КОНФЕРЕНЦИЈА ЗА БЕЗБЕДНОСТ И ЗДРАВЈЕ НА РАБОТА ЗБОРНИК ОКТОМВРИ ОХРИД МАКЕДОНИЈА ЗДРУЖЕНИЕ ЗА БЕЗБЕДНОСТ ПРИ РАБОТА ми АПРИЛ www.zbr28april.mk СОЈУЗ ЗА ЗАШТИТА ПРИ РАБОТА НА Р СРБИЈА www.savezznrsrbije.com Introduction About Us Euro Holography was established in 1999, offering the best European quality and the highest level of security to meet the needs of Governments & companies. Euro Holography responds rapidly to the demands of governments, banks and brand owners whose documents and products are threatened with counterfeit and fraud. Our competence and experience guarantee security not only for the present, but also for the future, and this is why we enjoy the trust of the leading organizations all over the world. Public revenue Prevent DANGER Why Euro Holography Health Economy Crime Our role Secure Protect High security printing Our Products Security Booklets Security Labels Certificates Security Seals ID cards Ta x s t a m p & Revenue w w w. e u r o h o l o g r a p h y. c o m КОНФЕРЕНЦИЈА ЗА БЕЗБЕДНОСТ И ЗДРАВЈЕ НА РАБОТА OSH PRIORITY ЗБОРНИК 9 - 12 ОКТОМВРИ, 2019 ОХРИД, МАКЕДОНИЈА OSH PRIORITY 2019: PROGRAMSKI ODBOR Prof. d-r Dejan Mirakovski, Univerzitet Goce Delcev Stip, Fakultet za prirodni i tehnicki nauki, Makedonija Prof. d-r Viktor Gavrilovski, Univerzitet Sv.Kiril i Metodij, Skopje, Masinski fakultet, Makedonija Prof. d-r Zlatko Petreski, Univerzitet Sv.Kiril i Metodij, Skopje, Masinski fakultet, Makedonija Prof. d-r Jasmina Calovska, Univerzitet Sv.Kiril i Metodij, Skopje, Masinski fakultet, Makedonija Prof. d-r Marija Hadzi-Nikolova, Univerzitet Goce Delcev Stip, Fakultet za prirodni i tehnicki nauki, Makedonija Prof. d-r Nikolinka Doneva, Univerzitet Goce Delcev Stip, Fakultet za prirodni i tehnicki nauki, Makedonija Prof. d-r Ivo Kuzmanov, Univerzitet Sv. Kliment Ohridski, Bitola, Tehnicki fakultet Prof. d-r Mile Spirovski, Univerzitet Sv. Kliment Ohridski, Bitola, Tehnicki fakultet Doc. d-r Afrodita Zendelska, Univerzitet Goce Delcev Stip, Fakultet za prirodni i tehnicki nauki, Makedonija Prof.dr Ivan Mijailović, Univerzitet u Nišu, Fakultet zaštite na radu, Srbija Prof.dr Miodrag Hadžistević, Univerzitet u Novom Sadu, Fakultet tehničkih nauka, Srbija Prof.dr Dejan Ubavin, Univerzitet u Novom Sadu, Fakultet tehničkih nauka, Srbija Prof. dr Ivan Krstić, Univerzitet u Nišu, Fakultet zaštite na radu, Srbija Prof. dr Evica Stojiljković, Univerzitet u Nišu, Fakultet zaštite na radu, Srbija Prof. dr Vesna Nikolic, Univerzitet u Nišu, Fakultet zaštite na radu, Srbija Prof. dr Goran Janackovic, Univerzitet u Nišu, Fakultet zaštite na radu, Srbija Prof. dr Dejan Vasovic, Univerzitet u Nišu, Fakultet zaštite na radu, Srbija Prof.dr Vladimir Mučenski, Univerzitet u Novom Sadu, Fakultet tehničkih nauka/Savez zaštite na radu Srbije, Srbija Doc. dr Dragan Adamović, Univerzitet u Novom Sadu, Fakultet tehničkih nauka/Savez zaštite na radu Srbije, Srbija Prof.dr Milan Trivunić, Univerzitet u Novom Sadu, Fakultet tehničkih nauka, Srbija Prof.dr Igor Peško, Univerzitet u Novom Sadu, Fakultet tehničkih nauka, Srbija Doc. dr Dragan Živanić, Univerzitet u Novom Sadu, Fakultet tehničkih nauka, Srbija Prof.dr Časlav Lačnjevac, Savez inženjera i tehničara Srbije, Srbija Dr Tahir Hanif, Simpleks menadžment - Velika Britanija Prof.dr Miloš Knežević, Univerzitet Crne Gore, Građevinski fakultet, Crna Gora Doc.dr Norbert Harmati, Univerzitet za arhitekturu i ekonomiju u Budimpešti, Fakultet za arhitekturu, Mađarska Prof.dr Laslo Mago, Univerzitet Sent Ištvan, Mašinski fakultet - Univerzitet u Budimpešti, Mađarska Prof.dr Tomaš Hanak, Tehnološki univerzitet u Brnu, Građevinski fakultet, Republika Češka Doc.dr Jana Koritarova, Tehnološki univerzitet u Brnu, Građevinski fakultet, Republika Češka Doc.dr Eva Vitkova, Tehnološki univerzitet u Brnu, Građevinski fakultet, Republika Češka Dr Robert Jeroničić, Ministarstvo za saobraćaj, Slovenija Dr Josip Taradi, Visoka škola za sigurnost – Zagreb, Hrvatska Assist. Prof. Blagovesta Dianova Vladkova, PhD - University of Mining and Geology “St. Iv. Rilski”, Sofia, Bulgaria PhD Marina Zdraveska Kochovska, specialist of nuclear medicine physics University institution of positron emission tomography, North Macedonia, Skopje доц. д-р инж. Петър Колев Петров, Технически университет – Габрово, Република България, гр.