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Therapeutic action
- Disinfectants
Indications
- Disinfection of medical devices, instruments, linen, floors and surfaces
Forms and strengths
The potency of chlorine disinfectants is expressed in terms of active chlorine in either:
- percentage (%)
- g/litre or mg/litre
- parts per million (ppm)
- chlorometric degree (1°chl. = approximately 0.3% active chorine)
1% = 10 g/litre = 10 000 ppm
1 mg/litre = 1 ppm = 0.0001%
The most widely used chlorine disinfectants are:
- Sodium dichloroisocyanurate (NaDCC), 1,67 g tab........................................1 g active chlorine/tab
- Calcium hypochlorite (HTH), granules...........................................................65-70% active chlorine
- Sodium hypochlorite solutions (liquid bleach):
- concentrated bleach ...................................................................36°chl. = 9.6% active chlorine
- bleach ...............................................................9°chl or 12°chl. = 2.6% or 3.6% active chlorine
- Chlorinated lime, powder .............................................................................25-35% active chlorine
Preparation and use
- The concentration required depends on the amount of organic material present (how clean/unclean the surface is).
- The active chlorine content must always be checked on the product packaging in order to adjust the dilution if necessary.
- Prepare solutions with cold water in non-metallic containers.
- A deposit in HTH solutions and chlorinated lime solutions is normal (use only the supernatant).
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Clean medical devices, equipment, surfaces and linen |
Surfaces, beds, utensils in case of cholera |
Surfaces, equipment contaminated with blood and other body fluid spills |
Corpses, excreta, boots in case of cholera |
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Concentration required, expressed in active chlorine |
0.1% |
0.2% |
0.5% |
2% |
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NaDCC |
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Calcium hypochlorite |
15 g/10 litres |
30 g/10 litres |
7.5 g/litre |
300 g/10 litres |
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Bleach |
For 5 litres: 200 ml |
For 5 litres: 400 ml |
For 1 litre: 200 ml |
For 5 litres: 4000 ml |
For more information, see Antiseptics and disinfectants, Part two.
Precautions
- Handle concentrated products with caution (avoid jolts and exposure to high temperatures or flames).
- Do not bring dry products, particularly HTH and chlorinated lime, in contact with organic materials (e.g. corpses): risk of explosion.
- Avoid inhaling vapours and dust when opening or handling the containers.
Remarks
- Sodium dichloroisocyanurate (NaDCC) is less corrosive than the other products.
- Bleach or concentrated bleach, or if not available HTH, may be used to prepare an antiseptic solution at 0.5% active chlorine (as substitute to Dakin's solution), provided sodium bicarbonate (one tablespoon per litre) is added to the final solution to neutralise the alkalinity (e.g. for one litre: 200 ml of bleach 2.6% + 800 ml distilled or filtered water, or if not available, boiled and cooled water + 1 tablespoon of sodium bicarbonate).
- Chloramine T (powder or tablet, 25% active chlorine) is another chlorine-releasing compound used above all as an antiseptic.
- Trichloro-isocyanuric acid (TCCA), in powder or granules (90% active chlorine), is very similar to NaDCC, but its use is limited due to its poor solubility.
Storage
Chlorinated lime, bleach and concentrated bleach are unstable. HTH is more stable. NaDCC is by far the most stable.