import type { NioshInput, NioshResult } from './types.js';
/**
 * Calculate NIOSH Recommended Weight Limit (RWL) and Lifting Index (LI)
 *
 * @formula RWL = LC × HM × VM × DM × AM × FM × CM
 *   - LC  = 23 kg (Load Constant)
 *   - HM  = 25 / H  (Horizontal Multiplier, max 1.0)
 *   - VM  = 1 − 0.003|V − 75|  (Vertical Multiplier)
 *   - DM  = 0.82 + 4.5 / D  (Distance Multiplier, D ≥ 25 cm)
 *   - AM  = 1 − 0.0032A  (Asymmetric Multiplier)
 *   - FM  = lookup(frequency, duration)
 *   - CM  = lookup(coupling, V)
 *   - LI  = Load Weight / RWL
 *
 * @reference NIOSH (1994). "Applications Manual for the Revised NIOSH Lifting Equation",
 *   Publication No. 94-110. U.S. Dept. of Health and Human Services.
 * @reference Waters, T.R., Putz-Anderson, V., Garg, A. (1993). "Revised NIOSH equation
 *   for the design and evaluation of manual lifting tasks". Ergonomics, 36(7), 749-776.
 *
 * @units H, V, D: cm; A: degrees; frequency: lifts/min; loadWeight: kg; RWL: kg
 *
 * @validation
 *   - Ideal conditions (all multipliers = 1.0): RWL = LC = 23 kg
 *   - Risk: low (LI ≤ 1), moderate (1 < LI ≤ 2), high (LI > 2)
 *
 * @param input - NIOSH lifting parameters
 * @returns NIOSH results including RWL, LI, multipliers, and risk level
 * @throws {RangeError} any distance, angle, frequency, or loadWeight is negative.
 * @remarks Distances below the equation's domain (H, D < 25 cm) are clamped per the
 *   NIOSH spec rather than rejected. When the frequency multiplier drives RWL to 0
 *   (sustained high-frequency lifting), liftingIndex is Infinity — an intentional
 *   sentinel meaning "no weight is acceptable for this task".
 *   Outputs are rounded: rwl/liftingIndex to 2 decimals, computed multipliers to 4;
 *   riskLevel is classified from the rounded liftingIndex so the two always agree.
 */
export declare function nioshLifting(input: NioshInput): NioshResult;
//# sourceMappingURL=nioshLifting.d.ts.map