Old buildings contain many materials which we now consider toxic or hazardous to health. These materials were either used directly in the construction of the buildings or were introduced later during its lifetime. Typical hazardous materials used in the construction were asbestos, lead and PCB others such as mercury or many specialty chemicals may have been introduced later. Once the building deteriorated and either need a complete refurbishment or demolition, lot of these hidden materials become exposed. Demolition operatives working with these hazardous materials are often unintentionally exposed to high levels of lead and other toxic substances.
I have carried out a lead survey on a large inner city building which is going to be completely refurbished. The buildings will be stripped to basic shell and new services and installation will be put in place. During the strip out phase of the operation many long enclosed parts of the building will be open. The demolition operatives will work with the materials, cut, scrape, and break many in the process. In order to prevent the potential exposure of the demolition operatives to toxic lead dust a survey of the whole building was commissioned.
The building consists of five floors which were partially stripped out from the internal furnishing. At the time of my lead survey the building was unoccupied as this would significantly affect my ability to carry out a thorough inspection. Lead survey is destructive in nature and requires gaining access to enclosed services, partition walls and ducting. The knowledge of other hazardous materials is essential because aggressive destructive inspection can disturb asbestos materials hidden in the fabric of the building.
The purpose of the lead surveys was to identify all lead containing materials in the building so the demolition contractor can adequately control the risk to his operatives. I have adopted a systematic approach in which I have divided the building to three distinct sections and then proceeded with the top to bottom survey in each one of them. I have exposed and access all the hidden and enclosed ducting, service risers and a representative number of structural support beams in the building. I order to provide comprehensive lead surveys I have collected samples from materials I have suspected contain materials. Because led was mainly used as an additive to the surface coating the range of possible materials within a building is very wide. However over the years I have developed enough experience to recognise material and elements of the building which were much more likely to contain lead than others.
All the collected samples contained some levels of lead in them. This is not unusual because elemental lead is naturally present in all materials from concrete used in construction to the surface paint on the window. This does not mean that lead was added to these materials, in fact it was naturally present it the base material. Most of the samples materials contained traces of lead in the concentration between 0.0008-0.1% which is not considered significant and such materials would not be classified as lead containing.
Currently the various regulation in the United Kingdom consider a concentration of lead above 0.5% as significant for was disposal purposes and such waste is classed as hazardous waste. In regards to the risk of operatives being exposed to high levels of lead during work the HSE considers 1% of lead content in material as significant. Work, such as cutting and grinding on material which contain more than 1% of lead can lead to significant exposure.
The lead survey I have carried out for my client allowed him to identify potential risk from lead of site and make arrangements that materials with high lead content are handled appropriately.