Underground railway environment in the UK Part 1: Review of thermal comfort

The thermal comfort conditions in underground railway environments in the UK, especially those found on the London underground railway system, have in recent years received exposure in the press. However, little has been written on the complications and difficulties associated with cooling an underground railway system with a massive heat load let alone one designed and constructed by Victorians. The deep and small tunnels make cooling of the underground railway environment differ from those normally encountered in conventional air conditioning and also the process is energy and capital intensive. This may lead to the conclusion that the acceptable thermal comfort criteria for say an office may not be achievable in an underground railway environment and perhaps thermal comfort criteria not quite equalling the office level maybe acceptable in such an environment. This part of the paper reviews published work on thermal comfort for the underground railway environment. The results will be correlated with the percentage of dissatisfied passengers due to the thermal conditions within the underground railway system. Based on these results, an attempt will be made to define “acceptable” thermal comfort criteria for an underground railway environment.