COMPLIANCE WITH THIS PUBLICATION IS MANDATORY

Transcription

1 BY ORDER OF THE COMMANDER MACDILL AIR FORCE BASE MACDILL AIR FORCE BASE INSTRUCTION APRIL 2015 Aerospace Medicine CONTROL OF THERMAL STRESS COMPLIANCE WITH THIS PUBLICATION IS MANDATORY ACCESSIBILITY: Publications and forms are available for downloading or ordering on the e- Publishing website at RELEASABILITY: There are no releasability restrictions on this publication. OPR: 6 AMDS/SGPB (Maj Carolyn A. Prill) Supersedes: MACDILLAFBI48-102, 1 August 2011 Certified by: 6 MDG/CC (Col Kevin M. Franke) Pages: 11 This instruction implements Air Force Policy Directive (AFPD) 48-1, Aerospace Medicine Program, and Air Force Pamphlet (AFPAM) , Thermal Injury. This instruction assigns responsibilities and gives guidance on preventing heat and cold stress. It applies to all industrial organizations and tenant units on MacDill Air Force Base (AFB). Ensure that all records created as a result of processes prescribed in this publication are maintained in accordance with Air Force Manual (AFMAN) , Management of Records, and disposed of in accordance with the Air Force Records Disposition Schedule (RDS) located at Refer recommended changes and questions about this publication to the Office of Primary Responsibility (OPR) using the Air Force (AF) Form 847, Recommendation for Change of Publication; route AF Forms 847 from the field through the appropriate functional chain of command. SUMMARY OF CHANGES This document has been substantially revised and must be completely reviewed. Major changes include: deletion of redundant explanation of Wet Bulb Globe Temperature (WBGT) Heat categories (paragraph ); removed definitions of Frost Nip and Frost Bite since they are listed in AFPAM , Thermal Injury (paragraph ); removed unnecessary definitions of Shivering and Reduced Manual Dexterity (paragraphs and ); removed Heat Illness Signs and Symptoms and First Aid paragraphs and replaced with table 5.1.; removed attachment 2 and all references to attachment 2.

2 2 MACDILLAFBI APRIL Terms Explained Acclimatization. Acclimatization is a series of physiological adjustments that occur when an individual is exposed to a hot climate. A period of approximately 2 weeks with progressive degrees of heat exposure and physical exertion should be allowed for substantial acclimatization (about 78 percent). Acclimatization to heat begins with the first exposure and is usually developed to about percent by the end of the first week. Full acclimatization is attained most quickly by gradually increasing work in the heat. Full heat acclimatization can be achieved by as little as two 50-minute periods of work in the heat each day. Once acclimatized, personnel will retain most of the adaptation for about one week after leaving a hot climate Heat Disorders. Heat disorder is a general term used to indicate any type of adverse heat-related health problems. Heat cramps, heat exhaustion, and heat stroke are all forms of heat disorder. Heat disorders may be recognized by one or more of the following symptoms: nausea, vomiting, fever, dizziness, headache, faintness, abnormal sweating, convulsions, lack of coordination, mental confusion, unconsciousness, and abdominal or leg cramps. Personnel most likely to be affected by the heat are those individuals who have just arrived from cooler regions of the country, are obese, or are in poor condition. Heat disorders are as follows: Heat Cramps. Heat cramps are painful intermittent spasms of the voluntary muscles. Cramps may result from exposure to high temperature for a relatively long time, particularly if accompanied by hard physical work. Cramps usually occur after heavy sweating and are the result of excessive loss of salt from the body. Even if the moisture is replaced by drinking plenty of water, the loss of salt by sweating may cause heat cramps Heat Exhaustion. The signs of heat exhaustion are profuse sweating, weakness, rapid pulse, dizziness, nausea, and headache. With heat exhaustion, the skin is cold and sometimes pale and clammy with sweat, and body temperature is normal or below normal. Nausea, vomiting, and unconsciousness may also occur Exertional Heat Injury (EHI) and Exertional Rhabdomyolysis. Exertional heat injury represents a continuum in severity between heat exhaustion and heat stroke. EHI patients show evidence of organ or tissue injury or dysfunction, but do not display sufficient neurological abnormalities to meet the usual criteria of heat stroke. EHI victims usually sweat profusely and will cool spontaneously after removal from the heat stress, however, in some, their core temperatures may continue to rise Heat Stroke. Heat stroke is caused by exposure to a hot environment in which the body is unable to cool itself sufficiently. This results in the body temperature rising rapidly. Heat stroke is a much more serious condition than heat cramps or heat exhaustion. The skin is usually hot, dry, and flushed. Patients may exhibit neurological symptoms such as combativeness. Increased body temperature, if uncontrolled, may lead to delirium, convulsions, coma, and even death. Heat stroke is a medical emergency Heat Stress. Heat stress is the combination of environmental and physical work factors that constitute the total heat load imposed on the body. The environmental factors of heat stress are the air temperature, radiant heat exchange, air movement, and water vapor

