Renato Barišić, Ivan Radoš RENATO BARIŠIĆ, IVAN RADOŠ Algebra – University College for Applied Computer Engineering, Zagreb, Croatia renato.barisic@racunarstvo.hr , ivan.rados@racunarstvo.hr
CROSAFETY – A SYSTEM FOR RAISING THE QUALITY LEVEL OF SAFETY Stručni rad/Professional paper Summary In the European Union every year there are more than 4 million accidents at work, of which more than 400,000 are injuries to the head and neck. Most accidents are caused by negligence and a false sense of security. Classic helmets offer only external protection, and impact force cannot be redirected. The CroSafety helmet is a specially designed helmet that absorbs the force of the blow and redirects it to the outer parts of the system and thus protects the head, neck and spine. The main advantage is increased head protection due to the absorption of impact forces through a unique dorsal addition. The system is designed to act preventively, and so that the employer has complete control over the health condition of the employees. Three sensors are built in to the helmet: an alcoholic-vapour detector, an EEG which monitors brain activity, and a sensor for measuring body temperature. The resulting information is sent by built-in communication to the supervising services, and the health of employees can be monitored and analysed in order, in certain cases, to act preventively. In particular, attention is turned to the quality of materials used, constant monitoring and improvement of the performance of the manufacturing process and system feedback. Keywords: accidents at work, protection, helmet, monitoring, prevention 1. INTRODUCTION The basis of this project is a large number of work related injuries, which are frequently caused by negligence and a false sense of safety. This product offers complete control over the workers and their health. Various innovative additions to this equipment create a highquality basis for a revolution in safety systems. The concept starts from the head as the most important part of the human body. Classic helmets which are available on most world markets provide only surface protection, while during a severe impact they cannot properly direct the force away from the parts of the head where the impact has occurred. The designed CroSafety helmet will amortize the force and directs it to the external parts, while the parts of the head remain protected. The practice has shown that most of protective equipment needs to be used under special working conditions (working at heights, working in depths, etc.) so two factors were considered that can affect workers' safety. The first factor is health, while the second one is the functional factor. The first factor refers to, for instance, epilepsy when working at heights, fever as a consequence of some kind of inflammation, or alcohol consumption on site, all of which reduce concentration and endanger workers' lives. Three sensors were built into this product which detect values and send them via a Bluetooth module to the central unit where everything is supervised by a representative of the company. This way, one person has complete insight into the health of the workers. The functional safety part has the functionality of being able to be used for working at heights without modifications or
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Renato Barišić, Ivan Radoš additions (it is possible to hook it up to a foothold and this way prevent a fall), it provides protection from UV radiation (during welding and working outdoors) and protection from tiny airborne particles (metal dust caused by sanding, fine stone, etc.). It also includes highvisibility elements (the vest has reflective parts and thus prevents the danger of a worker not being observed by other workers while operating a machine), an area which is designed for transfer and use of hand tools (the tool is attached to a strap which prevents tools from falling from a height and thus protects workers at lower levels), and many other functions as well. This product would be mainly aimed at employers and workers, and then to insurance companies which, if they use this product, can reduce the risk of insured event payments. It should be noted that this system detects additional information of great importance to employers and provides excellent indicators to insurance companies due to monitoring the behavior of employees. Two main indicators should be emphasized. The first one is measuring the distance of the central unit from the position of the workers (which provides insight into the worker's location at any time as well as the amount of time they spend there). The second indicator is information about the use of equipment (whether the worker uses protective equipment and to what extent). This can be useful for all the participants of the working process (for example, insurance companies can see whether the worker used protective equipment when the accident happened, and employers can obtain information about the extent to which their workers abide by the regulations concerning safety at work). Since Croatia became a full member of the European Union, the decision was made to compare the annual financial losses in the strongest EU member states and Croatia (Table 1). Table 1: Current situation Germany
France
UK
Croatia
EU
GDP per capita ($)
40,757
44,730
38,309
17,753
34,500
Total number of accidents at work (3 days or more of absence)
887,356
612,356
245,690
13,606
3,323,873
Total expense for the economy ($)
295,489,548
224,122,296
106,138,080
1,959,264
947,303,805
Note that the data are from the last Eurostat (2011), and that the numbers have been increasing. This table provides insight into the problems and leads to the conclusion that there is a huge market potential in the EU. All of the existing products available on the market have been defined through the ISO standard, which also means that there is only one standard in the EU and in the USA. This product sets a new standard of quality and business logic should be not to aspire only to satisfy the minimal conditions for placing the product on the market, but to stand out maximally with new, higher standards in the field of protective equipment.
