Evaluation Practice of Personal Protective Equipment Effect

2 Effect Factors of Personal Protective Equipment

From the point of view of human environment and system engineering , people are the main elements of the system. After the use of personal protective equipment, protective person becomes a person in the state, thus changing the direct links and interaction between man and machine and the environment, the impact of this change is generated extremely important and can not be ignored. Impact studies and evaluation of personal protective equipment for people, inseparable from the analysis of the personal protective equipment, the effect of factors, but also inseparable from the phase dependent on environmental conditions, that is, from the perspective of a people person protective equipment a system's operating environment.

In a certain operating environment , the role of personal protective equipment on people can be illustrated by Figure 1 .

The role and impact of personal protective equipment effect factors on people are the main aspects of the problem , which are embodied in three aspects :

1 Physiological effects - Personal protective equipment increases human physiological load , such as heat stress, respiratory stress, extra physical loads, etc .; 2 psychological effects - due to personal protective equipment, uncomfortable and protective behavior of pressure , increasing the psychological load;

(3) Ergonomics - The ergonomic performance of humans is declining , including restrictions on human sensory functions ( visual, auditory, speech, smell, etc. ) caused by the wearing of gas masks .

Protective clothing mechanical limitations on physical activities and manual dexterity of losses caused by antivirus gloves. In fact , these effects do not occur in isolation , and there are very complex interlinkages and roles between them.

Environmental factors , especially thermal environmental factors , further exacerbate the impact of personal protective equipment on human physiological load, psychological load , and ergonomics ; this compounding effect often severely impairs people's ability to work , in which compound heat stress effects It is the main form of expression. At the same time, analysis of the characteristics and differences in the characteristics of the people, is also of particular significance in the settlement of personal protective equipment and pleasant design and reduce their load.

Third, the personal protective equipment effect evaluation practice

We carry out the evaluation of personal protective equipment effects. Research practice has three important characteristics :

1 The related work mainly takes place in the process of equipment development tasks, and closely integrates the needs of each development ;

2 Emphasizing the characteristics of the PLA's personal protective equipment, personnel groups , and military operating environment ;

â‘¢ actively learn from foreign fruit research work to determine the research goals and direction, work to reduce blindness.

The following is a brief review and summary of some of our scientific research practices on personal protective equipment in the past decade.

1 . Heat Stress and Its Impact on Personal Protective Equipment

Heat stress personal protective equipment from the equipment itself thermal resistance and dampness, personal protective equipment is the most serious limiting factor. After the staff wear personal protective equipment, heat exchange with the surrounding environment of the human body to be constituted by personal protective equipment "Interface", the "interface" thermal resistance and wet resistance greatly limits the sensible and latent heat between the human body and the environment Exchange ability.

In the hot environment , the evaporation of sweat becomes the main way for human body to dissipate heat , and the poor moisture permeability of antivirus clothing has a greater influence than the thermal resistance factor , which is the root cause of a long-term protective equipment heat stress.

Personal Protective Equipment Heat stress on the human body inevitably leads to a physical stress response , that is, a heat stress response ; typical symptoms of a heat stress response include : elevated body temperature ( body heat storage ) , accelerated heart rate, and intense sweating. The degree of heat stress response of protective personnel depends on the nature of the protective clothing, the state of protection, the level of exercise, and the environmental conditions.

In general , heat stress in personal protective equipment in a mild environment does not lead to excessive thermal stress in the human body , but the heat stress in personal protective equipment in a hot environment is a strong heat stress response of personnel , and it is personnel work The main limiting factor of competence ; therefore , research on the effects of heat stress on personal protective equipment usually uses the thermal environment as the environmental condition for the test. Changing the inner and outer layer material of the protective clothing and functional requirements will affect the permeability of protective clothing, protective clothing several models comparative test carried out in laboratory conditions `.2 31 show, to different persons heat protective clothing should be Radical reactions can produce significant differences , and distinguish the heat stress level of protective clothing.

The protection status can be divided into two conditions: pre-protection ( wearing antivirus clothing ) and full protection ( wearing all personal protective equipment ) .

