In the field of fire safety, dry powder fire extinguishing agent has attracted much attention because of its wide application range and efficient fire extinguishing performance. However, the performance of dry powder fire extinguishing agent not only depends on its fire extinguishing effect, but also closely related to its water repellency. Dry powder fire extinguishing agent with good water repellency can better maintain its fire extinguishing performance and is not affected by moisture during the fire extinguishing process, so it is particularly important to test the water repellency of dry powder fire extinguishing agent.
The method of testing the water repellency of dry chemical powder extinguishing agent usually includes the following steps:
1.Prepare reagents and instruments: including sodium chloride (chemically pure), petri dish, pipette, dryer, etc.
2.Sample preparation: Place an excessive amount of dry powder extinguishing agent in a petri dish and smooth the surface with a scraper.
3.Drip operation: Use a pipette to drop 0.3mL of distilled water or third grade water at each of three different points on the dry powder surface (in accordance with GB/T 6682). Make sure that the distance between drip points and between drip points and the edge of the dish is not less than 10mm.
4.Setting of environmental conditions: Place the petri dish in a dryer with saturated sodium chloride solution at a temperature of (20±5) ℃. Set the relative humidity to about 75% and leave for (120±5) minutes.
5.Observation and recording: Take out the petri dish and gradually tilt it so that the water droplets roll off. Observe and record whether the dry powder fire extinguishing agent sample has obvious water absorption and caking phenomenon.
6.Results: Judging the water repellency of dry powder fire extinguishing agent according to the observation results. Some powder fire extinguishing agent samples did not show obvious phenomenon of water absorption and caking after testing, which indicated that their water repellency was good. If there is obvious water absorption and caking phenomenon, it indicates that its water repellency is poor.
In the process of testing the water repellency of dry powder fire extinguishing agent, the following matters need to be noted:
1.Reagents and instruments used should be kept clean and dry to avoid interference with test results.
2.The test should be conducted under standard environmental conditions, such as temperature, humidity, etc., to ensure the reliability of the test results.
3.Dripping operation should be accurate and rapid to avoid unnecessary interference with the dry powder fire extinguishing agent sample.
4.The results should be observed carefully and comprehensively to avoid missing important information.
In short, testing the water repellency of dry powder fire extinguishing agent is an important step to evaluate its performance and ensure fire safety. By following the above methods and precautions, the water repellency of dry powder fire extinguishing agent can be accurately tested, which provides a reference for the fire department to choose the appropriate fire extinguishing equipment.