The correct pipe insulation will provide an effective barrier against condensation provided that the surface of the insulation is above that of the dewpoint temperature of the air and that it also acts as a vapor barrier so that the water cannot pass through it to the surface of the pipe.
Therefore, you need to use a closed cell pipe insulation with a high emissivity surface - a high emissivity surface is essentially one that absorbs heat eg a product with a black finish. The best insulation to use in this instance is there for expanded nitrile rubber, a black closed cell foam product. Leading brands such as Eurobatex & Armaflex have particularly fine cell structures which makes them an ideal choice for this application.
With any installation of pipe insulation, making sure it is adequately sealed will ensure the best result.This is especially true of insulating for condensation control as you need the insulation to act as a vapor barrier. For best results with any pipe insulation you ought to use adhesive as this creates the strongest bond, but tape can work as well provided you make sure to cover all gaps and smooth any air bubbles out of it. If you do use only tape though it should be noted this will not be as effective as adhesive.
Now, usually at this point in one of our blogs we give you a table or some kind of reference guide; this cannot be done with condensation control however as there are too many variables to consider. However, what we can do is link you to a handy calculation program, here - Condensation Control Calculator
You should note that when it asks you for the pipe size, it refers to nominal pipe sizes in inches, you must adjust this to mm if that is how you are working. You use the 0.90 value for emmitance of surface if working with expanded nitrile rubber (referred to here as elastomeric foam). You will need to know the operating temperature of the pipe, the ambient temperature around it and the relative humidity in order to carry out one of these calculations.
If you would like to know more about the materials then you can either refer to our other blogs highlighting particular products or visit our website: Pipe Insulation Products