BOMI SMA cheat sheet

Preventive maintenance (PM) is scheduled by calendar interval or by meter/run-hour trigger; predictive maintenance (PdM) is triggered by measured condition (vibration, infrared, oil analysis).

PM frequency rule: set the interval so the probability of failure before the next service stays acceptably low, using manufacturer data plus failure history; shortening intervals raises labor cost roughly linearly.

Bathtub curve: infant mortality (burn-in failures), useful life (random, constant failure rate), and wear-out (increasing failure rate); PM is most effective against wear-out.

Mean time between failures (MTBF) = total operating time / number of failures; availability = MTBF / (MTBF + MTTR), where MTTR is mean time to repair.

Infrared thermography detects loose electrical connections and bearing/insulation heating while equipment runs; it requires line-of-sight and emissivity correction.

Vibration analysis flags imbalance (1x running speed), misalignment (2x), and bearing defects (high-frequency impact signatures) before functional failure.

Lubrication program rules: correct viscosity grade per manufacturer, filter before dispensing, avoid over-greasing sealed bearings, and record quantity and product per asset.

Water treatment for closed loops and cooling towers controls scale, corrosion, and biological growth; key readings are pH, conductivity, inhibitor residual, and biocide level.

Work order closeout must capture labor hours, parts consumed, cause code, and corrective action so history supports future PM interval and budget decisions.

Space planning uses usable area (carpetable) versus rentable area; the load factor = rentable area / usable area, and tenant rent is charged on rentable area.

Lease classification drives obligations: in a gross lease the landlord pays operating expenses; in a net lease the tenant pays taxes, insurance, and CAM (common area maintenance).

CAM reconciliation compares estimated CAM payments collected to actual expenses; the tenant owes or is credited the difference, subject to audit rights in the lease.

Capital planning rule: classify spending as capital (extends life or adds capacity, depreciated) versus operating expense (maintains current condition, expensed in period).

Life-cycle cost = initial cost + present value of operating, maintenance, and replacement costs minus salvage value; it is the correct basis for comparing equipment options.

Emergency preparedness for facilities follows a four-phase cycle: mitigation, preparedness, response, and recovery; drills and contact rosters must be updated at defined intervals.

OSHA-relevant facility duties include hazard communication labeling, lockout/tagout for servicing equipment, and maintaining clear egress paths and exit signage.

Key performance indicators for operations include work order completion rate, average response time, PM compliance percentage, and cost per square foot.

Energy use intensity (EUI) = annual site energy use (kBtu or GJ) / conditioned floor area; compare against a benchmark for the same building type and climate.

Degree days: heating degree days (HDD) accrue when daily mean temperature falls below the balance point (commonly 65 F / 18 C); cooling degree days (CDD) accrue above it.

Whole-building energy balance: purchased energy = envelope losses + ventilation/infiltration losses + internal gains + process loads, adjusted for HVAC and lighting efficiency.

Power relationships: watts = volts x amps x power factor for AC; kWh = kW x hours; a load run continuously for a year costs roughly kW x 8,760 x rate.

Lighting efficacy is measured in lumens per watt; LED retrofits typically cut lighting energy 40-60 percent versus fluorescent and reduce cooling load.

Economizer operation uses outdoor air for free cooling when outdoor enthalpy or dry-bulb is below return air conditions; faulty damper linkage is a common energy waste.

Demand charges are billed on the peak kW in a billing window; load staggering and storage can shave peaks without reducing total kWh.

Commissioning and retro-commissioning verify that systems operate as designed; measurement and verification of savings typically uses an avoided-energy baseline adjusted for weather.

Span of control: a maintenance supervisor typically oversees a crew whose size keeps daily direction and quality checks feasible; ratios are set by trade mix and shift coverage.

Budget categories for maintenance: labor (wages, benefits, overtime), materials and parts, contracted services, utilities, and capital; variance analysis compares actual to budget by line.

Staffing estimate: annual labor hours needed = (number of PM tasks x hours per task) + estimated corrective hours; divide by productive hours per technician (typically 1,600-1,800 per year after leave and training).

Work order priority system: emergency (safety or mission-critical, immediate), urgent (limited hours), routine (scheduled), and deferred; response targets should be written into service levels.

Inventory control: reorder point = (average daily usage x lead time in days) + safety stock; ABC analysis concentrates counting effort on high-value items.

Computerized maintenance management system (CMMS) data must have consistent asset IDs, failure codes, and labor recording; poor data quality defeats reporting.

Training and safety administration: documented job hazard analysis, required PPE, and refresher intervals support compliance and reduce injury-driven cost.

Outsourcing decision rule: contract out work requiring specialized certification, infrequent high-skill tasks, or peak overload; keep work in-house where response time and institutional knowledge dominate.