Electrons Contribute To Rust?

"Do the hinges isolate the doors, so they are floating electrically?"

I cannot get this confirmed, but I believe the doors to be bonded to the frame. Steel hinges with steel screws are used. The door/frame is painted in some shop before installation, so the mortise for butts is probably painted. However, screws for hinges are designed to cut away paint/primer as they are driven, so should be grounded.

Different grades of steel... might be. Would that contribute to this trouble?

Whatever offgassing is going on inside the buildings does not appear to be the culprit. Rust appears at interior and exterior skins more or less equally.

I just got another hint from him: rusty spots seem to be mostly at the top and bottom... well, that isn't really a lot of help because that is where rust starts to appear on a steel door almost always anyway.

GA and most likely cause. It is a dry area so may be some moisture trapped inside cooler door. My solution would be to go to a fiberglass door and forget steel. They have good durability, fire proof and corrosion proof properties.

pretty good.

CR58647,

I've never seen this before, where someone from another forum has somehow managed to post on CR4 without having a single relevant sylible to offer.

That's the only possible explaination for the unintelligible jibberish contained in your first two posts.

Amazing. Where do you think you are? Maybe we can help you find a path back there.

How well, Hi.

I was 2nding comment 16, I understand metals alloys can be mildly galvanic towards each other, depending on the alloying elements of the respective metal(s). Some even cold weld to each other when all air is gone from the surface, or maybe when surface content is changed. But..

..it's alright, i hava Map, please excuse the intrusion. i thought we were brainstorming. i guess i got the r in the wrong place.

Thanks for the clarification.

Welcome to the party.

We can always use an extra brain.

Thanx, I like reading through these. I'll definitely try and contribute from time2time.

No answer, but possible clues, possibly acting alone or in combination:

* As Lyn suggested, possible different materials. Frames may be brake formed uncoated steel then primed, skins electrocoated with tie coat for a primer. May need a real primer under finish coat.

* Seams in door edges allowing moisture in under paint (Could be caulked?)

* Incomplete paint application, especially where it won't be seen, top and bottom. (Pet peeve of mine.)

I'd try to find out exactly how the door and frame are manufactured differently.

Thanks for the replies guys.

RAMConsult said "This means the door breaths as the air inside it contracts and expands due to the temperature differences."

Correct, the doors have to be vented. If they were sealed they would expand and contract with the temperature swings and tear themselves apart. As you say, bad stuff in the air can certainly make its way to the interior. The doors are not exhibiting rust through, just surface rust.

I have actually sold this customer two different brands of hollow metal doors, the competitor selling yet another brand. Each manufacturer has his own assembly methods, techniques and materials. There is something at these facilities that is causing this very early rust out. I have, other than this application, a very small percentage of rusty door complaints... pretty dry around here.

To make things worse, in this circumstance I am selling the stuff to a lumberyard who sells it to the power co., so my info is not direct from the people reporting the trouble. The yard is reluctant to put me directly in contact with them... he's afraid I'll steal his customer away. This makes good input about conditions spotty.

I am advised that not all of the buildings with rust have battery arrays, so (if this is really true) that is not a common factor. The only common elements are the potential itself, and that it is the doors only, not the frames.

I am inclined to agree with the question from my partner, thinking that the doors, even they should be, are not bonded with the frame, thus isolating the door leaf.

I am inclined to believe this lack of equipotential is to blame for the rust, but cannot quite figure out why. Rusting is an electrochemical process... and then I get stuck!

[edit] Good call ozzb. The frames had not been fitted with raindrips (a hardware item designed to stop that problem), but will be soon.

[edit] We discussed galvanized A60 and G90, or even FRP as the material for future orders. My customer (lumberyard) seems a little reluctant to tell his customer he has been selling them the wrong stuff for years!

Honor is a valuable asset even in 21st century, make that clear to the lumberyard man, if after doing so, he is still reluctant, it means he has unfounded suspicions, probably because he would do it if he could; and he deserves that you, not steal but save that customer from him.

OK never mind, is just that I hate when someone doubts about my moral integrity.

Regards.

Just a thought is there cover above this door? Have seen doors on the flat face of a wall installed with out even a drip guard. Water will then run down the face and around the header and drip on the top of the door sash. The amount of water can be worsen depending which direction the door faces and the general direction storms and wind moves thru the area. Wind blowing across another open creating a vacuum at the door. If the cap end is not sealed well water runs inside and lays. They usually rust top and bottom. The core a lot time being foam filled seals most the metal except at the ends. This happens a lot if the door is not standard size and has been cut down.