Габрово ORGANIZACISKI ODBOR m-r Blagoja Bogoevski, Zdruzenie za bezbednost na rabota „28. April“ – Skopje – Makedonija Prof. dr Miomir Raos, Univerzitet u Nišu, Fakultet zaštite na radu, Srbija Dragoslav Radisavlјević, Savez zaštite na radu Srbije Prof. dr Vladimir Mučenski, Fakultet tehničkih nauka - Novi Sad/Savez zaštite na radu Srbije Goce Mladenoski, Zdruzenie za bezbednost na rabota „28. April“ – Skopje – Makedonija m-r Goran Sekovski, Zdruzenie za bezbednost na rabota „28. April“ – Skopje – Makedonija m-r Dejan Angelovski, Zdruzenie na inzineri za zastita na rabota „Tutela“ – Skopje – Makedonija m-r Borce Stojcevski, „Prorisk“ – Skopje – Makedonija Bojana Zoraja, Fakultet tehničkih nauka - Novi Sad/Savez zaštite na radu Srbije Prof. dr Tatjana Golubović, Univerzitet u Nišu, Fakultet zaštite na radu, Srbija Doc. dr Sveta Cvetanović, Univerzitet u Nišu - Fakultet zaštite na radu , Srbija Doc. dr Zoran Čepić, Fakultet tehničkih nauka - Novi Sad Predrag Nedelјković, Savez zaštite na radu Srbije Dragan Stojadinović, Udruženje za zaštitu na radu - Šid Dragana Bibić, Fakultet tehničkih nauka – Novi Sad Milena Senjak, Fakultet tehničkih nauka – Novi Sad Aleksandar Sibinovski SUGS Vlado Tasevski – Skopje Toni Vojneski, Drzaven inspektorat za trud – Skopje СОДРЖИНА / CONTENTS SYSTEMS APPROACH AND RISK MANAGEMENT SISTEMSKI PRISTUP I UPRAVLJANJE RIZIKOM Blagoja Bogoevski, ZBR “28 April”, Skopje, North Macedonia — 11 — EXPOSURE OF GAS STATION WORKERS TO HAZARDOUS BTEX COMPOUNDS EKSPOZICIJA RADNIKA NA BENZINSKIM STANICAMA HAZARDNIM BTEX JEDINJENJIMA Dragan Adamović, Faculty of Technical Sciences, University of Novi Sad — 17 — FIRE SAFETY MEASURES IN WAREHOUSES MERE ZAŠTITE NA RADU OD POŽARA U SKLADIŠTIMA Dragan Živanić, Faculty of Technical Sciences, University of Novi Sad — 23 — BENEFITS OF INTRODUCTION OF PROFESSIONAL EDUCATION AND HEALTH & SAFETY FOR EMPLOYEES IN PUBLIC UTILITIES COMPANY IN CITY OF BIJELJINA PREDNOSTI UVOĐENJA PROFESIONALNOG USAVRŠAVANJA I BEZBEDNOST I ZDRAVLJE NA RADU ZAPOSLENIH U JAVNOM KOMUNALNOM PREDUZEĆU U GRADU BIJELJINA Bojana Tot, University of Novi Sad, Faculty of technical sciences, — 33 — THE IMPORTANCE OF MULTI-HAZARD RISK ASSESSMENT Martina Petković, Higher Technical Professional School in Zvečan — 39 — SAFETY CLIMATE ASSESSMENT IN CONSTRUCTION ACTIVITIES – A METHODOLOGICAL APPROACH BlagojaBogoevski, ZBR “28 April”, Skopje, North Macedonia — 45 — ОБРАЗОВАЊЕ И КОМПЕТЕНЦИЈЕ СТРУЧЊАКА ЗА ЗАШТИТУ НА РАДУ – КОМПАРАТИВНИ ОСВРТ EDUCATION AND COMPETENCES OF PROFESSIONALS FOR WORKSAFETY - COMPARATIVE REVIEW BlagojaBogoevski, ZBR “28 April”, Skopje, R. North Macedonia — 55 — SAFETY AT WORK DURING DEMOLITION OF ASBESTOS-CONTAINING STRUCTURES ZAŠTITA NA RADU PRI RUŠENJU OBJEKATA KOJI SADRŽE AZBEST Milan Trivunić, University of Novi Sad, Faculty of Technical Sciences — 67 — OCCUPATION SAFETY RISKS AND MEASURES IN MUNICIPAL WASTE COLLECTION SYSTEM IN SERBIA RIZICI I MERE ZAŠTITE NA RADU U OBLASTI SAKUPLJANJA KOMUNALNOG OTPADA U SRBIJI Svjetlana Vujović, University of Novi Sad, Faculty of technical sciences — 77 — OCCUPATIONAL SAFETY MEASURES IN ORGANIC WASTE TREATMENT - COMPOSTING MERE ZAŠTITE NA RADU U TRETMANU ORGANSKOG OTPADA - KOMPOSTIRANJE Miodrag Živančev, University of Novi Sad, Faculty of technical sciences — 83 — КОЛИЧИНЕ УПОТРЕБЉЕНОГ АЗБЕСТА У СРБИЈИ И СВЕТУ ЗА ПЕРИОД 1930-2000 ГОДИНЕ QUANTITIES OF ASBESTOS USED IN SERBIA AND THE WORLD FOR THE PERIOD 1930-2000 Bojana Zoraja, Faculty of technical sciences — 89 — 1 6 t h I N T E RNAT IONA L C ON FE R E NC E OF O C CU PAT IONA L HE A LTH A N D S A FE T Y 16th INTERNATIONAL CONFERENCE OF OCCUPATIONAL HEALTH AND SAFETY O hr i d , Nor th Mace d oni a 9 th — 12 th O c tob e r 2019 Ohrid, North Macedonia 9th-12th October 2019 FIRE SAFETY MEASURES IN WAREHOUSES MERE ZAŠTITE NA RADU OD POŽARA U SKLADIŠTIMA Dragan Živanić, Faculty of Technical Sciences, Trg Dositeja Obradovića 6, 21000 Novi Sad, Republic of Serbia, zivanic@uns.ac.rs Nikola Ilanković, Faculty of Technical Sciences, Trg Dositeja Obradovića 6, 21000 Novi Sad, Republic of Serbia, ilankovic@uns.ac.rs Atila Zelić, Faculty of Technical Sciences, Trg Dositeja Obradovića 6, 21000 Novi Sad, Republic of Serbia, zelic@uns.ac.rs Abstract The subject of this paper are fire safety measures in warehouses. First various fire sources were explained and listed. Factors that affect fire ignition, fire spread and fire extinguishing were analyzed. Finally, fire protection measures were given in order to increase the level of fire safety and health at work in warehouses. Keywords: fire, safety, warehouse 1. Introduction Generally, warehousing does not have high fire risks, except if goods represent danger like with warehousing explosives, fuels, solvents etc. Nevertheless, when fire breaks out in a warehouse, it has devastating consequences. The reason for that are difficulties which occur during fire control and fire extinguishing in the early stage, even when automatic fire