posted on 2015-09-09, 15:46authored byOliver E. Jay, Matthew N. Cramer, Nicholas M. Ravanelli, Simon HodderSimon Hodder
Heat waves continue to claim lives, with the elderly and poor at greatest risk. A simple and cost-effective intervention is an electric fan, but public health agencies warn against their use despite no evidence refuting their efficacy in heat waves. A conceptual human heat balance model can be used to estimate the evaporative requirement for heat balance, the potential for evaporative heat loss from the skin, and the predicted sweat rate, with and without an electrical fan during heat wave conditions. Using criteria defined by the literature, it is clear that fans increase the predicted critical environmental limits for both the physiological compensation of endogenous/exogenous heat, and the onset of cardiovascular strain by an air temperature of ~3-4°C, irrespective of relative humidity (RH) for the young and elderly. Even above these critical limits, fans would apparently still provide marginal benefits at air temperatures as high as 51.1°C at 10%RH for young adults and 48.1°C at 10%RH for the elderly. Previous concerns that dehydration would be exacerbated with fan use do not seem likely, except under very hot (>40°C) and dry (<10%RH) conditions, when predicted sweat losses are only greater with fans by a minor amount (~20-30 mL/hour). Relative to the peak outdoor environmental conditions reported during ten of the most severe heat waves in recent history, fan use would be advisable in all of these situations, even when reducing the predicted maximum sweat output for the elderly. The protective benefit of fans appears to be underestimated by current guidelines.
History
School
Design and Creative Arts
Department
Design
Published in
APPLIED ERGONOMICS
Volume
46
Pages
137 - 143
Citation
JAY, O.E. ... et al, 2015. Should electric fans be used during a heat wave? Applied Ergonomics, 46, pp.137-143.
Publisher
Elsevier Science Ltd.
Version
AM (Accepted Manuscript)
Publisher statement
This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/
Acceptance date
2014-07-22
Publication date
2014-08-15
Copyright date
2015
Notes
This paper was accepted for publication in the journal Applied Ergonomics and the definitive published version can be found at: http://dx.doi.org/10.1016/j.apergo.2014.07.013