受限空间作业
一、受限空间定义 | Confined Space Definition
二、大气危害 | Atmospheric Hazards
三、进入准备 | Entry Preparation
四、应急救援 | Emergency Rescue
五、典型受限空间 | Typical Confined Spaces
场景一：电缆沟受限空间进入——气体检测争议 Cable Trench Confined Space Entry — Gas Testing Dispute We need to enter the 120m cable trench between the inverter station and the transformer to pull the auxiliary power cables. Trench is 1.5m deep × 0.8m wide — classified as confined space. I've done the pre-entry gas test. O₂: 20.7%, LEL: 0%, CO: 3 ppm, H₂S: 0 ppm. Readings are stable from the entrance. We're ready to go.
要进入逆变站和变压器之间的120m电缆沟、拉辅助电源电缆。沟深 1.5m×宽0.8m——分类为受限空间。做了进入前气体检测。O₂:20.7%、 LEL:0%、CO:3ppm、H₂S:0ppm。入口处读数稳定。准备好了。
You took the readings at the entrance. That's only the first 2 meters of a 120m trench. Cable trenches can have stratified gases — CO is heavier than air and can accumulate at the far end with no ventilation. I need you to lower the gas detector on a rope to the midpoint — 60 meters in — and the far end, 120 meters in. Let the detector sit at each point for 60 seconds before reading.
你在入口测的。那只是120m沟最前面2m。电缆沟可能有气体分层—— CO比空气重、可能在远处无通风处聚集。需要把气体检测仪用绳降到中 点——60m进去——和远端、120m进去。每点让检测仪待60秒再读数。
(lowers detector via rope) Midpoint 60m: O₂ — wait, it's dropping. 20.7... 20.5... 20.1... now stable at 19.9%. That's below the 20.0% threshold but above the 19.5% critical limit. CO: 18 ppm — still safe but elevated. Far end 120m: O₂ stable at 20.3%. CO: 8 ppm. So the midpoint has a pocket of lower oxygen. That's exactly what you warned about. I should have tested along the length. My mistake.
(用绳降检测仪)60m中点:O₂——等等、在下降。20.7...20.5...20.1... 现在稳定在19.9%。低于20.0%门槛但在19.5%危急限之上。CO:18ppm—— 仍安全但偏高。120m远端:O₂稳定20.3%。CO:8ppm。所以中点有低氧区。 正是你警告的。我应延长度方向检测。我的错。
Thank you for re-testing properly. Now we know the real condition: O₂ at the midpoint is marginal. Before entry: set up forced ventilation at the entrance, ducting extended to the 60m midpoint. Run for 15 minutes, then re-test. I want O₂ above 20.5% at all three points before anyone enters. The standby person will monitor the gas detector readings continuously via the remote display. If O₂ drops below 19.5% at any point, all entrants evacuate immediately.
感谢正确复测。现在知道了真实情况:中点O₂边缘。进入前:入口设强 制通风、风管延伸到60m中点。运行15分钟、复测。要三点全O₂在20.5% 以上才允许进入。监护员通过远程显示屏连续监测检测仪读数。如果O₂ 任何点降到19.5%以下、全体进入人员立即撤离。
场景二：受限空间救援演练 Confined Space Rescue Drill
This is an announced rescue drill — not a surprise. Scenario: a worker has collapsed inside the sedimentation tank — 4m diameter, 6m deep, single manhole access at the top. The gas monitor at the entrant's belt is reading O₂ at 18.2% and CO at 120 ppm — he's unresponsive. The standby person has called emergency. Rescue team — this is a non-entry rescue scenario. Execute.
这是通告的救援演练——非突袭。场景:一名工人在沉砂池内倒下—— 直径4m、深6m、顶部单个检查孔。进入人员腰挂检测仪读数O₂ 18.2%、 CO 120ppm——无反应。监护员已呼叫应急。救援队——这是非进入救援场 景。执行。
Non-entry rescue in progress. Deploying the tripod over the manhole. (team sets up tripod in 45 seconds) Tripod set — legs locked, pulley centered over the opening. Attaching the rescue winch cable to the entrant's dorsal D-ring via the pre-rigged retrieval line — we don't enter, we pull from outside. (cable attached) Winching now. (entrant dummy rises through the manhole — total extraction time: 2 minutes 15 seconds from drill start) Entrant extracted and on the ground. Moving to the safe zone 10m upwind for medical assessment. (checks watch) Total time from collapse to extraction: 3 minutes 38 seconds — within the 4-minute target for a hypoxic rescue.
非进入救援执行中。在检查孔上方展开三脚架。(45秒内架好)三脚架 就位——腿锁定、滑轮在开口中心对中。将救援卷扬机缆绳通过预挂回收 线接到进入人员背部D形环——我们不进入、从外面拉。(缆绳接好)起吊。 (假人从检查孔升起——自演练开始至取出总时间:2分15秒)进入者取出到 地面。移至10m上风安全区医疗评估。(看表)从倒下到取出的总时间:3分 38秒——在缺氧救援4分钟目标内。
Good execution. Debrief: what went well — tripod setup was fast, the pre-rigged retrieval line saved critical seconds, and you didn't attempt entry. What to improve: the winch operator took 10 seconds to find the correct crank direction — that's 10 seconds of hypoxia progression. Practice the winch operation monthly. Second: the standby person froze for about 8 seconds when the alarm sounded before calling emergency. Drill that muscle memory. Overall: pass. The drill record goes in the HSE log. Next drill in 6 weeks — that one will be a surprise.
执行好。讲评:做得好——三脚架架设快、预挂回收线节约关键秒数、 没尝试进入。改进:卷扬机操作员找对摇把方向花了10秒——那10秒是缺 氧进展。每月练卷扬机操作。第二:监护员报警响起后呆了约8秒才打应急 电话。练肌肉记忆。总体:通过。演练记录入HSE日志。六周后下次演练—— 那是突袭。