Industry News

The significance of performance measurement of water cannons and foam cannons to Isuzu fire trucks is mainly reflected in evaluating fire extinguishing effects, ensuring safety, guiding equipment selection and purchase, improving fire extinguishing efficiency, and reducing losses. By measuring parameters such as spray distance and spray angle, appropriate equipment and spray strategies can be selected according to actual needs to ensure the safety of firefighters and other personnel, control fire intensity, cool fire sources, suppress fire spread, etc., and reduce disaster losses and environmental impacts.

A. Determination of the range of water cannon and foam cannon:

1.Test conditions

The test site should be flat, with sufficient length and width. The fire truck should be parked at a suitable position on the site, and the gun elevation angle should be 30°±2°. Taking the intersection of the plumb line passing the muzzle and the ground as the origin, measure the range in the downwind direction.

2. Test operation

During the test, the wind speed should be less than 2m/s. Start the fire pump. After the inlet pressure of the gun reaches the rated injection pressure and the sprayed water or foam stabilizes, spray continuously for 30 seconds without changing the elevation angle. Use a stopwatch to measure the farthest point where the medium is continuously dropped for no less than 10 seconds. The distance from this point to the origin is the range of the gun.

B. Measurement of fire truck outlet water pressure and flow rate:

1.Test conditions

The test site should be flat, with sufficient length and width. The fire truck should be parked at a suitable position on the site, and the gun elevation angle should be 30°±2°. Taking the intersection of the plumb line passing the muzzle and the ground as the origin, measure the range in the downwind direction.

2. Test operation

Start the fire truck, adjust the speed of the pump and the opening of the outlet valve so that the water pressure and flow rate of the fire truck reach the values specified. After the operation is stable, read the water pressure and flow values.

C. Determination of mixing ratio:

Taking advantage of the characteristics of different refractive indexes of foam mixtures of different concentrations, a refractometer is used to measure the mixing ratio.

First, make a calibration curve, use a dropper to take out the foam liquid from the foam liquid tank of the fire truck, and drop 3mL, 6mL, and 9mL foam liquid into three 100mL measuring cylinders respectively; then add the water in the water tank of the semi-fire truck into each Set the measuring cylinder to 100 mL, mix thoroughly to make foam mixtures with standard concentrations of 3%, 6%, and 9%. Read the scales on the refractometer, and make the relationship between the refractometer scales and the concentration of the foam mixture on the graph paper. Calibration curve.

Use the foam mixture precipitated by the liquid elution time test as a sample, read the scale number on the refractometer, and find the mixing ratio of the sample from the calibration curve.

D. Determination of foaming multiple and 25% liquid drainage time

Place the foam collector and foam liquid analyzer near the center where the foam is expected to fall. The foam cannon sprays in other directions first, and then turns to the foam collector after the rated injection pressure is reached and stabilized. Start timing when the liquid drainage measuring device flows into the foam, which is used as the starting time of the liquid drainage time test; stop spraying after it is filled with foam, scrape off the excess foam on the top with a scraper, wipe the outer surface, and the sampling is completed.

E. Determination of foaming multiple

Weigh the mass of the liquid analyzer filled with foam, and use the equation to calculate the foaming multiple:

In the formula: N——foaming multiple;

Ve - the volume of the foam leakage measuring device, cm3;

W´e——The total mass of the foam liquid analyzer when it is filled with foam, g;

We——the mass of the foam leakage measuring device, g;

d——The density of the mixed liquid, take d=1g/m3.

Take the arithmetic mean of the test results of the two specimens.

F. Determination of 25% liquid drainage time

Remove the liquid receiving tank below the foam liquid measuring device and place it on the bench scale. Place the foam receiving tank above on the bracket. Pay attention to keep all the liquid that has separated out being injected into the liquid receiving tank. When the mass of the precipitated liquid reaches 25% of the liquid precipitation mass, stop timing and record the 25% liquid precipitation time. Take the arithmetic mean of the test results of the two specimens.25% liquid drainage mass is calculated according to the formula: where: Wf——25% liquid drainage mass.

G. Correction for the influence of test temperature

The temperature of the water in the foam mixture has a great influence on the foaming multiple and liquid drainage time. Therefore, the temperature of the water during the test should be controlled within the range of 15 to 25°C. The following modifications are made to protein foam fire extinguishing agents:

Foaming multiple - when the water temperature of the mixed solution is greater than 20°C, the foaming multiple will be reduced by 0.1 for every 1.7°C increase; when the mixed solution water temperature is less than 20°C, the foaming multiple will be increased by 0.1 for every 1.7°C decrease.

Liquid separation time - when the water temperature of the mixed liquid is greater than 20℃, the liquid precipitation time increases by 0.1min for every 1.7℃ increase; when the mixed liquid water temperature

If the water temperature is less than 20℃, the liquid separation time will be reduced by 0.1min for every 1.7℃ drop.