Laundry Chemical Dosage Calculator
Determine automatic chemical pump injection dosages (oz per hundredweight / cwt), active chlorine bleach PPM, and sour pH neutralization.
Recommended Tools & Equipment
Tested hardware and components for high reliability
How Commercial Wash Formulas & Chemical Dosing Work
Industrial laundry chemical dispensers inject liquid products calibrated in fluid ounces per hundredweight (cwt = 100 lbs of dry linen):
Hundredweight (cwt) = Washer Dry Weight (lbs) / 100
Pump Dose (fl oz) = Dosing Rate (oz/cwt) × cwt
Bleach PPM = (Bleach fl oz × % Sodium Hypochlorite × 7,800) / Wash Water Gallons
Target Residual Linen pH = 5.5 to 6.5 (Neutralized with sour)
The Sour Neutralization Rule: Washing at high alkaline pH (11.5) dissolves heavy body sebum and grease. However, if residual alkali is not neutralized in the final rinse with an acidic sour, damp linen will turn yellow under hot ironer chests and trigger severe contact dermatitis on guest skin.
Frequently Asked Questions
What is the role of an alkali builder in commercial laundry?
Alkali builders (such as sodium hydroxide or sodium metasilicate) elevate the wash water pH to 11.0–11.8. High pH saponifies animal and vegetable fats into soluble soap, swells cotton fibers to release entrapped soil, and prevents redeposition.
Why should chlorine bleach never be injected above 150°F?
Chlorine bleach (sodium hypochlorite) becomes aggressively corrosive to cellulose fibers above 150°F (65°C), chemically degrading cotton tensile strength and forming pinholes while releasing pungent toxic chlorine gas.
What is the target pH for finished hotel sheets and towels?
Human skin has a natural acid mantle of pH 5.5. Finished hotel textiles must be tested with a chemical indicator pencil (like Phenolphthalein or universal indicator) to confirm a final pH between 5.5 and 6.5.