These doors seem to be in a corrosive environment, as such I believe the secret to success here is in using a door designed for just such an environment....perhaps galvanized steel

http://www.vortexdoors.com/doors/hollow-metal-wood-doors/corrosion-resistant-doors-frames

Maybe you have induced potential from the power plant that's charging the doors?

Can you sneak over there and measure the doors for a minor induced charge?

I think I'd tell the lumber guy that if wants any free doors from you, you'll have to inspect the present installation.

Maybe a non-compete agreement for some period would ease his mind?

Never mind, I'm sure you've already thought of this.

"...that if wants any free doors from you..." The dreaded 'F' word!

Yeah, I already told him that I need to see them IN PLACE before any warranty replacement will be considered.

My customer just wants free doors , but I want to find the cause and do whatever needs doing so this is no longer a problem.

I said the only common element is building type... not so. The paint is, supposedly, the same in each case.

I have sold doors and hardware to countless coal powerplants, hydropower, substations... never had this trouble before.

Trying to think horses and not zebras, I am starting to have a feeling the report of the paint type as alkyd is probably untrue.

If anyone knows if there is some mysterious acceleration of rust propagation that may be in play, please let me know, but that may be a red herring. I'll keep you guys posted.

Your description makes me wonder if the correct primer has been used, and if the surface was thoroughly cleaned prior to the door being primed. It ought to last more than 2 years.

Where/how/what is the primer coat applied? I'd look into that make sure it is done properly.

We are commonly known as a second location manufacturer: we buy blank doors, window kits, frame rail, etc. and assemble them into whatever combination the customer has selected.

The frame and door parts we buy are primed by the manufacturer, and we touch up repair (with factory paint) as necessary after fabrication.

We sell about 150 doors and 3 of 4 hundred frames a week. Until yesterday, in the last year I have had one complaint about doors rusting through the finish.

I agree with you, and the end user: it ought to last more than two years. Around these parts it is common for a steel door, unless the finish is damaged by rough use, to only need painting every six or eight years. I am investigating, searching for the reason this one doesn't.

I'm not sure where this goes but see if they have grounded the frames and thus, the doors. Maybe check for resistance between the door and the frame and the ground.

When I worked on transmission lines, we used galvanized steel for everything. All of the substations had a grounding mat, but I don't know if it covered the whole substation; the electrical side is one of the black arts for me.

In all honesty, most of the rust cases like this are due to faulty surface prep.

I agree with Lynn on this. I'm thinking electrolysis. There are now cathodic protection systems available to others than the marine market. I know they are currently (no pun) in use for underground tanks and pipelines. They may have the means to test for this.

i doubt it. are the doors manufactured with the welds at the top and bottom of the doors? if they are, seal the seams with a fexible non-harding caulk before painting.

is salt a factor?

Do these particular doors include a steel threshold from the manufacturer? I cant tell you the number of 50s era concrete block buildings I have been to, that have steel doors with an aluminum threshold. They are usually installed with steel countersunk screws, that have been screwed into a wooden dowel hammered into a hole driven into the concrete. What with moisture conditions, and a plethora of different materials I have seen a wide variety of door degradation.

Ozone formation from high voltage arcing and UV can be an accelerating factor, but still, I would start investigating humidity, galvanic voltage diferences (that can turn most metals into sacrificial anodes), painting quality and salt. S.M.

The rusting issue may have something to do with the way the joints or seams are welded together specially for exterior doors. How the raw materials are prepared, like how they're cleaned, handled during production. If spot welding are used in joining those edges, not all points can be fused together, thus leaving open spots along the seams that will not be joined or fused together. Open spaces were moisture exist and rusting will begin specially if doors were not baked prior to or while being primed??

Identifying the exact failure mechanism is one way to approach the problem. Another approach is to realize that your steel doors are corroding and provide some form of cathodic corrosion protection. Zinc coating, sacrificial anodes, anti corrosion paint, or even electrical corrosion protection could be considered.

If small anodes made of magnesium were in contact with the steel in the general area of the corrosion at the bottom and top of the door, perhaps the electropotential would be sufficient to protect the steel from corrosion even through the high resistance of the air....

Might be a cheap and worthwhile thing to try on existing doors.

My first thought was the same as Simple Mind, i.e. OZONE. If you are not allowed access to the final fitting, find a pretext to add a rubber seal along one edge of a door. If ozone is present the rubber will fall to bits in no time.

P.S. most 'rubber' nowadays is synthetic.

Jim

I don't think the problem is electrical in nature. I think you have a moisture problem.

