LEAD IN THE WORPLACE
Checking for Lead
Before starting any works that might disturb or affect any paintwork, you should investigate whether you may have a lead paint issue.
Up until the mid 1960’s lead based paints were in common usage. White lead was added as a pigment to paints used in undercoat and top coat for use internally and externally on wood and metal. Red lead was widely used as an anti-corrosive primer coating for many types of steel work: including fences, railings, gates and structural elements.
The removal of old paint layers can generate large amounts of dust. The lead content of some old paints can be over 25%. Very old varnishes and glazed tiles may also contain high levels of lead.
In the UK lead was mostly removed from paint production by the 1980s, however there remains a large legacy of leaded paint in older buildings. Some older listed heritage buildings can still use leaded paint under licence.
Before starting any works that might disturb or affect any paintwork, you should investigate whether you may have a lead paint issue. It is not possible to detect whether paint contains lead by visual inspection alone. If the building is old you should be suspicious, even if the paintwork looks fresh, as lead is most likely to be in the lower levels
When checking for lead in paint, you have three options;
Taking a paint chip sample requires you to cut out a section of paint down to the substrate, which generally damages the paint work. There is a delay as the sample has to be sent to a laboratory for analysis, which usually returns the results in ppm or, if it is very high then as a simple percentage.
The chemical markers use a cocktail of chemicals that will change colour in the presence of lead e.g. shades of red. A score mark is cut in the paint down to the substrate and the chemical applied. Results are instant however they do not give a quantitative measurement of the amount of lead present, they can only really confirm the presence of lead. Other methods must be used to determine how much.
The third option of using an X-Ray Florescence (XRF) instrument is non-destructive and gives quantitive results in less than a minute. This means that multiple readings can be taken in a short period of time to help build up a more complete picture of the amount of lead present on various components within an area. The XRF instrument emits X-rays which ultimately cause the target area to fluoresce back, which is analysed to quantify the amount of lead present.
An XRF instrument is an expensive and specialist piece of equipment requiring fully trained operators to be certified as Radiation Protection Supervisors. Surveys utilising XRF technology offer by far the best solution for comprehensive results.
Beware lead can also turn up in places that you may not suspect – such as glazed tiles, older varnishes and even in UPVC frames. All these can be tested non-destructively with XRF.