Sleeping bag

A sleeping bag is an insulated covering for a person, essentially a lightweight quilt that can be closed with a zipper or similar means to form a tube, which functions as lightweight, portable bedding in situations where a person is sleeping outdoors (e.g. when camping, hiking, hill walking or climbing). Its primary purpose is to provide warmth and thermal insulation through its synthetic or down insulation. It also typically has a water-resistant or water-repellent cover that protects, to some extent, against wind chill and light precipitation, but a tent is usually used in addition to a sleeping bag, as it performs those functions better. The bottom surface also provides some cushioning, but a sleeping pad or camp cot is usually used in addition for that purpose. The bottom surface of a sleeping bag may be moderately water repellent, but a plastic tarp or groundsheet is often used to protect against moist ground.

There are a range of sleeping bag models designed for different purposes. Very lightly insulated sleeping bags are designed for summer camping use or for indoor use by children during slumber parties. Well-insulated bags are designed for cold weather use. The most well-insulated and lightweight sleeping bags, which are designed for serious hikers and adventurers, are more expensive than lightly insulated sleeping bags. One subcategory of cold-weather sleeping bag, the mummy bag, is so named because it has an insulated hood for the head. A bivouac sack (bivy) is a waterproof cover for a sleeping bag that may be used in place of a tent by minimalist, experienced hikers. A bivy bag may also be carried by day hikers as a backup or emergency shelter, to be used if they cannot make it back to their starting point by nightfall due to inclement weather or getting lost.

Concept and forms of bag

The concept holds in his name; it is a sleeping bag. Therefore, it must conform to the shape of the human body leaving however a necessary margin for ventilation, or freedom of movement. Any sleeping bag is characterized by the presence of an opening leaving the head outside of it, and usually an integrated hood to offer protection and comfort in the same way as for the rest of the body. This hood is adjustable by turnbuckles. Also on many models is a side zipper that allows easier access to the bag itself. The outside of the bag offers resistance to moisture and external aggressions.

A sleeping bag folds lengthwise and carefully wraps around to remove air, and then sits in a bag that varies in size, but usually not more than 12 liters. However, this practice is not recommended by some specialists, since the folds take place regularly in the same place, thus deteriorating the lining 3. The shape of a sleeping bag plays an important role in its performance in addition to determining comfort and volume.

The mummy bag is known for its lightness and ability to keep warm. Marrying body shapes, it reduces heat loss and offers a better warmth-to-weight ratio than a larger bag. However, some people find it too confining.
The barrel bag has swapped the thermal efficiency for more space. It does not have a hood, it is slightly pointed and has an oval style at the feet. It is also a bit bigger and heavier than the mummy bag.
The rectangular bag is not very popular with travelers in the wilderness because, in addition to its low insulation, it is bulky and heavy. Large and inexpensive, it is especially useful in hot weather.
The quilt or top bag is used by people looking to limit the weight of their bag. The insulating area (down or synthetic) in contact with the ground is replaced by the hiking mattress which is also insulating. The bag is thus lighter and the insulation remains correct.
Size, weight and volume
The size of the sleeping bags varies depending on the model. Some are adapted to the low measurements of children, while others benefit adults even of infrequent size (2.30 m).


Insulating capacities
The insulating capacity of the sleeping bag is a key factor that defines its framework of use. A sleeping bag is sold with 3 reference temperatures; T ° Comfort, T ° Limit, and T ° Extreme. If the most powerful sleeping bags in the world displayed extreme temperatures below -50° C 5, the mainstream range extends between 10° C and -10° C.

This insulation is done by the presence of the largest possible air in the foam of the bag and its cells. Indeed, the air is an insulator, and therefore transmits little heat, either the cold to the sleeping bag, or the heat contained inside it to the outside. Conversely, a wet or wet sleeping bag, besides its discomfort, will lose much of its insulating capacity. The human body can contribute to the humidification of the bag since it eliminates between a quarter and a third liters of water per night. It is therefore necessary, especially in hot weather, that the bag can breathe to have an optimal insulating capacity.

Insulation Materials
Two types of insulation are mainly used in the upholstery and therefore the insulation of sleeping bags: down and synthetics. These two types of insulation have very distinct qualities, each with its advantages and disadvantages.