The fact that they are at substations is irrelevant. Why would they only rust at the top and bottom? I'm thinking that the answer is that the top and bottom haven't received any finish paint..................only the dirt cheap factory primer. They open out, right?

I would also get away from the alkyd finish. It's not the king that it once was. It won't expand and contract in the least, and therefore, is prone to cracks, which will allow moisture to enter. Once it starts, it's like cancer.

My personal recommendation would be to get the specs changed to an acrylic finish, maybe Sherwin Williams DTM, (direct to metal). Also, two coats to the tops and bottoms of the doors..........................even if you have to do it yourself.

Painters drink too much and can't be trusted to do it on site. Especially considering that the bottoms need to be done pre-installation.

A drip edge above the doors wouldn't hurt either.

{edit} Also, if the tops and bottoms are tack welded...................yes, caulk up any openings that would allow water to enter.

kramarat:

I'm curious about the specifics of your recommendation to use caulk to seal the door as a barrier to water entry.

Are you trying to make an airtight seal? Is there any type of drain needed at the bottom of the door?

It seems variations in temperature and humidity complicate things, potentially creating a dew trap.

BTW, this isn't intended as a challenge to any statement you have said. I'm just looking to expand my understanding a little.

As long as moisture isn't trapped inside the door, it's fine. There is not much expansion and contraction that happens on a steel door. As far as the door being able to "breath", that can take place right at the lock set.

The primer on these doors is nothing fancy. The factory wants them protected long enough to get them to the job site, it won't hold up long term. If these are unprotected exterior doors, there's a good chance that moisture is getting into them via the unfinished tops and puddling on the bottom.

I just thought of something else. I wonder if these substations are kept at low temperature to protect the electronics. If that's the case, and the tops and bottoms aren't sealed, it's very possible that on warm moist days, the temperature differential between inside and out is causing condensation to form on the inside of the door, "sweating". I wonder if they're insulated. Either way, I would seal the tops and bottoms and finish them with paint.

Thanks for all the answers. Some really good input.

I sort of got wrapped up in the excitement when somebody (here at my shop) suggested that a contributing element of this accelerated rusting is electricity floating around in the air. Hearing hoofbeats, I was thinking 'Zebras!'. I know better.

I am pretty sure you guys are correct, and am now leaning towards what paint failures almost always are... poor prep work, poor application, or incorrect product. Those are tried and true, and one or more of those are probably the culprit here. That is undoubtedly why the previous vendor rejected the repeated and constant warranty claims... not a warranty issue!

I have sold this guy (the lumberyard) about a dozen or so of these, and just last Thursday I learned the end use. Users like this are generally more interested in quality than price, and the lumberyard, being stuck in the 'cheap' mode, has been ordering commodity product for him. A door and frame fabricated from G90 galvanized steel, or maybe FRP, would certainly be something to consider in the future.

If you can convince them to do an audit on the existing ventilation set up, and it's what I suspect, you might just get a medal. Their expensive equipment doesn't like moisture/condensation any more than your doors do.

I don't believe this is a door, or necessarily a paint problem. I believe the rust is a symptom of a problem that's inherent with the structure. You may be able to alleviate it with caulk and paint, but the original problem will still be there.

Depending on how much money/business you stand to loose, you may want to offer to pay for an analysis of the ventilation system in one these structures, (probably a few hundred $), with the stipulation that if too much, or lack of, proper building ventilation is the culprit, you get reimbursed the testing fee, and you won't be asked to give away any more "free" doors in the future.

Seems like a very honest and reasonable approach to me.

I've been called out on quite a few paint failures. It takes some detective work......................but I've never had to do a free repaint.

Doorman,

Most of these posts are looking at the acid and electronic side of this, but the other side of the coin has caused problems in the past for me.

Most of these type of doors are installed in concrete, bessa block (cinder block for the yanks) or brick walls.

Because of the flush mounting and usually no rain shield, the alkaline from the lime in the concrete or mortar, gets into the crevices around the top and bottom of the doors before they are painted and then work merry hell before the door surfaces are sealed by painting.

The other problem is the invariable acid wash before painting.

Just my two cents,

Regards,
Sapper

Yes Sapper, accelerants and admixtures in the grout of a block wall play hell with a hollow metal frame. If a contractor has his wits about him, he will ask us to provide a bituminous undercoating inside the frame when installing in new CMU (concrete masonry unit) wall. This has proven to be an effective barrier coating, adding many years to frames. These particular buildings are reported to be the engineered steel type, so this doesn't come into play in this case.

