4. Historical Building Review

The historical building review is the first step in the building survey and its aim is to clarify whether PCB-containing materials were used during the construction phase or during a subsequent renovation. Data is required, therefore, to verify the year of construction, any renovations carried out, and the materials used.

PCBs were used in building materials from approx. 1950 until 1 January 1977 when PCBs were banned in open applications (see Section 1.8, Rules). Data from the Danish Building and Housing Register (BBR) can be sampled and analysed to determine if the building was erected or renovated during this period. The construction of a building may have been underway several years prior to the registered year of construction and therefore not all buildings listed in the BBR as built after 1977 can be considered free of PCBs. Normally, it will take a maximum of two years to construct a building (i.e., until the end of 1978, as the ban took effect on 1 January 1977). Unless data exist documenting a particularly prolonged construction period or information about the use of materials produced pre-1977, buildings constructed after 1978 can be considered free of building materials containing PCBs.

If the building was erected pre-1950, a detailed investigation into the building’s maintenance and renovation history should be made. There is a risk that the materials used for extension, conversion, reconditioning, maintenance, and renovation during the period 1950–1978 may have contained PCBs.

If the building was constructed during the period 1950–1978 or work was carried out on the building during this period, it will be necessary to identify the building materials added to the building. Drawings, descriptions, and existing documents should be inspected, and the owner and operational staff asked about their knowledge of the building history. For renovation work, the focal point should be on those building parts with a maintenance frequency or durability of less than 30 years and building materials which might potentially have contained PCBs during this period (see Section 5.2, Construction Products Potentially Containing PCBs). This can be supplemented by a visual inspection.

The building materials potentially containing PCBs may have been replaced. In the survey conducted by Grontmij & COWI (2013) which included mapping of PCBs in materials and indoor air, tests showed that the frequency of high concentrations of PCBs in interior caulk was far higher between concrete slabs than around doors and windows. What may explain this is that doors and windows may have been replaced, as caulk between concrete slabs is not replaced (Grontmij & COWI, 2013). Furthermore, data from the mapping process indicated contrary documentation in several cases. While reports were made that windows with surrounding sealant had been replaced, samples indicated that only some of these had, in fact, been replaced (Grontmij & COWI, 2013)

When existing data indicate that caulk has been replaced during renovation, it is important to remember that adjacent materials can be polluted by old caulk. Likewise, PCB sources that are later replaced may have caused tertiary contamination of surface areas. If insulating glazing units potentially containing PCBs have been replaced (see Section 5.2.2, PCBs in Insulating Glazing Units), the casing may also be contaminated even though the glazing units are new.

It is safe to assume that buildings erected after 1978 are free of building materials with admixed PCBs, but the import and sale of electrical appliances with PCBs in so-called closed applications were not banned until 1986. Furthermore, certain types of electrical PCB-containing appliances were permitted for use until 2000 and others for their remaining lifespan (Ministry of Environment, 1998) (see Section 1.8, Rules, and Section 5.2.4, PCBs in Capacitors).

Leakage from a capacitor in a fluorescent light ballast can be a source of excessive concentrations of PCBs in indoor air (see Section 1.6.1, Factors Affecting PCB Concentrations). A leakage can also contaminate other materials in a building.

Certain foreign brands of insulating glazing units contained PCBs in sealant until 1980 (see Section 8.3.1, PCBs in Insulating Glazing Units).

In certain cases, building materials from houses dating from 1950–1978 may also have been reused in new houses.

Table 16 lists four categories based on the year of building in the BBR register and suspected contamination of building materials with PCBs plus the need for further intervention.

It may be necessary to inspect a building portfolio systematically to identify at risk buildings (e.g., an inspection of municipal buildings or the properties of a housing association). Each building should be considered an independent unit, although it is part of a large-scale development where the buildings look alike and appear to be built of the same types of materials. During the original building phase or renovation, different materials may have been used in the buildings.

This variation in materials used during the construction phase is illustrated by test results of caulk samples from the Farum Midtpunkt housing estate. The dwellings comprise several sections of buildings and PCBs were only used in the section that was built first (the flats in Birkhøjterrasserne). In this section, comprising six apartment blocks, caulk with a PCB content of approx. 200–200,000 mg/kg had been used. Moreover, chemical analyses indicate that the PCB-congener content in the caulk is attributable to two known products as well as to two types not matching known products (Frederiksen et al., 2012).