Shelter, Clothing & Fire
You can only last three to four hours in extreme conditions without adequate shelter. Maintaining your body temperature in hot or cold temperatures is vital for survival. This can be hard to do if you are out of your normal environment or the power to your home is out.
Knowledge of how to maintain your optimal body temperature can help you "Be Ready" to save your life or the life of someone you care about.
- Learn the science of sheltering and layering so you can create life saving shelters in any situation, then practice
- Gather sheltering supplies like blankets, tents, sleeping bags, Mylar, cold weather clothing, and clear plastic sheeting. Include sheltering items as needed in disaster supply kits
- Learn how to keep you home warm or cool as needed if the power goes out
- Learn how to safely build, start, and put out a fire using a variety of different starting and extinguishing methods, then practice
Purpose of Shelter
Without shelter, a person can die from exposure in three to four hours. The purpose of sheltering is to help our bodies maintain a normal body temperature of about 98.6°. The human body uses the hypothalamus to internally regulate temperatures by controlling the constriction and dilation of blood vessels, sweating, and shivering – but it can only do so much to counter the extremes in our environments.
What external, environmental influences can affect our body temperature? Obviously, temperature extremes of hot and cold can affect us as well as our exposure to the elements like wind and rain. If our bodies are wet from rain, being in water, or sweating we will lose heat faster than if we are dry.
Our circulatory system uses water to transport heat throughout our bodies, so our level of hydration is a factor as well. Just as a tuned-up car works best, our health and the quality of our diet can determine how well our bodies can maintain temperature. If we are physically exerting ourselves, we will be generating internal heat.
Our internal regulatory systems will be affected as well if we are taking medications or intoxicants like alcohol, nicotine, or drugs. These DO NOT warm the body, they cause the body to relax, giving the sensation of warming, but in reality the body is losing heat at a much faster rate.
If the body gets too cold and the temperature drops below 98.6 degrees, it is known as hypothermia. Symptoms include shivering. If you are shivering, you are in the first stages of hypothermia. Other symptoms are slurred speech, apathy, confusion, loss of fine motor skills, difficulty walking or maintaining balance. As severity increases, skin may turn pale or gray. Eventually shivering will stop and the internal organs start to shut down.
If the body gets too hot and the temperature rises above 98.6 degrees, it is known as hyperthermia. Symptoms include thirst, sweating, slurred speech, apathy, confusion, loss of fine motor skills, difficulty walking or maintaining balance, headache, dizziness, and nausea. As severity increases, there could be vomiting, cramps, rapid pulse and breathing. Eventually the body stops sweating and the internal organs start to shut down.
Hypothermia and hyperthermia both have different levels of severity and they can both be deadly. Watch yourself and others for the symptoms and treat as necessary.
The Science of Effective Emergency Sheltering
The purpose of a shelter is to help your body maintain its normal temperature. If you understand these concepts, you can use your available supplies and resources to make effective, life saving shelters for the given circumstances. In cold temperature situations, you usually want to retain and gain heat; whereas in warm temperatures, you want to promote heat loss or at least not increase your temperature. Remember that heat always travels from warmer areas to colder areas.
Conduction: Heat transfer through direct contact, such as bare feet on a cold floor. Ice packs use conduction to pull heat away from burns or sore muscles. Prevent conduction from your body in cold temperatures by wearing socks or when camping by making an insulation barrier between your sleeping area and the ground.
Convection: Heat transfer through air and liquid currents. Wind chill is a good example of convection. When the wind blows, it feels colder than the ambient temperature because the moving air is pulling heat away from your body. You use convection in warmer temperatures to cool down when you use a fan. Prevent convection in colder temperatures by wearing clothing or using shelters that block wind.
Radiation: Heat transfer through emission. A car’s radiator radiates heat to keep the engine from overheating. You experience radiation from the sun every day. In the same way you feel warmth from a campfire without having to touch the flame. You can even feel your own body radiating heat if you put your hand just above an area of skin. Prevent radiation heat loss in cold temperatures by using insulated clothing and shelters, and by using shelters that reflect your heat back to you.
Metabolism: Converting food into energy and heat. Food is your body’s source of fuel. Help your body regulate your temperature in cold weather by eating high calorie foods like energy bars, trail mix and fruit snacks. Water is an important part in the metabolism process, be sure to stay properly hydrated in warm and cold situations.
Evaporation: Heat transfer through converting liquid to gas. When your body sweats, the sweat evaporates, or changes from a liquid into a gas, which requires heat energy. This helps keep you cool. When you get out of a pool, even on a hot day, you feel cold until you dry off because of evaporation. Promote evaporation in hot temperatures by staying hydrated. In extreme situations you can even wear wet clothing. Prevent heat loss in the cold by staying dry, minimizing sweating, and by wearing artificial fiber clothing, which wicks moisture away from your skin. In humid climates, regulating temperature through evaporation is not effective.