As far as washing the brick veneer or CMU with muriatic acid... this practice is supposed to be disallowed around here, but that doesn't mean that some of these yahoos will not do it anyway... "That's the way I been doin' it fer years...". And yes, this will cause a paint failure that the owner wants me to participate in, even though it ain't my fault!

Why are the doors not made of GRP instead?

Does the end-user have a process containment problem, like vapours coming off the hydrochloric acid tank that supplies the ion exchange resin regenerant?

You have to consider the requirements to code as to what type of door you will use. In some applications we are required to use a blast type door with blow out plates or vents in case of an explosion, in some cold storage /deep freeze buildings -40 the only door that won't rust out in a year or two is a fiberglass door great to keep looking good but a pain to keep any hardware attached to it that wasn't originally designed into it from the factory. They don't hold fasteners very well, fiberglass just wasn't designed for security just good looks.

Er, actually it is Doorman that is concerned about the door, hence the original post.

Sorry, sometimes I answer a question that is not really a question. Just info, did not mean to question you with additional info. Just thought the question was asked thought I would answer for anyone else that might need the additional info. Duke

"...fiberglass just wasn't designed for security just good looks." I don't know about that. I have used frames and doors manufactured by CORRIM Company in hospitals, schools, wastewater treatment plants, meat packing facilities... these seem to hold up pretty well.

Not necessarily an endorsement for this particular manufacturer, I think most of the brands perform similarly.

"... great to keep looking good but a pain to keep any hardware attached to it that wasn't originally designed into it from the factory." Nature of the beast that is fiberglass. Compare to boats, car bodies...

I probably should have stated that a little better most of the fiberglass doors that I have personally worked on and serviced have been compromised in one way or another by bad contractors or other types of service person's like access control or alarm techs and locksmiths of which I am one and seen a lot of very seriously compromised doors in fiberglass and metal. Some have have had the fire ratings destroyed by unknowing so called professionals that don't know the codes they are supposed to be working within. I have seen more codes broken with after installation's repairs it really upsets me to no end. but I am off track and you are right there are a lot of good fiberglass doors out there, just hard to believe we can get as good security rating as heavy gauge steel.

Would a treatment like the Waxoil used inside car panels help. It won't cure the problem but would stop internal rust forming.

You may also want to nicely suggest that they check the design of the substation itself. If your doors are being subjected to conditions that are outside of normal parameters, I don't think you should be responsible for providing free replacements. You may have the opposite going on, from my last post. Hot inside, cool and damp outside.....................condensation is condensation though. It'll all cause rust.

http://www.csanyigroup.com/substation-ventilation

Regarding potential differences, I suspect that is a false trail, but acid fumes are a likely culprit. I remember visiting the in-laws in China, to save money on bottled gas they had bought one of those stoves which burns formed coal bricks (the bricks look like the rotating chamber in a wild west six-shooter and the stove is a recycled vegetable oil can with vermiculite / ash insulation) and it was used without any special vent arrangement - anyway between one visit and the next everything that was originally painted steel, fridge, fan, washing machine etc. had started to rust, blistering the paint. I suspected the acid fumes in the smoke at the time and based on that remarkable difference before and after I am strongly reminded of the consequences and therefore suspect the fumes in your case.

GA. 'Acid rain' in the kitchen in that particular case. All combustion oxide gases dissolve in water to form acids; could be, could be.

If this were Moi, I would look heavily into ditching the aluminium & seek Zinc railroad spikes, if they've been discovered yet!

I don't think given that the history of your products elsewhere that it is coincidental that the corrosion problems are occurring only at substations. Most people are familiar with galvanic corrosion, but the induced currents that exist at power stations/sub-stations/etc can be far more corrosive. A properly designed ground system would help prevent it, but poor bonding between the structures (fences, buildings, and doors!) and the ground will help speed up the process of eating away the metal.

The only commonality between the problems the electric company is experiencing is where they are installed (they've experienced the same problem with 2 different products).

At the risk of sounding redundant, when I run into rusting metal, water has always been the culprit. Not saying that other things can't cause it, but water/condensation is by far the most common.

I wonder if they will be able to get free equipment replacements too.

http://www.hsb.com/TheLocomotive/PreventativeMaintenanceCouldHaveSavedThousands.aspx

Corrosive gasses may play a role, moisture/humidity accelerates it. Relative humidity above 50% is a big no no.

http://www.corrosionmonitor.com/

Without water vapor (or liquid water), you would have no rust, galvanic corrosion or any other type of breakdown of metals I am aware of.

My understanding is that water (liquid or vapor) isn't required to oxidize metals it only speeds up the process considerably.

