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Prevention of IAQ Problems, Improving Maintenance, Housekeeping

This article discusses the prevention and control of indoor air quality (IAQ) problems by improving maintenance and housekeeping practices, with a focus on moisture control. It covers the influence of temperature, humidity, air movement, and air contaminants on air quality, as well as the importance of proper airflow and humidity levels. It also provides guidance on engineering development, inspection, testing, and maintenance to avoid the development of contamination and promote safe operating procedures.

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Prevention of IAQ Problems, Improving Maintenance, Housekeeping

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  1. Prevention of IAQ Problems, Improving Maintenance, Housekeeping

  2. Moisture Control • Who said: “An Ounce of Prevention Is Worth a Pound of Cure”? a. Benjamin Franklin b. Yogi Berra c. Farmers Almanac d. Socrates e. all of the above

  3. Air Quality • Air quality is influenced by: • Temperature; • Humidity • Air Movement • Air Contaminants

  4. Air Movement • Too little air flow causes stuffy and uncomfortable environment; • Too much causes draught & excessive cold. • Internal partitioning - “dead spaces”. • Balanced Air Conditioning. • Filter Maintenance • Air Changes per Hour (A.C.H.) - A.S. 1668.2 • 10 - 15 litres per second, per person is required • Obtain expert advice: • Occupational Hygeinist • Air Conditioning Engineer

  5. Humidity • Ideal relative humidity (R.H.) should be between 40% - 60% • Avoid extremes of R.H. (< 20% and > 80%) • Extremely low R.H. causes: • eyes, noses & throats to dry; • produces irritations & soreness; • increases susceptability to infection; • increases problems associated with static electricity. • High R.H. causes: • high moisture; • promotes growth of fungi and mould • Controls: • Air conditioning • admin controls - rostering for short periods • install dehumidification devices

  6. Prevention & Control Measures • Engineering development & design • Inspection, Testing & Maintenance • Avoid development of contamination • Safe operating procedures • Improved Maintenance • Housekeeping

  7. Improved Maintenance • Control microbial contamination in the building by regularly inspecting for, and promptly repairing, water and moisture intrusion problems • Control microbial problems in buildings by promptly drying wet or damp building materials following the IICRCs 500; • Remove and replace wet or damp building materials that have visible mold present

  8. Procedures • Visible mold, that is growing on building system components or other impermeable surfaces, should be removed by HEPA vacuuming, if dry: by physical removal from the surface while HEPA vacuuming: or by removing and replacing the affected building component. • Areas that are contaminated with settled spores, may be cleaned using an appropriate method for that material

  9. Housekeeping Procedures • Where wall cavities or other concealed areas of the building have been wet for over 72 hours, an investigation of the cavity or area must be performed to establish whether or not there has been an amplification of mold • While performing housekeeping, the use of containment must be considered in order to insure that there is not a contamination of the indoor environment

  10. Housekeeping Procedures • Correct the specific situation that allowed the mold amplification • Remove mold • Sanitize surface • Coat with a fungistat coating • Clearance inspection and sampling • Set up an Operations & Maintenance program

  11. Operations & Maintenance • Supervision • Training • PPE • SOPs • Clearance • Recordkeeping

  12. Procedures • Residential water loss • DOL: 72 hours prior • Inspection: Strong mold odor No visible mold

  13. Moisture in Buildings Most buildings start off wet All buildings get wet It’s OK for buildings to get wet as long as they dry out quickly It’s a rate issue

  14. Moisture Movement Rule #1 • Moisture movement Rule #1 • Liquid water will naturally tend to flow • It will travel laterally and vertically downward • It will follow the path of least resistance

  15. Moisture Movement Rule #2 • Moisture will enter into porous materials due to capillary action • A solid piece of wood will draw water up to 350-375 ft. ( height of the tallest tree) • A column of concrete placed in water will draw moisture up to 10 KM or 6 Miles.

  16. Moisture in Buildings • Capillary Rise groundwater through footing (footers) into concrete wall • Ring of dampness around base of foundation wall • Perimeter drains help keep water away from footers

  17. Moisture in Buildings • Capillary Action • Again water can be drawn into an opening of 3/16” or less • If two materials without capillary pores are placed close enough together, they create a capillary pore that can draw moisture. • How close ?

  18. Moisture in Buildings • Answer 3/16 “ or less • l l the distance between these two lines

  19. Moisture in Buildings • Materials like overlapping siding can create capillary gaps • Capillary rise in wood siding • Film of water on surface of siding • Water film draws up between laps of siding by capillary suction • Building paper • Sheathing

  20. Moisture in Buildings • Moisture movement rule #3 • Moisture moves through building materials by vapor diffusion • Vapor diffusion is the movement of moisture in a vapor state as a result of a vapor pressure difference (concentration gradient)

  21. Moisture in Buildings • Permeance factor is a measure of water flow through materials • Permeance factors (perms) specify the vapor flow in grains of moisture per hour, through one square foot of material surface, at one inch of mercury (1” Hg) of vapor pressure

  22. Moisture in Buildings • Diffusion vs. Air Leakage

  23. Moisture in Buildings • Q- How much water can be collected over an entire heating season in most cold climates?

  24. Moisture in Buildings • A- One-third quart of water can be collected by diffusion through a gypsum board without a vapor diffusion retarder. Whereas 30 quarts of water can be collected through air leakage.

