At a glance
- Examples of how to prepare chlorine disinfectant solutions in global healthcare settings.
- The materials on this page were created for use in global healthcare facilities with limited resources, particularly in low- and middle-income countries.
Example 1 — Using liquid bleach
Chlorine in liquid bleach comes in different concentrations. Any concentration can be used to make a dilute chlorine solution by applying the following formula:
(% chlorine in liquid bleach ∕ % chlorine desired) − 1 = Total parts of water for each part bleach A
Example: To make a 0.5% chlorine solution from 3.5% Bbleach:
[3.5% ∕ 0.5%] − 1 = 7 − 1 = 6 parts water for each part bleach
Therefore, you must add 1 part 3.5% bleach to 6 parts water to make a 0.5% chlorine solution.
Example 2 — Using bleach powder
If using bleach powderC, calculate the amount of bleach to be mixed with each liter of water by using the following formula:
[% chlorine desired ∕ % chlorine in bleach powder] × 1 000 = Grams of bleach powder for each liter of water
Example: To make a 0.5% chlorine solution from calcium hypochlorite (bleach) powder containing 35% active chlorine
[0.5% ∕ 35%] × 1 000 = 0.0143 × 1 000 = 14.3
Therefore, you must dissolve 14.3 grams of calcium hypochlorite (bleach) powder in each liter of water used to make a 0.5% chlorine solution.
Example 3 — Formula for making a dilute solution from a concentrated solution
Total Parts (TP) (H2O) = [% Concentrate ∕ % Dilute] − 1
Example: To make a 0.1% chlorine solution from 5% concentrated solution:
Calculate TP (H2O) = [5.0% ∕ 0.1%] − 1 = 50 − 1 = 49
Take one part concentrated solution and add to 49 parts boiled (filtered if necessary) water.
- "Parts" can be used for any unit of measure (e.g. ounce, liter or gallon) or any container used for measuring, such as a pitcher.
- In countries where French products are available, the amount of active chlorine is usually expressed in degrees chlorum. One-degree chlorum is equivalent to 0.3% active chlorine.
- When bleach powder is used; the resulting chlorine solution is likely to look cloudy (milky)
- AVSC International (1999). Infection Prevention Curriculum. Teacher’s Manual. New York, p.267.
- https://iris.who.int/handle/10665/130596