(5)We are very strict in our purchasing of parts and components and in our production and quality inspection before our gas fire extinguishing products are delivered to make sure that our users have confidence in and rest assured about the quality of our products.
2.Good sealing,no leaking and long service life
The parts and components used for the fire extinguishing system product“Belt and Road”exporting project(also called gas fire extinguishing system exporting project,or gas fire extinguishing system exporting)must have good sealing performance and stable quality.To ensure good sealing performance and stable quality of the products for the fire extinguishing system product“Belt and Road”exporting project(also called gas fire extinguishing system exporting project,or gas fire extinguishing system exporting),we must do the following.
(1)All the valves of fire extinguishing agent cylinders for the gas fire extinguishing systems must be forged from cold-drawn brass rods to prevent corrosion and rusting,and ensure quick and reliable starting.After forging,the crystal particles in the internal microstructure of the copper valves become finer,increasing the density of the material and making the sealing of the valves of fire extinguishing agent vessels to last longer and more reliable.It overcomes the poor sealing and other serious defects of the cylinder valves made from the low-cost stainless iron due to fine heat cracks,loose structure and gas holes that appear inside and on the surface of the castings caused by impurity and difference in solidification temperatures and shrinkage during the cooling process.
(2)It is advised to apply both radial and end-face sealing structures to the valve seals and the joints of the parts and components of the fire extinguishing agent cylinder groups,using sealing materials that are resistant to both corrosion and high temperatures to provide double protection to the sealing property.
(3)Gas fire extinguishing agent filling techniques of agent cylinder groups are different and agent filling techniques can significantly enhance the agent cylinder groups’one-time gas tightness test qualification rate to more than 99%,lowering changes of leakage,prolonging storage cycles,reducing users’maintenance costs and improving safety guarantee for the users.
(4)Gas tightness test must be very strict on cylinder valves and fire extinguishing agent cylinder groups.After filling the agent,the whole cylinder group has to be submerged in clear water for gas tightness test,twice at least,each time for no less than ten minutes.If no single bubble is seen leaked from the cylinder,it is considered to be qualified.This kind of gas tightness test by submerging a fire extinguishing agent cylinder group in clear water is simple,clear and reliable.Many gas fire extinguishing system manufacturers do no perform this kind of gas tightness test by submerging the whole cylinder groups under water.They normally brush some liquid soap on the screw threads where valves are connected to see if bubbles appear.It is hard to determine if a cylinder leaks using this kind of method and sealing of the cylinders can not be guaranteed in this way.
(5)A switch structure needs to be installed in front of the pressure gauge of the gas fire extinguishing system and the switch must be easy to operate and reliable.The threads connecting the pressure gauges must be high strength,high precision and highly sealed dry-seal NPT to ensure reliable sealing.
(6)There are two kinds of structures for high pressure connecting hoses:one has steel structure joints on both ends of the hose,one of which has a 90°elbow,and the flexible hose is at the straight tube part in the middle.This structure allows very limited adjustment in the height direction of the connecting hose and demands high precision in cold work welding of the framework for the agent storage cylinder,which is very difficult and takes a lot of work and may lead to poor sealing and excessive vibration of the connecting parts and leak of the agent when it is released.The other kind of high pressure connecting hose has stainless steel joints on both ends with an only short distance between them.The length of the flexible hose can be adjusted freely in both X axis and Y axis directions and the connection is fast and easy with good leak-tight performance.The vibration of the whole gas fire extinguishing system equipment is limited.
(7)A low pressure safety leak valve,or low leakage high sealing vale in another name,has to be installed in the starting pipe of the gas fire extinguishing system with a pipe network to prevent the gas starting device from activating the system by mistake due to slow leakage and effectively guarantee the quality of the product.
3.Good fire extinguishing performance
To judge the fire extinguishing performance of a gas fire extinguishing system(gas fire extinguishing equipment),we have to take into account the quality and sufficiency of the fire extinguishing agent,the leak-tight property and the pressure level of the agent cylinder group and if the system’s design parameters are correct.The key to judge if the fire-extinguishing performance is good or not is if the agent is qualified and if there is no shortage in quantity.Gas suppliers,engineering service providers and the users should perform joint supervision and inspection and take the following measures to ensure the quality of fire extinguishing agents:
(1)Strict prohibition of the use of unqualified fire extinguishing agents.In the fire extinguishing system,HFC-227ea and ABC superfine dry powder are the two kinds of agents most likely to involve cheating.
Unit price of HFC-227ea fire extinguishing agent varies greatly every year along with changes in the market,mostly between 60~150 yuan/kg,accounting for 50%to 70%of the total manufacturing cost of the whole fire extinguishing system.Main ways to cheat with HFC-227ea agents include:using water or other liquids or solids instead,or using lower purity HFC-227ea agents purchased in the market.
ABC superfine dry powder fire extinguishing agent is usually replaced with regular BC or regular ABC dry power agents,the unit prices of which can vary by more than four times.Designed fire extinguishing concentration of ABC superfine dry powder agent is 0.13kg/m3,while designed fire extinguishing concentration of regular dry powder is 0.65kg/m3 with a difference of around five times.
Measures to take:demanding manufacturers to provide Voluntary certification certificates of their products,and making a trip to the manufacturer’s place before it delivers the products and making random sampling of the fire extinguishing agent inside the cylinder groups on the purity and quantity in the presence of the manufacturer.
(2)Prohibition of shortage of quantity of fire extinguishing agent.In the fire extinguishing system,the HFC-227ea agent is usually the one to involve shortage of quantity.Ways of cheating include:(1)filling less-than-stipulated amount of agent into the cylinder,while the weight of the agent provided on the product plate is larger than the actual weight of the agent filled into the cylinder;(2)adding more nitrogen gas,the propellant to replace part of the weight of HFC-227ea.
The total weight of an HFC-227ea fire extinguishing agent storage cylinder consists three parts:1.the weight of the empty cylinder and the parts W1,including the valve,the siphon and the steel cylinder;2.the weight of the HFC-227ea fire extinguishing agent filled into the cylinder W2.The weight of fire extinguishing agent of a cylinder group is determined by the natural of the protected object,the size of the protected space and the total number of cylinder groups of the system;3.the weight of nitrogen gas,the propellant gas for HFC-227ea agent W3,the calculation formula is:W=W1+W2+W3.The cabinet HFC-227ea gas extinguishing device is also called HFC-227ea pre-engineered extinguishing system,the nitrogen gas in which is normally 1%to 3.7%of the total weight of the HFC-227ea filled in the cylinder group,while in an HFC-227ea gas extinguishing system with pipe networks,nitrogen is usually 4.4%to 7.1%of the total weight of HFC-227ea filled in the cylinder group.