Allowance for the free fit can be considered consisting of two parts with different purposes: the minimum required allowance for loose fit clothing PS.min and decorative-constructive allowance of PS.d.to. PS = PS.min + PD.to.
The magnitude of the components of the allowance for loose fit on different parts of clothes differs depending upon various factors.

Minimum required allowance for free customized fit

Regardless of the degree of conformance of the product when designing it is necessary to ensure the freedom of breath and movement, the minimum pressure on the body, and the presence of the air gap to regulate the heat transfer in clothing layer and skin respiration.
The basis for the proper establishment of allowances for free breathing and movements is the study of changes in body size in dynamics in comparison with the size in repose. The first work in this direction done by the research Institute of anthropology of Moscow state University and B. A. by Rozovym.
First of all, consider the changes that occur with body size when breathing. When you inhale the chest circumference increases. The difference in the girths of the chest, measured in deep inspiration and full expiration, in medicine called "the excursion of the chest". It is different for different people and depends on age, physical development of man, its training, and other factors: in athletes it is usually more than individuals not involved in sports. According to A. 3.Alimov, the excursion of the chest is equal to the average: persons not involved in sports, 5.5 cm, and the athletes and 6.5 - 8.0 cm (full bust).
To determine the allowance for free customized fit to the size of the clothes is more applicable other figure equal to the difference in the measurements of the chest when deep breathing and quiet breathing (table 11-1), as all body size for which designed clothes, obtained during quiet breathing.
If you change the position of the body and various movements of arms, legs, trunk bending during walking (i.e. in dynamics) to individual body size changes more than during breathing (table 11-2).

As can be seen from the table, different movements make different changes to the individual body size. The greatest change in the longitudinal dimensions of the trunk are marked at the instep and circular movements of the hands, the size of the zone of the lower extremities and the extremities when the body is tilted forward. Thus, the distance from the waist to the desired length of the folds increases by more than 45%, or about 15 cm, the length of the leg when bent at the hip and knee joints is about 8%.
The greatest changes of the transverse dimensions occur on the chest and 2 to 4 cm above the chest line, and in the back more than the chest.
Lateral dimensions above and below the line of the chest (girth of the waist, shoulder diameter etc.) change slightly.
As a rule, arc the dimensions of the body, such as breast width and shoulder width are changed to a greater extent than obratnye dimensions (chest girth). This is because in some movements more change body size in the front, other from behind. For example, the convergence of the blades or diverting hands ago causes an increase in the width of the chest up to 10% of the size in repose. The width of the back usually decreases. Lift and stretch arms forward, on the contrary, leads to a significant increase in the width of the back (30% of the size in repose).
Data on changes in body size in the calculation of allowances to the sizes of clothing you need to coordinate with the design, appearance and purpose of clothes.
It should be borne in mind that clothing may partially move from one part of body to other, the size of which at this point increase. Therefore, it is possible to slightly reduce the amount of the allowance for loose fit around the perimeter of this area of the body.
Allowances for movement in the longitudinal dimensions clothes usually are not given, as this may distort its appearance. In addition, the design of most products allows them to move freely along the body. In the presence of the cuffs, pinning the sleeve at the wrist, strap or belt, a tight cinch at the waist, you need to give allowance and the longitudinal dimensions for the formation of the inlet.
The amount of the minimum required allowance for the free breathing and movements should be calculated first of all for the main body size that determines the width of the scarf - bust. Design requirements the minimum required allowance should be differentiated depending on the purpose of clothing. So, for the special clothing needed to proceed, apparently, from the maximum changes of body size.
For household clothes, wearing which a man did not commit sudden movements, the minimum required allowance to the poluobhvat chest for free breathing and movements can be found on the basis of changes of this size with a deep breath.
As can be seen from table 11-1, a change of girth of the chest with a deep breath the average is 2 - 4% of the size during quiet breathing. This accounts for the extreme sizes (44 and 60), respectively, of 0.9 - 1.8 cm and 1.2 - 2.4 cm or 1.5 cm poluobhvat chest.It is obvious that the magnitude of the minimum required allowance may not be less than the magnitude of the changes in the chest with a deep breath plus 1/2 of the interval of indifference between adjacent sizes of clothes, as the clothes of this size are not only people, the size of the poluobhvat chest which is equal to the size of the clothes, and the dimensions of which are similar to within +-1/2 intervals of indifference. Then the minimum necessary allowance for the freedom of breathing rack 2-layer (dress, coat, jacket) may not be taken less than 1,5 + 1,0 = 2,5 cm
For coats, cloaks, belonging to the clothing of the 3rd layer, the value of the minimum required allowance should be increased by an amount equal to the allowance for the thickness of the clothing materials of the 2nd layer. If we take the thickness of the clothing materials of the 2nd layer on average is 0.25 - 0.30 cm (jacket, jacket), the allowance for the thickness of the clothing materials of the 2nd layer will be equal to 3,14 X (0,25 - 0,3) = 0,8 - 0,94 = 1,0 see Thus, for clothes 3-layer value of the minimum required allowance for freedom of breath cannot be taken less than 2.5 + 1,0 = 3,5 cm
Normal heat and also skin breathing is impossible without the presence in the clothing air layers. Modern clothes, especially heat, is a complex structure consisting of several layers of tissue. Formed between the individual layers of tissue and between the clothing and body surface air gap create a microclimate around human body. The dependence between the desired value of air layers and the basic parameters of microclimate is not installed. There are only approximate data calculated on the basis of the instructions of Professor F. F.Erismann, clothing fabrics of different fibrous composition. The magnitude of the air gap must not be less than: for clothing of wool fabric and 2.5 δ, δ of 3.0 silk and cotton 3,25 δ (where δ - the total thickness of the fabric in clothing). These data can be derived for the approximate calculation of the minimum allowances for air space for parts of the body that are closed clothing: for shoulder products along the lines of the chest, waist and hips, waist - at the hip line.
In some cases, for example when designing clothes jerseys, the air gap between the product and the body isn't provided at all. It is formed after a short socks from the accumulation of the material deformation and increase the size of the product.

