İtfaiye su alma ağızlarındaki tasarım basıncının, debi, püskürtme mesafesi ve itfaiyeciye gelen kuvvete olan etkisinin deneysel olarak incelenmesi
Experimental investigation of the effect of design pressure of the fire hose outlets on the flow rate, throw distance and reaction force affecting on firefighters
Yazar: DUHAN PORTAKAL
Danışman: PROF. DR. ABDURRAHMAN KILIÇ
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / Makine Mühendisliği Ana Bilim Dalı / Isı-Akışkan Bilim Dalı
Derece: Yüksek Lisans, 2020
Konu: Makine Mühendisliği = Mechanical Engineering

Özet:
Elle yangına müdahale sistemleri arasında yer alan itfaiye su alma ağzı sistemleri, bina içerisinde çıkabilecek bir yangını kontrol altına almak ve/veya söndürebilmek için itfaiye personeli ve/veya yetişmiş söndürme görevlisi tarafından kullanılmak üzere tesis edilir. 
Binaların Yangından Korunması Hakkında Yönetmelik'te (BYKHY, 2015), yetişmiş yangın söndürme görevlisi bulundurulmak mecburiyetinde olan yapılarda kullanılabilecek yassı hortumlu yangın dolapları için tasarım debisinin 400 l/dak ve tasarım basıncının en az 400 kPa olması gerektiği yazılıdır. Ancak yönetmeliğin itfaiye su alma ağzı ihtiyacını tarif eden hükümlerinde bu değerler tekrarlanmadığı için bazı tasarımcılar tarafından itfaiye su alma ağzı tasarım basıncı değerinin uluslararası geçerliliği kabul edilen standartlarda belirtildiği şekilde kullanılması gerektiği iddia edilmektedir. NFPA (National Fire Protection Association) yangın kodları ve standartlarının konuyla ilgili NFPA 14 standardında, profesyonel ekiplerin yangına müdahalesi için tesis edilen sistemlerde tasarım basıncının akış halinde en az 690 kPa olması gerektiği belirtilmiş olup, bu değer özellikle çok yüksek binalarda daha fazla sayıda düşey basınç zonları oluşturulmasını ve ilave kolon (riser) hatları çekilmesini gerektirir. Buna rağmen, ABD'de çok yüksek binaların yer aldığı bazı eyaletlerin yönetmeliklerinde, NFPA 14'te belirtilenden daha düşük basınç değerlerine göre tasarım yapılması dikkat çekicidir.
Yangına bina dışından müdahale için tabii zemin seviyesinde tesis edilen hidrant sisteminin tasarım debisi ve tasarım basıncı yönetmelikte (BYKHY, 2015) belirli olduğundan, bu çalışmada, özellikle yüksek binaların üst katlarında yer alan itfaiye su alma ağzındaki debi ve basıncın etkisinin incelenmesi için bir deney tesisatı yapılmıştır. Bunun için, mevcut bir tesise ait yangın pompa dairesinde, deneyleri yapabilmek için özel olarak ayrı bir tesisat çekilmiş ve yapılacak deneyler için gerekli ekipmanlar temin edilmiştir. İtfaiye su alma ağzına bağlanan hortumun girişindeki basınca bağlı olarak ne kadar su akışı sağlanabildiği, suyun hangi mesafeye kadar ulaştırılabildiği ve itfaiye su alma ağzını kullanan personele etki eden kuvvetlerin nasıl değiştiğini belirlemek için ölçümler yapılmıştır.
Deneysel çalışmalar kapsamında, farklı tipte hortum ve lanslar ile farklı orifis çaplarında su giriş basıncı değiştirilerek, su debisi, su atış mesafesi ve lans tepki kuvvetinin nasıl değiştiği incelenmiştir. 
İtfaiye su alma ağzında ne kadar su debisine veya su basıncına ihtiyaç olduğu yangına hangi aşamada müdahale edildiğine bağlıdır. Yeterince erken müdahale edilebilirse yangın bir bardak suyla söndürülebilir. Öte yandan yapılan deneysel çalışmaların sonuçları göstermiştir ki: ofis, konut, otel, hastane veya benzeri yangın yüküne sahip bir kullanım amacına hizmet veren bir yüksek binanın üst katlarında çıkan bir yangına, bir itfaiyecinin yassı hortumu tek başına tutarak müdahale edilebilmesi için, NFPA 14'teki tasarım basıncı (690 kPa) ve debisinin (950 l/dk), yapılan deneylerde çok yüksek olduğu görülmüştür. Dahası, ülkemizdeki itfaiyeler tarafından bu tür yangınlara müdahale etmek üzere yaygın olarak kullanılan yassı hortum ve lans gibi ekipmanların hiçbiri NFPA 14'teki basınç ve debi değerini verebilecek orifis çaplarına sahip değildir. 
