Can ThermaPure’s Heat Levels Damage Drywall/Gypsum?



Many clients and members of the industry have expressed concern about heating gypsum board, also called the plaster of Paris, a common building material.

What many people don’t realize is that these building materials are exposed to temperatures similar to a ThermaPureHeat treatment before they are used in construction. Often, materials are shipped through the deserts of Arizona and California, packed in trucks that are not temperature controlled. These temperatures may even exceed ThermaPure’s temperatures. Additionally, these temperatures are not monitored or distributed with the same expert care that ThermaPure technicians use.

Scientifically, gypsum board is used in buildings because of its unique and resilient properties. Gypsum board, like any other porous building material, will lose moisture through evaporation as the material is heated.  Heating to 100°C (212°F) will increase conductivity of the material, increase thermal expansion of the material, but the mass loss of the material is virtually unchanged.  As the gypsum board heats the energy is used in the gypsum to begin dehydration.  All of these minor physical events occur as the material begins to dehydrate.  This takes place up to the beginning of calcination at 100°C.  It does not appear that any damage is done when this activity takes place over a fairly rapid period of time, as is done in a ThermaPure process.  The significant changes to the material occur after calcination begins and most occur between 100°C and 200°C.

There are few studies that show what happens to a gypsum material that is heated up to 100°C (212°F) and then returned to ambient temps.  The sense is that the restoration to ambient temperatures will return the material to a normal state because no chemical change has taken place. Calcination is a process that occurs in gypsum board in which the level of both liquid and vapor moisture are dehydrated.  It appears this process begins at 80°C (176°F).  There are several citations in which the researchers talk about temperatures of 100°C (212°F) as the approximate temp that calcination begins.  Either of these temperatures are typically in excess of a ThermaPure process.  One of the research papers (Fuller) states that comprehensive strength of gypsum board actually increases up to 100°C.

With years of experience, and thousands of jobs completed successfully, ThermaPure is familiar with the complexity of heating structures. We have taken a simple concept, pasteurizing buildings, and applied it to modern homes and commercial buildings. Each job is analyzed individually for the best results.

Why Heat Over 105° F?

This article was originally published in the November/December issue of C&R magazine and has been reprinted with permission from the Restoration Industry Association

When you apply sauna-like temperatures to a structure and use filtration to capture contaminates before they spread, you use a method similar to the one that has been effective on food for more than a century. But only recently has the process been created to use in structures.

ThermaPureHeat uses heat on structures in a way that is similar to how Dr. Louis Pasteur used heat on food. Pasteur determined that by heating food products to a temperature of approximately 60 degrees C (140 degrees F) for several minutes, bacteria, viruses, protozoa, molds and yeasts in the food would be reduced to levels that would no longer cause the food to spoil or harm those who ate it. Pasteurization improved the shelf life of food products and, more importantly, reduced levels of contamination to allow for safe consumption without damage to the food.

Today, similar principles are used in structural pasteurization. Structural pasteurization is a process in which the temperature of a building or portion of a building is increased to a level that will reduce the targeted organ­ isms to acceptable levels while minimizing damage to the structure. This is a main component of ThermaPureHeat. Joe McLean, chief executive officer and co-founder of Alliance Environmental Group Inc., headquartered in Azusa, California, stated: “ThermaPure is a significant part of our business and provides us with a unique tool for our clients. Over the past three months, Alliance has done nearly 500 ThermaPureHeat projects. We solve many indoor problems with ThermaPure.”

During the past 10 years, ThermaPure  has acquired  the rights to insect patents;  been granted  patents for the remediation of mold, bacteria, viruses and volatile organic  com­ pounds in structures; and has eight patents that strengthen the control  of the technology for a range of indoor  air quality uses. Additionally, the intellectual property includes more than 3 5 trademarks and foreign patents. Although the company started as a technology to control insects, it has expanded the method to other uses, such as in the restoration industry. A structure damaged by water can be effectively remediated through heat. The results can be better than traditional restoration methods.