3 MACDILLAFBI APRIL pressure. Physical work contributes to the total heat stress of the job by producing metabolic heat in the body in proportion to the intensity of the work Wet Bulb Globe Temperature (WBGT) Index. The WBGT index is the most practical heat stress index for characterizing the effect of a heat stress environment on an individual because it takes into account humidity, wind speed, and radiant load. WBGT values are calculated by the following equations. All readings are given in degrees Fahrenheit. Note: The wet bulb temperature is always below the dry bulb temperature except when the relative humidity is 100 percent. At this point, both temperatures are equal Outdoors with solar load: WBGT = 0.7 WB BG DB Indoors or outdoors with no solar load: WBGT = 0.7 WB BG Legend: WB = Wet Bulb; BG = Black Globe; and DB = Dry Bulb Workload. The physical demands of duties being performed. For the purpose of heat stress, workload is divided into three categories. Examples of each category are given below: Light Work: Drill and ceremony, gate duty Medium Work: Mechanical work performed outdoors, carrying weapon while patrolling Heavy Work: Hand digging, assembly/disassembly of satellite communications equipment, aircraft washing Cold Stress: Cold environments pose a threat to the individual if they exceed the capacity of the body s thermo-regulatory response mechanisms Freezing Cold Injury (FCI) As skin temperature approaches 30 degrees Fahrenheit, intense constriction of blood vessels takes place with the potential for freezing of tissues and subsequent frostbite (FCI). The following freezing cold injuries are described: Hypothermia: A fall in the body s core temperature and one who becomes incapacitated as the result of a drop in core body temperature below 95 degrees Fahrenheit Chilblains: Caused by the repeated exposure of skin to temperatures just above freezing to as high as 60 degrees Fahrenheit. The cold exposure causes damage to the capillary beds (groups of small blood vessels) in the skin. This damage is permanent and the redness and itching will return with additional exposure. The redness and itching typically occur on cheeks, ears, fingers, and toes Non-Freezing Cold Injury (NFCI): Prolonged contact with water or wet clothing in the temperature range of 53 degrees Fahrenheit can result in a non-freezing cold injury where the peripheral nerves demyelinate with resultant swelling, numbness, and blanching followed some time later by intense pain and an increase in blood flow to the affected body area Other Effects of Cold. Further to FCI and NFCI, the following may also be seen in a cold environment:

