2/10/2011. Toxic Mold Hilton Hotel Hawaii Alerton Hilton settles over moldy Hawaii hotel SEATTLE POST-INTELLIGENCER Saturday, December 24, 2005

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1 2//11 Dew Point What is Dew Point? Kris Anderson, P.E What is Dew Point? Dew Point What is Dew Point? Dew point is the temperature at which dew starts to form or vapor to condense into a liquid. led Dehumidification Air Conditioning Steam Heating Ammonia Refrigeration Pool Environments Frosted Beer Mugs 1

2 2//11 Dew Point Uncontrolled Condensation Structural damage Cosmetic damage Interstitial titi condensation Pests Greenhouse plant disease Mold growth Toxic Mold Hilton Hotel Hawaii Alerton Hilton settles over moldy Hawaii hotel SEATTLE POST-INTELLIGENCER Saturday, December 24, 5 HONOLULU -- A judge has approved a $1.8 million class action settlement between Hilton Corp. and guests who stayed in a mold-infested Waikiki hotel tower, lawyers for the plaintiffs said. Experts said the mold was a variety that can trigger asthma and also irritate the eyes, nose and throat, but no serious health problems were reported. Mold overtook the 3-room Kalia Tower in the Hilton Hawaiian Village complex and forced its closure in 2, about a year after the $95 million building opened. The tab for cleanup was more than five times the original $ million estimate. The tower reopened in September 3. Hilton sued 18 companies and individuals, saying design and construction defects produced excessive humidity that encouraged the mold to grow. Hilton sues 18 companies over mold remediation costs at a Hawaiian hotel Honolulu Advisor April 22, 4 The suit alleges various construction and design defects contributed to mold growth including defects in the exterior finish, air intake and exhaust systems, door framing, fireproofing, linen chutes, drywall joints, lanai doors and orienting the building towards the prevailing winds. The hotel conglomerate blames the contractors for problems ranging from inadequate moisture sealant on the outside, to faulty air conditioning and air pressure systems, and an improper ''toilet exhaust system'' that leaked and overwhelmed fan coils that were supposed to pressurize the rooms and keep humid air out. Warm air often forms condensation where it encounters air-conditioned, cooler air, thus creating a habitat for mold, said Wong. Dew Point Calculation Dew point is a temperature which is related to the temperature and moisture content of the air of concern. Need two measurable air quality parameters: DB, RH, or WB Psychrometric Chart 2

3 32.. STANDARD AIR DRY BULB TEMPERATURE - F Chart by: HANDS DOWN SOFTWARE, STANDARD AIR DRY BULB TEMPERATURE - F Chart by: HANDS DOWN SOFTWARE, STANDARD AIR DRY BULB TEMPERATURE - F Chart by: HANDS DOWN SOFTWARE, //11 iphone apps, free PC calculators! (online ambient air dewpoint calculator) BAROMETRIC PRESSURE: in. HG 37 F % % % % % % Inside % % F, % % RELATIVE HUMIDITY HUMIDITY RATIO (or Specific Humidity) GRAINS OF MOISTURE PER POUND OF DRY AIR DEW POINT TEMPERAT TURE - F ENTHALPY - Btu per lb. of dry air and associated moisture OF MERCURY VAPOR PRESSURE - INCHES BAROMETRIC PRESSURE: in. HG 42 F 37 F % % % % % % Inside % % F, % % RELATIVE HUMIDITY F, %. HUMIDITY RATIO (or Specific Humidity) GRAINS OF MOISTURE PER POUND OF DRY AIR DEW POINT TEMPERAT TURE - F ENTHALPY - Btu per lb. of dry air and associated moisture OF MERCURY VAPOR PRESSURE - INCHES BAROMETRIC PRESSURE: in. HG 37 F 28 F F, % % % % % % % Inside % % F, % % RELATIVE HUMIDITY HUMIDITY RATIO (or Specific Humidity) GRAINS OF MOISTURE PER POUND OF DRY AIR DEW POINT TEMPERATU URE - F VAPOR PRESSURE - INCHES OF MERCURY R-Value is a material s resistance to heat transfer The better the wall system s resistance to heat flow the better it is at keeping critical surfaces at a temperature above dew point. R-Value is either based on a specific thickness or based on a unit measure Caveat for R-Value per inch if it declines with thickness Material R/ Inch R/ Thickness Insulation Materials Fiberglass Batt Fiberglass Blown (attic) Cellulose Blown (wall) Expanded Polystyrene (beadboard) 4. Extruded Polystyrene 5. Polyurethane (foamed-in-place) 6. Polyisocyanurate (foil-faced) 7. Construction Materials Concrete Block 8" 1.11 Brick 4" common. Poured Concrete.8 Soft Wood Lumber 1. 2" nominal (1 1/2") x4 (3 1/2") x6 (5 1/2") ColoradoENERGY.org 3