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Renato Barišić, Ivan Radoš 2. SYSTEM ELEMENTS AND TECHNOLOGIES After a minute market research and research into the needs of the employers, we have created a design of a product which could satisfy employers, insurance companies and legal institutions. It should be mentioned that all the technology planned to be implemented into this product can be found in other forms. What is revolutionary in this segment is applying these technologies in this form. The main functions of this product are shown on Figure 1 and listed in the following paragraphs. Figure 1: Product main functions
2.1. The ability of absorbing stronger blows The whole idea concerning this product resulted from the need to minimize the damage caused by an object falling from a height. Although head and neck injuries make a smaller percentage of on-site injuries, they are the ones with the highest fatality rate. The decision was made to use new materials in the making of the product. The helmet is designed to transfer the entire force of the blow to the outside brim. This solution works to a certain extent, but there is a point after which the spine is overloaded and suffers too much stress which can result in damage or serious injury. Different solutions were considered but in the end it was decided to redirect the force of the impact to the outer segments of the system. Outside segment is the addition to this product which will take over the excessive force and disburden the spine. The dorsal addition is designed so that it does not disturb the worker or diminish their working ability, while at the same time offering additional protection in case of falling on one’s back (Figure 2). Taking into consideration that a significant number of falls happens on stairs and that in those accidents workers end up falling on the spine (workers often fall on their back when carrying weight because their center of balance is shifted to the back part of the body), the conclusion can be made that this segment is important for the
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Renato Barišić, Ivan Radoš protection of the workers. The idea is also to have all the additions on this product functioning as one unit and to get the maximum out of the mechanical properties of each of the materials used. Figure 2: Helmet and dorsal addition
2.2. Additions for work at heights This product was designed to exploit its full potential in all of its applications. One of them is work at height so the product is equipped with different additions which enable work at heights. The waistline area of the harness enables carrying hand tools, which are tied to the worker by a self-retracting line. This serves to protect the other workers on the site from falling hand tools. When the work is finished the worker can put away the tools in a compartment on their belt. The belt also functions as a personal fall arrest system since it has buckles which the workers can use to connect themselves by a connection device to an anchorage. In case a worker falls off the platform the connection to the anchorage will stop the fall. To prevent the force of the fall from causing more damage than the fall itself, the force is distributed evenly across the entire body. This is achieved by the above mentioned dorsal addition which prevents distribution of too much force on a small area of the body. 2.3.
Alcohol evaporation sensor
There is awareness that most mistakes on building sites are caused by negligence and inappropriate behaviour of the workers on the site. A frequent problem is definitely alcohol which decreases work ability and creates a risk of mistakes which often have a fatal outcome. That problem was solved with the addition on the front part of the helmet. It is a sensor of alcohol evaporation which is already being used by some car manufacturers. Depending on the site (on some building sites liquids which release alcohol fumes are used in the work process), the limit is set and it serves as a parameter for alert. When the curve which records the percentage of alcohol fumes exceeds the set parameter, the construction site manager is alerted and the worker removed from the site. This significantly reduces irresponsible behaviour. 2.4.
Thermal imaging sensor
This sensor has a double function. Within the helmet it measures the body temperature of the worker. This information is used to analyze the health condition of the worker. It also allows us to track whether the worker is wearing protective equipment (if they are not wearing the
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Renato Barišić, Ivan Radoš helmet the sensor cannot produce any readings). If the worker does not comply with the rules they can be removed from the site. Thermal imaging helps track whether a worker has contracted some disease which might reduce their work ability. It is very useful in regular medical check-ups because every case of reduced work ability can lead to a fatal outcome. 2.5.