extinguishing systems are installed. Because of the narrowness of the warehouse aisles and corridors and the tendency to obtain maximum storing capacity which means huge amount of goods stored very close to each other, fire extinguishing demands great effort. Also, fatal casualties often occur during warehouse fire which produces even more responsibility for fire safety engineers. There are many factors which causing fire make easier. They are numerous and connected. Because of that, it is often difficult to determine the correct cause of the fire. Experiences with fires in warehouses show that big damages occur as a result of the next factors: • • • • • • • • • • Late fire detection; Rapid fire expanding; Irregularities in warehouse construction; Lack of compartment separation; Bad maintenance; Disproportion of the amount of goods; High levels of toxic evaporations and gases; Absence of automatic sprinklers; Irregularities in sprinkler installation; Absence of damage reduction plans. 1 23 1 6 t h I N T E RNAT IONA L C ON FE R E NC E OF O C CU PAT IONA L HE A LTH A N D S A FE T Y 16th INTERNATIONAL CONFERENCE OF OCCUPATIONAL HEALTH AND SAFETY O hr i d , Nor th Mace d oni a 9 th — 12 th O c tob e r 2019 Ohrid, North Macedonia 9th-12th October 2019 2. Fire sources Fire emerges because of the fast and continuous material combustion. This requires three key elements: • • • Fuel – which represents the burning material, materials like paper or gasoline; Oxygen – which can be found in the air and it is required for combustion; Energy – which raises the fuel temperature to the level for fire ignition. It can be introduced by open flame, spark or lighting. Without energy, fire ignition could not be possible. The usual fire sources in warehouses include [1]: • Power installations for electric energy, gas and heating. The risk is higher when bad maintenance is applied or when power installations are close to stored goods. Proper way for fire prevention from bad installations is predictive maintenance. This implies thermal imaging of the installations at least once a year. Thermal imaging, figure 1, is a technique which uses an infrared camera for measuring the surface temperature of different components. In most cases, increase of temperature at the weakest point of the installation happens before electric failures. This technique is extremely useful because it enables detection of floods one month before failure can happen. Furthermore, goods can be heated up and ignited if they are stored in the near vicinity of energy sources like heaters or lightning which produces heat. Goods have to be stored at least 1 m from the energy source. Lightnings should be also secured from the stored goods in order to prevent them to get damaged; Figure 1. Examples of thermal imaging • • Ignition sources characteristic for production processes. They can be found in warehouses used by industrial processes which use heat or open flames like industrial furnaces; Ignition sources connected with warehousing processes. Machines used for handling goods are often used in warehouses. These machines can be electric or driven by internal combustion engines. These machines are forklifts, pallet trolleys and cranes (stacker, overhead etc.). Generally, indoor warehouses use electric equipment which requires power supply from batteries which have to be periodically recharged. 2 24 1 6 t h I N T E RNAT IONA L C ON FE R E NC E OF O C CU PAT IONA L HE A LTH A N D S A FE T Y 16th INTERNATIONAL CONFERENCE OF OCCUPATIONAL HEALTH AND SAFETY • • • O hr i d , Nor th Mace d oni a 9 th — 12 th O c tob e r 2019 Ohrid, North Macedonia 9th-12th October 2019 Battery chargers represent special danger because during charging they release hydrogen gas. Hydrogen gas is highly combustible and presence of flammable materials around the charging are rises the risk level for fire ignition. In order to prevent fire ignition, it is necessary to use anti-explosion trucks in high risk areas. Also, the area where charging is done has to be without fire ignition sources and adequately ventilated. Power installations have to comply with up-to-date regulations and workers have to be without necklaces, wrist watches and other metal objects which can lead to short-circuits during operating with batteries. If the charging is done in the dark by any reason, the charging level must not be checked by using lighters or open flames. During automatic battery charging, the maximum number of batteries that can be charged together has to be respected. Next, daily and periodical checks of electric systems have to be performed. In the case when machines