(you are correct about it being necessary for galvanic corrosion though)

I figured I'd get a response from someone on that.

Is my understanding incorrect? Feel free to educate me if I'm wrong.

you do need an electrolyte, but that electrolyte does not necessarily have to be water, but it usually is. But unless the door is in a sealed chamber filled with dry nitrogen or something like that, there WILL be some level of moisture content in the atmosphere.

These are a common installation; the door and the coating are subject to rain, sunshine, bird poop, whatever may be on the hands of workers... water is definitely available for the rust process on an occasional basis.

Since these doors don't fail anywhere else, something is different about these substations. I think that excessive moisture/high RH is at least a major component.

I'd try to find out what. Free replacements every 2 years doesn't sound like a very good option. At the very least, they need to change their specs to a (wet area use) door.

I mean shoot, they got rid of the last door guy......................it sounds to me like they've been on the lookout for a new patsy to keep them in new doors. And found one.

Ok, I did a bit of "self-schooling"... again correct me if I'm wrong... what we call rust is a hydrated iron oxide, so by definition this type of corrosion would require water.

As far as requiring electrolytes to oxidize a metal, yes, typically this is a dominating factor in the corrosion rates. However, dry corrosion does occur (it is the very reason that oxy-acetylene cutting torches work, the heat just speeds up an otherwise slow reaction). True?

What I was getting at, getting back to the OP, was stray current corrosion which is not uncommon in areas that have high EM fields (and does require an electrolyte, typically soil). As already pointed out, all metals in these areas should, by code, be grounded, but a poor bond will set conditions to start eating at the metal.

Okay, good. There may be something to this.

"... but a poor bond will set conditions to start eating at the metal." This is, more or less, the idea I started with. I have not been able to find how this condition actually contributes to the accelerated rate of this reaction. Can you elaborate?

Sure. In a properly grounded system, any induced currents in the metallics because of the high EM fields would simply flow into the ground wires and, therefore no voltage potentials between any objects (which is the point).

Now let there be a slight resistance in one of the bonds. A slight resistance means a slight voltage difference (and it doesn't take much). With all the different types of metals, it doesn't take much voltage difference to set up a anode-cathode situation driven by the induced currents.

If that is what is happening the solution is the same as some have already mentioned, bond a sacrificial anode to the door (magnesium or zinc is most common) and it will eat that before your door.

I think I would further bond a ground strap from the door around the hinge to the frame just to make sure.

Yes, good point.

Simple: Any two dissimilar metals can make a "diode", ask any Navy or Coast Guard EM or ET. In the presence of RF this will/can generate vast amounts of RF noise. In your case, I see the hi voltage being rectified to DC (only going to take a few millivolts) to destroy the door in a 2 year period. Even stainless steel corrodes as a result of the reaction(s) of iron, chromium and manganese.

Looking at it another way, you have had 2 vendors, using multiple products with identical failure patterns. Barring sabotage coming from one of your clients employees, I seriously doubt you have a quality issue.

Again I would look to a cathodic protection system. If nothing else the installer will have the expertise necessary to determine if electrolysis is the problem. Who knows, it could be something as simple as a shorted alarm system applying DC to the door. Zincs will have to be installed on each panel, a cathodic system will protect the entire structure.

Oxidation is the addition of oxygen to a molecule or the removal of hydrogen from a molecule, so, technically you are right. Fruits oxidize, that's why they turn brown.

Let's just say that you need water get rust.

Actually oxidation-reduction involves a transfer of electrons and compounds with oxygen are not necessary to the process. It is strange to say a product is reduced if it gains electron and is oxidized if it gives up electrons but that is chemically what happens. In the water industry when corrosion was expected because of redox potential we would design dielectric unions. I was thinking about the door problem and I liked the diagrams presented by rorschart. The difference in temperature from inside the door or inside and outside of the building is likely enough to cause the humidity to condense on or inside the door. Almost any measured humidity would come in play and then become the electrolyte to complete a galvanic cell.

So what would one use as a dielectric isolation for a steel door. The alumina oxides have a range of screws and products that are resistant to oxidation. So it seems it would be possible to install a steel door and isolate it from the building if some sort of insulating material were used at the hinges and edges of the door in conjunction with aluminum-ceramic screws. It works in the water industry when for example you hook up a hot water system with dielectric unions. Since the edges of the door (top and bottom) are where most of the rust appears, it seems those are areas to use some rubberized gasket to insulate the door and prevent abrasion. If you could hang the door in mid air would it still corrode? If it does then there is a problem with the atmosphere in the building (ozone generation for example). In a situation where corrosion recurs every year or two, I go back to recommending a fiberglass door. I am sure there can be good fasteners to install hardware including those alumina oxide screws. Can you get doors completely made of alumina oxides? Or even painted with alumina based paints?

