SSMT – Disaster-Prevention Playbook (9.9–9.12)

Risk:
Structural icing from cold spray on exposed surfaces

Inputs:
Surface temperature at critical points.
Pivot tag T_m_tag = brine (or equivalent salt blend).
Short-window volatility V_T(15 min).

Guards (symbol space):
a_phase_surface := tanh(
    c_m * ( (T_surface_K - T_m_brine) / DeltaT_m_brine )
)

V_T := sqrt( Var_{15min}( e_T_surface ) )

Action (enter):
a_phase_surface <= -Phi_freeze
AND
V_T >= V_star
→ declare Icing Risk and escalate response

Clear (exit):
a_phase_surface >= +Phi_clear
for >= T_clear minutes
→ stand down

Notes:
• `a_phase_surface <= -Phi_freeze` means “symbolically below the brine pivot,” which indicates freeze formation risk.
• High volatility (`V_T`) indicates active icing dynamics, not just cold background.
• The same symbolic rule applies across different hulls or structures once the pivot is declared.

Risk:
Leaf or fruit damage from localized frost

Inputs:
Canopy / leaf temperature probes near worst-case microclimates.
Pivot tag T_m_tag = plant_tissue.

Guard (symbol space):
a_phase_leaf := tanh(
    c_m * ( (T_leaf_K - T_m_leaf) / DeltaT_m_leaf )
)

Action (enter):
a_phase_leaf <= -0.05
for >= 10 minutes
→ trigger localized protection (heat / mist / circulation)

Clear (exit):
a_phase_leaf >= +0.05
for >= 10 minutes
→ return to normal

Notes:
• This uses the symbolic phase dial (`a_phase_leaf`) instead of “below X °C.”
• The same thresholds work in different structures, because the pivot T_m_leaf travels with the manifest.
• Sensors should sit where frost forms first (vents, edges, shaded corners), not just in the center.

Risk:
Insufficient heating capacity during cold snaps

Inputs:
Outdoor symbolic contrast e_T_outdoor.
Supply-side contrast e_T_supply.

Guard (symbol space):
e_T_outdoor tracks external stress.
e_T_supply tracks delivered output versus expected band.

Action (enter):
Stage N if
e_T_outdoor <= -E_cold
AND
e_T_supply < target_e
→ bring next stage online

Clear (exit):
De-stage when
e_T_outdoor >= (-E_cold + E_hyst)
OR
e_T_supply >= target_e
→ scale back

Notes:
• `E_cold`, `E_hyst`, and `target_e` are declared once and reused across all serviced zones.
• This lets one policy scale across multiple buildings or regions without rewriting °C rules.

Risk:
Freeze in stagnant fluid segments

Inputs:
Fluid-line temperature at known stagnant segments.
Pivot tag T_m_tag = fluid (phase-change pivot).

Guard (symbol space):
a_phase_fluid := tanh(
    c_m * ( (T_fluid_K - T_m_fluid) / DeltaT_m_fluid )
)

Action (enter):
Trace ON while
a_phase_fluid <= 0.00
→ actively heat / protect line

Clear (exit):
Trace OFF when
a_phase_fluid >= +0.10
for >= T_clear minutes
→ release heat-trace

Notes:
• `a_phase_fluid <= 0.00` means “at or below the symbolic pivot,” so the system protects proactively, not after full freeze.
• Hysteresis via +0.10 prevents rapid ON/OFF chatter.
• Always confirm electrical load / safety rating before enabling automatic trace-on.

Phi_freeze   = 0.10
Phi_clear    = 0.10
E_hot        = 0.8
E_cold       = 0.8
E_hyst       = 0.2
T_hot_min    = 10 min
T_freeze_min = 20 min
T_clear      = 20 min