dive-deco/dist/gas.js

A TypeScript implementation of decompression calculation algorithms for scuba diving, featuring Bühlmann ZH-L16C algorithm with gradient factors, gas management, and oxygen toxicity tracking.

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.Gas = void 0;
const depth_1 = require("./depth");
// Alveolar water vapor pressure assuming 47 mm Hg at 37C (Buhlmann's value)
const ALVEOLI_WATER_VAPOR_PRESSURE = 0.0627;
class Gas {
    o2Pp;
    n2Pp;
    hePp;
    constructor(o2Pp, hePp) {
        if (o2Pp < 0 || o2Pp > 1) {
            throw new Error('Invalid O2 partial pressure');
        }
        if (hePp < 0 || hePp > 1) {
            throw new Error(`Invalid He partial pressure [${hePp}]`);
        }
        if (o2Pp + hePp > 1) {
            throw new Error("Invalid partial pressures, can't exceed 1ATA in total");
        }
        this.o2Pp = o2Pp;
        this.hePp = hePp;
        this.n2Pp = Math.round((1 - (o2Pp + hePp)) * 10000) / 10000;
    }
    static air() {
        return new Gas(0.21, 0);
    }
    get o2() {
        return this.o2Pp;
    }
    get n2() {
        return this.n2Pp;
    }
    get he() {
        return this.hePp;
    }
    id() {
        return `${Math.round(this.o2Pp * 100)}/${Math.round(this.hePp * 100)}`;
    }
    partialPressures(depth, surfacePressure) {
        const gasPressure = surfacePressure / 1000 + depth.asMeters() / 10;
        return this.gasPressuresCompound(gasPressure);
    }
    inspiredPartialPressures(depth, surfacePressure) {
        const gasPressure = surfacePressure / 1000 +
            depth.asMeters() / 10 -
            ALVEOLI_WATER_VAPOR_PRESSURE;
        return this.gasPressuresCompound(gasPressure);
    }
    gasPressuresCompound(gasPressure) {
        return {
            o2: this.o2Pp * gasPressure,
            n2: this.n2Pp * gasPressure,
            he: this.hePp * gasPressure,
        };
    }
    maxOperatingDepth(ppO2Limit) {
        return depth_1.Depth.fromMeters(10 * (ppO2Limit / this.o2Pp - 1));
    }
    equivalentNarcoticDepth(depth) {
        let end = depth
            .add(depth_1.Depth.fromMeters(10))
            .multiply(1 - this.hePp)
            .subtract(depth_1.Depth.fromMeters(10));
        if (end.lessThan(depth_1.Depth.zero())) {
            end = depth_1.Depth.zero();
        }
        return end;
    }
    toString() {
        return `${Math.round(this.o2Pp * 100)}/${Math.round(this.hePp * 100)}`;
    }
    equals(other) {
        return (this.o2Pp === other.o2Pp &&
            this.n2Pp === other.n2Pp &&
            this.hePp === other.hePp);
    }
}
exports.Gas = Gas;