Engineering Utilities: CFM Calculator and Pricing Engine

B2B Import ERP ships a pure, AI-free engineering calculation engine used across three surfaces: the public wizard form, the CRM diagnostic report, and the internal quoting tool. All functions are deterministic — given the same inputs they always return the same outputs — and carry zero side-effects. They do not call external APIs, touch the database, or require authentication. This makes them trivially testable with standard Jest unit tests. The engine consists of two primary modules:

src/utils/engineering.ts — airflow, volume, power, and noise calculations following ASHRAE standards.
src/utils/pricing.ts — COP/USD price estimation with urgency multipliers and volume-based scaling.

A third utility, src/utils/tenant.ts, provides CSS colour helpers used by the branding subsystem.

`calculateRequiredCfm`

Calculates the required airflow (in CFM — Cubic Feet per Minute) from the physical dimensions of a space and its operating environment, using ASHRAE Air Changes per Hour (ACH) norms.

// src/utils/engineering.ts
export function calculateRequiredCfm(
  dimensions: AreaDimensions,
  environment: string
): {
  cubicMeters: number;
  cubicFeet: number;
  ach: number;
  cfm: number;
}

Parameters

dimensions

AreaDimensions

required

Room dimensions in metres:

interface AreaDimensions {
  length: number; // metres
  width: number;  // metres
  height: number; // metres
}

environment

string

required

Operating environment key. Determines the ACH rate applied:

Key	ACH	Criticality	Notes
`heavy_plant`	45	ALTA	Heavy manufacturing / smelting
`fundicion`	45	ALTA	Foundry (alias for heavy_plant)
`mecanico`	20	MEDIA	Mechanical workshop
`alimentos`	15	BAJA	Food processing
`data_center` / `datacenter`	30	ALTA	Server rooms
`mining`	—	—	Not in the ACH map; defaults to 10 ACH. Use `heavy_plant` for mining environments requiring 45 ACH.
`warehouse` / `almacen`	8	BAJA	Warehouse / storage
`default`	10	BAJA	General purpose

Algorithm

volume_m3   = length × width × height
volume_ft3  = volume_m3 × 35.3147  (1 m³ = 35.3147 ft³)
ach         = ACH_BY_ENVIRONMENT[environment] ?? 10

# Pollutant factor adds +30% for heavy_plant and fundicion environments
pollutant_factor = (heavy_plant | fundicion) ? 1.3 : 1.0

cfm = round((volume_ft3 × ach / 60) × pollutant_factor)

Returns

{
  cubicMeters: number;  // rounded to 2 decimal places
  cubicFeet: number;    // rounded to 2 decimal places
  ach: number;          // air changes per hour used
  cfm: number;          // required airflow in CFM (integer)
}

Example

import { calculateRequiredCfm } from "@/utils/engineering";

const result = calculateRequiredCfm(
  { length: 30, width: 20, height: 8 },
  "data_center"
);
// result.cubicMeters  → 4800
// result.cfm          → ~85357  (4800 × 35.3147 × 30 / 60)

calculateRequiredCfm is a thin wrapper around generateEngineeringReport, which provides a richer DetailedEngineeringReport including power draw (HP and kW), noise level (dBA), equipment count, suggested distribution layout, and investment ranges. Use generateEngineeringReport directly when you need the full pre-engineering report.

`getAchForEnvironment`

Returns the Air Changes per Hour (ACH) rate for a given environment key, falling back to 10 (the default value) for unrecognised keys.

// src/utils/engineering.ts
export function getAchForEnvironment(environment: string): number

environment

string

required

An environment key from ACH_BY_ENVIRONMENT (see table in calculateRequiredCfm). Unknown keys return 10.

Returns a number — the ACH rate for the environment.

`calculateAirDensity`

Calculates corrected air density (kg/m³) for a given altitude and temperature using the standard pneumatic formula.