4 4 MACDILLAFBI APRIL Responsibilities Raynaud s Disease/Syndrome: Cold at a severity that does not affect normal people may cause severe arterial vasoconstriction, most commonly affecting the fingers, in individuals with Raynaud's Syndrome. In severe cases, this may lead to digital ulceration and tissue loss. Protection from the cold by suitable clothing, gloves, and shoes is usually sufficient, however, chemical hand warmers may be necessary. Individuals with Raynaud s are strongly advised not to smoke Muscle injury. Muscle and tendon tears may occur when a person is cold since muscle action is inefficient and may be uncoordinated in concert with joint stiffness. An active warm up, sufficiently energetic and prolonged to ensure that the whole body is warm, is an effective means for reducing the risk of injury and enhancing performance Commanders/Supervisors: Ensure personnel take heat stress preventive measures during the summer months and especially when the WBGT index reaches or exceeds 90 degrees Fahrenheit. Ensure that first line supervisors brief all personnel on an annual basis and prior to all exercises on heat stress prevention. Add heat stress hazards/training to workers on AF Form 55, Employee Safety and Health Record During the hot season, schedule physical conditioning and strenuous activities early in the day or late in the afternoon Wing Command Post (6 AMW/CP): Advises base organizations of the onset and conclusion of heat stress conditions. This is to be accomplished via base wide notification, a pop-up window from the MacDill AFB Emergency Notification System on base computer workstations, or via land-mobile radio message to group commanders Public Health (PH): Provides guidance and training on controlling heat stress during normal job-related functions at the request of the supervisor Upon the request of the commander, PH will provide a heat stress briefing to personnel who have the potential (occupational, recreational, deployment, etc.) of exposure to high-temperature environments Bioenvironmental Engineering (BE): Investigates the impact of heat stress on industrial workers required to wear personal protective equipment Monitors the WBGT four times daily between 1 May and 1 October when the forecast outside temperature is higher than or equal to 85degrees Fahrenheit as a daily high Monday through Friday (excluding holidays), unless inclement weather prevails. BE will determine when additional monitoring will be accomplished before 1 May or after 1 October as necessitated by heat stress conditions Determines the onset and conclusion of heat stress conditions and reports findings only when heat category changes to 6 AMW/CP at Defense Switched Network (DSN) or Commercial Notifications will be made at any time when the

5 MACDILLAFBI APRIL heat category changes. Once the final reading is taken at 1600 hours local time Monday through Friday, the heat category at that time will be in effect until sunset Investigates heat stress injuries through completion of AF Form 190, Occupational Illness/Injury Report, and inputs the data into the Air Force Safety Automated System (AFSAS). Also makes recommendations to the appropriate commander/supervisor on further prevention of heat stress injuries in their unit Advises commanders/supervisors on heat and cold stress preventive measures Remains responsible for the determination of the Wind Chill Index zones in accordance with AFPAM th Force Support Squadron: The Fitness Center will provide notice to all patrons of current heat and cold stress category. 3. Individual Factors Affecting Heat Stress or Increasing Potential for Heat Stress. There is wide variation in human tolerance to heat stress. Nevertheless, it is possible to identify factors that cause particular individuals to become heat casualties. The following personal factors must be considered when assessing individual heat injury risk: 3.1. Concurrent mild illness, e.g., diarrhea, viral illness, fever, including reactions to immunizations Inadequate acclimatization (2 hours/day of sweat work for 7 to 10 days are necessary). The process means you sweat more profusely and conserve more salt in your kidneys Obesity Lack of physical fitness and/or lack of sleep Recent alcohol intake Dehydration Medication or illegal drugs Lack of meals Previous heat/cold injury. 4. Preventive Measures. The following preventive measures are a guide to preventing heat stress. These measures provide some information for commanders and should not be construed as directive Prior to Exercise/Deployment/Work: Condition for acclimatization. Need at least 2 hours of sweat work each day for 7 to 10 days Accomplish all immunizations at least 7 days prior to exercise/deployment Screen out individuals with even minor illness, particularly any vomiting or diarrhea in the past 2-3 days, and pregnant women Be rested; 12 hours of rest/8 hours of sleep.