When the state of preventive care, although limits sweat evaporation cooling capacity of the body, but the head, face, neck, hand, foot cooling effect is not restricted, and even be enhanced: while the full protection status, can only rely on the permeability of protective clothing evaporative Heat dissipation. Therefore , the person's heat stress response in the full protection state is much stronger than the pre-protection state and can be fully confirmed from the test results in Table 1 . As the exercise load increases , the body's energy level increases accordingly , and most of these occur as heat , which actually results in increased levels of endogenous heat stress. Therefore, protection of personnel working in different strength, heat stress total receiving level are different, thermal stress caused by the exercise load can be quantified levels of heat stress in the test results in Table l also reflects this change .

2 . Wear time limit of personal protective equipment and its criteria

In the hot environment , the serious consequence of the heat stress of the personal protective equipment is the strong heat stress response of the protective personnel . With the prolongation of the protection time , the excessive heat storage of the human body may lead to dangerous situations such as heat failure , so personnel can only implement limited The protection of time , which is to reduce the operating time. The permissible wearing time ( wearing time limit ) of personal protective equipment has been used as an important evaluation indicator for the physiological performance of personal protective equipment . We define the wearing time limit of personal protective equipment as "When environmental protection and sports load conditions are met and when the protection personnel reach the thermal endurance limit duration (protection) job. " Human thermal tolerance is the physiological basis for determining the time limit for wearing , but it should also have specific criteria to operate. In the summary of test data on the basis of the criterion used abroad and analyzed a large number of verification according Monitorability, the principle can be observed, physical security, and internal consistency of the determined usability criterion and test methods to achieve increased 2 ℃, The book reached 1 80 times m/in lasting 5im n , symptoms of heat stroke aura , and the chief complaint strongly demanded that the trial be terminated.

The characteristics of the wearing time limit of personal protective equipment under laboratory simulation conditions are that the test conditions can be controlled, the effect indicators can be fully set and monitored, and the cost is small . However , there are also poor representativeness of the physical fitness level and habitual acceptance of the tested persons. Limitations ; and the characteristics and limitations of the field ( field ) test have a reversible nature , if you can strictly control the test conditions , then the field test results will have a strong objectivity, reliability and practicality , and to achieve The simulation test conversion lays a solid foundation.

To this end, we are at a scale of 40 50 subjects who (army soldiers) organized moist heat and dry heat, wearing a new time limit personal protective equipment operating at moderate intensity (march speed 5 km / h) Force test field conditions We investigated the protective status, load status, and the impact of training on acclimatization wearing time limits. The results show that: in a typical wet (dry) hot environment and moderate work intensity, wearing a time full protection status who are less than lh, while wearing a time limit to be reduced by about 20% Carried basic combat equipment; further heat acclimation training can improve There is no obvious effect of the person's level of heat stress response and wearing time limit ; in the pre-protected state , there is a significant difference in the wearing time limit of the personnel in the dry heat and hot and humid environment . The reason can be explained as the body's sweat evaporation and heat dissipation capacity in the dry heat environment. Strong influence.

Table 2 shows the main results of the time-limited test for wearing hot and dry heat.

3 . Effects of Personal Protective Equipment on Personnel Energy Consumption and Exercise Endurance

The personal energy consumption level after wearing personal protective equipment is related to the speed of the road, the slope of the road, and the weight of the body. It is worth considering whether the personal protective equipment additionally increases the user's physical energy consumption , and the test produced a positive conclusion.

The increase in energy consumption caused by personal protective equipment may be due to the extra weight of the equipment ; the mechanical friction caused by the distension and stiffness of the protective clothing and the hindrance to physical activity ; physiological stress causes an increase in functional consumption in the body. The consequences of increased personal energy consumption caused by personal protective equipment mainly include two aspects : on the one hand, the level of effective physical fitness is relatively reduced , and the duration of endurance work is reduced ; on the other hand, endogenous heat stress is increased. During submaximal exercise, it does not result in a significant increase in gas masks just art energy; but in extreme sports maximum power consumption reduced by about 8% of people, even in a high altitude environment still observed similar results. The physiological mechanisms that lead to this result are not yet fully clarified.