Respiration: Heat loss through breathing. You breathe out warm, moist air. You can’t stop breathing, so in cold temperature situations, wear a mask or scarf that covers your mouth and nose. Breathe through your nose to warm and moisten the air before it gets to your lungs, and to retain as much heat and moisture when you breathe out.
You could also say friction generates heat, like when you rub your hands together, but heat generation is very small and can be damaging to skin tissues in extreme situations like frost bite.
Preventing and Promoting Heat Transfer
After learning how your body gains or losses heat, it is important to learn how to prevent or promote those heat losses and gains.
Insulation: Trapping air to stop or slow the transfer of heat. Air is not a good heat conductor, so it works well as a barrier. Multiple small layers of clothing trap air for insulation and allow you to regulate to a comfortable temperature by adding or removing layers as needed. Insulation prevents conduction and radiation.
Reflection: Bouncing heat back to or away from your body. Heat, also known as infrared light, can be deflected and directed just like a flashlight beam and a mirror. Reflect your radiated body heat back to you in cold or reflect solar heat away from you in hot weather by using Mylar blankets, sleeping bags, or tents. If used properly, Mylar blankets can reflect 90% of your body's heat back to you, but there is no insulation. Be sure to have an insulating layer of clothing or cloth between your skin and the Mylar, otherwise it turns from reflecting your heat back, to conducting your heat away.
Protection: Keeping out the heat transferring elements like sun, water, wind, and physical dangers. Maintain your body temperature by protecting yourself from the elements. Stay dry and warm by wearing an outer layer that sheds water. Shelters that block wind and/or provide shade from the hot sun are also vital to survival in extreme temperatures.
Moisture Wicking: Pulling water away from the body. Artificial fiber clothing or shelters like polyester, fleece, and nylon or a non-plant fiber like wool can actually wick, or pull moisture, away from your skin. This is essential in cold weather. You do not want evaporation happening or ice forming next to your skin when you are cold. DO NOT wear cotton in cold weather situations since cotton holds moisture and causes evaporation next to your skin.
Emergency Cold Weather Clothing Layers
Use a 3 layer clothing system to maintain a normal body temperature in cold weather conditions. The main goals are to retain heat and stay dry by dispensing and repelling moisture.
Base Layer: The Base Layer of clothing is right next to your skin and is made from artificial fibers like polyester or nylon. Artificial fiber clothing wicks moisture away from your body, which can otherwise freeze or evaporate, both which make you colder.
Cotton underwear and even cotton thermal underwear should not be used because cotton holds moisture next to your body which promotes heat loss through evaporation and conduction.
Insulation Layer: The Insulation Layer of clothing needs to be breathable, like wool or fleece, allowing moisture to vent. Multiple small layers insulate by trapping non-heat conducting air between them. They also have the added benefit of being able to easily self-regulate to a comfortable temperature by adding or removing layers as necessary, rather than one bulky layer.
For shelters, wool or fleece blankets work wonderfully. Store plenty of blankets in your at home emergency supplies. You can never have too many blankets. In a pinch, you can use dry leaves, crumpled paper, or anything else that will trap air layers all around you.
Outside Protective Layer: The Outside Protective Layer of clothing protects against the elements such as wind, rain, snow and sun. Unless you are in an extremely wet environment, water resistant is usually better than water proof because it “breathes” better, letting moisture out.
A protective layer for your shelter, like a tarp, protects you from the ground. A tent also will protect you from other elemental hazards in the surrounding environment. A Mylar tent can reflect your body heat back to you in cold weather and reflect sun and heat away in hot. Any safe structures that block wind, rain or sun can save your life.
An understanding of cold weather clothing layers and the science of effective sheltering will help you to use your available resources to maintain body temperature and make effective, life saving shelters in an emergency situation.
Sheltering at Home in the Cold
HEADLINE! Cold Snap Freezes All City Utilities!
Just as in all preparedness plans, it is important to make your preparations before the emergency happens. Make your home ready for cold weather emergencies by applying the science concepts spoken of earlier on this page.
- Look for and create a warm room. Choose one room of the house as the designated warm room where everyone will spend most of their time. This saves on any limited heating resources you may have during the emergency situation.
- Select a room on the highest level of the house with a low ceiling. Since heat rises, these will be the warmest rooms. The low ceiling will hold the heat closer to where you need it to stay warm.
- Select a room with south facing windows. This will allow the direct sunlight to help provide heat during the day to your room. Keep all house windows clear and clean during the day to allow as much solar radiation in as possible. Think about turning your home into a make-shift solar oven.
- Insulate your windows with clear plastic sheeting. This allows sunlight in during the day, but creates an insulative layer of trapped air to hold in heat. The distance between the plastic sheeting and the window should be about one inch. Be sure no air can escape from between the plastic and the window. Use duct tape to seal off any drafts. At night use curtains, blankets or other insulative materials draped over windows to help hold in the heat.
- Isolate and insolate your warm room from the rest of the house. Again you only want to warm as few areas as possible to conserve your heating supplies. Cover doors, under doors and other openings with blankets or towels. Don’t forget to leave some ventilation to allow oxygen into the room for breathing, especially if using heaters, candles, or other indoor safe supplies that consume oxygen. Just a thought, avoid using any kind of open flame if at all possible to avoid the risk of fire.
