J Royal Naval Medical Service 2010, 96.3 150-163 Clinical Managing the risk of heat illness on board Type 23 frigates deploying to the Arabian Gulf T Stevenson, D Roiz de Sa Abstract following the Six Day War of 1967. The Egyptian Temperature extremes are commonplace in Army at the time were issued minimal supplies the Middle East, varying between 30 oC and of water, compared to the Israeli Army where 50 oC. During the summer months, soldiers were issued 1L water per hour per temperatures reach 50 oC consistently, with person (5). Egypt suffered approximately 20,000 high humidity and sea temperatures rarely casualties, the majority of which were attributed dropping below 33 oC (1). Sailing from the to heat illness, whereas Israel suffered no temperate climate of the UK, Ship’s crews are reported cases of heat illness (6). For a deploying to these extremes and working in population indigenous to a hot climate to suffer spaces within the Ship where temperatures such appalling rates of heat illness suggests that climb as high as 52 oC for at least 4 out of 6 management of the risks of heat illness is months. Type 23 frigates (T23) were designed paramount to operational success within a for anti-submarine warfare (2)(anecdotally population of British service personnel deploying assumed to be North Sea based), yet now to climatic extremes. In its most mild form the deploy continuously to hotter climates which effects of heat stress and strain can result in subjects personnel to increased heat stress symptoms ranging from dizziness, headaches, a putting them at risk of heat injury. These risks reduced capacity for physical work, reduced can be minimised with simple measures such cognitive and psychomotor performance (7,8) and as maintaining hydration, rest periods outside increased risks within the workplace of hot workspaces and finally cooling environment (9). In its most severe form it can techniques such as inserting the arms up to lead to collapse, coma, multiple organ failure and the elbows in cool water for 10 minutes. death. Reducing the risks of heat stress and During the 4 months spent in the Arabian Gulf prevention of heat illness in an operational unit of a 6 month tour, during the summer of 2010, involves identifying risks and managing them personnel on board the T23 frigate HMS accordingly. This paper will discuss the SOMERSET suffered no cases of heat illness contributing factors of heat stress that personnel despite the risks, due to employing these on operational warships can expect to find simple strategies. themselves exposed to during deployments to the Middle East such as OP TELIC or CALASH, Introduction and the methods used to minimise the risks of Heat illness is an all inclusive term which heat illness occurring in those personnel. The encompasses several conditions including those examples used will be from HMS SOMERSET, a of heat exhaustion and heatstroke (3). The Type 23 frigate deployed to the Gulf on OP effects of heat on health and wellbeing appear in TELIC in summer 2010. some of the earliest written documents of mankind as far back as Homer’s Iliad (ca 1100 Environment of the Gulf BC) and its significant effects on various military Ships can expect a rise in temperature once endeavours have regularly been reported in they have passed out of the Mediterranean history (4). An interesting example can be found Sea through the Suez Canal. Transit through 150 Managing the risk of heat illness on board Type 23 frigates 151 the Bab el-Mandeb Strait (BAM) into the Gulf the Cold War, with the first class of T23 ships of Aden (GOA) brings ships to the main area of appearing in 1984 (2). It was thus designed to operations for CALASH deployments and be conducting patrols mainly in the North counter-piracy patrols. Moving north east to Atlantic and North European waters; however the Gulf of Oman (GOO) then North West to its roles now are far more versatile. The design transit through the Strait of Hormuz (SOH) of the T23 appears to presage a secondary role brings ships to the Arabian Gulf where in more tropical climates; the ship has an CALASH deployments extend across the onboard Chilled Water System (CWS) Southern Arabian Gulf (SAG) and Central responsible for cooling the equipment and Arabian Gulf (CAG) and TELIC deployments machinery to allow them to remain operational. take place in the Northern Arabian Gulf (NAG). There are three CWS plants onboard the T23 Ships deploying to either tasking can expect a which are designed to work in a maximum 6 month tour of which at least 4 months will seawater temperature of 30 oC (3). In extreme be spent in the regions described above, tropical conditions, defined as a seawater encompassing either summer or winter. Whilst temperature of >33 oC, the CWS does not cope winter in the Gulf is more bearable with