diff --git a/scripts/sql/p1_historian.sql b/scripts/sql/p1_historian.sql
index 4168050..da79543 100644
--- a/scripts/sql/p1_historian.sql
+++ b/scripts/sql/p1_historian.sql
@@ -43,3 +43,10 @@ CREATE TABLE IF NOT EXISTS hc900.live_kpi (
   value double precision, unit text, state text, excluded_min int, status text,
   updated_at timestamptz NOT NULL DEFAULT now(),
   PRIMARY KEY (column_id, kpi, window_start));
+
+-- P1d: 실시간 알람 (edge-trigger: 진입 active, 해제 resolved)
+CREATE TABLE IF NOT EXISTS hc900.kpi_alert (
+  column_id text NOT NULL, rule text NOT NULL, severity text, active boolean NOT NULL DEFAULT true,
+  message text, value double precision,
+  opened_at timestamptz NOT NULL DEFAULT now(), updated_at timestamptz NOT NULL DEFAULT now(), resolved_at timestamptz,
+  PRIMARY KEY (column_id, rule));
diff --git a/src/Hc900Crawler/Controllers/ReportController.cs b/src/Hc900Crawler/Controllers/ReportController.cs
index d35ab3f..d75316d 100644
--- a/src/Hc900Crawler/Controllers/ReportController.cs
+++ b/src/Hc900Crawler/Controllers/ReportController.cs
@@ -53,6 +53,32 @@ public class ReportController : ControllerBase
         return Ok(new { Count = items.Count, Items = items });
     }
 
+    /// <summary>활성 알람(kpi_alert) — cleaning/drawdown 진입·폐합 이탈. active=false면 해제 포함.</summary>
+    [HttpGet("alerts")]
+    public async Task<IActionResult> Alerts(bool activeOnly = true, CancellationToken ct = default)
+    {
+        var conn = _db.Database.GetDbConnection();
+        if (conn.State != ConnectionState.Open) await conn.OpenAsync(ct);
+        await using var cmd = conn.CreateCommand();
+        cmd.CommandText = @"SELECT column_id, rule, severity, active, message, value, opened_at, updated_at, resolved_at
+                            FROM hc900.kpi_alert" + (activeOnly ? " WHERE active" : "") +
+                            " ORDER BY active DESC, opened_at DESC";
+        var items = new List<object>();
+        await using var rd = await cmd.ExecuteReaderAsync(ct);
+        while (await rd.ReadAsync(ct))
+            items.Add(new {
+                Column = rd.GetString(0), Rule = rd.GetString(1),
+                Severity = rd.IsDBNull(2) ? null : rd.GetString(2),
+                Active = rd.GetBoolean(3),
+                Message = rd.IsDBNull(4) ? null : rd.GetString(4),
+                Value = rd.IsDBNull(5) ? (double?)null : rd.GetDouble(5),
+                OpenedAt = rd.GetFieldValue<DateTime>(6),
+                UpdatedAt = rd.GetFieldValue<DateTime>(7),
+                ResolvedAt = rd.IsDBNull(8) ? (DateTime?)null : rd.GetFieldValue<DateTime>(8)
+            });
+        return Ok(new { Count = items.Count, Items = items });
+    }
+
     /// <summary>설정된 컬럼 목록(웹 UI 셀렉트용).</summary>
     [HttpGet("columns")]
     public IActionResult Columns()
diff --git a/src/Hc900Crawler/appsettings.json b/src/Hc900Crawler/appsettings.json
index 2423d3d..9c43427 100644
--- a/src/Hc900Crawler/appsettings.json
+++ b/src/Hc900Crawler/appsettings.json
@@ -95,7 +95,8 @@
     "LiveKpi": {
       "Enabled": true,
       "IntervalSeconds": 15,
-      "Source": "history_1s"
+      "Source": "history_1s",
+      "ClosureTolerancePct": 2.0
     },
     "Cleaning": {
       "VacMax": 300,
diff --git a/src/Infrastructure/Hc900/Hc900LiveKpiService.cs b/src/Infrastructure/Hc900/Hc900LiveKpiService.cs
