Also in: Disaster Response and Recovery
Water Main Chlorination Dose
The chlorine to charge a newly installed or repaired water main the AWWA C651 way.
Example
You enter
- Pipe inside diameter (in) 8
- Length of main (ft) 1000
- Chlorine dose (mg/L) 25
- Product available chlorine (%) 65
You get
- Pipe volume 2,611 gal
- Available (100%) chlorine 0.544 lb
- Dry product (weight % basis, e.g. cal-hypo) 0.838 lb
Checked against published worked examples from: AWWA.
Details, formula, and sources
ScopePipe volume, the pounds of available chlorine for the dose, and the product weight at its strength. Flush and pass a bacteriological test before return to service.
Formula or tablevolume_gal = 0.0408 x diameter_in^2 x length_ft; available_cl_lb = (volume / 1,000,000) x dose_mg/L x 8.34; product_lb = available_cl / (weight % / 100) for a dry product; liquid_gal = available_cl / (8.34 x trade % / 100) for a liquid labeled in trade percent.
Source and editionAWWA C651 Disinfecting Water Mains (by name).
Free accessAWWA C651 licensed; the dose/contact-time methods are public water-works practice.
What governsEstimate. AHJ and licensed professional govern.
API field namesdiameter_in, length_ft, dose_mg_l, product_pct, volume_gal, available_cl_lb, product_lb
- Dose / contact time continuous feed at least 25 mg/L with 10 mg/L left after 24 hours; slug at least 100 mg/L for at least 3 hours, rechlorinated if it drops below 50 mg/LAWWA C651
- Product strength cal-hypo (HTH-type) is roughly 65 to 70% available chlorine; liquid sodium hypochlorite is the label trade %product label
- Clearance flush and pass a bacteriological test, and dechlorinate any chlorinated water before dischargeAWWA C651