ThermaPureHeat as a Structural Drying Tool

ThermaPureHeat as a Structural Drying Tool ThermaPureHeat is a complete water loss restoration process because it combines high-temperature drying and sanitization in a single restoration process. The application of high-temperature drying has been increasing as many restoration contractors are now using it. Additionally, it is defined in the most recent version of the Institute of Inspection, Cleaning and Restoration Certification (IICRC) SSOO, Reference Guide for Professional Water Restoration. Structural pasteurization is recognized by the IICRC remediation standard, S520, as a process that can be effective in killing organisms.

According to an Xactimate/ThermaPure report, ThermaPureHeat is an effective restorative drying process for the following reasons:

  • High-temperature applications will dry most structures more quickly.
  • Applied appropriately, high-temperature drying is more thorough, reaching previously inaccessible areas such as wall cavities.
  • High-temperature drying is more effective with porous materials, resulting in fewer replacements.
  • The duration of the restoration process is faster, so loss mitigation is reduced by minimizing build back.
  • By reducing the duration of the restoration processes, Category 1 water losses are potentially resolved before they become contaminated.
  • High-temperature drying will sanitize the affected areas.
  • In a Category 2 water loss, structural pasteurization can resolve bacterial contamination concerns.
  • In a Category 3 water loss, ThermaPureHeat is effective in killing most species of bacteria, viruses, helminths and other unhealthy contaminants.
  • High-temperature drying and structural pasteurization are both processes recognized in the IICRC drying standard, SSOO, and the mold remediation standard, S520.

The Move Toward High-Temperature Drying and Structural Pasteurization

The  process of high-temperature drying and structural pasteurization  are becoming the preference  because it saves time and money, and it is effective in resolving issues before they turn into bigger problems. Specifically, ThermaPureHeat reduces drying cost (this has been demonstrated using Xactimate calculations), relocation expenses and business interruption costs, and it reduces or eliminates secondary damage (microbial contamination), demolition requirements and restoration/rebuild costs.

Recently, an independent testing facility, CodeBlue, tested “directed heat thermal energy drying against traditional drying methods.” Once the drying was complete, results were compared and it was confirmed that high-temperature drying reduces drying time.

By Larry Chase and Tim Gallagher

ThermaPure in Cleaning & Restoration Magazine

What is the advantage of using ThermaPure? A new article in C&R magazine, a publication by the Restoration Industry Association (RIA), answers this question. Check out the article, entitled “Why Heat Over 105 Degrees F” in this months issue.

C&R ThermaPure Article 1 Cover

What Temperature do You Need to Kill…

We talk a lot about how important heat is in the restoration and pest control industries. But how much heat is beneficiary? The link below cites the temperatures necessary to kill mold, bedbugs, termites, Ebola virus, salmonella, e. coli, and many more specimens.

2012’12’27_Table of TPH Targets – Thermal Death Point References



Cleaning Up After a Hurricane Disaster

We’re in hurricane season. Hurricane Gonzalo has filled headlines over the past week. But rather than focus on the destruction, at ThermaPure, we rebuild from the remnants. The path to mending from hurricane disaster begins with proper information.

The Real Damage Caused by Hurricanes

Extensive flooding has created significant environmental health concerns.  The potential contaminants in floodwaters include a variety of biological pathogens.  These pathogens present the opportunity for a number of water and excreta-related health problems and diseases.  Many of these pathogens can remain viable in a structure for up to a year.  Some can remain longer in a moist environment.  As structures dry, many can be aerosolized and move within the building.  Rodents and insects also act as vectors transporting these pathogens throughout a structure.  Disinfection of this group of pathogens in flooded structures is a complex and demanding problem.

Floodwaters present non-biological contamination problems as well.  Gasoline, pesticides and other chemicals may be carried by water into structures.  The volatile organic compounds (VOCs) associated with many of these chemicals present a potential hazard to occupants as they slowly off-gas over the next several months.

Understanding E. Coli Testing

Typical assessment of pathogens found in floodwater focuses on the measurement of Escherichia coli.  The presence of E. coli is used as a yardstick for the assumption of biological contaminants in structures impacted by floods or other sewage contaminated water.  Although this assessment is generally adequate to determine the presence of sewage related biological pathogens, it may not be adequate to determine the appropriate remedial response for the structure.  Some floodwater pathogens may be more difficult to kill or reduce to safe levels than E. coli.