index dbdcfdd..6693a88 100644
--- a/src/Infrastructure/Hc900/Hc900LiveKpiService.cs
+++ b/src/Infrastructure/Hc900/Hc900LiveKpiService.cs
@@ -26,6 +26,7 @@ public class Hc900LiveKpiService : BackgroundService
     private readonly bool _enabled;
     private readonly int _intervalSec;
     private readonly string _source;
+    private readonly double _closureTol;
 
     public Hc900LiveKpiService(IServiceScopeFactory scopeFactory, ILogger<Hc900LiveKpiService> logger,
         Hc900RealtimeService realtime, ReportColumnMap map, IConfiguration config)
@@ -34,6 +35,7 @@ public class Hc900LiveKpiService : BackgroundService
         _enabled     = config.GetValue("Report:LiveKpi:Enabled", true);
         _intervalSec = Math.Max(5, config.GetValue("Report:LiveKpi:IntervalSeconds", 15));
         _source      = config.GetValue("Report:LiveKpi:Source", "history_1s")!;   // 1초 버퍼 기본
+        _closureTol  = config.GetValue("Report:LiveKpi:ClosureTolerancePct", 2.0);
     }
 
     protected override async Task ExecuteAsync(CancellationToken stoppingToken)
@@ -75,6 +77,10 @@ public class Hc900LiveKpiService : BackgroundService
                         await UpsertAsync(conn, col, r.Metric, todayKst, r.Value, r.Unit, state, excl, r.Status, stoppingToken);
                         written++;
                     }
+
+                    // P1d: 실시간 알람 (운전모드 + 폐합 이탈)
+                    var closure = results.First(r => r.Metric == "mass_balance_closure");
+                    await EvaluateAlertsAsync(conn, col, closure, stoppingToken);
                 }
                 _logger.LogDebug("[LiveKpi] {N}개 KPI 갱신 @ {Day}", written, todayKst);
             }
@@ -111,7 +117,75 @@ CREATE TABLE IF NOT EXISTS hc900.live_kpi (
   column_id text NOT NULL, kpi text NOT NULL, window_start date NOT NULL,
   value double precision, unit text, state text, excluded_min int, status text,
   updated_at timestamptz NOT NULL DEFAULT now(),
-  PRIMARY KEY (column_id, kpi, window_start))";
+  PRIMARY KEY (column_id, kpi, window_start));
+CREATE TABLE IF NOT EXISTS hc900.kpi_alert (
+  column_id text NOT NULL, rule text NOT NULL, severity text, active boolean NOT NULL DEFAULT true,
+  message text, value double precision,
+  opened_at timestamptz NOT NULL DEFAULT now(), updated_at timestamptz NOT NULL DEFAULT now(), resolved_at timestamptz,
+  PRIMARY KEY (column_id, rule));";
         await cmd.ExecuteNonQueryAsync(ct);
     }
+
+    /// <summary>P1d 알람: 최신 샘플로 운전모드(cleaning/drawdown/normal) 판정 + 폐합 이탈 룰 → kpi_alert edge-trigger.</summary>
+    private async Task EvaluateAlertsAsync(System.Data.Common.DbConnection conn, string col, MetricResultDto closure, CancellationToken ct)
+    {
+        if (!_map.TryResolveCleaning(col, out var cl) || cl is null) return;
+
+        double? vac = null, prod = null, feed = null;
+        await using (var q = conn.CreateCommand())
+        {
+            q.CommandText = $@"SELECT
+  (SELECT value::float FROM hc900.{_source} WHERE tagname=@vac  AND recorded_at > now()-interval '3 min' ORDER BY recorded_at DESC LIMIT 1),
+  (SELECT value::float FROM hc900.{_source} WHERE tagname=@prod AND recorded_at > now()-interval '3 min' ORDER BY recorded_at DESC LIMIT 1),
+  (SELECT value::float FROM hc900.{_source} WHERE tagname=@feed AND recorded_at > now()-interval '3 min' ORDER BY recorded_at DESC LIMIT 1)";
