In the system of preventive measures aimed at ensuring safe working conditions and reducing occupational poisoning and diseases, personal protective equipment (PPE) for workers in production plays an important role. Their use becomes necessary in cases where difficulties arise in ensuring the safety of technological processes and production equipment with existing technical means and the conditions of contact of workers with factors harmful to health.

During everyday work, personal protective equipment is most often used as one of the links in the overall complex of preventive measures, while during emergency, repair and other occasional work, they become one of the main measures to ensure the safe performance of work.

The need to use PPE is regulated by the fundamental standards of the State Standardization System (GSS) and the Occupational Safety Standards System (OSSS). According to these regulatory documents, all newly developed and revised standards for production processes and equipment, materials and substances must include specific requirements for protective equipment for workers. In addition, the SSBT system identifies an independent classification group of standards for protective equipment for workers. In our country, specialized organizations and enterprises are engaged in the development, production, evaluation and supply of PPE. As a result of the existing system of control over the development and production of PPE by state and trade union bodies, most modern domestic PPE is characterized by high protective and performance properties, providing reliable protection from all kinds of dangerous and harmful production factors. The use of homemade PPE designs that have not passed certain stages of development, examination and implementation is strictly prohibited.

The effectiveness of using PPE is determined by the following basic requirements: the correct choice of a specific brand of PPE, maintaining PPE in good condition, training of personnel in the rules for using PPE in accordance with the operating instructions during the entire period of their use.

The purpose of using PPE is to reduce to acceptable values ​​or completely prevent the possible impact of harmful production factors on the body. Unlike collective protective equipment, PPE is directly on the person, therefore they are subject to requirements for minimal negative impact on the functional state and performance of the person. Depending on the purpose, personal protective equipment for workers is divided into the following classes: insulating suits; respiratory protection equipment; special clothing; special shoes; hand protection; head protection; face protection; eye protection; hearing protection; safety devices; protective dermatological products.

The main purpose of workwear is to provide reliable protection of the human body from various production factors while maintaining normal functional state and performance. In recent years, requirements for the aesthetic performance of workwear have increased.

All types of protective clothing are divided into groups and subgroups according to their protective properties. For example, there is special clothing for protection from thermal radiation, sparks and splashes of molten metal and scale; from oil, mechanical damage (abrasion) and low temperatures, etc. The protective, operational and hygienic properties of workwear primarily depend on the materials from which it is made, therefore special requirements are placed on the quality of fabrics. To achieve the required properties when sewing workwear, cotton, linen, wool, silk and synthetic fabrics are used, as well as fabrics with film coatings and made from a mixture of natural and synthetic fibers. To give fabrics certain protective properties, they are impregnated with various compounds (waterproof, water-repellent, heat-resistant, fire-resistant, oil-oil-resistant, acid-resistant, acid-repellent or light-resistant combined impregnations). Film-coated materials are generally intended to protect against hazardous and harmful liquid substances. Recently, widespread use of materials with a metallized coating has begun, which are intended for protection against infrared radiation. Semi-linen, asbestos, synthetic fabrics, as well as fiberglass fabrics are used as the basis for applying the metallized layer. Ensuring the protective properties of workwear depends not only on the properties of the materials used, but also on its design. Therefore, when creating workwear, they are guided by certain requirements that take into account the entire complex of indicators of its quality and purpose. These indicators are divided into common for all groups and subgroups of workwear and specialized ones, characterizing the protective properties of a specific group or subgroup in accordance with its purpose. General indicators of the quality of workwear mainly characterize its operational, hygienic and aesthetic properties. These include the strength and rigidity of the seam, wear time and time of continuous use; compliance of fabrics, materials and design with working conditions; resistance to washing, artistic and aesthetic indicators, etc.

