Ecological, Non-Toxic, Sensitive, 100% Effective and Entirely Safe

Thermo Lignum® WARMAIR against Woodworm, Moths and Carpet Beetles

Thermo Lignum WARMAIR as an integral part of Conservation and Restoration
We at Thermo Lignum® are no Conventional Pest Controllers.

From the very beginnings we have specialized in eradicating insect pests in Museum, Art Gallery and Historic House collections made from organic materials and consider the Thermo Lignum® service as an integral part of modern day conservation, restoration and insect pest management. Our technology has been continuously developed and refined over a period of more than twenty years.

For all things organic there is an insect which has evolved to regard it as food

That was the challenge behind the development of the Thermo Lignum® WARMAIR process.

Using only naturally occurring elements, air and water, sound biological principles and established laws of physics, all insects inhabiting organic materials will die at any life-cycle stage when exposed to our heat treatment regime. The absence of any chemicals or noxious gases during the process allows immediate reuse of the items upon completion of the treatment, without risk of harm to your health, the object, or the environment.

The species we most often encounter are:
those that eat timber

  • Common furniture beetle or woodworm (Anobium punctatum)
  • Death watch beetle (Xestobium rufovillosum)
  • Powder post beetle (Lyctus brunneus)
  • Longhorn beetle (Hylotrupes bajulus)

those that eat wool, fur, feathers, silk, and skins

  • Varied carpet beetle (Anthrenus verbasci)
  • Brown carpet beetle or Vodka beetle (Attagenus smirnovi)
  • Two-spot carpet beetle (Attagenus pellio)
  • Case-bearing clothes moth (Tinea pellionella)
  • Common or webbing clothes moth (Tineola bissseliella) 

and those that eat plant material, freeze-dried animals and entomological collections

  • Biscuit beetle or drug store beetle (Stegobium paniceum)
  • Cigarette beetle (Lasioderma serricorne)

Principles of WARMAIR Treatment

The Thermo Lignum process essentially targets the susceptibility of insects to elevated temperatures (50-55°C dependent on species) based upon incontrovertible biological evidence together with the research and findings of distinguished entomologists.

The key to using heat to kill insects in organic materials is to maintain the moisture content of the material at a constant level during the heating, holding and cooling cycle. This is achieved by controlling, through sophisticated software, the relative humidity (RH) and temperature of the atmosphere within the treatment chamber, thereby preventing any physical or structural change in the object due to evaporation or absorption of water.

Whilst the Thermo Lignum® WARMAIR process may appear fundamental, it has taken many years of comprehensive trials to make it appropriate for the treatment of very complex and valuable objects. In addition to extensive trials on a wide range of timbers, the method has been tested successfully on animal and synthetic adhesives, veneers, marquetry, metallic inlays, traditional and modern paints, gilt and polished furniture, lacquer and Japanwork, fur, feathers, leather and skins, ethnographic and natural history specimens, taxidermy, herbaria, paper and a wide spectrum of textiles.

Scematic Process Thermo Lignum Treatment
Schematic Process of a Thermo Lignum® WARMAIR treatment with controlled Relative Humidity in a sealed system (chamber or temporary housing of object)
Keylwerth'sches Diagramm Thermo Lignum
Keylwerth Diagram

Controlling relative humidity (RH): Keylwerth Diagram

All organic materials are hygroscopic (i.e. can absorb moisture). The amount of moisture they contain at any given time will vary according to the prevailing conditions of temperature and relative humidity (RH) in the atmosphere in which they exist.

The relationship between the relative humidity and temperature of the atmosphere on the one hand, and the moisture content of wood on the other, is not linear. The actual inter-relationship is indicated on the Keylwerth diagram. In order to keep the moisture content of wood constant whilst increasing the temperature surrounding it, the isotherm must be followed closely. The Thermo-Lignum® process does this by constantly monitoring both the RH and temperature of the atmosphere within the treatment chamber and the core temperature of the object being treated. The data obtained is fed into a computer-controlled system, which continuously modifies the conditions in the chamber as required.

our green believers

Our prestigious list of clients includes the Victoria & Albert Museum, the National Gallery, the Natural History Museum, Tate Britain, Tate Modern to mention only a few located in the UK. 

In Germany we have worked for the Reiss-Engelhorn Museum in Mannheim, the Bavarian Palace Department and the avant-garde Documenta in the city of Kassel.

Austrian clients, among many others, include the Salzburgmuseum, the Universalmuseum Joanneum Trautenfels, the Bundesmobiliendepot in Vienna and the Basilica Maria Taferl. 

Our clients’ confidence in the Thermo Lignum® technology is both reflected and confirmed in numerous scientific publications and studies, some of which have been undertaken by internationally eminent authorities in the field of museum entomology and Integrated Pest Management (IPM): 

First and foremost, David Pinninger MBE who has been both shadowing and validating the Thermo Lignum® treatment, as well as 

Robert E. Child BSc, recently retired as head of Conservation, National Museums and Galleries of Wales.

The leading German specialist on wood-boring insects, Dr.rer.nat. Uwe Noldt of the Johann Heinrich von Thünen Institut in Braunschweig, has been following Thermo Lignum® closely and has published a number of papers on our technique. 

A credible Concept from a Conservation Viewpoint

So sensitive is the process, that it is especially advantageous in the treatment of wood, whether plain, veneered or decorated with marquetry or Boulle, lacquer or Japanwork. 

Today we are able to use our sympathetic techniques in a wide range of applications since the problem affects more than just antiques and works of art.

Basically there are four different Applications of the Thermo Lignum Treatment

Treatment in our static Chambers
Treatment in our mobile Chambers
In-Situ Treatment
Treatment of Buildings