Efficient fumigation has always depended on applying the correct dosage of fumigant gas and maintaining the required concentration for the correct period of time. If this is done, then we know that we can kill all stages of insect life that are present within the building, container or commodity.
It is important that we monitor the concentration of fumigant gas both in the commodity and within the fumigation area But how much fumigation is adequately monitored with honest gas concentration readings being taken?
It is also widely known that temperature plays a big part in successful fumigation. The higher the temperature the more active the insect pests will be and so we can either use less fumigant gas or reduce the exposure period, or in certain circumstances both. The reduction of fumigant cost and exposure time can provide big savings to customers of fumigation and to fumigation companies themselves.
Referring to the DEFRA publication "Fumigation Guidelines", it states that "at least two sample lines are required for fumigation monitoring and the sample point positions should be chosen to ascertain both the distribution and the penetration of the fumigant". One sample line should be in the space and the other should be placed deep in the stack, within the commodity being treated.
Monitoring the gas concentration inside the commodity is a challenge that has to be met. A probe inserted deep into the centre sack or box of goods will give us the reading that will enable us to ensure that we have complete penetration of fumigant gas.
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Above is an example of a gas probe fitted with quick-lock connections enabling the test line to be speedily assembled and the gas sampling line to be taken out to an area where it is safe to take gas concentration readings.
In Methyl Bromide fumigation, an ordinary digital thermometer or thermocouple unit can be used. With Phosphine however, a shrouded electrical system should be used to prevent the gas corroding metals such as brass, copper, silver etc.
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This probe can be used for commodity temperature readings and left in situ throughout the fumigation period if required, no matter what fumigant is being used.
Fumigation will only be successful if we maintain the correct concentration of gas for the required period of time and at the optimum temperature to control all stages of insect life. If we do not monitor the fumigation, how will we know if we are successful? We owe it to our customers to prove that we are professional people.
Del Norton, Fumigation Consultant
Products shown are the new Stainless Steel probe, with quick-lock connections and extra-strong construction, and the new Temperature Probe with shrouded controls system. Both are available from Power Plastics Ltd, Station Road, Thirsk, North Yorkshire YO7 1PZ United Kingdom. Tel: (44) (0) 1845 525503 / Fax: (44) (0) 1845 525485 Email: firstname.lastname@example.org. www.powerplastics.co.uk