitchens• Others?

Take-aways or the ‘Ah hahs’

• Identify the contaminants that are in your building (they will be unique)

• First try to eliminate them, then capture them, then filter them.

• If all else fails, dilute them