Down is a natural material made up of very small feathers. It offers a very large volume composed of a large majority of air, which gives it an important insulating capacity. The insulation / weight ratio is therefore important. This compressible volume – although sometimes heterogeneous – is at the origin of the comfort procured. Down is said to have improved durability. However, moisture makes it lose some of its thermal performance, and is more difficult to dry than other materials. Also, the down has the disadvantage of being more expensive than the synthetic material whose factory production is done in large volumes.

Synthetic fiber offers a very affordable price through industrial production. They offer an insulating power and a variable resistance according to their composition, but have the main advantage impermeability, and thus, the assurance of a stable insulation. On the other hand, the quality of materials varies enormously, some materials will offer less durability. In addition, synthetic foams are generally less compressible than down, and heavier for equivalent comfort.

Sleeping Bag Types

Youth Hostel Sleeping Bag
The youth hostel sleeping bag or hut sleeping bag is a unlined, mostly rectangular sleeping bag made of simple fabric, which serves only hygienic purposes; he replaces the sheets and covers in youth hostels, mountain huts and nature friends’ houses as a personally brought-in object.

Mummy sleeping bag
The mummy sleeping bag owes its name to the mummy’s close-fitting cut with a framed head, which promises particularly high heat retention capacity at a comparatively low weight. It is therefore mainly used to sleep in a tent or outdoors; High-quality versions with elaborate, highly insulating filling material ensure comfortable sleep even in extreme frost. To sleep outdoors (without a tent) mummy sleeping bags are often combined with a bivouac sack, which additionally warms the outer shell and prevents possible precipitation and wind.

A variant of the mummy form is the egg shape. Especially in the chest and hip areas, these are significantly wider than mummy sleeping bags and thus represent a good compromise between heat retention and sleeping comfort. Especially for people who move or turn around during their sleep, or overweight, an egg sleeping bag is the best choice.

Sleeping bag with arms and legs
The sleeping bag with arms and legs has a body shape, so arms and legs, which gives advantages in mobility in the tent or at the campsite. The sleeping bag with arms and legs is particularly suitable for very nocturnal sleepers.

An expedition sleeping bag is designed for the needs of expeditions and high altitude mountaineering. The sleeping bag must protect its user from temperatures below -40 ° C. For this it has an extreme insulation. A distinction is made between synthetic fiber and down sleeping bags.

Synthetic sleeping bag
Synthetic fiber sleeping bags now cover temperatures of up to -40 ° C in extreme conditions. They use elaborate synthetic fibers, which have a very high thermal insulation. The main advantage of synthetic fiber sleeping bags lies in the insensitivity to water and moisture. But they are usually a bit heavier than down sleeping bags.

Down sleeping bag
Down sleeping bags are suitable in extreme conditions at temperatures down to -50 ° C. The sleeping bags use goose down as thermal insulation. The mixing ratio describes the relation of down to normal feathers in the filling, the higher the down, the better the sleeping bag is insulated. The down makes the sleeping bag but also sensitive to pressure and humidity. In the expedition area, mixing ratios of 90/10 to 97/3 (down / feathers) are used. There are quality differences in the down filling, it is given as a loft or fill power. The higher the loft, the better the sleeping bag will be.

Inner sleeping bag
An inner sleeping bag, also known as an inlay, is a type of thin sleeping bag made of cotton, fleece, silk, synthetic fibers or combinations of these materials, which is used in addition to the sleeping bag to the temperature range of the sleeping bag increase the moisture during sleep from the body and to protect the sleeping bag and how to keep bedding clean so as not to have to clean it so often. In addition, a ticking in warm temperatures is also flexible for use alone.

Sleeping Bags in Space
In the weightlessness of space, a regular bed would not work, as the top bed, pillows, and finally the sleeper itself would simply lift off the mattress and float away. Because of the lack of gravity neither a thick mattress nor a slatted frame are required, astronauts sleep in mostly mummy-shaped, thinly padded sleeping bags, which are fixed on the floor or on the wall of the sleeping cabin.

Baby sleeping bag
A baby sleeping bag is a special form of sleeping bag that is not intended for outdoor use but serves as a regular sleeping accommodation for infants.