One of the main general requirements for workwear, regardless of its protective properties, is to ensure the normal thermal state of a person. Clothing creates a certain microclimate around the body, depending, on the one hand, on human heat generation, and on the other, on the meteorological parameters of the external environment and the properties of clothing (its design, physical and chemical properties of materials, etc.). Indicators of the microclimate of the under-clothes space are its humidity and air temperature, as well as the carbon dioxide content in it. In conditions of thermal comfort, the relative humidity under clothing is 35 - 60%. This indicator can be used to judge the ability of clothing to transfer moisture from the surface of the body to the environment. Increased air humidity in the under-clothes space has an unfavorable effect both in conditions of high and low temperatures. Increased humidity in the underwear space when working in conditions of high dust or gas pollution contributes to skin irritation and increases the rate of penetration of harmful substances through the skin. The air temperature of the under-clothes space is a function of a person’s physical activity, therefore the optimal values ​​of this indicator vary depending on the intensity of work. Thus, for a person in a state of relative rest, a comfortable temperature in the body area is 30 - 32 °C, and during heavy physical work - 15 °C. In this regard, when assessing the hygienic properties of clothing based on the air temperature of the space underneath, it is necessary to take into account the physical activity of a person and environmental conditions. For example, when working in a cooling environment, a large decrease in air temperature directly under outer clothing indicates its insufficient thermal resistance, and when working in conditions exposed to wind, it indicates high air permeability.

Specialized quality indicators characterize the protective properties of workwear. These include the following: the tensile strength of the product and its parts (for workwear from mechanical stress and general industrial pollution); thermal conductivity, air permeability and vapor permeability (for workwear against high and low temperatures); protection factor and ability to decontaminate (for protective clothing against radioactive substances); lead equivalent (for X-ray protective clothing); electrical resistance and protection factor (for workwear against electrostatic charges, electromagnetic and electric fields); dust resistance and resistance to dust removal (for dust-proof clothing); acid-proof (for workwear against acids), alkali-proof (for workwear against alkalis), etc. Ensuring the specified requirements is achieved by using workwear in the model, in addition to appropriate materials, using various structural elements. Thus, when designing workwear for use in conditions of changing environmental parameters, the use of multi-layer insulation, fastened to the main fabric, insulated underwear, insulating pads and various ventilation devices is provided. This allows you to adjust the thermal resistance of clothing by changing the thickness of the insulation depending on the ambient temperature. Protection from the wind is provided by special valves along the fastening line of the jacket and trousers, a hood, headphones, and structural elements that protect the face. Overalls for protection against harmful liquid factors must have a minimum number of seams, as well as protective valves along the lines of fasteners and pockets; its cut should not prevent the flow of liquids. Structural elements that provide protection from dust-like harmful factors and microorganisms include all kinds of additional cuffs, valves, belts, capes, etc. In workwear, to protect against local exposure to oil, acids, alkalis, and petroleum products, linings from the appropriate materials resistant to these substances. One of the ways to improve a person’s heat exchange, and therefore his well-being, is to introduce special elements into the design to ensure air ventilation in the space under clothing. These include various yokes in the back and front areas, holes of various shapes at the bottom of the sleeve armholes, at the top or along the entire length of the crotch seams, etc.

Master the methods of hygienic assessment of fabrics for various purposes according to their physicochemical properties and personal protective equipment for the body, sensory organs, and respiratory organs.

Initial knowledge and skills

1. Anatomical features and physiological functions of the skin of the human body.

   Hygienic meaning and functions of clothing and footwear.

   Types and physical and chemical properties of clothing fabrics.

2.2. Be able to:

2.2.1. Work with a catathermometer, micrometer, torsion or analytical balance when determining the physical and chemical properties of fabrics.

Questions for self-study

Anatomical features and physiological functions of the skin of the human body.

Hygienic significance, functions, types of clothing for various purposes: household, industrial, hospital.

Main types of fabrics, their classification by origin and purpose.

Physico-chemical indicators characterizing the hygienic properties of fabrics for clothing for household, industrial, and hospital use.

Hygienic requirements for various layers of clothing depending on their functional purpose.

Hygienic features and criteria for assessing the microclimate of the underwear space.

Hygienic characteristics of the properties and possibilities of using natural fabrics in various layers of clothing for various purposes.

Hygienic characteristics of the properties and possibilities of using synthetic fabrics in different layers of clothing.

Hygienic requirements for hospital linen and clothing.

Classification by purpose and hygienic characteristics of industrial clothing fabrics.

Classification and characteristics of protective clothing against harmful factors in the working environment - physical, chemical, biological. Hygienic working conditions in it.

General scheme for hygienic assessment of fabric. Methodology for determining its individual indicators (thickness, specific gravity, porosity, capillarity, hygroscopicity, relative steam and thermal conductivity, resistance to acids, alkalis, organic solvents, mechanical action, thermal radiation, etc.).