Sonuç olarak, otel, konut, ofis, hastane ve benzeri yangın yüküne sahip binaların üst katlarındaki yangınlara yassı hortumla müdahale etmek için kullanılacak itfaiye su alma ağzındaki tasarım basıncının 400 kPa ve tasarım debisinin 400 l/dk alınması yeterli olmaktadır. Ayrıca, yukarıda belirtilen tasarım kriterleri ülkemiz itfaiyelerinde kullanılan yassı hortum ve lanslar ile karşılanabilmekte olup, bu tasarım kriterlerinde, yangın hortumu ve lansın bir itfaiyeci tarafından tek başına kontrol edilmesi de mümkün olur.

Abstract:
Among the manual fire extinguishing systems, fire hose outlets are aimed to control and/or suppress the fire inside a building using by firefighters and/or trained building staff. 
In addition to these fire hose outlets, hydrant systems installed on the ground level are also aimed to control and/or suppress the fire outside of building using by firefighters and/or trained building staff. However, fire hose cabinets and extinguishment cylinders can be used by any occupant in building to control and/or suppress the fire inside a building in an early stage. These all systems and equipment are part of manual fire extinguishing systems.
Automatic fire extinguishing systems are also installed to control the fire inside a building as well as manual fire extinguishing systems. Among the automatic fire extinguishing systems, water based sprinkler systems, dry pipe systems, pre-action systems, deluge systems, clean agent gas extinguishing systems, etc. are available. The main aim of the automatic fire extinguishing systems is control the fire at an early stage. Since these systems can not supress the fire, manual fire extinguishing systems are also needed to suppress the fire inside a building. Therefore, these two systems are not alternatives to each other, these systems that support each other. 
According to the Regulation on Fire Protection of Buildings (TFC, 2015), in buildings where trained fire extinguishing teams have to be employed, hose cabinets connected to flat hoses are required, where the design values are specified as 400 l/min for the flow rate and 400 kPa for the pressure. The diameter of these flat hoses must be selected as 50 mm and the connection diameter of the cabinet valves must also be selected as 50 mm. However, the design flow rate values (400 l/min) and the design pressure values (400 kPa) are not repeatedly mentioned in the provisions are given for the fire hose outlets, so that some mechanical designers claim that the reference values in the internationally recognized standards be followed. 
According to the corresponding NFPA (National Fire Protection Association) standard, i.e NFPA 14, there are three different classifications within the scope of manual fire extinguishing system. The first classification (Class I) is fire hose connection with an outlet with a diameter of 65 mm. The second classification (Class II) is fire hose connection with an outlet with a diameter of 40 mm. And the last classification (Class III) is a system that the first and second classification are using together in building. According to National Fire Protection Association (NFPA 14), the residual pressure at the fire hose outlets are classified as Class I is specified to be minimum 690 kPa, which indirectly increases the number of risers and vertical pressure zones during the mechanical system design of very high buildings. Besides, the minimum design flow rate at these fire hose outlets is specified to be minimum 950 l/min. According to NFPA 14, the residual pressure at the fire hose outlets are classified as Class II is specified to be minimum 400 kPa and to be maximum 690 kPa. Besides, the minimum design flow rate at these fire hose outlets is specified to be minimum 380 l/min.
On the other hand, it must be noted that, in some states of the USA, especially the ones with very tall buildings, local state regulations permit reducing the design pressure (690 kPa) specified in NFPA 14. According to this local state regulations, the minimum design pressure can be selected as 450 kPa at the fire hose outlets.
Since the design flow rate and pressure of the hydrant system installed on ground level to intervene the fire from outside the building is specified in the Regulation on Fire Protection of Buildings (TFC, 2015), in this study, experimental equipment are installed to interpret the design flow rate value and pressure value required in the fire hose outlets located on the upper floors of especially high-rise buildings. According to Regulation on Fire Protection of Buildings, the minimum design pressure value of hydrant systems must be 700 kPa and the minimum design flow rate of hydrant systems must be at least 1900 l/min. 