well, and may result in machinery and temperatures averaging 20 oC, this paper will equipment failures, in addition to raising the examine exposure during the summer months background temperature of the habitable areas. where ambient temperatures can climb to Whilst in the Gulf, HMS SOMERSET 50 oC in the NAG (1) and approximately 40 oC in experienced an average daily seawater the SAG, along with high levels of humidity. temperature of 34-35 oC. This lead to not only Furthermore sea surface temperatures of an increased background heat of the living around 32-34 oC can increase the strain on spaces, but extreme heat in the specific areas ships’ machinery to breaking point whilst as shown in Table 1. Furthermore a lot of deployed in these Gulf zones. weapons engineering (WE) equipment contain internal sensors which alarm when they exceed Type 23 Frigates the recommended working temperature of The Type 23 frigate (T23) was designed to fight 30 oC, as occurred throughout the majority of in anti-submarine warfare during the throes of the tour Location (inc. Location Marker) Maximum Ambient Air Temperature (if recorded) Main machinery spaces (CW Plant Room 4E, 50-58 oC Fwd AMR 4F, GTR 4G, MGR 4H, UAMR 1H, AvCat Pump Space 4K, Tiller Flat 3N) Hangar 1K 50 oC Galley 2F - 3J (Ship’s Office, overflow living space, offices) 38 oC Winch Well (onboard gym) 2M 48 oC Laundry 2L - Buffer’s Shack 2M-P 45 oC Quarterdeck 2N 40 oC Upper Deck / Seaboats 44 oC Table 1 – Examples of hot spaces within a Type 23 frigate (11). 152 J Royal Naval Medical Service 2010, Vol 96.3 These are just a few examples of hot spaces protection from UV radiation. Finally the upper within the ship, where the above readings were deck gun crews, seaman specialists and not occasional, but consistently measured on a boarding teams including Royal Marines whose day to day basis, particularly during the months activities include boarding operations, seaboat of July and August. The strain placed on the transfers and providing force protection at sea CWS resulted in several failures of the system, or alongside, were exposed to heat and sun for leading to a catastrophic rise in inboard prolonged durations, all whilst wearing body temperatures, the subsequent failure of armour, lifejackets and combat dress with numerous electrical and weapon systems, and headgear and weapons both during exercises the near incapacitation of the entire ship’s and live operations. company due to extreme heat, saved only by Physical training is widely encouraged to the actions of the Marine Engineering (ME) maintain fitness, but is also actively pursued by department. Amazingly, no members of the many to release the pressure of working long Ship’s Company developed heat illness, stretches of defence watches whilst deployed in probably due to the mitigation employed. theatre. Personnel take part either in organised By comparison, the CWS onboard a Type exercise such as upper deck circuit training, or 22 frigate (T22) manages better in these personal training such as running around the extreme conditions. This is due to the fact that, upper deck or exercising in the gym which is as a larger ship, the T22 operates with five situated in the winch well. This area remained at CWS plants compared to the three onboard a a constantly high temperature during the day, T23 and thus is able to further compensate for falling only to around 40 oC during the night high seawater temperatures. (whilst in theatre in the summer months). Exposure Risk of Heat Illness The Ship’s Company onboard a T23 are exposed The risk of heat illness comes mainly from to thermal stress under two main categories – exposure as outlined above, however there are the environment, and that produced by physical several other contributing factors which can be work or exercise, or a combination of both. predicted (3): Environmental conditions exert influence on the effectiveness of the body’s thermal cooling → Poor hydration systems. Conditions such as high environmental → Tiredness temperatures and high humidity, particularly in → Alcohol (or heavy indulgence the night combination with physical activity and military before) clothing are known to increase the risks of → Poor acclimatisation or new into theatre thermal stress and exertion associated → Workload heatstroke (12). ME department personnel → Poor nutrition spent a large amount of a watch in the main → Obesity machinery spaces, particularly during routine → Poor Aerobic fitness (13) maintenance and machinery breakdowns. Aircrew and aircrew engineers laboured for Individuals with a high aerobic fitness will both hours either in the Lynx helicopter or in the acclimatise faster than those who are less fit, hangar, both of which had continuously high and have a higher capacity for physical work; temperatures day and night.