View Full Version : Corrosion protection

12-01-2013, 07:36 AM
When ammonia systems have seen a few years and perhaps the insulation or paint wasn't installed/applied particularly well or there has been "on the run" repairs done that for one reason or another the insulation was not replaced and you discover some rusty pipework (on the cold pipes) and you know if you don't do something about it you will have a leak to deal with what products are available that can be applied to steel pipe work that dry or set quickly?

Its a tough ask, a cold pipe that might get hot on a defrost (+30degC to -30degC)is not an easy thing to protect with paint. If the insulation is vapour sealed there should be no rust but I don't think the insulation installers around here know that. Also, because it's at the point of finishing off a job where pipes are painted, corners are cut and some school leaver gets handed a brush and told to "go to it".

Also, what applications do you apply to valves to prevent them from rusting on a plant that is in operation?

We have used BlackGuard rust converter on pipes with variable success and tend to used Petrolatum Tape (Denso) on valves which, so far, seems to be working well.

12-01-2013, 08:56 AM
Its good to see the project installation teams are the same all over the world! I personally always feel the poor insulaters get the short end of the straw and are blamed for a lot of the project failures. It is the most visible portion and they always have their install time cut with project over runs. some sparky or pipe fitter climbing over your new layup must really be a ****!
Insulation is costed by the meter and they are squeezed in price and delivery time!
The best insulation for life cycle is metal clad (With rolled joints and rivet seams, not the strapped crap you see!) with primed and oiled pipework and a polyisocyanurate foam injection. Done well this is an excellent insulation with the longest life span. The only insulation that can take the "ladder climbing abuse" it gets subjected to.

To your question on rusting, Denso tape is still the best on the market and has not been surpassed.
I remember a non setting compound from Aus/NZ called Res-Q-Steel it was awesome but not seen it in the UK.

Painting is all in preparation and project time kills that! I would suggest a good primer (sets quickly) and we use a waxoyl spray application to seal. There is a clear preparation for pretty painted areas or the good old black vehicle under body stuff for some serious corrosion protection.

At least you get to care about your plant! UK is so price crazy that nobody wants to pay for decent maintenance anymore and the companies providing the service just want to maximise profit!

12-01-2013, 11:34 AM
Just a random thought, but POR-15? It's vaguely flexible and most certainly a rust preventer. Restorers of all things ferrous tend to swear by it.

14-01-2013, 10:26 PM
POR-15 was recommended to me for painting pallet racks in the cooler.
I did not try it as the humidity and temperature requirements were something we could not achieve.

21-01-2013, 10:17 PM
Proper protection from moisture is important. No matter how effective a container may be, there is always a possibility that a minute amount of moisture may seep in. This is an effective rust remover that quickly eliminate rust on ferrous metals: