Standards-referenced HSE calculations

Noise Exposure

Standards Australia/Standards New Zealand. AS/NZS 1269.1:2005 — Occupational noise management, Part 1: Measurement and assessment of noise immission and exposure. Exposure standard LAeq,8h = 85 dB(A), 3 dB exchange rate.

Assumes a 3 dB exchange rate (Australian standard). Peak (LC,peak) limit of 140 dB(C) is not assessed here — check impulsive/impact noise separately.

Confined Space Atmosphere

Standards Australia. AS 2865:2009 — Confined spaces. Gas thresholds: Safe Work Australia, Workplace Exposure Standards for Airborne Contaminants. Thresholds below are editable — set to your jurisdiction's current WES/HSIS values.

Default gas limits are commonly cited TWA figures — confirm current values against Safe Work Australia HSIS or your local regulator before use. Single-point check only, not a substitute for continuous monitoring.

Heat Stress (WBGT)

International Organization for Standardization. ISO 7243:2017 — Ergonomics of the thermal environment: Assessment of heat stress using the WBGT index (adopted as AS/NZS ISO 7243). Reference limits approximate ACGIH, TLVs and BEIs — Heat Stress and Strain TLV (current edition), for continuous work.

Reference limits shown are for continuous (100%) work. If WBGT exceeds the limit, apply a work/rest cycle rather than treating it as an automatic stop-work — consult the full ACGIH/ISO 7243 work-rest table. Thermal Work Limit (TWL), common on Australian mine sites, requires an iterative heat-balance calculation beyond a simple formula — use a validated TWL instrument or software for that index.

Vibration Exposure

International Organization for Standardization. ISO 5349-1:2001 — Measurement and evaluation of human exposure to hand-transmitted vibration; ISO 2631-1:1997 — Evaluation of human exposure to whole-body vibration. EAV/ELV values per EU Directive 2002/44/EC, commonly adopted in AU/NZ practice. A(8) = a × √(T/8)

HAV: EAV 2.5 m/s², ELV 5.0 m/s² A(8). WBV: EAV 0.5 m/s², ELV 1.15 m/s² A(8). Single-axis input — for tri-axial data use the dominant/vector sum per the instrument's output.

Dust / Respirable Silica TWA

Standards Australia. AS 2985:2009 — Workplace atmospheres: Method for sampling and gravimetric determination of respirable dust. Exposure standard editable — Safe Work Australia, Workplace Exposure Standards for Airborne Contaminants, commonly cites respirable crystalline silica at 0.05 mg/m³.

Linear time-weighted average to 8 hours (C × T ÷ 8) — appropriate for RCS and most particulate WES, which use linear (not logarithmic) averaging. Confirm the current exposure standard for your jurisdiction before relying on the default.

Fall Arrest Clearance

Standards Australia/Standards New Zealand. AS/NZS 1891.4:2009 — Industrial fall-arrest systems and devices: Selection, use and maintenance. Deceleration distance limit per AS/NZS 1891.1:2007 — Safety belts and harnesses. Total fall clearance = free fall + deceleration + harness stretch + safety margin.

Figures are generic defaults for planning only — always confirm against the specific energy absorber's tested deceleration distance and manufacturer's instructions.

Zone of Influence — Excavation Edge Setback

Safe Work Australia. (2015). Excavation Work: Code of Practice. Plant, vehicles, spoil, and stored materials must be kept outside an excavation's zone of influence — the area where surcharge loading could trigger instability or collapse — as determined by a geotechnical assessment. Absent that assessment, a widely used practical guide is a minimum setback at least equal to the excavation depth (a 1:1 rule), applied here with an editable safety margin.

This is a practical 1:1-depth-plus-margin guide, not a substitute for a geotechnical assessment — the true zone of influence depends on soil type, groundwater, vibration, and surcharge loads. Always confirm setback distances against a site-specific geotechnical assessment before positioning plant, vehicles, or stockpiles near an excavation edge.

Manual Handling (NIOSH Lifting Equation)

Waters, T.R., Putz-Anderson, V., Garg, A., & Fine, L.J. (1993). Revised NIOSH equation for the design and evaluation of manual lifting tasks. Ergonomics, 36(7), 749–776. See also NIOSH (1994), Applications Manual for the Revised NIOSH Lifting Equation (DHHS Publication No. 94-110). RWL = LC × HM × VM × DM × AM × FM × CM

Simplified for ≤8hr duration, V<75cm frequency/coupling tables. Excludes trunk twisting velocity and non-standard postures — treat borderline results (LI 0.8–1.2) as a trigger for full ergonomic assessment, not a final answer.

Rigging — Sling Angle Load Factor

Standards Australia. AS 4991:2004 — Lifting and rigging. Sling angle load factor is standard rigging trigonometry. Tension per leg = (Load ÷ legs) ÷ sin(θ), θ measured from horizontal.

Lower sling angles from horizontal sharply increase leg tension — below 45° the load factor rises quickly. Assumes symmetric rigging and even load distribution; uneven centre of gravity requires individual leg calculation.

Arc Flash — Incident Energy (Lee Method)

Lee, R.H. (1982). The other electrical hazard: Electric arc blast burns. IEEE Transactions on Industry Applications, IA-18(3), 246–251. PPE categories per NFPA 70E-2021, Standard for Electrical Safety in the Workplace. Open-air arc, systems ≤15kV — simplified estimate, not a substitute for a full IEEE 1584-2018 study.

