Ergonomics, 2013 Vol. 56, No. 4, 707–724, http://dx.doi.org/10.1080/00140139.2012.760756
Notes on the implementation of the IREQ model for the assessment of extreme cold environments Francesca Romana d’Ambrosio Alfanoa*, Boris Igor Palellab and Giuseppe Riccioc a
Dipartimento di Ingegneria Industriale, Universita` di Salerno, Via Ponte Don Melillo, 84084 Fisciano (Salerno), Italy; bDipartimento di Energetica, Termofluidodinamica Applicata e Condizionamenti Ambientali, Universita` degli Studi di Napoli Federico II, Piazzale Vincenzo Tecchio 80, 80125 Naples, Italy; cDipartimento di Energetica, Termofluidodinamica Applicata e Condizionamenti Ambientali, Universita` degli Studi di Napoli Federico II, Piazzale Vincenzo Tecchio 80, 80125 Naples, Italy
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(Received 3 September 2012; final version received 12 December 2012) This paper has been devoted to the difficulties that practitioners, skilled ergonomists or occupational health experts could find in the assessment of cold environments by means of (insulation required) IREQ model at the base of the (International Standardization Organization) ISO 11079 Standard. The in-depth analysis discussed here has underlined several difficulties about: (a) the graphical calculation of the predicted limit exposures; (b) some differences in both IREQ and (duration limit exposure) DLE values reported in ISO 11079; and (c) some errors and incongruities in the program available online for the assessment of DLEs. These occurrences lead to the systematic overestimation of the DLE that exceed up to 4 h, those obtained by means of the figures reported in the Standard with the consequent unreliable assessment. Such matters justify the need to promote, in the whole scientific community involved in the ergonomics of the thermal environment, an in-depth discussion on the best practice to be followed for the assessment of extreme cold environments by means of IREQ model. Practitioner summary: Incongruities in IREQ model and errors in the code suggested by ISO 11079 Standard prevent a reliable assessment of cold environments with DLE systematically overestimated. Therefore IREQ model has been theoretically investigated trying to help both neophytes and skilled ergonomists on the best practice to be followed. Keywords: required insulation (IREQ model); cold exposure; clothing thermal insulation; duration limit exposure; ISO Standard 11079
Introduction The thermal stress induced by the combination of indoor microclimatic or outdoor climatic parameters with behavioural features of the person (clothing and activity) is usually classified into cold stress and heat stress (Parsons 2003). Concerning cold stress, it can be related to prolonged exposure to cold, often combined with insufficient clothing or physical activity, with a whole-body cooling and a decrease in core temperature (Holme´r 2001; Ma¨kinen and Hassi 2009). This phenomenon is further worsened by the exposure to wind (Tikuisis, Ducharme, and Brajkovic 2007) or cold water (Golden and Tipton 1998; Kenny, Reardon, and Ducharme 2001; Wissler 2012), which increase the convective heat loss to the surrounding environment. Cooling can also occur when the exposition to low temperatures is restricted to small areas of the body surface with a local reduction of the skin temperature (e.g. nose, ears, cheeks, chin, fingers or toes) leading to non-freezing (trench foot, chilblains) or freezing (frostbite) cold injuries (Keim, Giusto, and Sullivan 2002; Ma¨kinen and Hassi 2009; National Institute for Occupational Safety and Health 2012). As stressed by Leblanc (1975), the first studies devoted to the topic dealt with military operations or expedition activities and that only in the past years the interest has moved to the working both outdoors and indoors (freezer rooms, special kitchens or industrial operation carried out at lower temperature), and to the health safeguarding during the climatic cold waves. As a matter of fact, working in cold environments not only results in accidents and injuries but also affects the performances of work due to the required protective measures (Holme´r et al. 2009). This increased interest in the occupational safety and health gave rise to the update of the legislation and the promotion of public awareness, education and investigation in this field (Council of the European Community 1989). This approach resulted in the formulation of a special three-phases strategy called SOBANE (Malchaire, Gebhardt, and Piette 1999; Malchaire and Piette 2006; Holme´r 2009), which inspired the International Standard (International Standardization Organization) ISO 15265 (ISO 2005a) devoted to the evaluation of the risk for the prevention of constraints or discomfort under thermal working conditions. This Standard provides a protocol of analysis characterised by an in-depth analysis of the working conditions aimed to identify quick solutions for easy problems or special investigations in complex situations. Particularly, to assess the class of risk in cold environments both in short and in long terms, ISO 15265 Standard requires the calculation of the IREQ (insulation required) index.
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