DEVELOPMENT OF TESTER USED IN EVALUATING UNDERWATER BREATHING APPARATUS

A test set-up called hyperbaric unmanned tester has been developed to assess the safety andreliability of deep sea respirator before manned testing. The tester possesses three basic capabili-ties: First, it is to simulate the operational conditions of underwater breathing apparatus. Thatis, it can reproduce ambient pressure as great as that of 300 meters deep sea water and ambienttemperature ranging between 4℃ and 40℃. It is also capable of reproducing the diver’s posture

Computer-Based Estimation of Spine Loading during Self-Contained Breathing Apparatus Carriage

Firefighters’low back disorders(LBDs)are closely related to excessive spine loading when using the self-contained breathing apparatus(SCBA)continuously.The purpose of this study was to quantify firefighters’spine loading and evaluate the effects of strap lengths of SCBA on altering spine loading.Computer-based musculoskeletal models of three varying-strapped SCBA conditions and a control condition(CC)with no SCBA equipped were developed.The model was driven using three-dimensional(3 D)inertial motion capture data from twelve male subjects performing a walking task and the predicted ground reaction force(GRF).Electromyography(EMG)activities were also recorded to validate the results from the model.The 4 th-5 th lumbar vertebra(L4/L5)joint reaction forces,as well as erector spinae and rectus abdominis forces,were finally obtained.Results demonstrated that carrying SCBA significantly increased the compressive force and anteroposterior shear force at the spine.The risk of potential LBDs increased by about 17.77%.Dynamic balance of erector spinae and rectus abdominis contraction was also disturbed when carrying SCBA,indicating a higher risk of spine muscle strain.Adjustment of SCBA strap length was an efficient method to influence spine loading.The medium-fitting strap(MS)with a length of around 101 cm generated minimum joint reaction forces and achieved the optimum dynamic balance of spine muscle contraction,which was recommended for firefighters.

Safety Parts of Body to Respiration with Breathing Apparatus in Dangerous Zone

People are witnesses of life imperilling and working background too, as today, even during the evolution. People＇s life interface is disturbed with different shapes of contamination： natural disasters （floods, earthquakes, volcanic eruptions and the other）; on purpose or accidentally-different shapes like： wars, fires, chemical fates, using of dangerous materials in production processes and everyday life... In these mentioned specific conditions, breathing is imperiled, like the vital function of men＇s life and working interfaces. With the technical-technology progress, it is enclosed the development equipment for protection and safety of the respiratory parts of body, faces and eyes, regard to breathing apparatus. Applying the breathing apparatus, the total protection of the respiratory parts of the body, faces and eyes to aggressive materials, smoke and warmth is enabled. Today in the world there are many producers of breathing apparatus with similar technical-technological solutions, of which should be mentioned the main ones： MSA Auer, Dr/iger and Interspiro. Using of the breathing apparatus in practice, continual performation of different activities without consequences for the health and life of the user is enabled, what firstly depends on the user＇s education, regular using, controlling examination and maintenance/servicing.

Effect of Respirator Resistance on Tolerant Capacity during Graded Load Exercise

Respirator breathing resistance impacts performance of wearers during constant work load. However, it is less clear as to how breathing resistance affects the tolerant capacity of users during graded work load. The present study investigated the tolerant capacity of 8 individuals during incremental work load. The 8 subjects were required to wear two matched respirators （respirators Ⅰ and Ⅱ which were designed to have different breathing resistances and the same dead space） respectively on separate days and then work to end points. Minute ventilation （VE）, breathing frequency （BF）, oxygen consumption （VO2） and heart rate （HR） were recorded during exercise, while tolerant time, response time and breathing discomfort were measured at the end of each test trial. The test variables were com-pared between the two respirators by using matched-pairs t-test. The results showed that the tolerant time was significantly reduced for the respiratorⅠwith higher level of breathing resistance when compared with its counterpart with lower breathing resistance （respirator Ⅱ） （P〈0.05）. The same changes occurred for response time. Results also showed a significant increase in VE and BF for respirator Ⅰwearers when the work load was above 125 W. The O2 consumption was similar under the two breathing resistance conditions. These findings suggested that the respiratory resistance caused by self-contained breathing apparatus （SCBA） has an impact on the tolerant capacity of users.