METRICS · CONTAINMENT & SAFETY
Airborne Spore Load
VC-MET-406 — viable airborne spore concentration in corridor air — the bioburden escape signal.
Current 18
Nominal 0–50
5 min cadence
PhytoSense Mesh
Definition
Airborne Spore Load is the concentration of viable fungal/plant spores in corridor air (CFU·m⁻³), measured by impaction samplers with rapid culture and optical confirmation. It is the bioburden that containment exists to suppress.
Why it matters
Spore load is the consequence metric for containment: it rises when a sphere leaks or a HEPA stage fails. It gates corridor access and PPE, and a sustained rise triggers source-localization across the mesh.
Formula
L = CFU counted / sampled volume [CFU · m⁻³] Impaction sampler draws a fixed volume; rapid culture and optical particle counting give a fast estimate confirmed by plate count. Reported as corridor mean with node map.
Inputs
| Input | Detail | Source |
|---|---|---|
| Impaction sampler | Fixed-volume air draw | PhytoSense Mesh |
| Optical count | Rapid particle estimate | PhytoSense Mesh |
| Culture | Confirmatory plate count | Lab |
Units & Scale
CFU·m⁻³, integer, corridor mean with node localization. Increasing-is-worse; upper thresholds apply.
Sampling & Source
- Sampled every 5 minutes by corridor impactors.
- Rapid optical estimate confirmed by culture.
- Sustained rise triggers source localization.
Thresholds
Nominal · 0–50 CFU·m⁻³ — clean corridor
OK
Warning · > 200 — bioburden advisory
WARN
Critical · > 800 — containment escape escalation
CRIT
Consequence signal. A spore-load rise is read together with sphere differential and HEPA loading to distinguish a containment leak from a filtration fault before corridor access is restricted.
Recent Trend
Zone roll-up, last 14 sampling periods (current 18):
VC-MET-406 · 14-period trend (current 18)
Interpretation Guidance
| Band | Reading | Likely Driver | Action |
|---|---|---|---|
| 0–50 | Clean | Effective containment | Standard access. |
| 51–200 | Elevated | Minor leak or filter load | Localize; check ΔP & HEPA. |
| 201–800 | WARN | Containment leak | Restrict access; PPE up. |
| > 800 | CRIT | Active escape | Corridor lockdown; isolate. |
Related Metrics
VC-MET-407
Pollen Load
Particulate sibling.
VC-MET-402Sphere Pressure Differential
Leak source.
VC-MET-408HEPA Filter Loading
Filtration state.
VC-MET-401Containment Integrity Index
Composite.
Related SOPs
- Corridor access & PPE — SOP Library.
- Monitoring — Monitoring Systems.