## 2 Metrological Study of the Regulatory Framework on the Occupational Exposure to Vibrations
### CEN/TR 15350:2013 on Estimation Method
#### 3.1.2 Reliability and Traceability  
Another relevant inconvenience has to do with the information employed for estimation methods. European Directive 2002/44/EC states that, when applying estimation methods, the assessment of the level of exposure may be based on information provided by the manufacturers concerning the level of emission from the work equipment used. As a consequence, the input values to be obtain completely depends on the type followed by the manufacturer (typically based on uniaxial or triaxial measurements), and then the values can vary from one supplier to another. From a metrological point of view, an additional disadvantage related to this variability is the impossibility to compare the values provided by manufacturers or suppliers. Having reliable and comparable results would ensure that the level of exposure is evaluated in a uniform way, despite the brand or equipment type employed. Even when data are directly collected from the manufacturers [31] and the test code employed for the equipment analyses is indicated (requirement necessary to apply the estimation method based in the CEN/TR:2013), there is a lack of information regarding the procedure or the data treatment when estimating their application in real operating conditions; this situation can endanger the risk assessment based on those values. Article 4 of European Directive 2002/44/EC states that to assess the level of exposure to mechanical vibration, observation of the specific working methods may be used and appropriate information on the likely magnitude of the equipment vibration may be referred to. According to this recommendation, regulations on the different State Members have developed mechanisms to provide such information. In Spain, where this directive is transposed into Spanish law through Royal Decree 1311/2005 [32], a database is available for sharing information regarding the level of exposure values. In order to provide a reliable source of information for specific working methods and equipment, the Spanish National Institute of Safety and Health at Work (INSST) has developed, together with manufacturers, regulators, and other entities, a database where likely values of vibration for different conditions and equipment are collected [33]. This data base makes it possible to access reliable information to apply the estimation methods and calculations as described in CEN/TR 15350:2013. Nevertheless, although those values can become very useful, neither the associated uncertainty, nor the procedure followed to measure or obtain those values are recorded. From a metrological point of view, it makes it impossible to establish a reliable comparison between different models of similar equipment (and so is advised when entering the data base information). Moreover, not analyzing this information can jeopardize the traceability of those measurements and any risk assessment based on those values. Similar data bases can be found in equivalent institutions in other countries. In the case of the Italian National Institute for Occupational Accident Insurance (INAIL), similar information is provided for different machines, brands and models [34]. In this case, even those cases where uncertainty is not provided, information about the procedure or standard applied for obtaining the values is provided. Like this, it might be possible to compare different results when the same procedure has been applied. Another advantage of this data base is that, even if a specific associated uncertainty value is not provided, each provided value includes a mean and a deviation, which can give some relevant information from a metrological point of view. Even if both data bases provided some useful information to carry out the estimation of the vibrations level during real applications, it may happen that the information differs from one source to another.