  25. Moisture Movement Rule #4 • Moisture moves from hot to cold • Moisture can move through building materials by diffusion or through a hole by air transport

  26. Moisture Movement Rule #5 • Moisture moves from an area of higher air pressure to an area of lower air pressure • (air transport)

  27. Moisture in Buildings • Stack effect • Stack effect is caused by warm air rising within a structure • As warm air rises, it creates a higher air pressure at the ceiling area and forces air out of the building • As the air leaves, or exfiltrates, it is displaced with outside air that is drawn into the building from the floor area (infiltrates) • Stack effect can result in up to .5 ACH or 150 cfm in one home

  28. Moisture in Buildings • Moisture content The water or moisture content of a material Is expressed as a percentage of the oven dry weight • Water or moisture content does not indicate the actual amount of water available to fungi

  29. Moisture in Buildings • Equilibrium Moisture Content • EMC • As humidity increases, hygroscopic materials will adsorb water until they reach equilibrium with the environment. • Equilibrium is the point at which the hygroscopic material is neither gaining nor losing moisture

  30. Moisture in Buildings • Relative Humidity • The amount of moisture in the air at a given temperature, as compared with the amount of moisture the air could hold before reaching saturation at that temperature

  31. Moisture in Buildings • Specific Humidity • The amount of water vapor in the air w/o reference to temperature • Measured in “grains per pound”(GGP) of dry air • The only way to directly compare the amount of moisture in one area mass to the amount of water vapor in another (when temperatures are different)

  32. Moisture in Buildings • Dew point: • The temperature at which water vapor begins to condense onto surfaces • Equal to 100% Relative Humidity

  33. Moisture in Buildings • Equilibrium Relative Humidity • ERH • If hygroscopic materials become saturated with water, they will lose moisture to the drier air until the air reaches equilibrium with the materials • Similarly, if the air becomes saturated, it will lose moisture to the drier materials until the air is in balance or equilibrium

  34. Moisture in Buildings • Water activity • A better measurement of water available to fungi is water activity

  35. Moisture in Buildings • Water activity • A measurement of available substrate moisture: • Aw – the decimal equivalent of the RH% inside the contained area • A volume of air measured inside a small contained area, at equilibrium with the material • Simulated equilibrium Rh (ERH) • Not MC • Not RH

  36. Moisture in Buildings • Water activity • A measurement of available substrate moisture

  37. Water Loss Scenario • Residential Water Loss • Assumptions: carpet & pad over underlayment walls are wet in all three rooms

  38. Water Loss Scenario • Use of Existing Drying Resources • It is highly recommended that unaffected drying resources within the building be used • To expedite drying. Drying resources may include, but are not necessarily limited to: • Activating the structure’s HVAC system turning on exhaust or ceiling fans and opening windows and doors when psychrometric conditions are favorable

  39. Water Loss Scenario • Careful consideration must be given to whether use of existing drying resources may negatively affect the indoor environment or pose a safety hazard. • HVAC systems contaminated with biological growth and other materials must not be used as a drying resource • Exhaust systems or ceiling fans that pose an electrical hazard must not be used as drying resources

  40. Water Loss Scenario • Solution: Turn off the HVAC system Seal off the supply vents and any returns that are in the contaminated area

  41. Water Loss Scenario • Decision: Worker Protection • Respirator • None • Face-piece respirators N95 • Air purifying respirator

  42. Water Loss Scenario Decision: Containment • Moisture Control Barrier: softer term – alleviates fear • Pros: control the spread of spores minimize further secondary damage Cons: concentrates moisture within containment

  43. Water Loss Scenario • Decision: Carpet and Pad • Will top down drying work? • Probably not a good idea - remove pad • Can carpet be dried on location? - possibly

  44. Water Loss Scenario • Problem: No negative pressure in wall cavities • Options: seal off openings through the wall (i.e.: light switches and outlets) • Reduce airflow through neg-air machine • Add wall drying unit • Add make-up air • Turn off neg-air machine

  45. Water Loss Scenario • Problem: Too much negative pressure in wall cavities • Options: • Expand the numbers of injectors per wall drying machine • Allow make-up air to flow into wall cavity

  46. Water Loss scenario • Problem: Mold is found underneath and behind the vanity in the bathroom • Issues: • Containment • Disposal of debris from remediation • Occupants access to restrooms • Occupants exposure

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