are driven by internal combustion engines, sparks can occur in exhausts which can lead to a fire in the warehouse. This is especially dangerous if the surrounding is consisted of flammable gasses, fumes or dust. In cases like that, it is recommended to provide devices for fire extinguishing or devices which contain sparks from exhausts; Other possible fire sources are in the relation with hot works. These types of operations include heat generation which can lead to fire ignition. This is the case with certain operations which are done during warehouse maintenance – soldering, drilling, welding etc. Conducting these operations requires following safety measures; One of the potential fire sources is the presence of smokers in warehouses. To control this type of risk, separate rooms have to be provided where smoking is allowed. Smokers have to be informed that smoking is forbidden outside of that room and controls have to be done at least once a month; Fire sources are connected with processes used for product shrink wrapping in thin plastic film. Some warehouses use this process to protect goods from braking. Shrinking-wrapping process use heat for sealing films. Thin plastic films are highly flammable and because of that fire risks are greater. 3. Fire load Fuel is the second factor that is required for fire ignition and to understand its role, it is necessary to consider what is connected to the term fire load. Generally, fire load of a warehouse is calculated by using multiple factors including the amount and heating value each flammable material that is present in the warehouse (construction material of the warehouse also). The nature of the stored goods is of the greatest importance. Depending on their characteristics, the speed of fire spread will be lower or higher. The seriousness of the fire will depend on the flammable material. Plastic and synthetic materials have the tendency to burn faster than natural materials like cardboard. Because of that, it is necessary to distinguish the following [2]: • Stored goods – including their packaging (paper, plastic etc.). It is required to consider if the warehouse is located in a space with high risks which is the case 3 25 O hr i d , Nor th Mace d oni a 9 th — 12 th O c tob e r 2019 1 6 t h I N T E RNAT IONA L C ON FE R E NC E OF O C CU PAT IONA L HE A LTH A N D S A FE T Y 16th INTERNATIONAL CONFERENCE OF OCCUPATIONAL HEALTH AND SAFETY • Ohrid, North Macedonia 9th-12th October 2019 when painting and varnishing operations are done. This rises the risk of fire and explosions; Construction material – includes material used for warehouse construction (concrete, wood, metal constructions), material used for covering of the structure (fiber cement, sheet metal, fiberglass) and materials used for isolation of roofs and walls (plaster, polyurethane). Usage of isolation materials like polyurethane and polystyrene increases the fire load because of their high level of flammability. In order to prevent fire ignition due to fire load, the following measures should be conducted: • • • • Products which represent danger and which can cause great damage or corrosion should be kept separated from products which are especially sensitive to such risks; Aisles and corridors which separate goods can be of great use while firefighting and rescuing. The most suitable width of aisles is 2,4 m. If possible, aisles should lead to doors or windows in order to make access easier; There should be at least 60 cm between stored goods and walls of the warehouse. This is especially important when stored goods can expand if they get wet; Goods should not be stored so that they are higher than the lower parts of roof beams or too close to roof trusses, figure 2. If automatic sprinklers are present, it is recommended to provide 1 m of distance between the highest point of the storage area and sprinklers heads. Minimal distance should not be under 60 cm. In case of fire detectors, it is recommended that the distance should be at least 1 m; Figure 2. Stored goods reaching the ceiling • • • Empty pallets should be stored outside production facilities and warehouses. They have to be placed in such a way that there is an appropriate distance between pallets and outside walls of buildings; Correct locations of extremely dangerous products such as toxic, corrosive or flammable products are of great importance for reducing fire loads. Such products have to be located on especially designated places and separated from other areas; In outdoor warehouses it is necessary to assure that there is no extra danger because of the proximity of stored goods to external devices (transformers, cooling towers, fuel reservoirs), buildings or power lines. 