Disinfection of Pipelines - Disinfection of Pipelines and Storage Facilities Field Guide - page 38

Example 1. A 6-in. diameter pipeline consisting of 10
sections of 18-ft pipe is to be chlorinated using chlorine tablets
and the tablet method. Calculate the number of tablets needed
for the job and describe how they will be placed. There is one
fire hydrant installed along the pipeline.
Use the checklist to ensure all of the information is collected.

❑ The pipeline diameter and length.

6-in. diameter and 10 sections of 18 ft or 180 ft total
length

❑ Valves, hydrants, tees, and other appurtenances.

One hydrant along the pipeline. Disinfect with 1 tablet.

❑ Volume of chlorination water to disinfect pipeline.

Tablet method does not use chlorinated water to fill the
pipeline, but the volume of the pipeline from Table 3-6
is 1.47 gal/ft 180 ft = 264.60 gal. Fill the line slowly:

from Table 3-1, a 90-gpm fill rate will be 1 ft/sec
velocity. Filling the line at this rate will take about
3min.

×

❑ Amount of chlorine needed to complete the disinfection

procedure.
From Table 3-8a, each 18-ft section requires 1 tablet,
so 10 tablets are needed for the job. Place 5 tablets at
the front end of the first section and 5 at the beginning
of the 6th section.

Example 2. The tablet method is used to chlorinate a
200-mm diameter pipeline that is 1,000 m in length. Calcium
hypochlorite granules are used and must be measured in the
field without a scale. Determine how much is needed for the job
and describe the procedure.
Use the checklist to ensure all of the information is collected.

❑ The pipeline diameter and length.
200-mm diameter and 1,000-m length