+            void P(string n, object? v) { var p = q.CreateParameter(); p.ParameterName = n; p.Value = v ?? DBNull.Value; q.Parameters.Add(p); }
+            P("@vac", cl.VacTag ?? ""); P("@prod", cl.ProductTag); P("@feed", cl.FeedTag);
+            await using var rd = await q.ExecuteReaderAsync(ct);
+            if (await rd.ReadAsync(ct))
+            {
+                vac  = rd.IsDBNull(0) ? null : rd.GetDouble(0);
+                prod = rd.IsDBNull(1) ? null : rd.GetDouble(1);
+                feed = rd.IsDBNull(2) ? null : rd.GetDouble(2);
+            }
+        }
+
+        var desired = new List<(string rule, string sev, string msg, double? val)>();
+        if (prod is not null || feed is not null)   // 데이터 있을 때만 평가(없으면 전부 해제)
+        {
+            bool isClean  = (prod ?? 0) < cl.ProductMin || (vac.HasValue && vac > cl.VacMax);
+            bool isDraw   = (feed ?? 0) < cl.FeedMin && (prod ?? 0) >= cl.ProductMin;
+            bool isNormal = (feed ?? 0) >= cl.FeedMin && (prod ?? 0) >= cl.ProductMin && (!vac.HasValue || vac <= cl.VacMax);
+            if (isClean) desired.Add(("cleaning", "info", "세정/비운전 진입(진공 高 또는 제품~0)", null));
+            else if (isDraw) desired.Add(("drawdown", "info", "drawdown — feed≈0 인데 출력(인벤토리 인출/컬럼간 이송)", feed));
+            if (isNormal && closure.Status == "ok" && closure.Value is double cv && Math.Abs(cv - 100) > _closureTol)
+                desired.Add(("closure_deviation", "warning", $"폐합 {cv:F1}% (100±{_closureTol}% 이탈 — 계량 드리프트/누설/이송 점검)", cv));
+        }
+        await SyncAlertsAsync(conn, col, desired, ct);
+    }
+
+    /// <summary>desired 룰은 active 유지/발화, 나머지 active 알람은 resolved 처리(edge-trigger).</summary>
+    private static async Task SyncAlertsAsync(System.Data.Common.DbConnection conn, string col,
+        List<(string rule, string sev, string msg, double? val)> desired, CancellationToken ct)
+    {
+        foreach (var (rule, sev, msg, val) in desired)
+        {
+            await using var up = conn.CreateCommand();
+            up.CommandText = @"
+INSERT INTO hc900.kpi_alert (column_id, rule, severity, active, message, value, opened_at, updated_at, resolved_at)
+VALUES (@c,@r,@s,true,@m,@v,now(),now(),NULL)
+ON CONFLICT (column_id, rule) DO UPDATE SET
+  severity=EXCLUDED.severity, active=true, message=EXCLUDED.message, value=EXCLUDED.value, updated_at=now(),
+  opened_at = CASE WHEN hc900.kpi_alert.active THEN hc900.kpi_alert.opened_at ELSE now() END,
+  resolved_at = NULL";
+            void P(string n, object? v) { var p = up.CreateParameter(); p.ParameterName = n; p.Value = v ?? DBNull.Value; up.Parameters.Add(p); }
+            P("@c", col); P("@r", rule); P("@s", sev); P("@m", msg); P("@v", val);
+            await up.ExecuteNonQueryAsync(ct);
+        }
+        await using var res = conn.CreateCommand();
+        res.CommandText = @"UPDATE hc900.kpi_alert SET active=false, resolved_at=now(), updated_at=now()
+                            WHERE column_id=@c AND active AND NOT (rule = ANY(@rules))";
+        var pc = res.CreateParameter(); pc.ParameterName = "@c"; pc.Value = col; res.Parameters.Add(pc);
+        var pr = res.CreateParameter(); pr.ParameterName = "@rules"; pr.Value = desired.Select(d => d.rule).ToArray(); res.Parameters.Add(pr);
+        await res.ExecuteNonQueryAsync(ct);
+    }
 }