In order to carry out the studies, an independent installation was provided in the fire pump room of an existing facility (Istanbul New Airport). This installation was connected to the supply side of main fire pump. At the supply side of fire pump, downstream of the check-valve, the test line is installed and this test line is using to test fire pump annually. The pipe that is using for this experimental study is given from the fire pump test line by adding control valve. After this control valve, pressure reducing valve and fire hose connection are located on the experimental study line. And also the necessary equipment were provided for the experimental studies to be carried out. These necessary equipment are ultrasonic flowmeter, fire hoses, nozzles, manometers and lasermeter. Especially ultrasonic flowmeter and manometers are installed on the experimental study line. Fire hoses and nozzles are connected to the fire hose connection and lasermeter is using to measure throw distance of water.  
Experimental measurements have been performed to evaluate how much water density can be provided and how far away water can be reached from the fire hose that is connected to the fire hose outlet with approximately 400 kPa inlet pressure in high rise buildings and evaluate the reaction forces affected by trained personnel and/or firefighter during the firefighting. This inlet pressure was measured by manometer located at the outlet side of fire hose connection. Three other manometers are also used for this experimental study. 
Within the scope of experimental studies, by changing the inlet pressure, density values, water throw distance and reaction force values were taken into account to evaluate in different types of hose and nozzle orifice diameters. In order to measure these parameters, some different measurement devices were used. These devices are manometer, ultrasonic flowmeter, lasermeter etc. 
Manometer was used to measure the pressure value at the inlet and outlet of the pressure-reducing valve, and also to measure the pressure value at the inlet and outlet of the fire hoses. Ultrasonic flowmeter was used to measure the flow rate of water inside the pipe. And also, lasermeter was used to measure the throw distance of water. However, reaction force values were not measured by any measurement device. These values were determined by using ampiric equation given from National Fire Protection Association (NFPA) standards. In order to determine the reaction forces value, some experimental results such as pressure value, flow rate etc. were used. It must be notes that, all measurement devices have an uncertainty value during the measurement. Since these experimental results measured by using measurement devices were used to determine the reaction force values, an uncertainty analysis was done and this analysis was explained within the scope of experimental studies.
The necessity of pressure and flow rate at the fire hose outlets is changeable. In case of a fire in any building, first of all, fire hose cabinets are used by any occupant in building to intervene the fire. If the fire is not suppressed by using these fire hose cabinets, then the fire hose outlets is needed to supress the fire. Depending on the using time of fire hose outlets, especially the necessity of flow rate may vary. If the fire is intervened in an early stage of fire, a glass of water could be enough to suppress the fire in building. However, if the fire is intervened in a late stage of fire, the flow rate that is specified in international standards such as National Fire Protection Association (NFPA) or British Standards (BS) could also not be enough to supress the fire in building. 
On the other hand, the results of the experimental study show that it is not possible that only one firefighter can handle the fire hose which is connected to the fire hose outlet at the design pressure value (690 kPa) and at the design flow rate (950 l/min) specified in NFPA 14 in low hazard buildings i.e office building, residential building, hotel building, hospital, etc.  Moreover, the design values specified in NFPA 14 can not be provided from the fire hoses and nozzles using by the fire department in Turkey. 
Fire department in Turkey has typical equipment to intervene the fire inside a building. These equipment are typical fire hoses with a diameter of 65 mm (B) and with a diameter of 50 mm (C), fog nozzle with a diameter of 65 mm (B) and straight nozzles with a diameter of 65 mm (B) and with a diameter of 50 mm (C). These equipment were generally used to intervene the fire inside a typical low and ordinary hazard building. These equipment were also used in this experimental study. The results of this experimental study also show that, the design pressure value and design flow rate value can not be obtained from the typical equipment by using the fire department in Turkey. 
The other equipment such as foam generator, foam nozzles etc. are out of the scope of this experimental study. Because these foam equipment are only used to intervene the fire in industrial facility. Since the necessity of the flow rate for intervene the fire in high hazard building is much more than the necessity of the flow rate for intervene the fire in low hazard building, the orifice diameter of fog nozzles are bigger than the orifice diameter of typical nozzles. However, the industrial facility is out of scope of this experimental study and all equipment using by fire department in industrial facility are also out of scope of this experimental study.
As a result, the design pressure value could be selected as 400 kPa and the design flow rate could be selected as 400 l/min at the fire hose outlets to intervene the fire at the upper floor of low hazard high building i.e hotel building, office building, residential building, hospital, etc. Besides, the abovementioned design values could be provided from the fire hoses and nozzles using by the fire department in Turkey and only one firefighter can handle the fire hose and nozzle alone at these design values.