4 26 1 6 t h I N T E RNAT IONA L C ON FE R E NC E OF O C CU PAT IONA L HE A LTH A N D S A FE T Y 16th INTERNATIONAL CONFERENCE OF OCCUPATIONAL HEALTH AND SAFETY O hr i d , Nor th Mace d oni a 9 th — 12 th O c tob e r 2019 Ohrid, North Macedonia 9th-12th October 2019 4. Oxygen The most influent factors which can lead to fire ignition and fire spread are the type of the warehouse and the design and layout of vertical and horizontal hollow spaces and openings. Generally, indoor warehouses are designed with specific storage capacity. Because of the financial reasons, warehouses are used up to their maximum which leads to high stacks with minimum distance between them. In the case when warehouses do not have free horizontal spaces and/or with spaces located above 2 m, more free space inside racks allows air to circulate freely which helps fire spreading. On the other hand, if goods are denser on the racks, the fire is less serious. Stable racks are less probable to collapse and because of that, fix areas will be standing during fire where fire can spread easily. In the case of collapsing racks, the fire can be controlled with less effort [3]. Waste has to be classified and placed in suitable containers. If possible, these containers should be located outside production facilities and warehouses and to be distanced from outside walls. In these cases, waste should be dealt with and removed in proper time periods. Concentration of flammable materials has to be avoided in areas which are used for packing, unpacking, classification etc. The amount of free space affects fire intensity. Palletized storage means that pallets are organized in such a manner that they create free space at intervals of 2 m. These free spaces improve fire spreading which is hard to extinguish. Storing goods on shelves is considerably dangerous from the aspect of fire safety. This type of storing increases the number of surfaces which can burn and enables bigger air flow which helps combustion processes. Stored goods are kept in stable positions which also helps fire spreading. This storing configuration, especially on great heights, means that water from sprinklers cannot enter in free spaces or voids which are often narrow. The narrower and higher the spaces are, the more difficult it is for water to enter them which extends fire duration. Additionally, because of the lack of shelf connection to the floor or stable warehouse construction, fire on one shelf can lead to its collapsing which can lead to domino effect and to collapsing of nearby shelves. Storing goods on racks is also dangerous because of the heights of the racks which can be up to 50 m. Because of that height and narrow aisles and corridors, when fire breaks out on lover levels, water from water sprinklers installed on the ceiling has difficulties to reach the fire. Then it is necessary to manually extinguish fire by using fire hoses and fire extinguishers which is quite risky because rapid fire spread can weaken metal racks because steel changes its properties when the temperature hits 538o C [4]. The design and arrangement of vertical and horizontal hollow spaces and openings is important. Vertical spaces include lift shafts, stairwells, interior courtyards and horizontal include openings such as doors, forklift access and windows. The existence and arrangement of these spaces is convenient for fire spread when the fire breaks out. Fire spread is also supported by the lack of compartmentalization. Compartmentalization means separating production and storing areas or separating two different areas in big warehouses. This helps preventing that fire, gasses or fumes spread to other areas. 5 27 1 6 t h I N T E RNAT IONA L C ON FE R E NC E OF O C CU PAT IONA L HE A LTH A N D S A FE T Y 16th INTERNATIONAL CONFERENCE OF OCCUPATIONAL HEALTH AND SAFETY O hr i d , Nor th Mace d oni a 9 th — 12 th O c tob e r 2019 Ohrid, North Macedonia 9th-12th October 2019 5. Risk vulnerability Beside factors that are mentioned above, there are other factors that produce higher risks. These factors include fragile nature of specified goods and the severity of the damage which can be caused to the warehouse or goods by certain construction materials. These factors are [1]: • • • • • The existence of electronic or precise equipment of great significance for the company; The existence of documents of great strategic value for the company; Product that are subjected to damage due to combustion gasses or due to corrosion; Luxury or valuable goods; Food products such as