Design types
A basic sleeping bag is simply a square blanket or quilt, fitted with a zipper on two or three sides, which enables users to get into the bag and then close it up. A sleeping bag of this type is packed by being folded in half or thirds, rolled up, and bound with straps or cords with cord locks. The basic design works well for most camping needs but is inadequate under more demanding circumstances.

The second major type of sleeping bag, sometimes called a mummy bag because of its shape, is different in a number of important ways. It tapers from the head end to the foot end, reducing its volume and surface area, and improving its overall heat retention properties. Some bags are designed especially to accommodate women’s body shapes. Most mummy bags do not unzip all the way to the feet, because the zipper is a weak point in any sleeping bag’s insulating qualities. Together with the tapered shape, this design feature helps protect the feet, which are more vulnerable to heat loss than other parts of the body. Another design feature is a drawstring, equipped with a cord lock, at the head end to help prevent the escape of warm air. A mummy bag often cannot be rolled like a rectangular bag. Instead, it is simply stuffed into a stuff sack or compression sack.

The bottom of a sleeping bag typically does not provide significant insulation, because body weight crushes the loft of the insulation material. It is therefore necessary to use a pad or other less crush-able insulation underneath the sleeper, especially in cold weather. Due to this, some sleeping bags do not include insulation on the bottom. Some include a sleeve for holding a sleeping pad. Additionally, some campers, especially ultralight backpackers or hammock campers, have started to use a top quilt, essentially a sleeping bag without a back. Some top quilts include a foot box, while others are just simple blankets.

Many insulating materials are available for sleeping bags. Inexpensive sleeping bags for warm weather use or use by children indoors typically have a layer of synthetic quilt insulation. Outdoor professionals and serious amateur adventurers usually prefer either synthetic fill (e.g. PrimaLoft), or natural fill (e.g. down), and they have debated the merits of these materials for years.

Synthetic fill does not readily absorb water, dries easily, and provides some warmth even when thoroughly soaked. These properties may save the owner’s life if, for example, the sleeping bag is accidentally dropped into water on a cold day. Synthetic material is also firm and resilient, so it insulates well even underneath a person’s weight. On the flipside, synthetic fill cannot be compressed as much as down and it weighs more, causing such bags to take up more space and weight when not in use. Furthermore, synthetic insulation tends to break down faster than its natural counterpart.

Down fill weighs less than synthetic and retains heat better, but usually costs more. Down must be kept dry; a soaked, down sleeping bag may provide even less insulation than no sleeping bag at all, leading to hypothermia. Newer, more technically advanced sleeping bags often have water-resistant shells and can be used in damper conditions. It is also recommended to keep a sleeping bag in a larger sack (storage sack) as opposed to the small traveling sack (compression bag) during long periods of storage. However, many regular backpackers and hikers agree that hanging a sleeping bag, taking care to move the position of the bag on the hanger at intervals so as to not create a “dead spot” (a spot where the fill has been crushed so that it is no longer useful), is the best method of storing a bag for long durations.

Other materials, notably cotton and wool, have also been used for sleeping bags. Wool repels water nicely and also resists compression, but it weighs much more than any alternative. Cotton suffers from high water retention and significant weight, but its low cost makes it an attractive option for uses like stationary camping or car camping where these drawbacks are of little consequence. Cotton insulation does not provide warmth if it becomes wet (due to the sleeping bag falling into water), so cotton-insulated sleeping bags are not used by professionals or serious hikers.

Temperature ratings
In Europe, the EN 13537 standard normalizes the temperatures at which a sleeping bag can be used. A test, relying on a heated mannequin, provides four temperatures:

the upper limit is the highest temperature at which a ‘standard’ adult man is able to have a comfortable night’s sleep without excess sweating.
the comfort rating is based on a ‘standard’ adult woman having a comfortable night’s sleep.
the lower limit is based on the lowest temperature at which a ‘standard’ adult man is deemed to be able to have a comfortable night’s sleep.
the extreme rating is a survival only rating for a ‘standard’ adult man. This is an extreme survival rating only and it is not advisable to rely on this rating for general use.
The transition zone, in between the comfort and lower temperature, is usually considered as the best purchase guideline.