NFPA 70E indicative PPE categories: Cat 1 ≤4 cal/cm², Cat 2 ≤8, Cat 3 ≤25, Cat 4 ≤40; above 40 cal/cm² is outside standard PPE ratings — de-energize instead. Enclosed equipment (switchgear, MCCs) behaves differently to open air; commission a full arc flash study for definitive boundaries and PPE selection.

Injury Frequency & Severity Rates

Standards Australia. AS 1885.1-1990 — Workplace injury and disease recording standard. DART rate per US Dept of Labor (OSHA), Recordkeeping, 29 CFR 1904. Rate = (Count × Base hours) ÷ Total hours worked.

TRIFR = Total Recordable Injury Frequency Rate. LTIFR = Lost Time Injury Frequency Rate. AIFR = All Injury Frequency Rate. DART and Severity Rate follow OSHA convention (200,000 hrs) regardless of the base selected above, per standard practice. Near-miss ratio is a leading-indicator reference (Bird/Heinrich triangle), not a compliance figure.

Fatigue — Hours-Based Screen

Indicative thresholds informed by Dawson, D., & McCulloch, K. (2005). Managing fatigue: It's about sleep. Sleep Medicine Reviews, 9(5), 365–380, and common resource-sector fatigue management guidance (e.g. Queensland Government mining industry fatigue risk guidance). Generic hours-worked screen — editable, not a validated biomathematical model (e.g. FAID).

Thresholds vary widely between enterprise agreements and jurisdictions — the defaults are common FIFO/mining reference points, not a fixed regulatory limit. For a defensible fatigue risk assessment use a validated tool (e.g. FAID) rather than this screen alone.

Tailings Storage Facility — Freeboard

Australian National Committee on Large Dams (ANCOLD). (2019). Guidelines on Tailings Dams: Planning, Design, Construction, Operation and Closure. Freeboard = dam crest RL − pond surface RL.

Minimum freeboard is site- and design-specific (storm/flood allowance per the facility's Operating, Maintenance and Surveillance manual) — the default is illustrative only. This is a single-point check; it doesn't replace the facility's water balance or storage capacity model.

References

Full source list for all 13 calculators. Standards are periodically revised — confirm current edition before relying on a figure for a compliance decision.

Standards Australia/Standards New Zealand. AS/NZS 1269.1:2005 — Occupational noise management, Part 1: Measurement and assessment of noise immission and exposure.

Standards Australia. AS 2865:2009 — Confined spaces. Safe Work Australia. Workplace Exposure Standards for Airborne Contaminants.

International Organization for Standardization. ISO 7243:2017 — Ergonomics of the thermal environment: Assessment of heat stress using the WBGT index (adopted as AS/NZS ISO 7243). American Conference of Governmental Industrial Hygienists. TLVs and BEIs — Heat Stress and Strain TLV (current edition).

International Organization for Standardization. ISO 5349-1:2001 — Measurement and evaluation of human exposure to hand-transmitted vibration. ISO 2631-1:1997 — Evaluation of human exposure to whole-body vibration. European Parliament and Council. Directive 2002/44/EC (EAV/ELV reference values).

Standards Australia. AS 2985:2009 — Workplace atmospheres: Method for sampling and gravimetric determination of respirable dust. Safe Work Australia. Workplace Exposure Standards for Airborne Contaminants.

Standards Australia/Standards New Zealand. AS/NZS 1891.4:2009 — Industrial fall-arrest systems and devices: Selection, use and maintenance. AS/NZS 1891.1:2007 — Safety belts and harnesses.

Safe Work Australia. (2015). Excavation Work: Code of Practice.

Waters, T.R., Putz-Anderson, V., Garg, A., & Fine, L.J. (1993). Revised NIOSH equation for the design and evaluation of manual lifting tasks. Ergonomics, 36(7), 749–776. National Institute for Occupational Safety and Health. (1994). Applications Manual for the Revised NIOSH Lifting Equation (DHHS Publication No. 94-110).

Standards Australia. AS 4991:2004 — Lifting and rigging.

Lee, R.H. (1982). The other electrical hazard: Electric arc blast burns. IEEE Transactions on Industry Applications, IA-18(3), 246–251. National Fire Protection Association. NFPA 70E-2021 — Standard for Electrical Safety in the Workplace.

Standards Australia. AS 1885.1-1990 — Workplace injury and disease recording standard. United States Department of Labor, Occupational Safety and Health Administration. Recordkeeping, 29 CFR 1904.

Dawson, D., & McCulloch, K. (2005). Managing fatigue: It's about sleep. Sleep Medicine Reviews, 9(5), 365–380. Queensland Government, Department of Natural Resources and Mines. Fatigue Risk Management Systems for the Mining Industry (guidance note).

Australian National Committee on Large Dams. (2019). Guidelines on Tailings Dams: Planning, Design, Construction, Operation and Closure.

This list reflects the primary source used for each formula or threshold. Several editable defaults (gas WES, fatigue thresholds, TSF minimum freeboard, excavation setback margin) point to guidance rather than a single fixed number — confirm the version in force for your site and jurisdiction.