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MECHANICAL AND HVAC SYSTEMS FOR CONSTRUCTION

INDOOR AIR QUALITY. MECHANICAL AND HVAC SYSTEMS FOR CONSTRUCTION. Today’s Goals A LONG WAY TO GO AND A SHORT TIME TO GET THERE Introductions Code Search – Building Codes And ASHRAE Definitions Of Some Of The Applicable Terms A Brief Discussion Of Psychrometrics

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MECHANICAL AND HVAC SYSTEMS FOR CONSTRUCTION

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  1. INDOOR AIR QUALITY MECHANICAL AND HVACSYSTEMS FOR CONSTRUCTION

  2. Today’s Goals A LONG WAY TO GO AND A SHORT TIME TO GET THERE • Introductions • Code Search – Building Codes And ASHRAE • Definitions Of Some Of The Applicable Terms • A Brief Discussion Of Psychrometrics • A Short History Of The Evolution Of Air-Conditioning And The Rise Of IAQ Awareness • Contributing Factors – Contaminants, Moisture, Etc. • IAQ Responsibilities of Owners, Architects and Engineers, and Construction Managers Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  3. WHO ARE YOU? • What name and numbers do we give the college computer system so you get recognized for being here? • There will be a sign-in sheet for • each class. • If you don’t sign in, you will not get • credit for attendance. Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  4. WHO ARE YOU? • Computer not withstanding -- what do you prefer to be called? • Why are you taking this class? • What are you expecting to learn • by being here? Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  5. What is Indoor Air Quality? “Even though quality cannot be defined, you know what quality is…” Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  6. What is Indoor Air Quality? • Florida Building Code – Mechanical • The Building Code is Law! • Paragraph 401.1 says: “This chapter shall govern the ventilation of spaces within a building intended to be occupied.” Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  7. What is Indoor Air Quality? • Florida Building Code – Mechanical • There are requirements for Minimum Ventilation Rates, but no mention of “Indoor Air Quality.” • Paragraph 403.4 says: “…mechanical ventilation may be implemented in compliance with ASHRAE 62…” Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  8. What is Indoor Air Quality? • ASHRAE 62 --- Ventilation For Acceptable Indoor Air Quality • AMERICAN SOCIETY OF HEATING, REFRIGERATING and AIR-CONDITIONING ENGINEERS • Founded 1899 as ASHVE Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  9. What is Indoor Air Quality? ASHRAE 62 ---Section 3 “acceptable indoor air quality: air in which there are no known contaminates at harmful concentrations as determined by cognizant authorities and with which a substantial majority (80% or more) of the people exposed do not express dissatisfaction.” Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  10. What is Indoor Air Quality? • From ASHRAE 62, Section 2 Scope: • “2.4 This standard considers chemical, physical, and biological contaminants that can affect air quality. Thermal comfort requirements are not included in this standard.” Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  11. What is Indoor Air Quality? From ASHRAE 55, Scope: “2.4 This standard does not address non-thermal environmental factors such as air quality…” Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  12. What is Indoor Air Quality? From ASHRAE 55: The “Comfort Zone” • “Comfort” is also defined as conditions where 80% of the population reports that they are not dissatisfied. Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  13. What is Indoor Air Quality? • You’d think a well designed building system that provides • Ventilation air in appropriate quantities • Adequate protection from contaminant sources • Filtration, heating, cooling and dehumidification • Appropriate supply distribution systems • Appropriate exhaust and return systems • System control • ought to provide “Acceptable Indoor Air Quality” Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  14. So What’s The Big Issue? “…case extended the chain of liability for problems with the HVAC system not only to the manufacturers and sellers of the system, but to everyone involved in the design and construction of the system, architects, engineers, installers, and anyone else who might have been involved.” Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  15. So What’s The Big Issue? …the building's occupants filed a personal injury lawsuit against the architect, contractors, and HVAC contractors, alleging that their illnesses were caused by the design of the ventilation system and the presence of volatile organic compounds…” Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  16. So What’s The Big Issue? “…$3 million…” “…$25.8 million…” “…$24 million…” “…$35 million…” “…$11 million…” “A lawyer is a learned gentleman who rescues your estate from your enemies and keeps it himself. “ …. Henry Brougham (1778-1868) Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  17. So What’s The Big Issue? “Newspapers are unable, seemingly, to discriminate between a bicycle accident and the collapse of civilization” …George Bernard Shaw Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  18. So What’s The Big Issue? “Hillsborough County Public Schools never has had an IAQ problem attributable to a fresh air rate of 7.5 cfm per student…” “IAQ problems …are attributable to negative building air pressure, leaky roofs, missing vapor barriers, broken chilled-water valves, oversized direct-expansion equipment, poor control calibration, leaky windows, dirty filters, and the like.”HPAC Engineering Dec 2010 Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  19. Some Definitions • SBS Sick Building Syndrome • A building is defined as sick if 20 percent or more of the building's occupants complain of such problems as headache, eye irritation, nausea, sore throats, dry or itchy skin, sinus congestion, nose irritation, fatigue and dizziness for more than two weeks; if the symptoms are relieved when the complainant leaves the building; and, if no specific cause of the problem can be identified. Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  20. Some Definitions • BRI Building Related Illness • An identifiable illness or disease caused by conditions in or nearby a facility. • Fug (fŭg) n: A heavy, stale atmosphere, especially the musty air of an overcrowded or poorly ventilated room. Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  21. Some Definitions • Aspergillosis One of a group of diseases of animals and humans caused by various species of Aspergillus. Aspergillus is a genus consisting of several hundred mold species found in various climates worldwide. Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  22. PSYCHROMETRICS • DRY BULB TEMPERATURE • the temperature of air measured by a thermometer freely exposed to the air but shielded from radiation and moisture. • WET BULB TEMPERATURE • the lowest temperature that can be reached by the evaporation of water only. Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  23. PSYCHROMETRICS • DEW POINT TEMPERATURE • the temperature to which humid air must be cooled for water vapor to condense into water. The dew point is a saturation temperature. • RELATIVE HUMIDITY • The ratio of the amount of moisture in air to the maximum moisture it could hold at saturation. • Sling Psychrometer Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  24. PSYCHROMETRICS The Psychrometric Chart Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  25. PSYCHROMETRICS Dry Bulb Temperatures Run Vertically Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  26. PSYCHROMETRICS Dry Bulb Temperatures Run Vertically Wet Bulb Temperatures Run Diagonally Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  27. PSYCHROMETRICS Dry Bulb Temperatures Run Vertically Wet Bulb Temperatures Run Diagonally Relative Humidity Lines Are Curved Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  28. A Brief History of Applied Air-Conditioning • 20 Students – 1 Teacher • Approximately 20’ By 30’ --- 10’ To 12’ Ceiling -- Steam Radiators -- Tall, Operable Windows – Cross Ventilation Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  29. A Brief History of Applied Air-Conditioning • Acoustic Tile Ceiling At About 9’ • Smaller Windows With Minimum Operability • Chilled Water Or Direct Expansion Air-conditioning Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  30. A Brief History of Applied Air-Conditioning Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  31. A Brief History of Applied Air-Conditioning Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  32. Moisture Intrusion Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  33. Moisture Intrusion Masonry Cavity Wall • Flashing • Insulation • Air Space • Caulking • Backer Rod • Weep Hole Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  34. Moisture Intrusion Masonry Cavity Wall • Flashing • Insulation • Air Space • Caulking • Backer Rod • Weep Hole • Cant • Tapered • Insulation Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  35. Underslab Vapor Barrier Water Can Get Through A Floor Slab As A Result Of Hydrostatic Pressure Capillary Action Vapor Pressure Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  36. Contaminant Intrusion Intakes and Vents Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  37. ‘Would Someone Really Let A Roof Get That Nasty?’ Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  38. Contaminant Intrusion Intakes and Vents Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  39. Some More Definitions • VOCVolitile Organic Compound • organic chemical compounds which have significant vapor pressures and which can affect the environment and human health. VOCs are numerous, varied, and ubiquitous. VOCs are typically not acutely • toxic but can have chronic effects. Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  40. Where Do VOCs Occur in a Project? • FUEL CONTAINERS OR DEVICES USING GASOLINE, KEROSENE, FUEL OIL AND PRODUCTS WITH PETROLEUM DISTILLATES: PAINT THINNER, OIL-BASED STAINS AND PAINT, AEROSOL OR LIQUID INSECT PEST PRODUCTS, MINERAL SPIRITS, FURNITURE POLISHES • BTEX (benzene, toluene, ethylbenzene, xylene), hexane, cyclohexane, 1,2,4-trimethylbenzene Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  41. Where Do VOCs Occur in a Project? • PVC CEMENT AND PRIMER, VARIOUS ADHESIVES, CONTACT CEMENT • Tetrahydrofuran, cyclohexane, methyl ethyl ketone (MEK), toluene, acetone, hexane, 1,1,1-trichloroethane, methyl-iso-butyl ketone (MIBK) Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  42. Where Do VOCs Occur in a Project? • PAINT STRIPPER, ADHESIVE REMOVERS • Methylene chloride, toluene, older products may contain carbon tetrachloride • Degreasers, aerosol penetrating oils, commercial solvents, electronics cleaners, spray lubricants • Methylene chloride, PERC, TCE, toluene, xylenes, methyl ethyl ketone, 1,1,1-trichloroethane Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  43. Where Do VOCs Occur in a Project? • REFRIGERANT FROM AIR CONDITIONERS, FREEZERS, REFRIGERATORS, DEHUMIDIFIERS • Freons (trichlorofluoromethane, dichlorodifluoromethane) • Aerosol spray products for some paints, cosmetics, leather treatments, pesticides • Heptane, butane, pentane Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  44. Where Do VOCs Occur in a Project? • UPHOLSTERED FURNITURE, CARPETS, PLYWOOD, PRESSED WOOD PRODUCTS • Formaldehyde Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  45. How About Another New Contaminant? • TOXIC DRYWALL • “The problem began to emerge about a year ago. Tests found that Chinese drywall imported during the peak years of the building boom emits sulfide gases. The gases corrode copper coils in air conditioning systems and wiring in appliances and electrical outlets.” • NPR Morning Edition 10/27/2009 Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  46. How About Another New Contaminant? “Citizens Property Insurance Corp. [is] issuing notices to alert policy holders that their coverage will be dropped.” Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  47. How About This? Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  48. How About This? Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  49. Architect’s Responsibility Design Selections That Minimize The Chances Of Moisture And Contaminant Intrusion Including Careful detailing of wall, roof, and flooring systems Careful selection of caulking and flashing details Careful selection of furnishings and paints Adequate room for mechanical systems Mechanical and HVAC Systems for ConstructionIndoor Air Quality

  50. Engineer’s Responsibility Design Selections That Minimize The Chances Of Moisture And Contaminant Intrusion Selection of systems and equipment that Adequately ventilate and exhaust the space Adequately filter, dehumidify, and condition the supply air Adequately insulate cold mechanical system surfaces Adequately drain any condensate Have proper control systems Mechanical and HVAC Systems for ConstructionIndoor Air Quality

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