- Make a “nest” or a room within your warm room. Use small tents, blankets, couch cushions, etc. to isolate and insulate your nest and make it even warmer than the larger warm room. Couch cushions just like the fort you made as a kid are excellent for insulation.
- Get cozy with the family. Radiation from body heat can be used to keep each other warm and warm the inside of the nest. Get Mom, Dad, the kids, Grandma, and Grandpa all together in the same nest. Sleep together inside the same tent, even in the same bed or sleeping bag if possible.
- Eat high calorie foods and stay hydrated to generate heat from your metabolism, the process of breaking down food into energy. When possible, eat hot, simple to prepare meals to help in maintaining your body temperature.
- Use indoor safe heaters, fireplaces, or woodstoves. There are many commercially available alternative fuel heaters that are safe to use indoors. Be sure to allow a sufficient supply of oxygen to enter into your room and check the manufacture’s guidelines to know how to safely use your device. Keep a ready supply of fuel for your heater or fireplace.
Don’t forget the dangers of Carbon Monoxide (CO). Don’t use fuel burning camp equipment indoors. Don’t use gas appliances like the oven, stove, or dryer to heat your home. Don’t use gas powered tools indoors (generators, etc). Large propane bottles are never to be indoors, so have a long enough hose to allow the bottle to stay outside while the indoor safe heater is inside. Check the manufactures directions for safe operation.
Sheltering at Home in the Heat
HEADLINE! Heat Wave Knocks Out All City Utilities!
Just as in all preparedness plans, it is important to make your preparations before the emergency happens. Make your home ready for hot weather emergencies by applying the science concepts spoken of earlier on this page.
- Before the emergency, install an adequate number of attic vents to allow accumulated heat to be dispelled from your home. Additionally, have energy rated and UV protective windows installed. These measures will lower your utilities bills and help your home be cooler when the power is out.
- During the heat wave emergency, look for and create cool rooms. Choose rooms of the house as designated cool rooms where everyone will spend most of their time. This saves on any limited resources you may have during the emergency situation.
- Select rooms on the lowest level of the house. Since heat rises, these will be the coolest rooms. Following this principle, sleep with your mattress directly on the floor to be cooler by a few more degrees than you would be otherwise a few feet higher on the bed frame.
- Select rooms with only north-facing windows. This will block the heat and light from the southern sun during the day and still allow for outside cool air at night. Cover all windows, especially south and west-facing, with aluminum foil or Mylar blankets. Apply foil or Mylar directly to the windows, eliminating as much air between them as possible. This not only blocks the light and heat of the sun, but reflects it away, preventing the heating up of inside air.
- Keep all doors and windows closed during the day to keep out hot air, and then open upper level windows at night to let accumulated heat escape.
- In dry climates, in addition to foil or Mylar, promote evaporation by hanging wet blankets or sheets in front of windows and doors. As the moisture evaporates from the blankets, it creates a cooling effect. Hospitals often do this during heat waves to keep their bed-ridden patients cool. In extreme heat, sleeping in wet sheets and clothing can also help keep you cool. Unfortunately, this does not work well in areas of high humidity where the surrounding air is already saturated with moisture, hampering evaporation.
- Be sure to limit your activities during the hottest part of the day. Use caution when exerting yourself especially in high humidity areas where sweating does little to cool you down.
- Staying hydrated is important to help your body maintain its own cooling system. Have plenty of stored water on hand to maintain your level of hydration.
- If you have to cook to prepare your meals, which is a distinct possibility if the power is out and the freezer starts to defrost, cook outdoors to keep the heat out of the house.
Safely Build a Fire
Fire provides heat, light, a means of cooking and boiling, safety, and signaling. Know how to safely make a fire before your life depends on it. Always practice fire safety.
Building and lighting a safe fire requires four things:
- A DRY BASE. Build fire on dry ground or other dry material. Make a five-foot radius around the fire to prevent spreading.
- TINDER. Tinder includes very dry grass, weeds, cattail down, or shreds from the inside of tree bark. Pocket lint and cotton are
also good tinder.
- An IGNITION SOURCE. A match, lighter, magnesium rod and striker, or magnifying lens are all good ignition sources. Learn different methods.
- KINDLING. Kindling is what the fast burning tinder ignites. Gather kindling in at least three different sizes. Begin with dry wood about toothpick to matchstick size. Build these in a tee-pee around the tinder BEFORE lighting. Build a second tee-pee of Q-tip sized kindling around the first tee-pee. Finally build a third tee-pee of pencil sized kindling.
Ignite the tinder. As it starts to smoke, gently blow on the tinder to encourage combustion. Once the burning tinder ignites the kindling and it starts burning and popping, add larger fuel to the fire.
Making a fire is an important preparedness skill. So is putting it out. Have a means of putting out a fire before you ever light it like a bucket of water or a shovel to scoop dirt on top. Be sure fires are cool to the touch before you leave.