Added PoundPerSquareFoot and PoundPerThousandSquareFeet

[fischero19]

Standard for paper grammage/base weight in North America is lbs/MSF (pound per 1000 square feet) instead of g/m².
Conversion factor is standardized by TAPPI (free sample of TIP 0800-01 can be found here).

I also added lbs/ft² for completeness.

[angularsen]

Thanks, looks good, only minor change needed

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[angularsen]

Thanks for adding these — lbs/MSF is widely used in the North American paper industry and a good addition. A few fixes needed:

1. PluralName is identical to SingularName

Both units have the plural name set to the same value as the singular. Should be:

• "PoundsPerSquareFoot" (not "PoundPerSquareFoot")
• "PoundsPerThousandSquareFeet" (not "PoundPerThousandSquareFeet")

2. Use exact conversion factor for ft²

0.092903 is a rounded value. The exact value is 0.09290304 (since 1 ft = 0.3048 m exactly, 1 ft² = 0.3048² = 0.09290304 m²). Please update both conversion functions:

"FromUnitToBaseFunc": "{x} * 0.45359237 / 0.09290304",
"FromBaseToUnitFunc": "{x} / (0.45359237 / 0.09290304)",

and similarly for PoundPerThousandSquareFeet:

"FromUnitToBaseFunc": "{x} * (0.45359237 / 0.09290304) / 1000",
"FromBaseToUnitFunc": "{x} / (0.45359237 / 0.09290304) * 1000",

3. Minor: abbreviation convention

lbs is technically the plural abbreviation. The standard singular form is lb/ft² and lb/MSF. Not a blocker, but worth considering.

After fixing the JSON, please regenerate code with generate-code.bat and rebuild.

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[claude]

Code Review

Adding PoundPerSquareFoot and PoundPerThousandSquareFeet to AreaDensity.

PoundPerSquareFoot (lb/ft²) is a widely-used area density unit in construction, engineering, and paper manufacturing. PoundPerThousandSquareFeet (lbs/MSF) is the North American standard for paper/substrate grammage, standardised by TAPPI. Both are reasonable additions.

Issues

1. Plural names are wrong
The JSON has the same value for SingularName and PluralName:

"SingularName": "PoundPerSquareFoot",
"PluralName": "PoundPerSquareFoot"

The plural should be PoundsPerSquareFoot and PoundsPerThousandSquareFeet (note the leading s). This affects generated property and method names (the existing KilogramPerSquareMeter quantity uses KilogramsPerSquareMeter as the plural).

2. Slightly imprecise foot² conversion constant
The conversion uses 0.092903 m² for one square foot. The exact value is 0.09290304 m² (= 0.3048²). The difference is ~4 × 10⁻⁸, which is within 1e-5 tolerance, but it's better practice to use the exact value. Compare with how Length defines the foot as exactly 0.3048 m.

3. Minor: asymmetric inverse formula
PoundPerSquareFoot:

• FromUnitToBaseFunc: {x} * 0.45359237 / 0.092903
• FromBaseToUnitFunc: {x} / (0.45359237 / 0.092903)

The inverse wraps in parentheses which is correct, but a style nit: use {x} * (0.092903 / 0.45359237) to match the convention of other units (multiply in both directions, just swap numerator/denominator).

4. PoundPerThousandSquareFeet — single abbreviation
Only lbs/MSF is listed. Many North American paper weight specs also write it as lb/1000ft². Optionally adding that as a secondary abbreviation would improve parsing coverage, but not required.

Summary

The units are well-justified and widely used. Please fix the plural names and the conversion constant, then this should be good to go.