Safety exam formulas with worked examples
27 formulas for the calculation questions on the ASP, CSP and CHST. Each page shows a worked example, the blueprint domain it belongs to, practice questions that use it, and the source's own words.
Every worked example is computed by the same code as our calculators and checked against the value printed in the source, or a hand calculation. Checked 2026-10-16.
Injury and illness rates
Noise
- Noise doseD = 100 × (C1/T1 + C2/T2 + … + Cn/Tn)ASP, CSP, CHST
- Noise TWA from doseTWA = 16.61 × log10(D ÷ 100) + 90ASP, CSP, CHST
- Reference duration for a sound levelT = 8 ÷ 2^((L − 90) ÷ 5)ASP, CSP, CHST
- Adding decibelsLtotal = 10 × log10(10^(L1/10) + 10^(L2/10) + … + 10^(Ln/10))ASP, CSP, CHST
- Sound level at a distanceLp2 = Lp1 + 20 × log10(d1 ÷ d2)ASP, CSP, CHST
- Hearing protector NRR (estimated exposure)Single, A-weighted: TWA − (NRR − 7)ASP, CSP, CHST
Air contaminants and ventilation
Ergonomics, heat and cold
Construction, rigging and falls
- Excavation sloping (simple slope, 20 ft or less)Horizontal run = depth × H:V ratioASP, CSP, CHST
- Choker hitch capacity by angle of chokeCapacity = choker rating × angle factorASP, CSP, CHST
- Sling tension from the load angle factorLAF = 1 ÷ sin(horizontal angle) = sling length ÷ vertical heightASP, CSP, CHST
- Personal fall arrest distancesFree fall ≤ 6 ftASP, CSP, CHST
- Secondary containment capacityCapacity ≥ the greater of 10% of total container volume or the largest containerASP, CSP
Radiation
Statistics, probability and physics
Printable sheets and definitions
The same formulas as one printable page per exam: ASP formula sheet (27), CSP formula sheet (23) and CHST formula sheet (20). For the terms behind them, see the safety exam glossary.
See where you stand
The free 25-question diagnostic scores you on every blueprint domain, calculations included, and shows the source behind each answer.