One of the difficulties with using E. coli as an indicator pathogen for environmental fecal contamination is that its survival rate must be equal to or greater than other bacteria or pathogens found in contaminated environments.  Recent studies of E. coli contaminations indicate that there is a possibility of human infection up to 10 months after the original contamination.[1]  Other species are known to have even greater durability.  Salmonella, for example, has a longer life outside of the host and therefore has the potential of infecting a larger number of species, including flies, cockroaches and other vectors.  This may be true of other microbes as well.  It is important to note that floodwater contaminated structures can remain a health concern for a long period of time.  This is particularly true if the building remains moist or wet.  In fact, the conditions will worsen over time.

Other Pathogens Distributed by Hurricanes

The bulk of data used in this paper regarding pathogens in floodwater is found in studies provided to assist in the management or design of water supply and sanitation systems.[2]  Because of the size and magnitude of some of the hurricane floodplains the contaminated water and attendant pathogens are comparable to sewage contamination.  Efficacy studies regarding the thermal death rate of floodwater pathogens are derived from these sources.

Pathogens found in buildings affected by sewage-impacted floodwaters include bacteria, viruses, protozoa, and helminthes.  According to the World Health Organization (WHO) these pathogens impact human health.  Although it is not the purpose of this paper to understand specific health concerns associated with these pathogens, it is the intent to understand the resolution – structural pasteurization of floodwater contaminated buildings.  Included in these categories are a few of the assumed water and excreta-related pathogens.

  • Bacteria:
    • Escherichia coli
    • Salmonella enterica
  • Viruses
    • Rotovirus
  • Protozoa
    • Giardia lamblia
    • Entamoeba hystolitica
  • Helminths
    • Nematodes – roundworms, hookworms, Ascaris lumbricoides
    • Cestodes – tapeworms

The potential for infection of occupants in a structure comes from various vectors.  The vectors found to transport or transmit these pathogens in buildings include[3]:

  • Feco-oral
  • Water-washed
  • Water-based
  • Excreta-based insect and rodent vectors
  • Aerosol

The importance of this is to demonstrate the dynamic nature of a floodwater-contaminated building.  Occupants can be affected by a wide variety of routes and vectors making the resolution more complex.  ThermaPureHeat® is the only process that effectively treats all of the pathogens present as well as impacting the vectors and routes.

Thermal Inactivity of Specific Pathogens

Temperature is a more thorough intervention process in the inactivation of enteric pathogens.  According to the WHO, “…heating to pasteurization temperatures (generally 60C) for periods of minutes to tens of minutes will destroy most waterborne pathogens of concern” (Sobsey, 2002)[4].  This general statement may be adequate to recommend utilization of heat for the disinfection of floodwater-impacted structures.  However, for the purpose of this paper, more specific targets have been identified to further define the efficacy of the process.  The following table shows specific pathogens that can be rendered inactive by temperatures within the range of ThermaPureHeat®:


Genus, Species



Death Rate



Escherichia coli Bacteria 60C/140F 45 minutes Padhye & Doyle[5]
Salmonella Bacteria 60C/140F I hour Feachem[6]
Shigella Bacteria 55C/131F 1 hour Feachem[7]
Giardia lamblia Protozoa 60C/140F 2-3 minutes Univ of Utah[8]
Entamoeba hisolytica Protozoa 60C/140F 1 minute Feachem[9]
Rotovirus Virus 63C/145F 30 minutes G.N. Woode[10]
Poliovirus 1 Virus 60C/140F 5 minutes Wiley (1969)[11]
Enteroviruses Virus 60C/140F 2 hours Feachem[12]
Ascaris lumbricoides Helminths 55C/131F 1 hour Feachem[13]