fruit, vegetable and meet which are especially sensitive to combustion fumes. They can suffer great damage if exposed to fumes. Further complications exist with these products because of the usage of cold rooms for storing before shipping them to final users. Sandwich panels that are used for construction of these cold rooms represent an additional risk factor. Sandwich panels are made of natural highly flammable organic materials such as polyurethane and polystyrene. Beside that, when these panels burn, they produce highly toxic fumes. The control and extinguishing these types of fires is very complex because of the construction of these panels where organic material is placed between two sheet metal parts. Even if water is sprinkled on the surface of these panels, the cooling effect is not enough sufficient and the fire continues to burn inside. There are also other factors which can increase the risk. They include the usage of flammable or/and explosive cooling gasses such as ethane and prophane. The leakage in the cooling circuit can produce highly flammable atmosphere which results with explosions. These types of cooling gasses are not usually used in the food industry. Instead of them, cooling gasses of high and medium safety are used. Typical example is ammonia. While its flammability is low, its toxicity is high. It has a suffocating effect and it is estimated that the maximum exposure to it without danger for humans is 25 ppm. This represents a higher risk not only for people in the surroundings of cold rooms, but also for stored goods which can get contaminated. In these cases, if employees are constantly present, regulations demand installation of one or more ammonia detectors with the detection sensibility of 2% or placement of emergency stop buttons which should be located outside. Conveyor systems are often used in warehouses, especially where automatic order picking systems are present. The drive mechanism presents the area with high risk. One of conveyor systems types is the belt conveyor. The drive from the drive pulley to the belt is transferred via friction. In case of bad contact conditions (low coefficient of friction between the drive pulley and the belt, improper tensioning of the belt), belt slippage can occur which produces excessive heating of the belt that can lead to fire breakouts. Because of that, it is recommended to place automatic fire protection systems when using conveyor systems [4]. 6 28 O hr i d , Nor th Mace d oni a 9 th — 12 th O c tob e r 2019 1 6 t h I N T E RNAT IONA L C ON FE R E NC E OF O C CU PAT IONA L HE A LTH A N D S A FE T Y 16th INTERNATIONAL CONFERENCE OF OCCUPATIONAL HEALTH AND SAFETY Ohrid, North Macedonia 9th-12th October 2019 6. Additional risks due to external factors External factors are those which can increase the risk level because of situations that are not located in the warehouse. Usually, they are located in the surrounding of the warehouse. Significant examples of these external factors are: • Nearby buildings. Sometimes the origin of the fire is not in the warehouse itself, it is in the nearby building. Presence of a firewall between buildings or different storing areas can prevent fire spreading from the roof of one building to the roof of the other building; • Different roof heights on nearby buildings; • Presence of trees and bushes around the warehouse can lead to fire spread inside the warehouse. In ideal case, the surrounding of a warehouse should be free from vegetation; • Fires caused by persons that are not connected to the warehouse which is called arson. This can happen because of the burning pallets which are placed outside the warehouse, crates, cardboard waste and so on; • Outside storage areas in warehouses are great risks. They are exposed to a high number of fire sources such as lightning, fires caused by foreign persons, presence of vegetation. Despite that, there are few cases where outside storage areas are justified. It is justified when products do not demand fire protection like metal barrels, when the products have low value, when the products have high fire risks like empty pallets and when bulk products are stored in great amounts which prevent them to be stored indoor, figure 3. Even in these cases, it is necessary to estimate and consider certain conditions in order to provide proper protection. The first estimation is required to secure that goods which are stored outside do not represent danger which could lead to an interruption in normal business activities, production stoppage or any kind of damage for third persons like nearby companies. The second consideration refers to the location of stored goods. It has to be ensured that by storing goods outside does not create the possibility of exposure to fire danger for outside equipment (transformers, cold rooms and so on), buildings, power lines, pipes etc. Figure 3. Pallets stored outside The outside storing area has to be properly lit and, if possible, equipped with safety fence in order to prevent intrusions. 