The effect of moisture on the heat transfer performance of insulated flat-roof constructions

Powell, Frank J; Robinson, Henry E

doi:10.6028/nbs.bss.37

Cited by 13 publications

(10 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Research conducted at the National Institute of Standards and Technology in the 1960s found that roof systems with concrete decks whose interior surfaces were moderately vapor-permeable tended to dry out during a simulated summer exposure [2]. More recently, Sheahan has proposed a technique for determining the time required to dry a roof system [3]; the Single Ply Roofing Institute's (SPRI) Recover Subcommittee has refined this methodology, and is now in the process of generating a database to validate the calculation procedure [4].…”

Section: Introduction T I--ie 1991 National Roofing Contractors Assocmentioning

confidence: 99%

The Simulated Impact of Climate on the Drying Times of a Wetted Low-Slope Roof System

Desjarlais

Kyle

Christian

1993

Journal of Thermal Insulation and Building Envelopes

View full text Add to dashboard Cite

The 1991 National Roofing Contractors Association Annual Roofing Survey predicts increases in recover, the reroofing practice of installing a new roof over an existing failed roof. For 1992, the survey estimates that $5¼ billion will be spent on recover. Market trends suggest that recover will become an increasingly more popular option in reroofing. The most controversial aspect of recover pertains to the presence of water in the failed roof. For recover to be a viable reroofing option, this water must have a means of escaping the roof system; entrapped water in the roof would lead to the eventual mechanical failure of the deck and fasteners The rate that water can be driven from a roof system will dictate whether recover can be considered as a reroofing option for that system A combined heat and mass transfer mathematical model has been used to simulate the sensitivity of climate on drying times of a simple roof system. The results are compared to a baseline case where the roof system is held at isothermal conditions. Significant differences in drying times were computed, ranging from 300 days for Miami, FL to 930 days for Bismarck, ND. Three of the four climates that were modeled required drying times in excess of the isothermal case; the U.S climate tends to extend the required drying times for a large portion of the country.

show abstract

Section: Introduction T I--ie 1991 National Roofing Contractors Assocmentioning

confidence: 99%

The Simulated Impact of Climate on the Drying Times of a Wetted Low-Slope Roof System

Desjarlais

Kyle

Christian

1993

Journal of Thermal Insulation and Building Envelopes

View full text Add to dashboard Cite

show abstract

“…Starting with fiberboard uniformly wetted to about 1096 by volume, their results showed a rapid increase in conductivity as moisture redistributed toward the cold side, followed by a gradual decrease in conductivity over a 200-hour test period. Powell and Robinson (1971) [5] studied the effect on heat transfer under dynamic boundary conditions. They placed insulation samples in a test chamber where one surface was exposed to normal indoor conditions and the other to simulated diurnal cycles for both winter and summer.…”

Section: Introduction Nlike a Built-up Roof In Which The Insulation mentioning

confidence: 99%

Moisture Gain of Spray-Applied Insulations and Its Effect on Effective Thermal Conductivity-Part I

Modi

Benner

1985

Journal of Thermal Insulation

View full text Add to dashboard Cite

The presence of free water in fibrous insulating materials can have a very detrimental effect on their thermal and physical properties. Fiberglass and cellulose insulations were spray-applied to horizontal aluminum plates and exposed to air at relative humidities of 30, 50, and 70% and temperature differences of 20 and 27 C°. The moisture gain was determined by periodically weighing the samples, and the effect of the moisture on the heat flow and temperature distribution was measured by heat flow sensors and thermocouples. Drying was also investigated by reducing the relative humidity to 10% once steady state had been reached. The rate of moisture gain and the total moisture gain increased with increasing relative humidity and temperature difference, and, after an initial increase, the apparent thermal conductivity would attain a quasi-steady state value that was directly proportional to the moisture gain.

show abstract

“…Powell and Robinson [10] investigated the effect of moisture on heat transfer through insulated concrete deck roof constructions with attached built-up bituminous membranes. No other studies to date, however, were available in the open literature on roofing systems containing insulation with a built-up roofing (BUR) membrane.…”

Section: Introductionmentioning

confidence: 99%

The Effect of moisture on the thermal conductance of roofing systems

Knab¹,

Jenkins²,

Mathey³

1980

View full text Add to dashboard Cite

The effect of moisture on the heat transfer performance of insulated flat-roof constructions

Cited by 13 publications

References 2 publications

The Simulated Impact of Climate on the Drying Times of a Wetted Low-Slope Roof System

The Simulated Impact of Climate on the Drying Times of a Wetted Low-Slope Roof System

Moisture Gain of Spray-Applied Insulations and Its Effect on Effective Thermal Conductivity-Part I

The Effect of moisture on the thermal conductance of roofing systems

Contact Info

Product

Resources

About