EEG monitor
The biggest innovation is definitely the EEG monitor. Its role is to detect an individual’s fear of heights and health irregularities. This part of the system is very important because it serves as a staff filtering tool, i.e. it can eliminate employees which should not be working at height. We can also detect if somebody suffers from epilepsy, which is one of the more frequent causes of falls from a height. It should be emphasized that the intention here is not to prevent someone from working, but rather to assign the job to somebody who can do it with less risk of suffering injury. People who are unable to work under certain conditions should be given a job which they can do without endangering themselves or others in their working environment. 2.6.
Central Management Unit
The Central Management Unit (CMU) is located on the back side of the helmet in the lower brim (Figure 3). The CMU’s role corresponds to that of the brain in human body. It gathers data from the sensors processes it and decides what to do with the result. The CMU detects any damage to the protective equipment and alerts all the participants on the construction site that there has been an accident. It also records all the data received by the sensor and compares it to basic data it has for each individual. If there is a deviation from the set parameters, it informs the central unit (the site manager’s computer) that the worker is exhibiting certain irregularities. To protect the worker from unwanted radiation (when the signal is being sent to the central unit), the device would only send data in case of deviations from the set parameters or at the request from the central unit. The site manager who operates the central unit can send a signal (PING) and measure the response (how long it takes the signal to return) which lets them know if the worker is on the site or not. This function is useful on sites which have more than one hundred employees. If the site stretches through an area where the signal would not be strong enough to connect to the central unit, additional devices can be added to serve as proxies. One of the possibilities is to divide the construction site into several zones, with each zone having its own unit which sends/receives data from the central unit. Figure 3: Central Management Unit
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Renato Barišić, Ivan Radoš The CMU is strategically located at the position where there is least chance for damage in case of a blow. The CMU would be powered by Lithium-ion batteries which are designed to withstand sixteen hours of non-stop work. After finishing work, the worker leaves the helmet to recharge until the next day. 2.7.
WiFi Crisis Management System
When an accident occurs involving one or more workers, the system detects irregularities using the aforementioned sensors. The first thing it does is broadcast an SOS signal to all in the vicinity of the worker who has had in an accident (Figure 4). Figure 4: SOS signal broadcast
The protective equipment worn by the injured worker is the same as all other worker on the site are wearing. Their equipment receives the SOS signal and the workers are informed that there has been an accident. On bigger construction sites it is not always possible to know which worker has had an accident nor the exact location. This is why a locating procedure needs to be performed. This procedure is the same locating procedure that mobile phone services providers can perform. All workers (their equipment) in the vicinity ping towards the source of the signal. The intersection of signals will locate the location of the accident. This provides the workers with the possibility to reach the injured worker sooner. By means of an active pinging system, a sound is produced on the equipment of other workers. The closer they get to the accident location, the response time of the WiFi signal from the injured worker is shorter and the sound is less intermittent. During this process, the equipment on other workers serves as a transmitter for sending a signal to the central unit. The central unit receives all the location parameters and forwards the call to the emergency services. Using this system reduces the period of time needed for providing the injured worker with assistance. 3. HELMET PERFORMANCE TESTS Two performance tests, i.e. standards, were considered for helmet performance testing and certification: ISO 3873:1977 and EN 397:2012.
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Renato Barišić, Ivan Radoš 2.8.
ISO 3873:1977
The international standard ISO 3873:1977 was published in 1977 as a result of the work of the subcommittee dealing especially with industrial safety helmets. This standard, approved by practically all the member states of the ISO, sets out the essential features required of a safety helmet together with the related testing methods. Testing methods and tests may be divided into two groups (Table 2): • Obligatory tests – tests to be applied to all types of helmets for whatever use they may be intended: shock-absorbing capacity, resistance to perforation and resistance to flame, • Optional tests – tests intended to be applied to safety helmets designed for special groups of users: dielectric strength, resistance to lateral deformation and resistance to low temperature. Table 2: Testing requirements of ISO 3873:1977 Characteristic
Description
Criteria
Obligatory tests Absorption of shocks
A hemispherical mass of 5 kg is allowed to fall from a height of 1 m and the force transmitted by the helmet to fixed false (dummy) head is measured.
The maximum force measured should not exceed 500 daN.
The test is repeated on a helmet at temperatures of –10°, +50 °C and under wet conditions. Resistance to penetration
The helmet is struck within a zone of 100 mm in diameter on its uppermost point using a conical punch weighing 3 kg and a tip angle of 60°.
The tip of the punch must not come into contact with the false (dummy) head.