// src/utils/engineering.ts
export function calculateAirDensity(
  altitudeMsnm: number,  // altitude in metres above sea level
  tempCelsius: number    // ambient temperature in °C
): number

altitudeMsnm

number

required

Altitude in metres above sea level. 0 = sea level (standard density 1.204 kg/m³ at 20 °C).

tempCelsius

number

required

Ambient temperature in °C.

Returns air density in kg/m³, rounded to 3 decimal places. Lower altitudes and lower temperatures produce higher density values.

Formula

p0              = 1.204 kg/m³  (standard density at sea level, 20 °C)
tempCorrection  = 293.15 / (tempCelsius + 273.15)
altCorrection   = (1 − 2.2557×10⁻⁵ × altitudeMsnm)^5.25588
airDensity      = p0 × tempCorrection × altCorrection

`generateEngineeringReport`

Full pre-engineering calculation engine. Extends the CFM calculation with altitude/temperature corrections, motor power sizing, noise estimation, equipment count, and investment range.

export function generateEngineeringReport(
  dimensions: AreaDimensions,
  environment: string,
  altitudeMsnm: number,   // altitude in metres above sea level
  tempCelsius: number,    // ambient temperature in °C
  hasDucts: boolean       // adds 1.5 inWG static pressure when true
): DetailedEngineeringReport

Returns:

interface DetailedEngineeringReport {
  cubicMeters: number;
  cubicFeet: number;
  ach: number;
  cfm: number;
  airDensity: number;          // kg/m³ corrected for altitude and temp
  staticPressure: number;      // inWG: 0.5 (no ducts) or 1.5 (with ducts)
  powerHp: number;             // HP = (CFM × SP) / 6356
  powerKw: number;             // kW = HP × 0.746 / 0.94 (IE4 efficiency)
  noiseDba: number;            // 68 dBA base + 10 × log10(eqCount)
  eqCount: number;             // ceil(cfm / 7500) — standard 7,500 CFM fans
  distribution: string;        // e.g. "4 Inyectores + 4 Extractores tipo Hongo"
  investmentRangeMinCop: number;
  investmentRangeMaxCop: number;
  investmentRangeMinUsd: number;
  investmentRangeMaxUsd: number;
  airVelocityFpm: number;
  criticality: "ALTA" | "MEDIA" | "BAJA";
}

`estimatePrice`

Generates a budgetary price range in COP and USD based on service type, urgency, and the physical volume of the installation.

// src/utils/pricing.ts
export function estimatePrice(
  serviceType: string,
  urgency: string,
  volumeCubicMeters: number
): PriceEstimation

Parameters

serviceType

string

required

Service category. Determines the base price in COP:

Key	Base Price (COP)
`fabricacion`	$1,200,000
`venta`	$800,000
`reparacion`	$500,000
`mantenimiento`	$300,000
`default` / `otro`	$500,000

urgency

"baja" | "media" | "alta"

required

Urgency multiplier applied after the volume modifier:

Key	Multiplier
`alta`	×1.35 (+35%)
`media`	×1.10 (+10%)
`baja`	×1.00 (no increment)

volumeCubicMeters

number

required

Volume of the installation in m³. Every 100 m³ adds 5% to the base price: volumeModifier = 1 + max(0, volume / 100) × 0.05.

Algorithm

base_price    = BASE_PRICE_BY_SERVICE[serviceType]
vol_modifier  = 1 + max(0, volume / 100) × 0.05
subtotal      = round(base_price × vol_modifier)
total_cop     = round(subtotal × urgency_multiplier)
total_usd     = round(total_cop / 4000, 2)    -- 1 USD = 4,000 COP

# ±15% deviation for commercial range
range_min_cop = round(total_cop × 0.85)
range_max_cop = round(total_cop × 1.15)

Returns

interface PriceEstimation {
  basePriceCop: number;
  urgencyMultiplier: number;
  subtotalCop: number;
  estimatedTotalCop: number;
  estimatedTotalUsd: number;
  rangeMinCop: number;
  rangeMaxCop: number;
  rangeMinUsd: number;
  rangeMaxUsd: number;
  rate: number;  // always 4000 (1 USD = 4,000 COP)
}

