Technical Trade SchoolBAS-300 service-series
BAS-307
Ten concept and evidence figures

BAS-307 Visual Aid Library

Figure-use rule

Each figure is an orientation and reasoning aid, not a project drawing. Learners must pair it with the current sequence, point list, wiring/piping documents, manufacturer instructions, and as-found evidence.

Figure 1 — Program purpose, risk, and success measures critical

Normal-rule anchor

Fault count and checklist completion are activity metrics; success requires verified condition, closure, recurrence, and outcome evidence.

Case overlay

A team closes many analytics tickets while comfort complaints and repeat faults rise.

Calculation/evidence callout: Calculate verified closure, recurrence, critical overdue, and false-positive rates with severity retained.

Figure 2 — Asset and maintenance requirement register critical

Normal-rule anchor

“Check annually” is not production-ready until the asset, source, method, acceptance condition, role, evidence, and exception path are defined.

Case overlay

A generic PM list assigns the same interval to critical AHUs and noncritical storage-room units.

Calculation/evidence callout: Calculate risk rank and interval status only within source/warranty limits; compare due, completed, deferred, and overdue tasks.

Figure 3 — Integrated BAS and HVAC preventive maintenance critical

Normal-rule anchor

A trend pattern can prioritize field work but does not certify physical cause, and a successful backup file is not proven recovery until integrity and an approved restore process are verified.

Case overlay

Fan power rises and airflow falls while the supervisor backup is unverified; sensor drift, filter loading, and recovery risk all require separate evidence and ownership.

Calculation/evidence callout: Calculate data and backup age, override duration, starts, duty cycle, ΔT/load indicators, runtime/peer deviation, and maintenance coverage by asset criticality.

Figure 4 — Data-quality gate critical

Normal-rule anchor

Analytics applied to unfit data produces confident-looking noise; fitness is specific to the question and time scale.

Case overlay

An economizer rule uses a stale mixed-air sensor and unsynchronized outdoor-air data.

Calculation/evidence callout: Calculate completeness, data age, clock offset, sampling adequacy, and valid-mode coverage before analysis.

Figure 5 — Transparent FDD rule anatomy

Normal-rule anchor

A useful rule says when it applies, what data it trusts, how long the condition persists, what excludes it, and how it is field-verified.

Case overlay

A simultaneous-heating/cooling rule fires during legitimate dehumidification reheat.

Calculation/evidence callout: Calculate residual/threshold, persistence, deadband, confidence inputs, and reset timing from the declared rule.

Figure 6 — Baselines, normalization, and pattern methods

Normal-rule anchor

A baseline is only valid for the population, modes, weather/load range, and system configuration from which it was built.

Case overlay

Post-retrofit energy is compared to a mild prior month without weather or occupancy normalization.

Calculation/evidence callout: Calculate supplied baseline, residual, percent deviation, degree-day/load normalization, and confidence limits using the stated method.

Figure 7 — False positives and missed faults critical

Normal-rule anchor

A false positive is evidence about data, rule, context, or system change; suppressing it without diagnosis can create a missed fault.

Case overlay

A rule floods after a scheduled control-sequence update changed the expected SAT target.

Calculation/evidence callout: Calculate precision, recall awareness, false-positive rate, missed-fault count, and revised threshold/persistence on labeled cases.

Figure 8 — Triage, work orders, and responsible routing critical

Normal-rule anchor

A low-confidence critical-safety indication receives controlled escalation; a high-confidence low-impact finding may wait.

Case overlay

A portfolio has one possible freeze-protection failure and twenty minor efficiency findings.

Calculation/evidence callout: Use stated risk, impact, confidence, recurrence, and effort weights while allowing critical-risk override of the score.

Figure 9 — Verification, value, and closure critical

Normal-rule anchor

A cleared analytic flag is not verified repair; closure needs field/as-left evidence and a suitable recurrence window.

Case overlay

A valve fault disappears after a rule reset, but no field inspection or affected-mode retest occurred.

Calculation/evidence callout: Calculate verified runtime/energy change from stated baseline and assumptions and report uncertainty and non-energy outcomes.

Figure 10 — Portfolio governance and continuous improvement critical

Normal-rule anchor

Every live analytic rule and suppression needs an owner, version, reason, effective date, review/expiry, and rollback.

Case overlay

A critical rule has been suppressed indefinitely because it generated too many tickets.

Calculation/evidence callout: Reconcile active rules, versions, suppressions, expired exceptions, verified findings, recurrence, and owner actions.