Application of ThermaPureHeat® Technology

The efficacy of ThermaPureHeat® in its simplest form is a result of the combination of temperature and duration.  The complexity of any sanitization is achieving efficacy in all areas of the structure.  What differentiates ThermaPureHeat® is the ability to sanitize the entire structure, including inaccessible areas.  Buildings are complex and the requirement for uniform temperature throughout a structure is necessary to achieve efficacy.  Heat technicians are thoroughly trained in construction materials, thermal dynamics and the intended targets.  Buildings have materials that conduct heat, that create radiant losses, and that are heat sinks.  The heat technician must understand each of these conditions.  Temperatures are monitored real-time in difficult to heat locations.  In a wooden structure these places might be under sill plates and between header boards.  Crawlspaces and sub-areas provide additional difficulties.  All structures can be treated by ThermaPureHeat®

The process of pasteurization of a structure appears to uniformly impact these pathogens related to floodwaters.  Other methods of pasteurization are not as uniform in result.  For example, Giardia cysts are resistant to chlorination and a wide range of pH.[14]  Other methods may not be ovacidal such as in the case of helminths.  Ascaris eggs are hardier than the larvae.  Other processes are not as safe and are not as effective.  Heat, as a pasteurization, is uniform and non-discriminatory in application.  Pasteurization of a building is an effective process to reduce pathogens to safe levels.


All buildings affected by floodwaters should be sanitized.  The most thorough method of sanitizing is ThermaPureHeat®.  ThermaPure has extensive experience with hurricane and flooding disasters, such as those caused by Hurricane Katrina.

ThermaPureHeat® is a patented, non-chemical, engineered process that “pasteurizes” structures.  This process is the most effective because it is the only process that kills or inactivates the majority of pathogens present.  Additionally, it is the only treatment that inactivates these pathogens in inaccessible areas.  By more thoroughly drying the structure it prevents these pathogens from vectoring from other sources and becoming viable.  Vector sources include rodents, cockroaches, and other insects.  Added value for the process is the reduction of VOCs that may have resulted from chemical contamination associated with the floodwaters.  Much like the pasteurization of food products, ThermaPureHeat® reduces the biological contaminants in a structure to levels safe for occupants.

1 Varma, J.K., et al, (2003). “An outbreak of Escherichia coli infection following exposure to a contaminated building”. Journal of American Medical Association, 290(20), 2709-2712.

2 Feachem, R. et al,(1983). Sanitation and Disease Health Aspects of Excreta and Wastewater Management. Wiley, Dorchester, England.

3 Mara, D.D., Feachem, R.G.A., (1999) “Waterborne and Excreta-Related Disease: Unitary Environmental Classification”, Journal of Environmental Engineering-ASCE, 125 (4), 334-339.

4 Sobsey, M., (2002) “Managing water in the home, accelerated health basis of improved water supply”, World Health Organization.

5 Padhye, N.V. and doyle, M.P. 1992. “Escherichia Coli 0157:H7: Epidemiology, pathogenesis, and methods for detection in foods”. J. Food Protect. 55(7):555-565.

6 Feachem, R. et al,(1983) Sanitation and Disease Health Aspects of Excreta and Wastewater Management, Wiley, Dorchester, England, p278.

7 Feachem, R. et al,(1983) Sanitation and Disease Health Aspects of Excreta and Wastewater Management, Wiley, Dorchester, England, p294.

8 Wilderness Medicine, (2005) University of Utah, School of Medicine.

9 Feachem, R. et al,(1983) Sanitation and Disease Health Aspects of Excreta and Wastewater Management, Wiley, Dorchester, England, p342.

10 Feachem, R. et al,(1983) Sanitation and Disease Health Aspects of Excreta and Wastewater Management, Wiley, Dorchester, England, p188.

11 Feachem, et al, (1983).

12 Feachem, et al, (1983)

13 Feachem, et al, (1983).

14 Feachem, et al, (1982) p354.

Mold Remediation Check List

Here is a great check list for mold removal. The list came from a ThermaPure member, Precision Environmental. Take a look. Checklist for Mold Removal


Checklist for Mold Removal

ThermaPure on Ebola

Can Heat Sanitize the Ebola Virus?

The diagnosis of Thomas Eric Duncan, as Texas resident, with the ebola virus, has dominated US headlines for the past week. Here at ThermaPure, we would like to offer our dearest sympathies to his family and friends regarding his passing, and acknowledge the difficulty of facing this virus. ThermaPure has a lot of experience in containing and sanitizing contagions. Although we hope ebolavirus doesn’t continue to spread, we have done some precautionary research.

