Using the Thermo lignum Using the Thermo lignum heat process for treatment heat process for treatment
of natural history specimensof natural history specimens--
Research and practical Research and practical experienceexperience
David PinnigerDavid Pinniger
Integrated pest management is Integrated pest management is essential to prevent insect damage essential to prevent insect damage
to collectionsto collections
Main components of IPMMain components of IPM
Checking for pestsChecking for pests
Good housekepingGood housekeping
Good environment without extremes Good environment without extremes of temperature or humidityof temperature or humidity
Quarantine procedures to prevent Quarantine procedures to prevent introduction of live pestsintroduction of live pests
Safe and effective control treatments Safe and effective control treatments for objectsfor objects
Options for control treatmentsOptions for control treatments
Low temperatureLow temperature
AnoxiaAnoxia
Carbon dioxideCarbon dioxide
High temperatureHigh temperature
Low temperatureLow temperature
-20°C for 2 -20°C for 2 weeksweeks
-3o°C for 3-5 -3o°C for 3-5 daysdays
Effective but Effective but objects MUST objects MUST be bagged to be bagged to prevent prevent moisture moisture changeschanges
Carbon dioxideCarbon dioxide
Effective, but Effective, but exposure can exposure can take 3 weeks take 3 weeks or moreor more
Issues with Issues with registration in registration in some some countriescountries
AnoxiaAnoxia Can be effective, Can be effective,
but exposure but exposure can take 3 – 5 can take 3 – 5 weeks weeks
Difficult to Difficult to maintain 0.3% maintain 0.3% oxygen for a oxygen for a long periodlong period
Not effective for Not effective for some wood some wood borersborers
Heat treatmentHeat treatment
Historical use of heat to kill Historical use of heat to kill insectsinsects
Heating food on sheets in Heating food on sheets in tropics tropics
Heating buildings to kill food Heating buildings to kill food pestspests
Heating insect drawers to kill Heating insect drawers to kill carpet beetlescarpet beetles
How high a temperature do you How high a temperature do you need to kill insects?need to kill insects?
5252°°C for most museum pestsC for most museum pests
5555°° C g for some woodborers C g for some woodborers such as such as HylotrupesHylotrupes
1 to 2 hours exposure will kill 1 to 2 hours exposure will kill
insect eggs, larvae, pupae and insect eggs, larvae, pupae and adultsadults
The main issues using heat with The main issues using heat with uncontrolled humidityuncontrolled humidity
Drying out of objectsDrying out of objects Splitting, shrinkage and crackingSplitting, shrinkage and cracking
What happens if you control the What happens if you control the humidity to a set level?humidity to a set level?
There is no There is no transfer of transfer of moisture from moisture from the object to the the object to the environmentenvironment
No shrinkage, No shrinkage, cracking or cracking or distortiondistortion
Development of the Development of the ThermoLignum ChamberThermoLignum Chamber
Computer controlled heat/ Computer controlled heat/ chamber with RH control chamber with RH control developed in Germanydeveloped in Germany
UK chamber in operation since UK chamber in operation since 19941994
Chambers also in Austria, Norway Chambers also in Austria, Norway Switzerland and BelgiumSwitzerland and Belgium
Operating systemOperating system
The key is to introduce moisture in the The key is to introduce moisture in the heating cycleheating cycle
Remove moisture in the cooling cycleRemove moisture in the cooling cycle
Practical treatmentsPractical treatmentsObjects treated for major UK museums Objects treated for major UK museums
include:-include:-
BooksBooks ArchivesArchives TextilesTextiles LeatherLeather UpholsteryUpholstery Wooden objectsWooden objects Contemporary ArtContemporary Art
Trials at the Natural History Trials at the Natural History Museum LondonMuseum London
MammalsMammals BirdsBirds CrustaceaCrustacea InsectsInsects Vascular plantsVascular plants BryophytesBryophytes LichensLichens FishFish
Further trials to measure relative Further trials to measure relative humidity inside insect drawershumidity inside insect drawers
Generally very stable and consistent Generally very stable and consistent conditions in closed insect drawersconditions in closed insect drawers
Key issuesKey issues
Spacing of drawers Spacing of drawers to ensure sufficient to ensure sufficient air circulation spaceair circulation space
[See Ackery [See Ackery et alet al 2005 for details] 2005 for details]
What is the effect of heat What is the effect of heat treatment on DNA?treatment on DNA?
Some concerns that 52Some concerns that 52°C°C may affect may affect subsequent DNA extraction from subsequent DNA extraction from specimensspecimens
Trials of fresh and aged insect Trials of fresh and aged insect material at the NHM London showed material at the NHM London showed no effect on DNA extractionno effect on DNA extraction
[See Ackery [See Ackery et alet al 2004 for details] 2004 for details]
Other researchOther research
Kigawa et alKigawa et al 20032003
Tested the effects of a range of Tested the effects of a range of treatments on DNA of fungi and treatments on DNA of fungi and chicken meatchicken meat
Heat, freezing and anoxic treatments Heat, freezing and anoxic treatments had no measurable effects on DNAhad no measurable effects on DNA
Practical treatments of natural Practical treatments of natural history collections in the UKhistory collections in the UK
Scarborough, EnglandScarborough, England
Practical treatments of natural Practical treatments of natural history collections in the UKhistory collections in the UK
Kew HerbariumKew Herbarium
Key benefits in practiceKey benefits in practice
Speed of treatment - 24 hour cycleSpeed of treatment - 24 hour cycle
No need to bag objects – particularly No need to bag objects – particularly costly with large scale freezing costly with large scale freezing programmesprogrammes
Energy consumption - Need for Energy consumption - Need for detailed cost breakdown of -30C for 3-4 detailed cost breakdown of -30C for 3-4 days and +52C for a few hoursdays and +52C for a few hours
Heat treatments in the future?Heat treatments in the future?
Ensure that there is clear understanding of Ensure that there is clear understanding of
the difference between heat treatments with the difference between heat treatments with and without controlled humidity and without controlled humidity
Demonstrate the low risks to collections Demonstrate the low risks to collections from controlled humidity heat treatmentsfrom controlled humidity heat treatments
Wider acceptance in the light of advantages Wider acceptance in the light of advantages of labour input and energy budgetof labour input and energy budget