1. Structure and content of the lesson

Laboratory lesson. In the first half, the teacher checks the students' preparation for the lesson. Theoretical issues are considered, according to their list in paragraph 3 and appendices 1, 2. In the second half of the lesson, students receive individual assignments to study tissue samples for various purposes, in which a number of physical and chemical parameters are determined:

porosity and breathability;

• specific gravity (density);

  capillarity;

  thermal conductivity;

  vapor permeability, evaporation capacity;

  hygroscopicity;

  acid resistance;

  alkali resistance;

  resistance to organic solvents.

The determination of these indicators is carried out according to the methods given in Appendices 3, 4 and recommended in the mandatory literature. It is advisable to record the summarized results in a table in the following form:

Results of tissue sample examination ___________________________

(its name and purpose)

Students complete the study by justifying conclusions characterizing the origin and properties of the fabric, indicating the type (layer) of clothing for which it is advisable to use this fabric.

General hygiene: lecture notes Yuri Yurievich Eliseev

Clothing hygiene

Clothing hygiene

An important part of personal hygiene is clothing hygiene.

According to F. F. Erisman, clothing is a kind of ring of protection from unfavorable natural conditions, mechanical influences, protects the surface of the body from pollution, excess solar radiation, and other unfavorable factors of the domestic and industrial environment.

Currently, the concept of a clothing package includes the following main components: underwear (1st layer), suits and dresses (2nd layer), outerwear (3rd layer).

According to the purpose and nature of use, clothing is distinguished between household, professional (working clothing), sports, military, hospital, ritual, etc.

Everyday clothing must meet the following basic hygiene requirements:

1) provide an optimal microclimate under clothing and promote thermal comfort;

2) do not impede breathing, blood circulation and movement, do not displace or compress internal organs, do not disrupt the functions of the musculoskeletal system;

3) be strong enough, easy to clean from external and internal contaminants;

5) have a relatively small mass (up to 8-10% of a person’s body weight).

The most important indicator of the quality of clothing and its hygienic properties is the microclimate under clothing. At an ambient temperature of 18-22 °C, the following parameters of the underwear microclimate are recommended: air temperature - 32.5-34.5 °C, relative humidity - 55-60%.

The hygienic properties of clothing depend on a combination of a number of factors. The main ones are the type of fabric, the nature of its manufacture, and the cut of the clothing. Various fibers are used to make fabric - natural, chemical, artificial and synthetic. Natural fibers can be organic (plant, animal) and inorganic. Plant (cellulosic) organic fibers include cotton, flax, sisal, jute, hemp and others; organic fibers of animal origin (protein) include wool and silk. Inorganic (mineral) fibers, such as asbestos, may be used to make some types of workwear.

In recent years, chemical fibers, which are also divided into organic and inorganic, have become increasingly important. The main group of fibers of chemical origin are organic. They can be artificial and synthetic. Artificial fibers include viscose, acetate, triacetate, casein, etc. They are obtained by chemical processing of cellulose and other raw materials of natural origin.

Synthetic fibers are obtained by chemical synthesis from oil, coal, gas and other organic raw materials. Based on their origin and chemical structure, heterocidal and carbocidal synthetic fibers are distinguished. Heterocides include polyamide (nylon, perlon, xylon, etc.), polyester (lavsan, terylene, dacron), polyurethane, carbicides include polyvinyl chloride (chlorin, vinol), polyvinyl alcohol (vinylon, kuralon), polyacrylonitrile (nitron, orlon ).

The hygienic advantages or disadvantages of certain fabrics primarily depend on the physicochemical properties of the original fibers. The most important hygienic values ​​of these properties are air and vapor permeability, moisture capacity, hygroscopicity, and thermal conductivity.

Air permeability characterizes the ability of a fabric to pass air through its pores, which determines the ventilation of the underwear space and the convection transfer of heat from the surface of the body. The breathability of a fabric depends on its structure, porosity, thickness and degree of moisture. Breathability is closely related to the fabric's ability to absorb water. The faster the pores of a fabric fill with moisture, the less breathable it becomes. When determining the degree of air permeability, a pressure of 49 Pa (5 mm water column) is considered standard.

The air permeability of household fabrics ranges from 2 to 60,000 l/m2 at a pressure of 1 mm of water. Art. According to the degree of breathability, windproof fabrics are distinguished (air permeability 3.57-25 l/m2) with low, medium, high and very high air permeability (more than 1250.1 l/m2).

