[Evaluation of metabolic rate for a correct risk assessment of thermal environments].

Background: The new law n.81/2008 recognises microclimate as one of physical agents for which risk assessment becomes obligatory. To achieve this it is necessary to evaluate suitable indices, based on heat balance equation, which depend on six parameters: the first four are related to thermal environment and the last two are related to the worker (metabolic rate and thermal insulation). The first four parameters are directly measurable in situ by using a multiple data acquisition unit provided with suitable sensors. Parameters related to the worker are not directly measurable. This aspect represents one of the problems which can lead to an inaccurate risk assessment.

Objectives: Aim of the paper was to identify a method which leads to a correct evaluation of the metabolic rate related to the worker under study.

Methods: It was decided to follow the procedures described by the standard UNI EN ISO 8996:2005 which presents four different levels to evaluate metabolic rate, each one with an increasing degree of accuracy. Seven workers were selected: three performed light tasks and the other four did heavy work.

Results: The study showed that the results appear to be in acceptable agreement in the case of light work while there were detectable differences in value for heavy tasks.

Conclusions: The Authors believe it is necessary to stress the importance of a suitable estimation of the metabolic rate in order to carry out a correct risk assessment which quantifies the risk exactly.