LEO goes GER (lose electrons oxidation - gain electrons reduction) is still strong in my memory from my first chemistry teacher.

So what would one use as a dielectric isolation for a steel door.

Unless I'm misunderstanding, this would be highly inadvisable (because the door is installed near high voltage lines, transformers, etc, all metal must be grounded (it can kill if it isn't).

Although I would agree that changing door materials is a worthwhile solution! (at least for the power company)

LEO goes GER is a good way to remember. If the door is painted with an insulating material, I would not be concerned. Think of the door as a big wrench but fixed to one point. Is carrying a wrench into an electric building dangerous? Likely more than a door as the wrench is mobile. I am not a door person but do know there are products out there that can isolate the door. Isolation alone does not guarantee no rust, as it can show up on a large unprotected surface. Pipes are easier as the connections occur at small exposures. Cars left alone still rust after an extended time.

So am I understanding correctly that you are suggesting that he knowingly and willfully violate electric code????

No. Just trying to minimize the galvanic cell. Code overrules my suggestion.

Lots of good points. Thanks guys.

kevinm said "It works in the water industry when for example you hook up a hot water system with dielectric unions." I have two separate components at play, the steel door frame (anchored to the exterior walls of the metal building) and the door leaf. The frames are not exhibiting this accelerated rusting. So if isolated, I am assuming the doors are building up static charge.

Now, one of the thing that must happen for the rust to form is the steel be exposed to oxygen and water; that is, the coating is compromised. Can the static be contributing to ozone cracking of the paint coating? If yes, that is probably the beginning vehicle, with the info offered by you guys explaining the accelerated rate.

I have asked my customer about excessive rusting of other steel components of the buildings, but have not gotten any cogent response.

[edit] I agree completely, this installation is a good candidate for FRP frames and doors, but I only learned of the actual end use a week ago. I have several customers who are lumberyards, material brokers of one type or another. These guys are reluctant to share info about their book of business, they seldom really know what they are buying and selling (from me, anyway), and they seldom understand the true technical needs of their customers.

'...(you are correct about it being necessary for galvanic corrosion though)...'

.

If dissimilar metals in electrical contact are immersed in a non-aqueous liquid or solid electrolyte, the conditions necessary for galvanic corrosion are met sans water....or am I missing something.

.

.

perhaps ozone generation caused by the high electrical potentials? perhaps some zinc sacrificial anodes might be in order. or possibly eddy currents generated in the doors due to magnetic fields. I would try electrically bonding some zinc anodes to the doors top and bottom and see if that helps solve the problem.

If the hinge pin exhibits much more severe wear than the normally produced by rotation, then you have a electro-abrassion issue. Ground to the door to the frame with a flex strap as Lyn sugests, but if the pin is normal then keep investigating and tell me what it is when you find it.

Regards

DOORMAN how about switching to a stainless steel door that is designed for an extreme environment of moisture or acids. We have run into a few in labs that just because of their highly corrosive environments a SS door was a requirement by the architect and the end user. Just an additional thought. All in all this might eliminate the problem, but might make it so you never replace a door. That may put a dent in your pocket book over time. Duke

Another "vote" for induced 'eddy' currents from strong electromatic field(s).

Alright. I guess at some level all corrosion has an electrical component.

http://www.ndt-ed.org/EducationResources/CommunityCollege/Materials/Physical_Chemical/Corrosion.htm

Yes, corrosion is an electrochemical process. See #7.

Yeah. But beyond that, I was admitting that the EMF from the equipment can be playing a direct role..............................along with moisture.

Interesting.

Agreed, this whole discussion is interesting.

But the question was, and seems only partly resolved... Why the paint failure? That is what is happening at the end of the day. I find it difficult to believe otherwise.

The paint coating is obviously working, sealing the steel. Otherwise the rust would propogate in a few months instead of two years. No moisture/oxygen exposure means no rust, with or without the EMF proximity.

During the discussion and subsequent investigation, I am leaning towards ozone cracking of the paint film, thus compromising the coating and exposing the steel. Of course, by leaning towards ozone cracking I am prone to falling on my face!

I gather that this is a new one for you as well?

Here's another angle, edge coverage. Or top/bottom coverage. The sides of the door are solid, bent pieces, I assume. Seams would be top and bottom. Are the sharp edges getting good coverage? Could that be where the problem starts?