6 6 MACDILLAFBI APRIL No alcohol 24 hours prior to working in hot climate Prehydrate before work; drink at least one quart of water Identify individuals at higher risk (i.e., previous heat/cold injury) During Exercise/Deployment/Work: After air transport, replace water loss in flight (one quart for every four hours in flight) Provide sufficient water cooled to at least 60 degrees Fahrenheit Bioenvironmental Engineering can provide you with current WBGT readings. During deployments, the independent duty medical technician (IDMT) or equivalent should perform the WBGT readings using the WBGT kit, National Stock Number (NSN) or other approved instrument Work rest cycles and fluid replacement guideline: Table 4.1. Work Rest Cycles and Fluid Replacement Guideline. RECOMMENDED WORK-REST REGIMEN (PER HOUR) and WATER INTAKE (QUARTS PER HOUR) LIGHT WORK MODERATE HEAVY WORK WORK / WORK / WORK / REST REST REST HEAT CATEGORY WGBT INDEX (F) WATER INTAKE (Qt/Hr) WATER INTAKE (Qt/Hr) WATER INTAKE (Qt/Hr) 1 (White) No Limit 0.50 No Limit /20 min (Green) No Limit /10 min /30 min (Yellow) No Limit /20 min /30 min (Red) No limit /30 min /40 min (Black) > 90 50/10 min /40 min /50 min 1.00 This regimen ONLY applies to OUTDOOR activities in direct sunlight. These heat categories are consistent with those in the Airman s Manual (AFMAN ) and the Training Guidelines for Acclimatized Personnel in AFPAM , Thermal Injury. Notes: 1. If wearing MOPP Level 4, add 10 F to Wet Bulb Globe Temperature (WBGT). If wearing personal body armor in humid climates, add 5 F to WBGT. 2. Rest means minimal physical activity (sitting or standing), accomplished in shade if possible. 3. Caution: Daily fluid intake should not exceed 12 quarts. Hourly fluid intake should not exceed 1 quart. The work/rest time and fluid replacement volumes will sustain performance and hydration for at least 4 hours of work in the specified work category. Individual water needs may vary +/ qt/hr. Work Intensities of Military Tasks Light (Easy) Work 1. Weapons maintenance Moderate Work Walking on loose sand at 2.5 Heavy (Hard) Work 1. Walking on hard surface

7 MACDILLAFBI APRIL Walking on hard surface at 2.5 mph, with <30 pound load Marksmanship training Tower operations Operations NCOs/officers Pilot ground activities Command post and unit control center activities mph, with no load Walking on hard surface at 3.5 mph <40 pound load Calisthenics Patrolling Individual movement techniques such as low/high crawl Refueling Avionics shop Aircraft maintenance Unit post attack reconnaissanc at 3.5 mph, with >40 pound load Walking on loose sand at 2.5 mph, with any load 2. Armament crew 3. Heavy aircraft repair 4. Specialized teams such as CBRN reconnaissance, search and recovery, rapid runway repair, CCA, fire protection, decontamination, medical, damage assessment, and repair, and EOD 5. Symptoms of Heat Stress and Emergency Actions. Heat stress symptoms include one or more of the following: headaches, dizziness, faintness, nausea, vomiting, fever, profuse or decreased sweating, cramps, convulsions, lack of coordination, and unconsciousness Heat Stroke is a MEDICAL EMERGENCY. Immediately call an ambulance (911) while simultaneously conducting rapid active cooling measures (remove victim to cool shady place, remove clothing, keep skin moist, soak victim with cool water, give vicftim sips of water if conscious. Monitor airway and breathing). Active cooling should be discontinued when the rectal temperature reaches 101 degrees Fahrenheit to avoid hypothermia General Measures for Common Signs/Symptoms of Heat Injury: Table 5.1. Heat Illness Signs and symptoms and First Aid Illness Signs and Symptoms First Aid Heat Syncope Fainting when standing erect and immobile in the heat. Remove to cool area. Allow to recline and provide cool water. Recovery will be prompt and complete. Heat Cramps Heat Exhaustion Heatstroke- Medical Emergency Active sweating, muscle cramps. Profuse sweating, headache, weakness, and nausea; skin cool and moist. High body temperature; skin dry and hot; unconsciousness, convulsions, or delirium. Remove to cool area. Massage extremities. Contact medical facility. Remove to cool area. Elevate feet. Loosen clothing and apply wet cloths. Evacuate to medical facility. THIS IS A MEDICAL EMERGENCY. Call medical facility first. Lower body temperature immediately. Remove clothing, immerse in water, if available. Otherwise, sprinkle with water and fan to increase evaporation, massage extremities and trunk. Move to medical facility. Continue cooling measures during transportation.