Vapor permeability characterizes the ability of a fabric to pass water vapor through its pores. Absolute vapor permeability is characterized by the amount of water vapor (mg) passing through 2 cm 2 of fabric within 1 hour at a temperature of 20 ° C and a relative humidity of 60%. Relative vapor permeability is the percentage ratio of the amount of water vapor passing through the fabric to the amount of water evaporating from an open vessel. For different fabrics this figure varies from 15 to 60%.

Evaporation of sweat from the surface of the body is one of the main ways of heat transfer. Under conditions of thermal comfort, 40-50 g of moisture evaporates from the surface of the skin within 1 hour. Sweat production of more than 150 g/h is associated with thermal discomfort. Such discomfort also occurs when the steam pressure in the underwear space is above 2 GPa. Therefore, good vapor permeability of the fabric is one of the factors in ensuring thermal comfort.

Removal of moisture through clothing is possible by diffusion of water vapor, evaporation from the surface of moistened clothing, or evaporation of sweat condensation from layers of this clothing. The most preferred way to remove moisture is the diffusion of water vapor (other ways increase thermal conductivity, reduce air permeability, and reduce porosity).

One of the most hygienically important properties of fabric is its hygroscopicity, which characterizes the ability of fabric fibers to absorb water vapor from the air and from the surface of the body and retain it under certain conditions. Wool fabrics have the greatest hygroscopicity (20% or more), which allows them to maintain high heat-protective properties even when moistened. Synthetic fabrics have minimal hygroscopicity. An important characteristic of fabrics (especially used for the manufacture of linen, shirts and dresses, and towels) is their ability to absorb droplet-liquid moisture. This ability is assessed by tissue capillarity. The highest capillarity is for cotton and linen fabrics (110-120 mm/h or more).

Under normal temperature and humidity conditions, cotton fabrics retain 7-9%, linen - 9-11%, wool - 12-16%, acetate - 4-5%, viscose - 11-13%, nylon - 2-4%, lavsan – 1%, chlorine – less than 0.1% moisture.

The thermal protective properties of a fabric are determined by its thermal conductivity, which depends on its porosity, thickness, the nature of the weave of fibers, etc. The thermal conductivity of fabrics characterizes thermal resistance, to determine which it is necessary to measure the amount of heat flow and skin temperature. The density of the thermal cover is determined by the amount of heat lost from a unit of body surface per unit of time, by convection and radiation with a temperature gradient on the outer and inner surface of the tissue equal to 1 °C, and is expressed in W/m2.

As a unit of the heat-protective ability of fabric (the ability to reduce the density of heat flow), the value clo (from the English clothes - “clothing”) is adopted, which characterizes the thermal insulation of indoor clothing equal to 0.18 ° C m / 2 h / kcal. One unit of clo provides a state of thermal comfort if the heat generation of a quietly sitting person is approximately 50 kcal/m 2 h, and the surrounding microclimate is characterized by an air temperature of 21 ° C, a relative humidity of 50%, and an air speed of 0.1 m/s.

Wet fabric has a high heat capacity and therefore absorbs heat from the body much faster, contributing to its cooling and hypothermia.

In addition to the above, fabric properties such as the ability to transmit ultraviolet radiation, reflect visible radiation, and the time it takes for moisture to evaporate from the surface of the body are of great hygienic importance. The degree of transparency of synthetic fabrics for UV radiation is 70%; for other fabrics this value is much less (0.1-0.2%).

The main hygienic advantage of fabrics made from natural fibers is their high hygroscopicity and good air conductivity. That is why cotton and linen fabrics are used to make linen and linen products. The hygienic advantages of woolen fabrics are especially great - their porosity is 75-85%, they have high hygroscopicity.

Viscose, acetate and triacetate fabrics, obtained by chemical processing of wood cellulose, are characterized by a high ability to sorb water vapor on their surface; they have high moisture absorption. However, viscose fabrics are characterized by prolonged evaporation, which causes significant heat loss from the surface of the skin and can lead to hypothermia.

Acetate fabrics are similar in properties to viscose. However, their hygroscopicity and moisture capacity are significantly lower than those of viscose, and when they are worn, electrostatic charges are formed.