Example

import { estimatePrice } from "@/utils/pricing";

const estimate = estimatePrice("fabricacion", "alta", 500);
// basePriceCop       → 1,200,000
// urgencyMultiplier  → 1.35
// volumeModifier     → 1 + (500/100) × 0.05 = 1.25
// subtotalCop        → 1,500,000
// estimatedTotalCop  → 2,025,000
// rangeMinCop        → 1,721,250
// rangeMaxCop        → 2,328,750

`parseToHslChannels`

Converts any standard CSS colour (hex #RRGGBB, hsl(), hsla(), or already-formatted space-separated channels) into Tailwind CSS v4’s space-separated HSL channel format "H S% L%".

// src/utils/tenant.ts
export function parseToHslChannels(color: string): string

color

string

required

Input colour in any of these formats:

#0284c7 — 6-digit hex
#abc — 3-digit hex (expanded internally)
hsl(199, 89%, 48%) — CSS hsl()
hsla(199, 89%, 48%, 1) — CSS hsla()
"199 89% 48%" — already in channel format (returned as-is)

Returns "H S% L%" e.g. "199 89% 48%". Falls back to "240 5.9% 10%" for unrecognised formats.

Example

import { parseToHslChannels } from "@/utils/tenant";

parseToHslChannels("#0284c7");      // → "199 89% 48%"
parseToHslChannels("hsl(199, 89%, 48%)"); // → "199 89% 48%"
parseToHslChannels("199 89% 48%");  // → "199 89% 48%"  (no-op)

`formatColorForDb`

Converts space-separated HSL channel format back into a valid hsl() CSS string for storing in tenant_settings.config_value, which enforces a format constraint.

// src/utils/tenant.ts
export function formatColorForDb(color: string): string

color

string

required

Space-separated HSL channels: "H S% L%".

Returns "hsl(H, S%, L%)" — e.g. "hsl(199, 89%, 48%)". If the input doesn’t match the channel pattern it is returned unchanged.

Example

import { formatColorForDb } from "@/utils/tenant";

formatColorForDb("199 89% 48%"); // → "hsl(199, 89%, 48%)"
formatColorForDb("hsl(199, 89%, 48%)"); // → "hsl(199, 89%, 48%)"  (passthrough)

The branding save flow calls parseToHslChannels on user-input colours (which may come in any format from a colour picker), then calls formatColorForDb before writing to tenant_settings. This ensures consistency across both Tailwind CSS v4 CSS variable injection and database persistence.

API & Actions

Database

Deployment

Engineering Utilities: CFM Calculator and Pricing Engine

`calculateRequiredCfm`

Parameters

Algorithm

Returns

Example

`getAchForEnvironment`

`calculateAirDensity`

Formula

`generateEngineeringReport`

`estimatePrice`

Parameters

Algorithm

Returns

Example

`parseToHslChannels`

Example

`formatColorForDb`

Example

Build docs developers (and LLMs) love

API & Actions

Database

Deployment

Documentation Index

​calculateRequiredCfm

​Parameters

​Algorithm

​Returns

​Example

​getAchForEnvironment

​calculateAirDensity

​Formula

​generateEngineeringReport

​estimatePrice

​Parameters

​Algorithm

​Returns

​Example

​parseToHslChannels

​Example

​formatColorForDb

​Example

Build docs developers (and LLMs) love

`calculateRequiredCfm`

Parameters

Algorithm

Returns

Example

`getAchForEnvironment`

`calculateAirDensity`

Formula

`generateEngineeringReport`

`estimatePrice`

Parameters

Algorithm

Returns

Example

`parseToHslChannels`

Example

`formatColorForDb`

Example