The Critical 3 Minutes of a “Furnace Runout”, Emergency Mitigation and Personnel Evacuation SOP in the Melting Shop
In a foundry melting shop, ก “furnace runout” (where molten iron burns through the furnace lining and approaches the induction coil) is one of the most catastrophic and destructive accidents possible. Once the 1600℃ molten iron breaches the lining and heads straight for the induction coil, the operators are usually left with a reaction window of only about 3 นาที.
Within these critical 3 นาที, every single action determines the line between life and death for everyone in the shop.
ฉัน. Strict Myth-Busting: Can You Shut Off the Cooling Water During a Runout?
Among many older workshops or untrained workers, a highly lethal myth persists: “If you see a runout or molten iron leaking, shut off the coil cooling water immediately to prevent the water ท่อ from burning through.”
This is an absolute suicide mission!
Why must you NEVER shut off the water?
The induction coil of a medium-frequency furnace consists of hollow copper tubing. The cooling water flowing inside is the เท่านั้น barrier protecting the coil from melting instantly.
- If water flow is maintained: Even if the molten iron approaches or lightly touches the coil, the flowing water will carry away the vast majority of the heat. This delays the melting of the coil, buying precious seconds for personnel evacuation and emergency handling.
- If water is shut off immediately: Without flowing water to cool the copper tubing, the 1600℃ molten iron will completely melt the copper coil within seconds.
- Triggering a massive steam explosion: Once the copper tube melts, any residual water inside will come into direct contact with the 1600℃ molten iron. One gram of water turns into steam and expands over a thousand times in volume. This causes a horrific molten iron-water steam explosion, which will instantly obliterate the furnace platform, blow the roof off the workshop, and leave zero chance of survival for anyone nearby.
The Core Ironclad Rule: Unless the entire furnace body has completely cooled down, or it is confirmed that the coil has broken extensively and water cannot be replenished, you must fight to ensure the continuous operation of the cooling water system (or switch to the emergency water source/gravity-fed reservoir) during the first phase of emergency response!
ครั้งที่สอง. ที่ “Critical 3 Minutes” Emergency Mitigation SOP
When the furnace platform monitors trigger a leak alarm, or if the furnace bottom/wall is visibly glowing red, or if molten iron is seen seeping out, immediately activate the following Standard Operating Procedure (สบส):
[Minute 1: Decisive Cut-off & Hazard Isolation]
- Hit the High-Voltage/Medium-Frequency Emergency Stop:
- The discoverer or primary operator must immediately press the red E-stop button on the control console to cut off the medium-frequency power.
- วัตถุประสงค์: Stops electromagnetic stirring and continuous heating, preventing the molten iron from further eroding the damaged lining due to turbulence, while eliminating high-voltage electrical hazards.
- Cut Off the Hydraulic System (If Applicable):
- Shut down the tilting hydraulic pump station to prevent hydraulic oil lines from being ruptured by high-temperature molten iron, which could ignite a secondary fire.
- Raise the Alarm: Press the workshop’s audio-visual alarm and shout: “Runout on Furnace X!” to notify all platform and pit personnel to prepare for evacuation.
[Minute 2: Defend the Cooling Water & Prepare Drainage]
- Verify/Switch the Cooling Water System:
- Check the coil cooling water pressure gauge. If a main power failure causes the primary water pump to stop, immediately switch manually or automatically to the diesel emergency water pump, or open the emergency gravity-feed valve from the high-level water reservoir.
- Keep the water flowing without interruption! ในขั้นตอนนี้, monitor the water outlet temperature and flow rate to assess the extent of coil damage.
- Prepare the Emergency Iron Capture Pit (If molten iron is not yet gushing extensively):
- Quickly check the emergency capture pit (or emergency sand basin) in front of or beneath the furnace.
- Life-or-Death Checkpoint: The emergency pit must be completely free of standing water, damp materials, or flammable/explosive items! If there is water in the pit, the incoming molten iron will cause an immediate localized explosion. Once confirmed dry, prepare to guide the molten iron safely toward the capture pit.
[Minute 3: Safe Tilting & Ultimate Mitigation]
- Controlled Furnace Tilting (Depending on the situation):
- If the furnace lining has not completely collapsed and the hydraulic or mechanical tilting mechanism is still operational, rapidly tilt the furnace to pour the remaining molten iron into a safe, dry ladle or the emergency capture pit, ensuring no one is in front of the furnace.
- หลักการ: Reduces the static pressure of the molten iron inside the furnace, preventing it from continuing to penetrate laterally toward the coil and furnace shell.
- Abandon Futile Salvage & Shift to Total Defense:
- If the molten iron has already breached the coil on a large scale, spilled onto the floor causing a major fire, or is accompanied by violent popping sounds (moisture reaction), operators must abandon the furnace platform immediately. Any attempts to step forward and bury it with sand are strictly forbidden.
III. Workshop Personnel Evacuation and Routing Regulations
In a furnace runout accident, the areas most prone to causing mass casualties are the pits beneath the furnace platform, the basement, and the area directly in front of the furnace.
[Runout Alarm Triggered]
│
├─ Platform Operators -> Execute Power Cut/Water Maintenance SOP -> Evacuate to [Lateral Safety Aisles]
│
└─ Pit/Slagging/Auxiliary Workers -> Hear Alarm -> DO NOT Retrieve Belongings -> Move [Upward & Outward] Against Iron Flow
1. Evacuation Route Selection Principles
- Pit Personnel Have Absolute Priority: Upon hearing the alarm, anyone working in the pit beneath the furnace for slagging, การซ่อมบำรุง, or auxiliary tasks must immediately drop all tools and climb out of the pit via safety ladders within 10 วินาที. If the molten iron burns through the bottom of the furnace, the pit will instantly become an inferno, and radiant heat and toxic fumes will rapidly accumulate.
- Never Run Downward; Always Evacuate Upward and Outward: Everyone must flee toward safety exits that lead away from the furnace, to higher ground, and where there is good air ventilation.
- Avoid the Direct Front and Bottom: It is strictly forbidden to pass through channels directly beneath a leaking furnace or directly in front of the pouring spout.
2. Workshop Organization and Roll Call
- No Reverse Entry: No one is allowed to return to the workshop under any circumstances for reasons like “getting a phone, retrieving a jacket, or checking equipment” until the professional firefighting and safety team has declared it safe.
- Designated Assembly & Roll Call: All workshop personnel must gather at a designated safe assembly point outside the factory building (เช่น, an open yard). Shift supervisors must complete a headcount within 3 นาที and immediately report to the emergency commander-in-chief: “Shift X reports: X expected, X present, 0 trapped (or X missing).”
IV. Tactical Summary: The Safety Bottom Line of the Melting Shop
The evolution of a furnace runout accident is measured in seconds. The melting shop must strictly implement the following “Three Iron Rules” daily:
- Routine Drills: Every melting operator must be able to find the “Emergency Stop Button” และ “Emergency Water Valve” with their eyes closed.
- Strict Equipment Checks: The emergency iron capture pit must never be used to store debris and must be kept dry at all times. The emergency diesel water pump must be tested weekly to ensure seamless startup during a power outage.
- Mindset Imprint: Firmly memorize the 7-word rule: “Cut Power, Keep Water, Evacuate!” Never close the cooling water valve during a runout!