It's pretty common for doors painted in situ to have the top and bottom marginally coated or skipped altogether. These subject doorsd are painted in a shop somewhere and then installed. The customer tells me (oh brother, here it comes) that "Of course the tops and bottoms are painted".

It is reported the rust spots are scattered about the faces of the doors, not concentrated on the top and bottom edges. You are correct, this is a common place for rust to start, but it is reported to not be the case here.

Here is the manufacturers spec of the primer they use.

I can't find the painting instructions online. I have a .pdf I will send to anyone who asks to see it thru IM.

Thanks for all the ideas. This is what makes CR4 such a great place!

If I read the spec right (page 11), the frames get a 2-part epoxy primer while the doors get an alkyd enamel primer. But it's not clear that the primer is standard on all doors and frames. The spec seems to be a universal spec and specifics depend on the specific product.

Also on page 11 in the Prime Paint Tests section there is a statement '...product can be provided with factory applied baked-on primers complying ...' which may imply that the doors you're getting only have the phosphate treatment.

From page 5, it sounds as if doors and frames can be cold rolled, galvanized or galvannealed. I guess this depends on the door purchase spec? If the doors you're getting are cold rolled (not galvanized or galvannealed) and then phosphatized only (no primer), then a coat of alkyd enamel is applied by the customer, in my opinion, that's not a very good system for an industrial environment. What color are the doors and frames? The phosphate tie coat I've seen is yellowish while most primers are gray.

While some on here are focusing on induced currents and ozone, and they may be accelerators, I still think the problem is more basic. In any case, I've spent most of my years on the customer side and most materials of construction issues were not covered by warranty, since chemical exposures are 'out of our control'.

You are reading it correctly; it is a spec of available items from the manufacturer.

From the OP: "Doors are 18 Gauge cold rolled steel, frames are 16 Ga CRS. These are provided to my customer primed, intended for finish painting in the field. It is indicated that the doors are finish painted with alkyd enamel, which is in accord with manufacturers' instructions."

We can't stock steel doors and frames in every variable, and the local market sort of drives what a distributor will stock for that market, or segment he is targeting. We stock the 18 GA CRS doors, primed, intended for final finish by others. This is pretty common in most markets, and is usually okay for most applications.

Would this be appropriate for this application? If I knew the project was intended to be a five year site (it is anticipated that in 5 years or less, this facility will be extensively remodeled or replaced), then, yes it may be appropriate. Twenty year site? Fifty year site? Almost certainly no, it is incorrect. When I am not privy to any of that end user information, and my customer orders a commodity door, I fill the order. Boom! Do ya want some fries with that? That is how the commodity door market works. They don't want to answer a bunch of questions, they just want to make a sale.

Information provided to me indicates there is no chemical exposure... now, this is sort of a wide brush for him to use, but I have to accept the comment at face value, for now.

[edit] "Ozone counts as a chemical" Bingo! Pretty hard for me to believe there are no chemical fumes in these buildings. In fact, we all know better.

ozone counts as a chemical.

I didn't mean my response as condemnation of you or yours. While a homeowner can reasonably expect to be sold merchandise fit for reasonable home use, a more sophisticated (commercial/industrial/utility) customer is expected to have the resources to order materials to fit his specific circumstances. The vendor's responsibility is to meet the spec. (Re: 'chemical', substitute 'environmental')

I certainly didn't find offense in your remark. To the contrary, it gave me an opportunity to better explain some of the fuzzy areas of this discussion.

If I seemed snarky, I didn't intend to be.

I agree, industrial users understand that the door they see at a big box lumberyard for $150 bucks will not be appropriate for their facilities in any way, shape, or form. However, tell a homeowner that a door is $1,850 bucks and he would have a massive myocardial infarction on the spot!

Not just doors, this applies to all industrial products... flooring, furniture, light fixtures, HVAC equipment, cooking equipment, tools...

You are exactly right. They try to tell me all the time the doors were ordered with all the reinforcements for door closers,panic bars,deadbolt or whole door reinforcements for high security installations like detention areas or jails. When I get there and find one guy installing the door I have to stop them and check to then find out that the contractor or end user canceled our spec's for their own that is the end of that project until the code enforcement people give them their version of a reality haircut about bypassing reg's it usually gets real ugly until they learn they are not the AHJ (Authority Having Jurisdiction) it's a real crowd pleaser when they come out of a reality check meeting with local & state code enforcement organizations with their tails between their legs. Just saying Duke

you should go over a freshly painted and installed door with a "holiday detector" essentially a high voltage power supply feeding a wire brush. if there is any arcing from the brush to the door, you don't have a good electrically insulating paint coating. that is what is done on buried epoxy coated pipe to verify that the coating is intact and without pinholes.