Estimates of allowances for air layer to poluobhvat of the chest, waist and hips for clothing are given in table. 11-3.
Rack 2-layer (dresses, jacket, jacket) are given in table. 11-3 data can be taken as allowances for air layer.
For clothing 3-layer seam allowance to air layer will be equal to the sum of allowances between the clothing of the 1st and 2nd layers and 2nd and 3rd layers. The total allowance for air space for coats will be thus equal to: (1,90 - 2,36) + (2,80 - 3,54) = 4,7 - 5,9 see
Minimum required allowance for free customized fit to poluobhvat chest can be determined from comparison of allowances for free breathing and air space and take equal the amount of the allowance that is more. For women's easy dresses minimum allowance for freedom of breath and movement (2.5 cm) significantly exceeds the allowance for an air layer (0,4 - 1,0 cm). For jacket, jacket it is also more allowance for air layer, which averages about 2 cm (1.9 to 2.4 cm).For coats minimum allowance for an air layer is equal to the average of 5.5 cm (4.7 - 5.9 cm), while the allowance for freedom of breath and the thickness of the material of the 2nd layer is 3.5 cm.
It follows that for dress, jacket, and jacket minimum required allowance for loose fit at the chest line, you can take the same, equal to 2.5 cm For coats minimum required allowance for loose fit may not be taken less than 5 - 6 cm.
On the recommendations of CNIISHP minimum required allowance called technical gain. The value of the technical allowances established for dresses 2 cm, coat or jacket - 3 cm, coat - 4 see

Decorative and constructive allowance for silhouette

Decorative and constructive allowance, also called the increase in decorative and constructive design, the allowance for the allowance or silhouette to silhouette form, depends on the type of clothes, the shape-silhouette, model decoration.
Practical observations and investigations show that the decorative and constructive allowances are determined in the process of creative work of fashion artist and designer on the model. Therefore, they cannot be calculated or regulated with sufficient accuracy only on the basis of a sketch, drawing, models to manufacture the primary sample of this product. The correct definition of decorative and constructive allowances depends, therefore, almost exclusively on the skill and experience of artist and designer.
For practical purposes it is advisable to give some generalization and systematization of materials for allowances, for example, in the form of recommendations of the all-Union House of models on the allowances for "leading" in every season, the silhouettes of the clothes, etc.

The average values of decorative and constructive allowances to the width of the backrest and shelves depending on the kind of clothing, fabric and silhouette, calculated on the basis of data on the total increases recommended TSNIISHP can be used as a guide when building the initial drawings of clothing items.
Decorative and constructive allowance for the width of the openings aligned with the width of the sleeves.