made between process and non-process areas to prevent the spread of contamination. For example, wipes from doorknobs on changing rooms might indicate ineffective changing or washing procedures. Typical wipe test sample locations are: Process areas: handrails on staircases • valve handles (pipework, sample points, etc.) • adjustable LEV hoods or dampers • door handles • plant telephones (if present) • desk surface • fume cupboard aerofoil and sash • laboratory bench • Non-process areas: Control room desktop • Personal Protective Equipment store • changing room lockers • shower area floors • door handles/tables/light switches in rest rooms • Check integrity of control measures. It may be impractical to detect low level, intermittent leaks by air sampling, but the accumulation of deposited dust on proximal surfaces can be detected by wipe sampling even if they are invisible to the eye. Raise awareness. Wipe samples can be a useful educational tool to teach process operators and supervisors about the effectiveness of control measures and the need to adhere strictly to procedures. For example, samples may be taken from the inside of Personal Protective Equipment to check for adherence to changing and cleaning procedures. Assess surface cleanliness. Validation of cleaning activities may be needed for decommissioning purposes before disposal of equipment or for maintenance. There may sometimes be opportunities to combine a hygiene assessment with swab sampling for quality assurance purposes. Assess or predict personal exposure. Surface wipe tests provide an indicator of the potential exposure by skin contact which might then lead to skin absorption or inadvertent ingestion. A lot of research work is underway to develop methods of direct monitoring of skin exposure, using for example fluorescent dyes. However, no generally accepted method is yet available. 5.7.2 Standards for Surface Contamination It is difficult to set standards for surface cleanliness, and a number of methods have been used to establish acceptable levels: One approach is to use relative levels, eg. the percentage removal achieved based on tests before and after cleaning, or the ratio of levels in a process area to those in a non-process area. Another approach is to establish a baseline by testing after a thorough cleaning process.
made between process and non-process areas to prevent the spread of contamination. For example, wipes from doorknobs on changing rooms might indicate ineffective changing or washing procedures. Typical wipe test sample locations are: Process areas: • handrails on staircases • valve handles (pipework, sample points, etc.) • adjustable LEV hoods or dampers • door handles • plant telephones (if present) • desk surface • fume cupboard aerofoil and sash • laboratory bench Non-process areas: • Control room desktop • Personal Protective Equipment store • changing room lockers • shower area floors • door handles/tables/light switches in rest rooms Check integrity of control measures. It may be impractical to detect low level, intermittent leaks by air sampling, but the accumulation of deposited dust on proximal surfaces can be detected by wipe sampling even if they are invisible to the eye. Raise awareness. Wipe samples can be a useful educational tool to teach process operators and supervisors about the effectiveness of control measures and the need to adhere strictly to procedures. For example, samples may be taken from the inside of Personal Protective Equipment to check for adherence to changing and cleaning procedures. Assess surface cleanliness. Validation of cleaning activities may be needed for decommissioning purposes before disposal of equipment or for maintenance. There may sometimes be opportunities to combine a hygiene assessment with swab sampling for quality assurance purposes. Assess or predict personal exposure. Surface wipe tests provide an indicator of the potential exposure by skin contact which might then lead to skin absorption or inadvertent ingestion. A lot of research work is underway to develop methods of direct monitoring of skin exposure, using for example fluorescent dyes. However, no generally accepted method is yet available. 5.7.2 Standards for Surface Contamination It is difficult to set standards for surface cleanliness, and a number of methods have been used to establish acceptable levels: One approach is to use relative levels, eg. the percentage removal achieved based on tests before and after cleaning, or the ratio of levels in a process area to those in a non-process area. Another approach is to establish a baseline by testing after a thorough cleaning process.
Exposure_Assessment_25Apr2014.docx