According the CDC’s website, the ebola virus can stay active on indoor surfaces for up to six days. This is unfortunate news.  Common colds typically remain infections on surfaces for less than a day. However, ebola was found, “Relative to other enveloped viruses, to be quite sensitive to inactivation by ultraviolet light and drying.” The Public Health Agency of Canada states that ebola can be inactivated by heating it to 60 degrees Celsius, 140 degrees Fahrenheit, for thirty to sixty minutes.

ThermaPureHeat equipment can reach 212°F and remain there for hours in a properly prepared structure. In the past, the ThermaPure technology has been deployed for treating dangerous pathogens such as anthrax and MRSA. This powerful technology should only be used to treat dangerous pathogens under the direction of a qualified Environmental Engineering Professional. The CDC and Public Health Agency of Canada should consider the use of structural pasteurization prior to remediation efforts. This may result in the protection of remediation technicians and waist handlers.

Will Ebola Virus Grow with Flu Season?

Ebola has been found to remain active longer at lower temperatures. These findings are based on lab experiments and not tests conducted in a more natural environment. As we approach colder months, only time will tell with certainty how the ebola virus will react.

Dave Hedman’s Top 5 Expert Tips for Hotel Stay

Scour the internet and you will find thousands of travel tips to avoid indoor toxins and nasty creatures in hotels, from “magic” sprays to portable cocoons for sleeping in. The truth is, as much as we would like the assurance of a perfectly clean environment when we are traveling, we are busy.

As an indoor environmental expert, Dave Hedman, CEO of ThermaPure, has overseen thousands of projects ranging from anthrax, to mold, to bed bugs. He knows what can be hiding behind those perfectly plastered walls and in those stylish duvet covers. So, what does he do when he travels?

Pick a Clean and Chemicaly Safe Hotel Room

  1. Request a room with windows that open. Nothing can substitute for fresh air when it comes to limiting your exposure to indoor pollutants. When you are making your reservation, be sure to ask if the rooms have windows that open.
  2. Ask if the hotel has rooms for the chemically sensitive. More and more hotels are becoming chemically conscious, and are setting aside rooms that only use green cleaning products, etc.
  3. Trust your nose. Your sense of smell is free, portable, and the most reliable tool you have. Sniff for musty, sweet, or chemical smells. The musty and sweet smells could be indicators of mold. Chemical smells can be an indication that the hotel is trying to mask the smell of mold, or that the room has recently been sprayed with chemicals to treat a pest, such as bed bugs.
  4. Ask to look at multiple rooms. You may not want to be a pain, but remember; only you have your best interests in mind when it comes to limiting pollutants. On a trip last month, Dave asked to look at three different rooms before he picked one. He was glad he did, because each room had a distinctly different odor, even though they looked very similar.
  5. Take bed bug precautions. Place your suitcase on the folding stand as soon as you get into the room. Bed bugs have a difficult time climbing metal surfaces. Then inspect the mattress for bed bugs, and the dark marks they leave, that look a lot like pen scratches.

Bedbug Holiday Travel Tips

With the holidays coming up, here is some good information on how to avoid bed bugs:  Bed bug tips for the holidays

The Botany of Desire

Here at ThermaPure, we enthusiastically support authors who explore the wonders of nature. Michael Pollan’s The Botany of Desire: A Plant’s-Eye View of the World is one of those authors. One of the most memorable quotes from Pollan’s book is “For great many species today, ‘fitness’ means the ability to get along in a world in which humankind has become the most powerful evolutionary force.”

“For great many species today, ‘fitness’

We spend a lot of time thinking about being fit ourselves (or lack thereof), but do we spend that much time considering the wellbeing of other species? Pollan reminds us of the potential we have to influence the environment around us.

ThermaPure is a powerful Integrated Pest Management (IPM) tool and has replaced thousands of pounds of toxic chemicals through the use of a green technology, limiting the exposure of chemicals to both humans and the environments in which they live.