Nuevos Catálogos / New Catalogues PROTECCIÓN LABORAL 53 | 4oTrimestre07 · Do workers need some additional type of personal protective equipment (for instance, eye protection, hearing protection)? Type of equipment and Necessary Protection Factor (NPF). By answering the questions above we should be able to determine what the necessary protection factor is. The guide tells us “NPF is the highest permissible leak level in accordance to approval requi- rements for the corresponding device. It shows maximum protec- tion performance, based on mathematics. So in order to know what the minimum protection level is we have to know the level of concentration of the contaminant, and the threshold limit value (TLV) for that substance. TLV will represent the maximum concentration of a given substance in the air, calculating an ave- rage over a period of reference (usually 8 hours), during which there is no evidence of probable injury caused by inhaling, for workers exposed to the said concentration day after day”. The section includes a list of respiratory protection devices and their corresponding nominal protection factor, based on the CEN 529 report. There is also an example of how to calculate this pro- tection factor, which means dividing the concentration of this toxic substance by the TLV (Threshold Limit Value). Thus, for lead dust contamination in the workplace with a level of concentra- tion of 3 mg/m3, and a TLV of 0.1 mg/m3, the minimum protec- tion factor is 30. The Guide also warns “in such cases as when toxic substances are present as fumes or particles the nominal protection factor needs to be found separately for each case. In order to choose the right filtering device, you should use the highest protection factor avai- lable”. Maximum concentration levels of contaminants. We are reminded that “It is possible to find out the maximum permissible concentration by multiplying the nominal protec- tion factor (as shown in Chart 1) by the TLV. So, maximum per- missible concentration is equal to Nominal Protection Factor x TLV”. An example illustrates how to find out the Maximum Permissible Concentration of chloride. TLV is 0.5 ppm (threshold limit value), and in the event of using a full mask (nominal protection factor 2000) the result is 1,000 ppm (parts per million) or 0.1% of the volume, which would be the maximum permissible concentration for this toxic substance. Choosing the right filter. The Guide has been designed to make is easier to choose in a num- ber of complex situations. We are reminded that, “toxic substances may be found in several ways: sprays (solid / particles), fumes (gas, fumes). So when choosing filters, you may wish to find pro- tection against one of both forms: Solid / particles: dust, fibres, gas, microorganisms (virus, bacteria, fungi, spores), and mist. Gas: gases and fumes. The table below shows the colour code for the filters in accordan- ce to EN 14387, showing what type of filter is needed to protect against the toxic substances present. After classifying filter types the Guide offers a simple example: Fil- ter A2B2-P3 (Brown-grey-white). A filter with this colour code will be suitable to protect against the following contaminants: · · · A. Fumes and gases of organic compounds with boiling point over 65°C to concentrations covered by Class 2 filters, and B. Inorganic fumes or gases, like chloride, hydrogen sulfur, hydrogen cyanide, up to concentrations covered by Class 2 fil- ters, and P. Particles up to concentrations covered by Class 3 filters. Warnings. The Warnings section of the Guide reminds us we should not use respiratory protection devices with filters in the presence of: · · · · · · · · · Oxygen-deficient atmospheres (Volume of Oxygen <17%). Confined or poorly ventilated spaces, like warehouses, small rooms, tunnels or boats. Whenever the concentration of toxic contaminants is not known or if it poses immediate threat to health or life. A higher toxic substance concentration than the permissible maximum and/or if concentration exceeds the capacity of filter type. Contaminants with little or no warning properties, such as smell, taste or itching, as is the case with dyes, benzene, formic acid, hexane, methyl-chloride, methanol, etc. We are also reminded we should immediately leave the work zone and take off the respirator if: There is shortness of breath (an increase of respiratory resis- tance). We feel dizzy, faint and/or in anguish. We detect toxicity through smell, taste or itchiness. The respiratory protection device is damaged or too old. Dräger’s Guide for the selection of light respiratory protection equipment recommends us “to make sure the respiratory pro- tection device fits properly, and in the presence of particles or fumes, to use a combination filter to filter fumes and particles”. Filter lifetime. The last section of the Guide presents a question that users do not always find it easy to answer. Evidently, the lifetime of a respira- tory filter will depend on its size and use conditions. Factors that impact on its lifetime may include level of concentration and com- bination of toxic substances. Each filter needs to be treated indivi- dually. The Guide also includes a chart with comprehensive information on the different fields of application, and the recommended types of masks and filters for each case. End users with questions regarding filters for respiratory protec- tion may order the Guide for the selection and use of filtering res- piratory protection equipment from Dräger’s distributors, or con- tact the company’s customer service department by phone. PARA MÁS INFORMACIÓN, CONTACTE CON: comercial@prensa-tecnica.com // FOR FURTHER INFORMATION, CONTACT: comercial@prensa-tecnica.com