Hang on. I was stuck on the rust. I saw a site yesterday that mentioned a specific type of paint for substations. Let me go find it.

I can't find it, but isn't the rust coming from underneath the paint?

"I can't find it, but isn't the rust coming from underneath the paint?"

Yes, that is the report. It is also reported it is not rusting through, but surface rust and paint blisters. With that in mind, it makes me think there are tiny cracks that are forming in the paint film.

This Wiki article about ozone cracking is sort of guiding this line of thinking.

ozone can certainly do that which would also argue against FRP doors as the ozone would attack them directly as well. but the issue of it being only the doors and not the frame still has me thinking that there is a grounding/bonding issue with the hinges. if you could keep the door at the same electrical potential as the frame then it should not rust any faster than the frame does assuming that the frame is painted and galvanized the same way the door is. I AM presuming that all of the sheet metal is electrogalvanized. right?

"I AM presuming that all of the sheet metal is electrogalvanized. right?"

Negative. Cold rolled 18 GA, per ASTM A1008/A1008M; a stock door for me, and common in the door business. As stated, my customer (lumberyard) simply orders stuff for an undefined end user. I am only finding out now what the end use facilities are.

"ozone can certainly do that which would also argue against FRP doors as the ozone would attack them directly as well" Can you expand on this? In my thinking, the static charge within the steel door leaf is contributing to ozone generation (is this really what is going on?). Is this a misconception on my part? Will the same static be built up in the FRP door.

"if you could keep the door at the same electrical potential ..." If we can determine this (ground strap) will be useful, this will be my suggestion to the end user. I can't see how it would hurt, but I'd like to be confident that it is sound advice with some basis as opposed to a wild dart thrown at an unknown target, hoping for a score.

Ozone is being generated by electrical discharges and high electrostatic potentials in the switchgear itself and being trapped in the room. Ozone is well known for attacking most all plastics and causing them to crack and oxidize (because it breaks down to o2 and atomic oxygen. Atomic oxygen is about the most corrosive thing around. it will oxidize dang near anything.) FRP will become brittle in a high ozone atmosphere rather quickly.

I think if the doors had been made from electrogalvanized sheet they would be holding up better because the zinc would help to protect them, but that would only go so far. if you have a lot of stray current being induced in the doors that is not being bled off to ground effectively that could certainly contribute to the problem.

Negative. Cold rolled 18 GA, per ASTM A1008/A1008M; a stock door for me, and common in the door business. As stated, my customer (lumberyard) simply orders stuff for an undefined end user. I am only finding out now what the end use facilities are.

You're getting screwed here. It's like you're selling interior wall paint to a middle man, and he's telling people they can paint their swimming pools with it.

I ran through some substation design sites yesterday, and neither the coatings nor the structural, (door) materials are off the shelf stuff.

Good simile.

Yes, this sort of customer simply tells me what he wants, I very seldom get any real info about application or end use. It sometimes sucks to be a Doorman.

It scares me to death sometimes... these material brokers want to get involved in some very high-tech applications of access control and life safety, and they often simply parrot what the owner wants with no regard to practical constructability or model codes. I recently had a $4,500 door (sold to a lumberyard) get rejected by a building official after it was installed (I made it crystal clear, in writing, returned with the end user signature, this setup would not pass inspection anywhere in the U.S.). He wants a refund. Nope. He's upset, and he is not bashful about telling my boss he is upset. Boss told him nope. At least I got that backup.

It sometimes sucks to be a Doorman.

Hey, at least you get all the hot chicks.

Running OT here, but it sounds to me like you need to get into the retail business on the high end/odd application stuff. Either that or get them to sign off on all doors that are delivered in good condition, and make it very clear in the contract that that is the end of your responsibility. You can't be held accountable for installation errors, damage, wrong application..........................or anything else.

I think they're using standard doors with cheap oil based paint on them, in a place where they don't belong, and expecting you to eat the failures. F**k that!!!

I'm with K-man here. if they can't be bothered to check with you to see if the product is fit for intended purpose then you can't be held liable if it isn't. here is a tidbit that might give you a feel for what we are talking about here. in radiology labs where they have MRI machines, the edges of the doors and the thresholds and frames all have brass/copper wiping contacts on all four sides for two reasons. to bleed off any eddy currents being generated by that huge superconducting electromagnet (mind you the doors are not steel, they are copper clad wood/particle board.) just a few feet away, and to ensure a completely closed electrically conductive Faraday cage around the room.