Test to be performed under the conditions which gave the worst results in the shock test. Resistance to flame
The helmet is exposed for 10 s to a Bunsen burner flame of 10 mm in diameter using propane.
The outer shell should not continue to burn more than 5 s after it has been withdrawn from the flame.
The helmet is filled with a solution of NaCl and is itself immersed in a bath of the same solution. The electric leakage under an applied voltage of 1200 V, 50 Hz is measured.
The leakage current should not be greater than 1.2 mA.
Optional tests Dielectric strength
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Renato Barišić, Ivan Radoš Lateral rigidity
The helmet is placed sideways between two parallel plates and subjected to a compressive pressure of 430 N.
The deformation under load should not exceed 40 mm, and the permanent deformation should not be more than 15 mm.
Low-temperature test
The helmet is subject to the shock and penetration tests at a temperature of -20 °C.
The helmet must fulfil the foregoing requirements for these two tests.
2.9.
EN 397:2012
The European standard EN 397:2012 is used as a reference for the certification of helmets. This Standard specifies physical and performance requirements, methods of test and marking requirements for industrial safety helmets. The mandatory requirements of EN 397:2012 apply to helmets for general use in industry in the European Union as mandated by 89/686/EEC for personal protective equipment. Additional optional performance requirements are included to apply only where specifically claimed by the helmet manufacturer. Industrial safety helmets are intended primarily to provide protection to the wearer against falling objects and consequential brain injury and skull fracture. Where helmets are of the type intended to protect a static user from predominantly falling hazards, a series of impact tests are carried out using a fixed headform, with a falling mass striker. The helmet under test is placed onto a suitably-sized (and dimensioned) headform, mounted on top of a load cell, which in turn is mounted to a rigid (and monolithic) base. A striker, in this case with a hemispherical surface, of a suitable mass (5 kg) is dropped onto the helmet from a specific height (1 meter). The force transmitted through the helmet is measured using the load cell beneath the headform, and recorded onto a graph. For a helmet to meet the requirements of EN 397, the maximum transmitted force, after suitable signal conditioning, cannot exceed 5 kN. This test is carried out on several helmet samples, following preconditioning to high temperature, low temperature, water immersion and UV ageing. Most specifications for protective helmets include a number of requirements for the design of a helmet in addition to the specific performance requirements. These typically encompass the area of coverage provided by the helmet, as well as the field of vision afforded to the user when worn. Helmets can only protect when retained on the head, therefore, a chin strap may be supplied to ensure retention in typical workplace conditions. EN 397 requires that either the helmet shell or the headband is fitted with a chinstrap or with the means of attaching one, i.e. anchorage points. Any chinstrap supplied must have a minimum width of 10 mm when untensioned and be attached either to the shell or to the headband. The strength of the strap anchorage(s) should be sufficient to enable any attached chin strap to hold the helmet on the head but not so great that the strap would become a strangulation hazard. In the method for measuring chin strap anchorage strength specified in EN 397 the helmet is mounted onto a suitably sized headform and the chin strap passed around an artificial jaw. A tensile force is then applied to the artificial jaw at a rate of 20 N/min until the artificial jaw is released, due to failure only of the anchorage(s). The standard requires that the force at which this occurs shall be no less than 150 N and no more than 250 N. EN 397 includes a number of optional tests on helmets where additional protection is claimed. Helmets can claim protection against very high or very low temperatures, splashes of molten metal, electrical voltages up to 440 V, and lateral deformation. Each of these categories includes tests to prove the helmet’s suitability for protection against these hazards.