Synthetic fabrics have attracted particular attention from hygienists in recent years. Currently, more than 50% of clothing types are made using them. These fabrics have a number of advantages: they have good mechanical strength, are resistant to abrasion, chemical and biological factors, have antibacterial properties, elasticity, etc. The disadvantages include low hygroscopicity and, as a result, sweat is not absorbed by the fibers, but accumulates in air pores, impairing air exchange and the heat-protective properties of the fabric. At high ambient temperatures, conditions are created for the body to overheat, and at low temperatures, conditions are created for hypothermia. Synthetic fabrics have 20-30 times less ability to absorb water than woolen fabrics. The higher the moisture permeability of the fabric, the worse its heat-protective properties. In addition, synthetic fabrics are capable of retaining unpleasant odors and are less washable than natural ones. Destruction of fiber components due to their chemical instability and migration of chlorine compounds and other substances into the environment and underwear space are possible. Migration, for example, of formaldehyde-containing substances continues for several months and can create a concentration several times higher than the maximum permissible concentration for atmospheric air. This can lead to skin resorptive, irritant and allergenic effects.

Electrostatic voltage when wearing clothes made of synthetic fabrics can be up to 4-5 kV/cm, with a norm of no more than 250-300 V/cm. Synthetic fabrics should not be used for underwear of newborns, toddlers, preschoolers and primary school children. When making rompers and tights, it is allowed to add no more than 20% synthetic and acetate fibers.

Basic hygienic requirements for fabrics of various origins are presented in Table 6.

Table 6. Hygienic requirements for various types of fabrics.

Hygiene requirements for various components of a clothing package

The components of a clothing package perform different functions, which is why the hygienic requirements for the fabrics from which they are made are different.

The first layer of the clothing package is underwear. The main physiological and hygienic purpose of this layer is the absorption of sweat and other skin secretions, good ventilation between the skin and underwear. Therefore, the fabrics from which underwear is made must be highly hygroscopic, hydrophilic, air- and vapor-permeable. Natural fabrics best meet these requirements. The second layer of clothing (suits, dresses) should ensure the creation of an optimal microclimate under clothing, help remove fumes and air from the laundry and correspond to the nature of the work performed. From a hygienic point of view, the most important requirement for the second layer of clothing is its high vapor permeability. For the manufacture of suits and other types of second layer, you can use both natural and synthetic fabrics. The most appropriate are mixed fabrics (for example, lavsan mixed with wool), which have improved sorption properties, reduced electrification, high vapor permeability, low thermal conductivity, combined with good performance and appearance.

The main functional purpose of the third layer (outerwear) is protection from cold, wind, and adverse weather conditions. Fabrics for this layer must have low thermal conductivity, high wind resistance, moisture resistance (low hygroscopicity), and abrasion resistance. Natural or synthetic furs meet these requirements. It is advisable to use combinations of different fabrics (for example, combine a top wind- and moisture-proof layer made of synthetic fabric with a heat-insulating lining made of a mixture of artificial and natural fur and wool). Recommended standards for some material indicators for various layers of clothing are presented in table No. 7

Chlorine staple fiber was previously widely used for the manufacture of medicinal knitted underwear. Chlorine underwear has good heat-protective properties and, due to the so-called triboelectric effect (accumulation of an electrostatic charge on the surface of the material as a result of its friction against the skin), has a beneficial effect on patients with rheumatism and radiculitis. This linen is highly hygroscopic and at the same time air and vapor permeable. The disadvantage of chlorine linen is its instability to washing at high temperatures. In this regard, medical underwear made from polyvinyl chloride has an advantage.

Antimicrobial underwear has been developed and is being used. Preparations of the nitrofuran series can be used as bactericidal agents for antimicrobial linen.

Additional requirements apply to children's clothing. Due to a less perfect mechanism of thermoregulation, a significantly larger specific ratio of the size of the body surface to a unit of its mass in children than in adults, more intense peripheral blood circulation (a large mass of blood flows in the peripheral capillaries), they are more easily cooled in the cold season and overheated in the summer. Therefore, children's clothing should have higher thermal insulation properties in winter and promote heat transfer in summer. It is important that the clothing is not bulky, does not interfere with movement, and does not cause disturbances in musculoskeletal tissues and ligaments. Children's clothing should have a minimum number of scars and seams, and the cut should be loose.

Differences in natural and climatic conditions in Russia also determine hygienic requirements for clothing. 16 zones with different requirements for the heat-protective properties of clothing have been identified. So, for example, for the zone of mixed and deciduous forests of the central zone of the European part of Russia, a comfortable state in the summer is provided by clothing with thermal protection of 0.1-1.5 Clo, in winter - 3-5 Clo, depending on the nature and severity of the work.