4 2//11 ORNL Online Simple Whole Wall R-value Calculator ( Component R-Value Studs R-Value Cavity Wall - Outside Air Film Siding - Wood Bevel.. Plywood Sheathing - 1/2" /2" Fiberglass Batt 1 31/2" Stud /2" Drywall.. Inside Air Film Percent for 16" o.c. + Additional studs % % Assembly R-Value Total Wall Component R-Values Wall Component U-Values Total Wall Assembly R-Value ColoradoENERGY.org ORNL Online Simple Whole Wall R-value Calculator ( Basic Equation: t surf = t in in R film /R total total x (t in in t out ) t surf Temperature of material surface R Thermal Resistance t in & t out Interior and exterior air temp Cavity Wall: t surf =.68/13.73 x ( ) t surf = 67, RH = 37.8 Stud Wall: t surf =.68/7.12 x ( ) t surf = 64.3, RH =

5 2//11 Rim Joist: t surf =.68/4.17 x ( ) t surf =.2, RH = 47.9 If interior RH rises to % dewpoint will be reached on the surface. Rim joists exposed to moist basements are most susceptible. Material Thermal Resistance Thermal Bridging Micro Environments Interstitial spaces Stack effect Negative pressure Positive pressure Wind Stack effect Looseness of air barrier Temperature Difference Pipe chases, elevator shafts, atriums Negative pressure Induced by mechanical system air balance (by design, installation, or malfunction) Attic exhaust ventilation fans Stack effect on lower floors Numerous, continuous, unfiltered, unconditioned air streams which bypass thermal and vapor barriers. 5

6 2//11 Inside Air/Moisture Path Rough opening membrane Upper Sill Blocking Lower Sill Blocking Metal Stud Window Frame Window membrane Pre-Cast Sill Outside Positive pressure Forces warm moist air out into the building envelope Ideally neutral to slight positive pressure (+.3 wg) Brick Cavity Sketch #1 Thermal Bridging Thermally conductive building elements which pass through the building thermal plane. Metal and wood studs, headers, wall plates, rim joists, and trusses. Pipes, ducts, conduit, and structural steel. Floor slabs, pre-cast architectural elements, foundations. 6

7 2//11 Inside Outside Air Leakage Condensation Wind Can develop significant temporary pressure fluctuations and override building systems. This is a temporary situation not the norm, unless the prevailing winds are steady. Effect can be dampened by a good air barrier system and building pressurization. Mirco Environmnet Condensation Micro Environments Areas unintentionally created which reduce interior surface temperatures of exterior walls which increases humidity levels. Wall hangings, curtains, furniture, closets, storage spaces, corners of rooms anywhere air space next to the exterior wall is not ventilated. Interstitial Condensation Inside the wall cavities, chases, roof assemblies, etc. Involves vapor and air barrier location, R-values of components, and permeability of components. Requires a vapor pressure analysis. Exaserbated by negative pressure and wind. 7

8 2//11 Interstitial Condensation Computer modeling exists such as MOIST, Moisture Expert, etc. Analysis is complex since moisture exists in various forms, is driven by various forces, and behaves in various ways in different material. Vapor Analysis Moisture moves from high vapor pressure to low vapor pressure as it seeks to equalize. In winter months vapor moves from inside to outside until it hits a surface below its dewpoint where it condenses. In summer months vapor moves from outside to inside until it hits a surface below its dewpoint where it condenses. Vapor can also move opposite to airflow in low flow conditions. Warm Weather Condensation Moisture is on the outside condensing on cold surfaces inside. Thermal Bridging Material Thermal Resistance Vapor barrier and retarders 8

9 2//11 Control interior moisture Eliminate wet basements Exhaust interior moisture sources to the outside, or dehumidify. Pressurize the building evenly. Size HVAC cooling equipment correctly Control max humidity to % in the winter, % in the summer. Control Air Barrier Reduce stack effect with good air barrier Air barrier should be designed continuous through walls and ceilings Install a continuous thermal plane Continuity through various architectural elements and transitions is critical. New design methods are going toward external foam board insulation and membrane, which act as thermal, air and vapor barriers, and as the water plane. Building frame is inside the thermal plane. Eliminate or reduce thermal bridging Use spacers in structural members to reduce conduction area. Seal wall cavities and air bypass particularly at door and window jambs, sills, and headers. Vapor barrier and retarders Do not design a wall with two vapor barrier layers. (vinyl wallpaper, foam board insulation are vapor barriers) Design one vapor retarder/barrier layer placed to reduce vapor condensation on the inner drywall layer Design a tight air barrier and ensure that it gets built that way. 9

10 2//11 Eliminate micro environments Leave space between the exterior wall and furniture to allow air movement. Ventilate closets on outside walls. Generally allow space for the exterior walls to establish a minimum surface film. Add supplemental heating to areas prone to cold micro environments (e.g. windows). Eliminate micro environments Energy code compliance is minimum. ASHRAE has maintained R-38 for commercial attic insulation levels since at least IECC went from using ASHRAE s R-38 in 3, to R- in 6, and back to R-38 in 9. Be sure insulation on cold surfaces is continuous through structures. Insulate and vapor seal all cold water and chilled water tanks and pipes. Be sure the wall systems can dry well The complexity of wall systems can lead to their failure to be built correctly. Use materials that can breath well in both directions from the vapor barrier/retarder. When it does condense at least it can dry quickly and not cause a problem. Be sure the wall systems can dry well Use materials that can be wetted occasionally without damage. Pressed board window sills cannot handle condensation. QUESTIONS?