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Renato Barišić, Ivan Radoš 4. APPLICATIONS Protective helmets and waistcoats are parts of equipment which are omnipresent and play an important role in many industries. Not without a reason. As progress of any society in a great, if not the greatest measure, depends on its industry, and industry equals man, that same man has to be, as much as possible, protected. Throughout history, protective helmet has undergone changes in design, in the quality of protective materials as well as in prices and production methods. Entering the 21st century, it was believed that the conditions for smart helmets and matching waistcoats are finally created on the market. Therefore CroSafety smart helmet and matching waistcoat is not a breakthrough, but only a logical sequence of development of occupational safety. Safety product is mainly focused on working scenarios that can be fatal for working personnel, but it can find many other application forms. One of many usages that CroSafety product can be applied is in Skiing. Ski sports are all using some sort of head protection (it is obligated on many ski sites). Most of head injuries are fatal for user despite of protection. This product provides more protection from force impact that can appear during the ski sports. Product is also equipped for avalanche situations and fast tracking of injured person. Tracking application that CroSafety protection system offers is great when injured person is not in plain sight. In many avalanche scenarios, person is trapped below the snow. It’s a very slow process to find an injured person in short amount of time till his oxygen runs out. CroSafety product provides a simple solution of that problem. By means of an active pinging system, a sound is produced on the equipment of rescue team. The closer they get to the accident location, the response time of the WiFi signal from the injured skier is shorter and the sound is less intermittent. Using the parameters of direction and distance, the team can get to the injured skier sooner and can start providing first aid. Same problem solution can be used in fast aquatics sports (jet ski, etc...), instead of snow cover it can now be searched for person underneath water. Other safety segments of CroSafety product can also be used for cliff climbing. In addition of head and application for tracking injured person, height protection system is also included. Placed in industrial surroundings, gear uses buckles to tie up for working station and preventing potential fall into depth or from heights. Climber can now attach himself for mountain and continue climbing. Product when worn does not reduce level of agility, so climber can be safe and doesn't need sacrifice user experience. Creator of CroSafety is also considering how to adopt solution in military purpose. Idea is to build a bullet proof helmet. Main problem is how to stop a bullet not breaking neck with force that bullet produces. In this specific situation, product would be using neck and back add on to absorb all the energy (force) that bullet produces during the impact. That way person wearing this gear would be safer in area of head from bullets or explosion debris. 5. PRODUCTION Project Crosafety is in phase of prototyping. We are currently evaluating the impact that product can have on working site. Evaluation also includes actively speaking with company owners and company workers. All testing is currently round only on software base. Evaluation is actively done by Solid Works and Catia application packages. In next period product will be created in 3D model using 3d printing, which will give some basic information about the product. After 3D model is set and all basic information is gain, project can go in to next phase – production.
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Renato Barišić, Ivan Radoš Developing a new product involves a number of stages which are typically centered around the key areas shown in Figure 5. It shows well known areas used in different production and marketing strategies and methodologies. Figure 5: New product development areas
6. CONCLUSION Classic helmets which are over the most part of world market provide only surface protection and during a severe impact cannot properly direct the force from the parts of the head where the impact occurred. CroSafety has designed a helmet which amortizes all the force and allocates it to the external parts, while the parts of the head remain completely protected. In addition, the boundary has been set in the force absorption through a unique dorsal addition enriches this product. In order to absorb as much of the force without injuring the spine, it was decided that the excessive force, which the spine itself cannot endure, should be transferred to dorsal addition with avoiding additional pressure to the spine in this way. Practice has shown that the most protective equipment should be used under special working conditions (working at heights, working in depths, etc.) so design has followed two things which can affect workers' safety. The first one is health care, while the second one is the functional part. In this paper it was shown that this product can be used in many different fields. Also, it was emphasized that quality is a big part of every segment of this product and has one of biggest roles of safety management. REFERENCES [1] Dassault Systemes, Virtual Ergonomics: Taking Human Factors into Account for Improved Product and Process, http://3eos.com/, 2014. [2] European Standards, http://www.en-standard.eu/csn-en-397-a1-industrial-safety-helmets/, 2014. [3] R.F. Herrick, Encyclopedia of Occupational Health and Safety, International Labor Organization, Geneva, 2011. [4] I. Klarić, Tehnološki procesi organske industrije (I. dio), Sveučilište u Splitu, Split, 2008. [5] ISO, http://www.iso.org/iso/catalogue_detail.htm?csnumber=9468, 2014. [6] SATRA Technology Center, http://www.satra.co.uk/portal/index.php, 2014. [7] Traceparts, Katalog CAD modela, http://www.tracepartsonline.net/, 2014. [8] B. Vranješ, Zavarivanje i montaža (predavanja), Zagreb, 2007. [9] R. Zelenika, Metodologija i tehnologija izrade znanstvenog i stručnog djela (četvrto izdanje), Ekonomski fakultet u Rijeci, Rijeka, 2000.
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