Normally closed fire doors refer to those safety doors that need to be closed at all times in order to prevent the spread of smoke after a fire in a building, which is an important line of defense for fire safety in high-rise buildings. However, the reporter recently followed the fire supervisor in shopping malls, high-rise residential buildings and other places in many cities and found that the normally closed fire doors installed in some places have product quality problems, and some are even substandard products.
In Dexing City, Jiangxi Province, the reporter followed the inspectors to visit a newly opened hotel, the newly installed fire door of the hotel, the door leaf appeared to open inflexible jamming.
The inspectors judged that the fire door was an unqualified product according to the on-site judgment rules of fire products, and at the same time, part of the fire door of the hotel could not be closed normally and completely, once a fire occurred, smoke and fire would spread along the gap to the stairwell, and the inspectors required the hotel responsible personnel to immediately rectify the scene.
In Huai'an, Jiangsu Province, fire supervisors also discovered safety hazards related to fire doors during an inspection of a shopping mall. This fire door lacks a sequencer, which is used in the door control system of the fire door, ensuring that the double or multiple fire doors are closed in a specific order, which is essential for fire and smoke protection. If the fire door is closed in the wrong order, it will not really play the role of fire barrier. At the same time, the inspectors also found that the sealing strip of the fire door was also missing.
Subsequently, the inspectors dismantled the fire door on the spot, and found that there was no filling in the so-called fire door, which was essentially a wooden door, which not only could not play any role in fire prevention and smoke insulation, but also could play a role in supporting combustion when a fire occurred, resulting in new safety hazards.
In response to the unqualified fire protection products detected, the Jiangsu Huai'an Fire Department issued a notice of correction to the user within a time limit.
In Ningbo City, Zhejiang Province, a KTV that is about to be renovated and completed, the fire supervisor found that there are hidden dangers in the fire door used during the inspection, the fire door installed in the place is inconsistent with the identity provided by the manufacturer, and the information of the fire door is not consistent with the installation of the product, the Ningbo fire department from the 29 doors involved, take part of the sample, send it to the professional fire product testing agency in Zhejiang Province, and conduct a simulated fire experiment on the sampled fire door.
Yang Chuang, an engineer of a product inspection institute in Zhejiang: There is a piece of fireproof glass on the surface of the sample, and according to the relevant provisions of the standard, the fireproof glass must also meet the average temperature rise of no more than 140 degrees Celsius within one hour. The monitoring showed that after only more than 10 minutes of experimentation, the average temperature rise and the maximum temperature rise of this glass had exceeded the standard requirements, and it was a substandard product.
According to the test results, these fire doors are far from the relevant national standards and regulations, and the safety performance is in vain. When a fire breaks out, a Class B fire door is not only to resist the spread of fire for 1 hour, but also to buy time for people to escape and time for the fire department to rescue. In the end, the fire department sealed the batch of products that were unqualified in the test results. At the same time, the evidence and clues were handed over to the police for investigation.
Unqualified fire doors have huge fire risks
Fire doors should be kept normally closed under normal circumstances, which has the effect of preventing the spread of fire and smoke, and are widely used in hotels, shopping malls and residential corridors, so their safety is of paramount importance. So, what kind of harm will there be in the use of substandard fire doors? The reporter followed the experts of the National Fireproof Building Materials Quality Inspection and Testing Center to conduct a test.
In the test site of the Sichuan Fire Research Institute, the test personnel installed a qualified fire door and an unqualified fire door side by side on the opening of the same combustion furnace, and equipped with a temperature detector to simulate the temperature of the fire scene through the diesel fuel continuously burning in the combustion furnace.
In the standard test scenario, the tester adjusts the size of the flame by setting the oil volume of the nozzle, and creates a temperature environment according to the standard heating curve. After the start of the trial, there was no significant change in the appearance of the two fire doors. As the temperature in the furnace rises rapidly, when the test is carried out for about 3 minutes, white smoke begins to leak out from the cracks of the unqualified fire doors. At 4 minutes and 17 seconds, yellow smoke began to emit from the unqualified fire door, while the qualified fire door basically did not change.
At 4 minutes and 32 seconds, there was a sudden obvious fire in the upper right corner of the unqualified fire door. Experts said that the phenomenon of fire jumping indicates that the separating components have been substantially damaged, that is to say, the unqualified fire door did not play a role in fire prevention at this time.
The field testers used infrared thermometers to measure the temperature of the two fire doors.
Through the thermal imager, it can be seen that the temperature of the inferior fire door at this time has reached more than 300 degrees, while the temperature of the same position of the qualified fire door is only more than 20 degrees. In order to show the thermal insulation effect of the two fire doors more intuitively, the on-site staff brought two sheets of A4 paper of the same specification and placed them on the façade of the two doors respectively, and the paper did not change significantly on the qualified fire door, and when the tester put the paper on the façade of the unqualified fire door, the paper burned up in just a few seconds.
Zhao Chenggang, Director of the Quality and Technology Department of the National Fireproof Building Materials Quality Inspection and Testing Center: The performance of these two fire doors will bring two different safety areas and two different protection effects. At the same time, I also saw that a good fire door was closed, and although there was a raging fire inside, it was still a relatively safe space outside.
After the test, the staff broke down the fire door.
Zhao Chenggang, Director of the Quality and Technology Department of the National Fireproof Building Materials Quality Inspection and Testing Center: Through the door panel cut by the firefighters just now, you can see the typical structure inside the fire door, this layer of door core material, usually composed of non-combustible, inorganic insulation materials, according to different thicknesses, different densities, installed in the fire door, will meet the requirements of different fire door grades, forming the effect of fire insulation at different times.
According to experts, manufacturers of inferior fire doors usually replace the inorganic flame retardant materials that should be filled in the fire door with honeycomb cardboard, and there is no difference between the steel and sealing strips used on other surfaces and the processing technology and qualified fire doors, and consumers are difficult to distinguish from the appearance alone, so it is recommended that consumers buy qualified products from regular channels when purchasing.
Expert: Check if there is a 3C certification fire protection S standard
So, how is the fire level of the fire door divided? How do we identify unqualified fire door products in our daily life? According to experts, we should check whether it has 3C certification and whether there is a fire S standard.
Li Sicheng, Dean of the School of Fire Prevention Engineering of Chinese People's Police University: The current fire door standard is the GB12955 standard, and according to the requirements of the standard, the fire door is divided into Class A fire door, Class B fire door and Class C fire door. Generally, the fire resistance time of Class A fire door is 1.5 hours, Class B fire door is 1 hour, and Class C fire door is 0.5 hours. Generally, the Grade A fire door is a door placed on the firewall, the door of the front room of the closed stairwell is a Class B fire door, the front room is a transitional space leading to the stairwell, and the Class C fire door is generally used to check the shaft.
According to experts, in daily life, unqualified fire doors are usually difficult to identify, and the integrity, thermal insulation and support of fire doors should be tested through fire resistance tests.
Li Sicheng, Dean of the School of Fire Prevention Engineering of the Chinese People's Police University: Whether it can meet its performance requirements through the appearance is generally difficult to say, and can only be seen from the outside from the degree of component damage. For example, if you take the board apart to see if there is material inside, if you look at the cardboard, it will definitely not meet the requirements.
Liu Jingxu, Chief of the Fire Control Technology Section of the Baoji Fire and Rescue Detachment of Shaanxi Province: First of all, check whether it has 3C certification, and the second point is to check whether its specifications and models are consistent with the actual situation. The third point is to check its fire S mark and scan the QR code. Check its manufacturer and flow direction information, as well as whether the specifications and models are consistent with the nameplate.