8 8 MACDILLAFBI APRIL Factors Affecting Cold Stress or Increasing Potential for Cold Stress. Methodical reviews of accidental cold injuries have identified the following individual risk factors in a cold environment and must be considered: 6.1. Alcohol Mind acting/altering medication Insufficient clothing Wetness from either the environment or sweat Lean body mass Physical exhaustion Pre-existing or current illness Previous cold injury. 7. Preventive Measures for Cold Exposure. The following precautions may reduce cold exposure: 7.1. Elimination of nonessential outdoor tasks When possible, performing tasks indoors Provision of temporary shelter for essential outdoor work, preferably heated, or provision for a warming tent Increasing the number of personnel allocated to a task and operating a rotational duty system Layered protective clothing systems are available to both aircrew and ground crew Workload and Fluid Intake in Cold Environments. In cold environments, the principle routes of fluid loss and subsequent deficit are cold induced diuresis, respiratory water loss, cold weather clothing, and the metabolic cost of movement and reduced fluid intake. Theoretically, glycerol solutions may be appropriate fluid replacement in cold environments to delay gastric emptying and promote fluid absorption, however, this area requires further study. Personnel are to be encouraged to stay hydrated and consume meals Working Practice Guidance in Cold Environment Standard (35 F). Wear gloves and cover metal handles and bars with thermal insulation Moderate (20 to 30 F). Follow standard precautions, no outdoor operations with water (vehicle/aircraft washing), wear gloves and total body protection, avoid heavy sweating, change wet clothes immediately, implement the buddy system. (50 MINUTES WORK/20 MINUTES WARMING.) For further guidance with colder climates, see AFPAM Symptoms of Cold Stress and Emergency Actions. If body heat loss exceeds heat production, hypothermia will develop. The condition is defined as occurring when the body s

9 MACDILLAFBI APRIL core temperature falls to 95 degrees Fahrenheit or below. Recognizing the early signs and symptoms of hypothermia is the key to treatment and management. These include: 8.1. Symptoms: Profound shivering Slurred speech Psychological symptoms including aggressive or withdrawn behavior Progressive reduction in the shivering response and loss of consciousness Treatment: Remove the person from the cold environment and allow the affected body part to re-warm spontaneously. For further information on treatment of Cold Stress symptoms, please see AFPAM , Thermal Injury. DANIEL H. TULLEY, Colonel, USAF Commander

10 10 MACDILLAFBI APRIL 2015 References Attachment 1 GLOSSARY OF REFERENCES AND SUPPORTING INFORMATION AFMAN , Management of Records, 1 March 2008 AFPAM , Airman s Manual, 1 March 2009 AFPAM , Thermal Injury, 18 November 2002 AFPD 48-1, Aerospace Medicine Program, 23 October 2005 Fundamentals of Industrial Hygiene, Chapter 12 (Temperature Extremes) American Conference of Governmental Industrial Hygienists, Threshold Limit Values for Physical Agents in the Work Environment, current edition AFMOA/CC Revised Policy on the Role of Sports Drinks in the Prevention of Dehydration and Heat Illness Prescribed Forms: None Adopted Forms: AF Form 55, Employee Safety and Health Record AF Form 190, Occupational Illness/Injury Report AF Form 847, Recommendation for Change of Publication Abbreviations and Acronyms: 6 AMW/CP 6th Air Mobility Wing, Command Post AF Air Force AFB Air Force Base AFI Air Force Instruction AFMAN Air Force Manual AFPAM Air Force Pamphlet AFPD Air Force Policy Directive AFSAS Air Force Safety Automated System BG Black Globe DB Dry Bulb DSN Defense Switched Network FCI Freezing Cold Injury FITS Fighter Index of Thermal Stress MOPP Mission-Oriented Protective Postures

11 MACDILLAFBI APRIL NFCI Non-Freezing Cold Injury NSN National Stock Number OPR Office of Primary Responsibility PH Public Health RDS Records Disposition Schedule WBGT Wet Bulb Globe Thermometer WB Wet Bulb WCT Wind Chill Temperature