Miljøprojekt, 1154 – Måling af asbestforurening i forbindelse med tagrenovering

Måling af asbestforurening i forbindelse med tagrenovering

Summary and conclusions

Background and objective

The Danish Technological Institute has on behalf of the Ministry of Environment carried out a project with the title: “Measurement of asbestos contamination in relation to renovation of roofs”.

The project is initiated due to a frequently common situation where the Ministry of Environment is contacted by local communities and citizens about possible asbestos contamination of soil. The Ministry lacks guidelines for handling such calls.

The objective of the project is to gain more knowledge about the level of asbestos fibres released from eternit roofs during renovation and fire. This is to be compared with the normal release due the daily erosion of the roof surface. Furthermore, the project should give insight into the possible health risks caused by the asbestos content in soil.

The problem is associated with two facts:

there is no threshold limits for the content of asbestos in soil
there is no a priori information about the level of release of asbestos to the soil in relation to renovation of an asbestos containing roof.

The investigation

The Danish Technological Institute has collected moss and soil samples shortly after the cleaning of a roof and again after the cleaning of the ground. Furthermore, samples have been collected around a house where no roof renovation has taken place. These samples serve as reference samples. All samples have been analysed for content of asbestos.

Within the time frame of the project it has not been possible to get an agreement with a renovation company carrying out a full exchange of roof tiles. Furthermore, it has not been possible to find a case related to a fire scenario. Thus, we have decided to focus on roof cleaning cases only.

In order to collect the practical experience from the local communities a questionnaire has been forwarded to all the communities in Denmark.

A search on the internet has been carried out in order quantify the number of companies offering a roof renovation service. Afterwards contact to two trade associations has been taken, i.e., Dansk Byggeri Tagmalerforening and Dansk Asbestforening. The investigation programme has been carried out in collaboration with the Dansk Byggeri Tagmalerforening.

A limited literature search has been undertaken with the purpose of revealing any facts about health risks of asbestos fibres in and on soil.

Main conclusion

Based on the results of the project the level of asbestos is not above the background level when the roof cleaning is carried out according to the written procedure.

We could suggest an impartial random check of the renovation work. Furthermore, a possible continuation of the project should include more scenarios, e.g., house fire, total renewal of a roof, and internal building renovation. In order to reach a better statistical validity of the results more cases should be included. Furthermore, a better assessment of the background level of asbestos fibres should be carried out.

The limited literature search did not reveal any papers specifically related to the health risks associated with roof renovation and possible personnel exposure from asbestos in soil.

Results

In order to compare the results from one case to another a 4-level classification system has been introduced. Class 0 covers the case where no asbestos fibres have been identified in a moss or a soil sample. Class 3 covers the case where a lot of fibres have been identified.

Some of the moss samples taken from the roof contain many fibres (Class 3). Soil, moss, and sludge samples taken from a none-renovated roof (reference) in general contain few fibres (Class 1). However, some moss samples contain many fibres (Class 3).

Soil samples taken shortly after a roof cleaning contain many asbestos fibres (Class 3). After the routine cleaning of the ground soil samples only contain a few fibres (Class 1).

72 communities responded to the questionnaire. The overall feed back is that the general information level is to low implying a non-optimal consultancy from the office to the citizens and companies facing an asbestos problem. Some communities provide a home page with relevant information. For most communities the number of contacts on asbestos matter is constant and low over the period 2004 to 2006. Only for special cases papers are filled. The consultancy is mainly provided over the phone.

According to the trade association 150 companies are providing a roof renovation and a painting of the cleaned roof. Only 28 companies are members of Dansk Byggeri Tagmalerforening. In the southern part of Jutland German companies are operating. The companies involved in internal building renovation are members of the association Dansk Asbestforening. The association counts 13 members.