Chapter 647 - 459: This Isn’t Door Control at All!_2

Both exterior and interior attacks need to be adapted according to whether there are trapped persons, which we will discuss in the next step, but the first step is to open the door.

How to open the door is crucial for firefighters to enter the fire scene. Even if it means entering through a window or by breaking through the top, firefighters must reach the door first to provide an entryway for their teammates’ equipment and hose.

I won’t go into breaking down the door; that’s a practical operation.

I will only discuss what information exists in a door at a fire scene and what you should do in front of a door.

First, the temperature at the fire scene.

To assess whether the fire has reached the area near the door, first use gloves to feel for it. Additionally, if the fire is intense, you will feel it when your body is close.

If there is no sensation, you may use the back of your hand to test for heat. Remember, the back of your hand will naturally retract when stimulated.

Secondly, the technique of door control. This is still a relatively new concept in Western firefighting and is in the exploratory phase. I have studied some firefighting concepts in Hong Kong, and they include this concept of door control."

Instructor said with a hint of pride.

"Earlier we mentioned the neutral plane in a fire scene, which is the foundational principle for this technique. Who can tell me what the neutral plane is?"

Instructor finally brought up this important concept, but in the form of a question.

"Fang..."

He had barely uttered a word.

"Report!"

Jin Guotao quickly raised his hand and reported loudly, not giving him the chance to direct the question towards Fang Huai.

The instructor paused for a moment and then turned his head, raising his hand:

"Okay, you go ahead."

Jin Guotao wasn’t entirely prepared, stumbling over his words:

"The neutral plane... refers to a boundary within the fire scene... that neither draws in nor exhausts air!"

"Hmm... not accurate. It’s not the fire scene, but within a confined fire scene or building. The boundary where the hot and cold air meet is called the neutral plane, with the high-temperature smoke layer above and the cold air layer below."

Instructor shook his head and looked at Fang Huai again:

"Fang Huai, do you know the significance of the neutral plane?"

Here we go again.

Everyone’s gaze turned to Fang Huai.

This time, almost everyone felt that the Instructor was being somewhat deliberate.

The Instructor was actually planning to trouble Fang Huai for the last time.

That way, if Fang Huai refused to let them guide him, the instructor could proudly say in front of the leadership later, "This kid’s theory really isn’t great. I have asked him three questions in class, and he couldn’t answer any."

Chinese people like the number "three"; once or twice might be a coincidence, but three times establish a definitive pattern.

This was the third time he asked him a question.

But this time, Fang Huai wouldn’t give him any more chances.

The 1.82-meter-tall figure stood up, his posture very upright.

His speech, too, was much more assertive than before as he sought no longer for answers with tentativeness.

"Report! The fire scene’s neutral plane is a concept proposed by the International Fire Service Training Academy (IFSTA), derived from the principle of thermal stratification, known as the natural plane."

"In a building fire, due to the proportional relationship between air pressure and temperature, thick smoke will vent out of any window. As hot smoke reaches the window, it billows out upwards, while cold air enters from below the window sill, feeding the fire.

Its significance is manifold.

First, for escape, artificially creating a neutral plane.

We know that high temperatures and toxic smoke in a fire are contained in the smoke layer; most people in a fire die not from burns but from suffocation or smoke inhalation. The high-temperature thick smoke in the smoke layer is fraught with danger.

Covering the eyes, ears, mouth, and nose with a wet towel, as commonly advised, is actually incorrect because wetting the towel wastes valuable escape time and cannot effectively block carbon monoxide or smoke.

Therefore, besides escaping in a low posture, another effective way to increase chances of survival and minimize smoke inhalation damage is to create an artificial neutral plane.

If the trapped person takes up a bedsheet, curtain, or blanket, holds it high with both hands, and places it above the head, bending the upper body down, they can create an artificial neutral zone enabling the head to stay below the neutral zone. Smoke would then rise from behind the upper side of the bedsheet, allowing the trapped person to avoid smoke inhalation and reducing the risk of scalding from the hot smoke.

Secondly, to assess the interior fire conditions.

The neutral zone usually lies just over 10 centimeters above the bottom of the smoke layer; by observing the neutral zone, one is essentially observing the smoke layer. The development of the fire situation can be gleaned from the height of the neutral zone.

Smoke is a byproduct of combustion, so when entering a fire scene, a higher neutral zone with thin smoke indicates an early stage of fire; the lower it is, the more dangerous the situation could be, with the potential for flashover or backdraft. If the smoke layer suddenly rises and thickness decreases, it means ventilation conditions have improved. If it drops rapidly, it indicates a backdraft has occurred and the smoke has filled the room.

Recent research indicates that when the smoke layer descends to about one meter from the ground, the fire development is nearing a flashover.

At that point, one should not haphazardly enter the fire scene.

Third, to control the smoke layer.

Upon entering the fire scene, cooling the smoke layer with water, and having a standard for the height of the smoke layer enable firm control of the risks of flashovers and backdrafts.

Fourth, as the instructor mentioned in the last class, is to determine the fire’s origin by observing the smoke movement.

Report, complete."

As Fang Huai finished speaking, the surroundings were very quiet.

There was the sound of pages turning.

Seems like this page is missing, huh?

The "neutral plane" described in the book was just a principle, wasn’t it?

The instructor was somewhat astonished and wanted to say something, but Fang Huai had given a very comprehensive explanation, and there was the mention of a "1-meter flashover line," research he was unaware of.