A sleeping bag’s rating typically indicates the lowest temperature at which it will keep the average sleeper warm. For example, with a 0° bag, a person should be able to sleep in 0° temperature, but not necessarily comfortably.

There is no standard measurement rating in the U.S., so a 20° bag from one company may not provide the same warmth as a 20° from another company. Other important variables include what the user plans to wear while sleeping, what type of sleeping pad is used, and how well the user holds heat in the bag.

It has been shown that moisture (either externally, or from sweating) severely decreases the insulating effect of sleeping bags.

Indoor sleeping bags
Indoor sleeping bags, sometimes called slumber bags, are widely available, often for use particularly by children. These are usually not designed to be weatherproof and are often made of natural fabrics instead of the synthetic fabrics commonly used for outdoor sleeping bags. Children’s sleeping bags in particular often feature elaborate, brightly colored printed designs, such as images of popular media characters. Slumber bags make floor sleeping more comfortable, and are often used for sleepovers, family visits, and other situations where there are not enough beds for everyone.

Infant use
An infant sleeping bag is a bag-like garment or covering worn by infants for sleeping in. Infant sleeping bags differ from regular sleeping bags in design and purpose, being designed primarily for indoor rather than outdoor use, and usually featuring either arm holes or sleeves.

The definition used in the British Standard for safety of children’s sleep bags is “sleep bags for the use of children with a minimum weight of 4 kg designed to provide sufficient warmth so as to remove the need for additional bedding when sleeping in a cot or similar product in which a child is contained.” It goes on to exclude “garments with sleeves and feet, i.e. sleep suits or baby grows, or to products designed primarily for outdoor use or to keep children warm when in a pushchair.”

Performance data
The temperature specifications of sleeping bags have been based on DIN 7943 in Germany so far. European standard EN 13537 replaced this DIN standard in 2005 with a more differentiated standard for the temperature specifications of sleeping bags. The EN is based on a laboratory evaluation method, also finds the different temperature sensation of men and women now considered and is, each in their own comfort areas, for both sexes separated.

The comfort area describes the temperature range within which an inexperienced user feels comfortable at all times. When interpreting the norm values, it should be noted that the lower limit of the comfort range is lower for men than for women.

Within the risk area or survival area, one can expect a strong sense of cold, up to the risk of damage to health. This information should not be the basis of the usage decision. The sleep can be interrupted here often by the strong feeling of cold and is not so relaxing. Below the risk area, frostbite is expected.

The EN standard refers to civil sleeping bags in which medium weight, long functional underwear is worn.

Indicated according to European Standard EN 13537:

The comfort range (TCom) related to the “norm woman” (25 years, 60 kg, 160 cm).

The lower limit (TLim), relative to the comfort range of the “norm man” (25 years, 70 kg, 173 cm). It describes the lower temperature value at which the male subject can sleep comfortably for one night.

The survival area (TExt). It carries the risk of hypothermia and should not be regarded as a practical area for the “normal consumer” and used to make a purchase decision.

Representation of the areas

These values are summarized graphically in a bar chart. On the diagram, the upper end of the comfort range is indicated first, followed by the lowest comfort temperature of the woman – this area is highlighted in red.

The lowest comfort temperature of the man is given next – this area is highlighted in yellow.

Finally, the extreme temperature is indicated, it indicates the lower end of the survival area – this area is highlighted in blue.

Criticizing this norm, whose values are determined with a doll, is that the sweating and movement of a person during sleep is not taken into account.

Evaluation of different performance figures
The cold resistance of people depends strongly on the physical habituation and on the current physical and mental state of the person. Anyone who was exposed to physical exertion, hunger, wetness, etc. during the day – which, for example, can regularly be the case when hiking, mountaineering etc. – will be less cold-resistant during the night. Here, the sleeping bag within the red area – the comfort area (TCom) – should be used or selected.

Under the more practical verification method of the EU standard, the majority of sleeping bags no longer achieve the excessive performance values specified under the old DIN standard.

The US ASTM F1720 standard makes the performance of a sleeping bag even more positive than the other two standards do.

