Wood preservation
Wood Pest Control for construction and wood work is compared to preventive wood protection combating active wood -acting animal and fungal wood pests. The timber pest in the forestry sector is a custom theme.
- 5.1 General
- 5.2 combating
Legal / Normative regulations
The fight against fungal and animal wood pests in Germany is governed mainly in DIN 68800-4. In contrast to parts 2 and 3 of the standard that have preventive wood protection measures for the content, part 4 is not introduced by the building and thus has no force of law. The recommendations of this standard part are considered as accepted technical rules and insofar are generally a requirement for proper control measure. In justified individual cases (for example in the range of listed buildings ) but it may be useful to apply a different standard from the special procedures.
For certain pest species, especially for dry rot, the house longhorn beetles or termites in some states is considered one anchored in the local building code mandatory reporting.
In connection with wood pest control measures are often more legislation touches, such as the Chemicals Act and the Hazardous Substances Regulation.
Process technologies
The currently approved in Germany wood pest control methods can be divided into the following categories:
Chemical wood pest
Here fungal and animal wood pests are controlled using approved by wood preservatives inventory of chemical wood preservatives. Chemical control of wood-destroying insects can be roughly divided into two areas.
- Chemical control by treating the wood surface
- Chemical control by borehole injections
A standardized combat fungal pests in wood is generally not possible with chemical agents. Wood preservatives against fungi are only used preventively in the wood. The only standardized measure for combating fungi in the wood is currently in the dismantling or the pruning of infested wood parts. ( Exceptions are possible in monument preservation valuable components. ) When infestation by wood-destroying fungi in the masonry (especially by dry rot ) Chemicals (so-called " sponge blocking agent" ), however, are used to isolate the infestation.
Hot air process
By heating of infested wood components wood animal pests are killed. The fight in hot air process takes place essentially in two application techniques:
- To the wooden parts or the whole construction of a wooden building with mobile equipment.
- In mostly stationary humidity controlled environmental chambers with closed air cycles. The application is aimed at portable timber structures. By accurately controlling the temperature and humidity also very sensitive parts can be treated in this technique.
- Small items such as watch cases can be sufficiently heated in a sauna. Metal parts should be removed prior to shipping.
Mobile fight on buildings
Broad Process Engineering: With Hochleistungslufterhitzern large amounts of hot air are blown into the roof truss ( 12,000 m³ / h at 120 ° C ~ ). Through continuous flow around all exposed wood construction with hot air they are slowly heated.
At a temperature from 55 ° C in the wood inside, destruction of the larvae and eggs in it begins. After 60 minutes, is done in each case by the high tolerance time, the kill. The operation of the thermal process is that the contained insects are killed by protein coagulation in all stages (eggs, larvae, pupae, beetles) by sufficiently high temperatures throughout the wood cross section. Through regular monitoring of air and wood core temperature by sensing the kill is controlled. The heating can be with appropriate planning and special technique in difficult to access or use shielded areas (for example, developed a pitched roof, turnarounds, ceiling voids or similar). From experience, the heating time for an average roof approximately 6 to 14 hours is necessary.
By this method, can be heated by the wood without introducing chemical agents a 100 percent immediate destruction of all wood pests reach. The success of the operation depends upon a conscientious planning, a professional workmanship and the associated quality assurance measures. With the control measures only Companies with appropriate expertise are to entrust (for example, proof of expertise for wood protection in construction ) that have expertise, proven experience and the necessary equipment (see respective state building regulations, DIN 68800-4 and VOB).
The thermal processes do not provide proactive protection against new infestations of wood-destroying insects.
Resistance: The area to be treated themselves need not have complete tightness, as constantly hot air is supplied, which then has to make the inflowing hot air space. However, an uncontrolled escape of the hot air supplied through larger openings such as windows, doorways, etc., is not useful. Rather, the targeted air escape at the lowest points of the space (eg eaves of the roof ) should
Temperatures: The property is subject to special review in heat tolerance. The air temperature should not exceed 120 ° C in the long term in the space to be treated. The outlet of the feed pipe is at least one meter away from highly flammable (building material class B3 according to DIN 4102-1, paper, cardboard, etc.) to keep. In the presence of heat-sensitive components (plastics, electronic components, etc. ) within the rooms to be heated are to take appropriate action.
Stationary Equipment
The stationary systems use the same principle of use. To treat appropriately designed chambers are used where mainly be treated transportable parts. In a closed circuit is electronically controlled according to the air temperature and moistened.
Overheating by microwave
A magnetron with attached horn penetrates the wood and it overheated within about three minutes all ( hydrous ) creatures. This requires a sufficiently strong magnetic field, which is why the irradiated volume in a 500 W magnetron should not exceed 10 dm ³. By packaging the target volume with a metal foil, the field strength can be increased, reducing the amount of time. The procedure has proven especially in the rafters, but it does not provide preventive protection against re-infestation by wood-destroying insects.
Fumigation
There are two groups of gases which are applied:
- Gases, they are used because of their high toxicity requires proof of a special skill of the user.
- Gases that act predominantly suffocating and are not subject to limitation of use.
Through fumigation of infested timbers are in buildings or in chambers (for example, container fumigation ) killed animal wood pests.