Calculator Inputs
Use the form to estimate sweep interval, sweeps per shift, manpower demand, and cost. Use advanced modifiers for specific sites.
Example Data Table
These sample inputs illustrate how risk and productivity shift the recommended interval.
| Scenario | Area (m²) | Crew | Coverage (m²/hr/person) | Activity | Traffic | Weather | Criticality | Incidents/mo | Housekeeping |
|---|---|---|---|---|---|---|---|---|---|
| Light work, sheltered zone | 1200 | 1 | 1800 | 2 | 2 | 1 | 3 | 0.5 | 4 |
| Busy haul route, open site | 3500 | 2 | 2200 | 4 | 5 | 4 | 4 | 2 | 3 |
| High criticality, frequent finds | 2500 | 3 | 2500 | 4 | 4 | 3 | 5 | 4 | 2 |
Formula Used
This calculator uses a transparent, auditable model so you can justify intervals during reviews.
How to Use
- Enter shift pattern, sweep area, crew count, and coverage rate.
- Select risk ratings that match your work zone conditions.
- Add incident history and housekeeping quality for realism.
- Use advanced modifiers to match your surface and site phase.
- Press Calculate to view results above the form.
- Download CSV or PDF for audits, briefings, and records.
Operational drivers for sweep cadence
FOD sweep frequency is governed by debris generation and debris migration. Cutting, grinding, hauling, and packaging increase source strength, while vehicle routes and wind move material into travel lanes. A formal cadence reduces punctures, slips, equipment damage, and schedule disruption. For planning, separate hot spots such as cutting stations and haul-road exits from low-activity buffers.
Risk scoring converts conditions into an interval
The calculator blends activity, traffic, weather exposure, and criticality with incident history and housekeeping quality. Each input is rated on a 1–5 scale and combined with weights to create a risk percentage. Higher risk tightens the recommended interval and increases sweeps per shift. Interval limits are constrained for practicality, typically from 15 to 720 minutes.
Productivity links area, crew, and time per sweep
Sweep effort is estimated from the area to be covered, the coverage rate per person, and crew size. An overhead allowance adds time for dumping, turning, spot checks, and repositioning. This produces hours per sweep and total sweep hours per day, helping planners verify staffing feasibility. For example, 2,500 m² with two people at 2,500 m²/hour each takes about 0.5 hours before overhead.
Site modifiers reflect surfaces, detection, and phase
Surface and construction phase multipliers shorten the interval when rough textures or overlapping trades increase retention and generation. A controls multiplier can slightly extend the interval when inspections, magnet sweeps, and tool accountability are strong. Use these multipliers to match paving, gravel, or steel-deck environments, then validate by reviewing debris finds.
Cost, utilization, and continuous improvement
Loaded labor rate includes hourly pay plus burden. Annual cost is derived from daily sweep hours multiplied by operating days. Utilization compares required sweep hours to available crew hours per day. If utilization is high, split zones, upgrade equipment, or improve housekeeping to regain margin. Exported summaries create an audit-ready record. Track incidents monthly, update inputs, and confirm the cadence stays aligned with site conditions.
FAQs
What does the risk percentage represent?
It is a combined score from activity, traffic, weather, criticality, incident history, and housekeeping. A higher value indicates more frequent debris generation or migration, so the recommended sweep interval becomes shorter.
How should I rate housekeeping quality?
Base it on observed tool control, waste handling, and end-of-shift cleanliness. If debris is routinely found after work, select 1–2. If lanes stay clear and audits pass, select 4–5.
Can I use different intervals for different zones?
Yes. Run the calculator for each zone using its area and risk inputs. Hot spots often need tighter cadences than buffers, which reduces total labor without lowering safety.
How do the multipliers affect the interval?
Surface and phase multipliers shorten the interval when conditions trap or create more debris. The controls multiplier can extend the interval slightly when inspections and accountability are strong.
What if labor utilization is too high?
Reduce the sweep area per run, split the site into sections, increase crew size, or improve housekeeping controls. Upgrading sweep equipment or increasing coverage rate also lowers required hours.
Is the exported report suitable for audits?
The CSV and PDF capture inputs, results, and timestamp for traceability. Pair exports with daily logs of debris finds and corrective actions to demonstrate continuous improvement.