7 29 1 6 t h I N T E RNAT IONA L C ON FE R E NC E OF O C CU PAT IONA L HE A LTH A N D S A FE T Y 16th INTERNATIONAL CONFERENCE OF OCCUPATIONAL HEALTH AND SAFETY O hr i d , Nor th Mace d oni a 9 th — 12 th O c tob e r 2019 Ohrid, North Macedonia 9th-12th October 2019 It is also important to consider the characteristics of stored goods. Stacks of materials must have certain volume and height. It is not recommended to have volumes higher than 700 m3 or heights more than 6 m. Empty pallets should be arranged in rectangular areas following next parameters: • • • • • Maximum storage height: h = 7 m; Maximum length of the longest side of the rectangle: Lmax = 2h = 14 m; Maximum surface of the rectangle: Smax = 100 m2; Minimum distance between storage areas (aisle width): h/2 = 3.5 m; Minimum distance from walls of buildings: same as maximum storage height or at least 3 m. It is necessary to secure proper width of aisles between stacks in order to provide the possibility for manual fire extinguishing with fire hoses. It is important to have properly placed fire extinguisher and to have water hydrants on distances that do not precede 80 m. Adequate maintenance and periodic inspections of the area are necessary in order to provide fulfillment of minimum safety conditions. Site security patrols should include outside storing areas in order to detect any problems as fast as possible. 7. Fire protection measures Fire protection measures installed in warehouses affect the ability of fire control and extinguishing in a way to minimize possible consequences. First measure which should be considered refers to construction material used for warehouses. Because of high levels of heat-resistance, the most suitable materials are concrete and steel covered with plaster or fibrous silicate panels or sprayed with layers of perlite or vermiculite mortar. When steel is protected with intumescent paint, it has to be ensured that the paint covers the entire construction. Also, it is very important for renew paint on spots where hits occur. Such coatings are not resistant to long lasting or highly intensive fires which can happen in warehouses. Next preferred choice for construction material is the usage of big, massive wooden beams because of their slow combustion and structural stability compared to uncoated steel construction. Steel constructions without additional protection against fire are not advisable to use because steel gets unstable when the surrounding temperature reaches 538o C [5]. Heat deformation of the construction can lead to roof collapsing or rack collapsing which can fall on water pipes connected to sprinkler system. Water loss leaves sprinklers to be useless which enables fire to be out of control. Constructions with flammable materials are not advised to be used, like light wood, because of their fast combustion. Other important factor is the warehouse ventilation system. In typical situations, fire spreads in two directions: horizontally and vertically. When the fire spreads, heat rises vertically and 8 30 1 6 t h I N T E RNAT IONA L C ON FE R E NC E OF O C CU PAT IONA L HE A LTH A N D S A FE T Y 16th INTERNATIONAL CONFERENCE OF OCCUPATIONAL HEALTH AND SAFETY O hr i d , Nor th Mace d oni a 9 th — 12 th O c tob e r 2019 Ohrid, North Macedonia 9th-12th October 2019 combustion gasses accumulate under the roof. Those gasses are extremely hot and that heat can lead to roof and building collapsing. Experience with fires in warehouses suggests that this type of problems can be solved by placing windows near the roof. Window glass will break when the heat rises to the top and the heat will flee through broken windows without damaging roof construction. This effect is more prominent in steel constructions than in concrete constructions because of the better heat conducting abilities of steel. Generally, ventilation provided by windows or opening in the higher parts of the warehouse is enough to dissipate hot gasses. At the end, active fire protection measures have to be carefully planned in order to circle the fire protection system. Among them, the most important measures are: • • Automatic detection systems installed in order to provide 24-hour fire detection possibility. These