Performance data of military sleeping bags are outside the EU standard and also in combination with other specific equipment of the soldier. Therefore, they also indicate by far too positive performance values for the civilian user. In addition, the military data also very young men are used, which is why – because of the significantly different metabolic services – is based on an even higher cold resistance of the assumed user.

However, the new laboratory-oriented EN is also critically discussed, since, for example, constructive optimization of the air-tightness of the outer shell in the laboratory can achieve very good results. However, the behavior of the sleeping bag that is equally relevant for the practice of absorbing perspiration or the influence of restless sleep has not taken into account the sleeping bag’s capacity under the experimental set-up of the standard.

A sleeping bag is cleaned for the same reason that a bed changes; the human body sweats, odors become imbued, and dirt settles over time. Moisture can lead to the proliferation of bacteria or mold. These phenomena cause a deterioration of the material. The outer wall of the bag also takes dust, soil or various micro-elements that can lead to aging of the textile. So, whether it’s hygiene or maintenance, it’s best to keep a clean sleeping bag.

Several operations are possible. The simplest is to ventilate the sleeping bag for discharging a part of the internal moisture generated by the human body which rejects up to one third of liters of water per night. Thus, one gains in durability and one avoids the impregnation of odors. For a more complete maintenance, it is possible to use the washing, whether by hand or washing machine in accordance with the prescriptions given by the mark, but this technique is to be avoided as much as possible for the duvets. Indeed, besides the fact that most washing machines do not support the necessary load, there is a risk of heterogenization of the insulation, and the drying time of the bag extends beyond two days, even in using a tumble dryer. For synthetic materials, the use of washing machines is less delicate, but by reducing the amount of soap used, and leaving aside the softener. The drying time when firmly wrung out is around 24h. There are, among other things, specially optimized cleaners which retain the maximum insulating properties while protecting the outer casing of the bag.

The bulking power of down on down sleeping bags is measured in cuin.

Sleeping bag accessories
Sleeping mats. It can go from simple foam and aluminum carpet, very light, compact and inexpensive, but which allows a better insulation between the ground and the sleeping bag, the inflatable carpet, weighing about 1 kilo, which also allows insulation, but which also has the advantage of being more comfortable, passing by the foam mat (karrimat), lightweight but bulky and less comfortable than the inflatable carpet. The inflatable mat can be inflated directly through the mouth, in less than 5 minutes. For more efficiency, it is possible to put on the ground first, a foam and aluminum carpet, then over, an inflatable carpet, thus better protecting the inflatable carpet, cold soil and sometimes messy, and have less risk of damaging the inflatable carpet by sharp objects on the floor.
Silk sheet, cotton, fleece for hiking. They make it possible to avoid dirtying the sleeping bag and thus washing it too often, which makes losing the power of insulation during washing. The cloth of silk, cotton, or fleece also make it possible to improve the temperature of the sleeping bag by 2 to 3 degrees.
A waterproof and breathable polyamide bag with a weight of approximately 500 grams. It better protects the sleeping bag from moisture, wind, and dirt and also improves the temperature of the sleeping bag by 2-3 degrees.
A hat. The head is a vital organ, having a lot of blood. The loss of heat is very important in the head when it is cold.

In the field of ultralight hiking lightweight alternatives are often used, the weight saving is mainly based on the choice of materials not necessarily missing material is omitted. Ray Jardine suggested that the bottom part of the sleeping bag should be omitted to save weight, as it would be squeezed by the body weight of the sleeper anyway and thus could hardly isolate. He designed a lightweight quilt with a closed foot box, so that the lower end could not slip. In his books, Jardine disseminates building instructions for self-sewing, several manufacturers took up the principle, and various variants developed. For top bagsthe underside is only a fabric, in which the mattress can be inserted. In Quilts these back eliminated so that a quilt a quilt with foot comes close. There are also models that combine sleeping bag and mattress.

Hammock camping uses under-quilts that isolate the hammock down. Because they were squeezed into the hammock by the weight of the sleeper and thus lose much of the thermal insulation effect, you hang them from below to the hammock. So-called Half-Length-Underquilts are only half as long as the Full-Length-Under-Quilts and insulate from the shoulders to the buttocks. A short sleeping mat or clothes are placed under the legs.

Source from Wikipedia