In general , endurance exercise ability is an important indicator of physical fitness evaluation. The test results in Table 3 show that endurance exercise capacity limitations of personal protective equipment personnel, particularly the staggering impact of full protection status, the reason can be explained by fundamental analysis above.

4 . Personal protective equipment comfort evaluation

Research on the comfort of personal protective equipment has always been widely considered . From the broad sense , comfort is considered as an important limiting factor in the use of personal protective equipment. The current personal protective equipment is far from enabling people to reach a comfortable level , objectively reflecting the level of comfort of personal protective equipment and the endurance of personnel , and thus judging the degree of comfort of personal protective equipment is an important starting point for research. In conjunction with the requirements for the development of equipment , in recent years we have focused on the issue of the evaluation of gas mask comfort. Gas mask is applied to the head face loads breathing resistance, respiratory dead space, pressure, weight, etc., the combined effect of these load factors led to the discomfort of the wearer; research has also pointed out that the senses are limited, face shield and other factors increase With psychological load , some people may have serious reactions.

The early 1990s, we used a rating scale test head and cheek caused several gas masks tenderness, tenderness under the collar, ears and neck tenderness, inspiratory breath comfortable and relaxed nature, and there is a useful method of fuzzy mathematics comfort level test mask of a comprehensive evaluation, achieve better results. Afterwards , we also used 40 categories of indicators for testing and evaluation . According to the analysis results and the difficulties of designing gas masks , we identified and determined n items of evaluation indicators , which have a high application value.

5 . Research on Ergonomics of Personal Protective Equipment

In recent years , we have conducted a number of specific ergonomic evaluation tests for new types of personal protective equipment. the experiment shows:

â‘  personal protective equipment may hinder the activities of limbs, such as standing long jump, positioning high jump, step across, bent, leg on song after leg lift and other activities have a significant impact, the greatest impact on the bow, looking upward movements, to turn Head and partial head also have a certain degree of influence ;

â‘¡ personal protective equipment have significant impact on the javelin a kind of tactical operations involve the whole body motion component, decomposition, assembly of firearms only involves finger dexterity, feel the tactical operations of a class have a very significant impact, while the prone shooting a The impact of quasi-static tactical operations is relatively limited. It is believed that personal protective equipment, the impact on the soldiers tactical operation efficiency is mainly determined by the decline in activity in the human body caused by personal protective equipment.

The sensory function of protective personnel is also an important factor affecting ergonomics. After wearing the mask as a serious decline in the ability to call, the effective distance calls gas mask portion is less than 20 m, 1/4 13 a distance approximately normal call /. These kinds of results are difficult to meet the requirements of the modern battlefield environment for personnel comprehensive capabilities, and the impact on the effectiveness of military operations is very obvious.

Fourth, the conclusion

The peculiarity of personal protective equipment lies in its direct and close effect on personnel ; on the one hand , it solves specific threats.

The problem of survivability of people in the threat environment , on the other hand, its various load factors have reduced people's work efficiency. Therefore , the development of personal protective equipment needs to continuously resolve these conflicting issues and aspects and achieve a new balance . Its fundamental purpose is to improve the effectiveness of protective personnel.

Evaluation of the effect of the practice of personal protective equipment has become an important part of research equipment and the contents of the review and summary, we have demonstrated significant progress and achievements in the professional direction. In addition, we also established a system test methods more systematic.

The main problems facing the future evaluation of personal protective equipment and scientific research are mainly the following two aspects :

From the perspective of equipment development requirements , the conclusions on the physiology and ergonomics of personal protective equipment should be translated into technical indicators that guide the demonstration and design of equipment ; from the perspective of military application requirements , the conclusions on the physiology and ergonomics of personal protective equipment should be translated into guidance on the use of equipment. , training and combat methods and procedures.

Therefore, we must increase the breadth and depth of research and evaluation work, the evaluation model based tests to improve the model-based evaluation model theory, the human-machine-environment system engineering theory and methods of this will play an important role in guiding .

The information in this article comes from the Internet and was reorganized and edited by China Rescue Equipment Network.