systems have to be connected to alarm systems. It is important to provide at least 1 m distance from fire detectors and stored good; Automatic extinguishing systems are the best way to prevent fire spread in warehouses. Sprinklers are proven to be very successful, but when certain fires break out like fires occurring with plastics and or flammable liquids, additional protection for the structured is required (coating and painting). Also, when sprinklers are installed in the ceiling, water droplets can get evaporated due to hot gasses. Because of that, sprinklers can be placed in intermediate levels of the racks, figure 4. Figure 4. Sprinklers placed in intermediate levels of racks Design of sprinkler systems has to be according to current standards. For the design to be adequate, it has to provide safety for shelves and racks, but not to stored goods on them. That represents a fire risk. When planning sprinkler systems, it is important to plan that the entire warehouse is protected and that any other building that is connected to the warehouse is also protected. Building are not considered to be connected when they are separated by walls which have a fire resistance level of at least 60 min. Doors and other openings have to be designed to close by themselves when fire breaks out. Their fire resistance has to be at least half of fire resistance of separating walls. To provide proper safety and effectiveness of sprinkler systems, the distance of the warehouse and flammable goods outside has to be at least 10 m 9 31 1 6 t h I N T E RNAT IONA L C ON FE R E NC E OF O C CU PAT IONA L HE A LTH A N D S A FE T Y 16th INTERNATIONAL CONFERENCE OF OCCUPATIONAL HEALTH AND SAFETY • O hr i d , Nor th Mace d oni a 9 th — 12 th O c tob e r 2019 Ohrid, North Macedonia 9th-12th October 2019 or 1,5 times of the height of the stored goods. This can be ignored if there is a separating wall with proper fire resistance; Manual extinguishing equipment must include fire extinguishers, fire hose cabinets and fire hydrants. In order to ensure maximum effectiveness of fire protection systems, it is necessary to provide proper maintenance of the equipment and installations and to provide proper practical trainings for warehouse staff in the use of fire protection systems. Stored products must never block the passage to fire extinguishing equipment. Maintenance musts be done according to Regulations on Fire Protection Installations. Investment in fire protection measures is sometimes useless because of the improper maintenance. The best way to evade that is to secure proper training for maintenance staff. Less significant operations can be done by warehouse maintenance staff, but for certain big operations, independent authorized companies have to be responsible for carrying them out. Regarding to staff training, the most important factor for fire detection and fire control is the human factor. Because of that, it is necessary to train the staff and to enable them to fight fires when they are in the initial phase. Beside that, it is important to develop and implement an emergency plan which includes training activities involving annual fire drills. 8. Conclusion Losses that occur during fire in warehouses can be extremely high due to the amount of stored goods. Beside the loss of the goods, fires in warehouses represent danger for the staff working in it, especially for staff members which get caught in middle of a spreading fire or for staff members trained to fight fire at early stages. Fire breakouts can have severe consequences on the reputation of the warehouse management. It can threaten future business plans which can endanger recovery. Because of that, warehouses are very sensitive to fire risk and in order provide proper safety in the warehouse, exceptional safety measures have to be applied. References [1] Warehouse Safety Guide, Mapfre RE, Spain, 2008, https://bit.ly/2YHrxNh, (7th August 2019.) [2] Tanubrata, M.,. Fire Safety Design in Building, Jurnal Teknik Sipil. 3. (2019), pp: 4153. DOI:10.28932/jts.v3i1.1271. [3] Rasbash, D., Ramachandran, G., Kandola, B., Watts, J. and Law, M.: Performance of Fire Safety Measures: In Evaluation of Fire Safety, (2006), DOI: 10.1002/0470020083.ch10 [4] Šostakov, R., Zelić, A., Živanić, D.: Occupational Safety and Protection with Internal Transport Devices, Faculty of Technical Sciences, Novi Sad, Republic of Serbia, ISBN: 74651-54641745 [5] Zhao, J.C., Shen, Z.Y.: Experimental studies of the behaviour of unprotected steel frames in fire, Journal of Constructional Steel Research. 50, (1999), pp. 137-150. DOI: 10.1016/S0143-974X(98)00246-6. 10 32