PTT (Improving Test Results by Washing with Potassium Permanganate)

PTT (Improving Test Results by Washing with Potassium Permanganate)

Causes of PTT Failures:

A failure of a PTT occurs only when a contaminant reacts with Potassium Permanganate. Such reactions are caused by all inhibited products and organic matter. Potassium Permanganate does not react with hydrocarbons.

Recommended Procedure:

By spraying, or recirculation washing, the tank with Potassium Permanganate you will pass the PTT time (just by pre-empting the surveyors medium).  First, clean the tank has to a water-white standard before applying the Potassium Permanganate by spraying. 

The different ways of spraying Potassium Permanganate with good results are:

1/ Put one tablespoon of Permanganate in a 200 litre drum with around 100-150 litres of fresh water.  Use a high-pressure drum pump and spray gun and constantly replace the fresh water in the drum whilst spraying as this mixture is strong.  Spray the tank for about 45-60 minutes.

2/ Mix six table spoons of Potassium Permanganate crystals in 2 m3 of water  and recirculation wash for half an hour.  If the mixture turns to a straw-like colour (indicating high contaminates are present) before the half-hour, then renew the mixture.

3/ Steam the tank, inserting a strong mixture of Potassium Permanganate, for about 60 minutes.

In all cases the tank must be thoroughly washed afterwards to remove the Potassium Permanganate/sludge.  There are no known coating restrictions.

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