Static shocks everywhere in the building! - Page 1
Forum section: electronics / projects

author: GoatZero
author_rank: Regular Contributor
timestamp: April 11, 2015, 01:19:35 am
content: I just came from the local library, it’s quite big, and most of it is made of an architectural design using mostly painted metal book shelves painted with some kind of anticorrosive paint along with glass floor all over the place, everything was fine and nice, until I started to get static electricity shocks around every single book shelf (yes the painted ones) in every floor almost all the time I took around 13 shocks in less than 20 minAs you can see most of the metal structure it’s joined by huge bolts (screws) so there is continuity all over the place (I checked) also there is a possibility to the metal structure to be joined to the structural studs of the buildingI’m trying to find out how is it possible to "fix" something of this magnitude As an antecedent I installed an antistatic mat in my own home lab, along with the nonexistent at the time grounding rod and wiring across all the home, I do know antistatic mats have a huge impedance that “slows” the flow of current to mains earth while it discharges the body slowly to protect electronics of voltage differences between the desk, user and electronics, being at the same potential, like in the following pictureMy theory for the library is that the users being insulated of earth and by being walking around a glass floor, are generating static electricity just by walking with their clothes on, the electrons find no way to discharge around the glass and as soon as they touch any metal book shelve they get discharged, there’s a chance of the system being grounded to mains earth, but as I recall a door knob can shock you like this even by not being grounded so I’m not sure, and a bit confused nowI’m thinking on several ways to solve this1) The first idea that came to my mind was to to an arragement like an antistatic mat, add a 10MOhms power resistor to join the book shelves in several points to mains earth, this “might” slow the current flow of electrons and no shocks will be sensed, however my common sense tells me that the mat itsle fhas a high impedance unlike the book shelve, this might work to slow the flow across the resistor but it would make nothing for the user that will still get shocked due to the low resistance of the metal book shelves and THEN it will be slowed down across the resistor2) Second I thought of painting the shelves but then I noticed they were already painted and the shock were happening even above the painting3) I thought about looking for the bounding point to mains earth and, leave the metal structure as a “floating circuit” with no connection to mains earth, but this might get complicated since as i said before the metal structure might be touching the internal building structureAnd from all this possible solutions, several questions arise,a) Can static shocks occur from grounded and ungrounded metals?b) How do you prevent getting zapped when everything around you is metal and glass floors?c) What is the worst case scenario if I unbound the metal structure from mains earth? (Not contacts, nor lighting rods, just make sure to leave the metal book shelves ungrounded), will the user still get shocked?

author: NiHaoMike
author_rank: Super Contributor
timestamp: April 11, 2015, 01:23:32 am
content: Does the HVAC system use electrostatic air filters? Those work by charging up the air.

author: Marco
author_rank: Super Contributor
timestamp: April 11, 2015, 01:38:01 am
content: A simple google will show that glass floors are infamous for producing static electricity (in combination with your shoes through triboelectric effect). Short of installing rails so you can go everywhere wearing an earthing strap or coating the glass there is no true solution. Higher humidity would help a little, trying to wear different types of shoes could help a lot too (polyurethane tends to be good against static, but on glass it's bad).

author: jlmoon
author_rank: Unknown
timestamp: April 11, 2015, 01:46:03 am
content: When you're in that library, just imagine you're inside a giant Leyden jar. One giant high voltage cap.

author: Smokey
author_rank: Super Contributor
timestamp: April 11, 2015, 01:54:19 am
content: That library is amazing! Is the Ark of the Covenant in there somewhere? It almost looks Photoshopped.To quote Ghostbusters..."Nobody ever made them like this! I mean, the architect was either a certified genius or an authentic wacko!"

author: IanB
author_rank: Super Contributor
timestamp: April 11, 2015, 02:01:50 am
content: That library looks like the inside of a Borg cube! Is it a university library?As for the static, you can't really fix the structure, you need to fix the person. Walking barefoot would help, but the library rules may take exception to people not wearing shoes. The next best option would be to wear leather soled shoes or sandals. Avoid rubber soled shoes as they will insulate you and allow you to build up a static charge on your body.

author: pickle9000
author_rank: Super Contributor
timestamp: April 11, 2015, 02:16:20 am
content: Quote from: jlmoon on April 11, 2015, 01:46:03 amBetter yet, dress up as a borg and go zapping everyone.

author: GoatZero
author_rank: Regular Contributor
timestamp: April 11, 2015, 05:01:40 am
content: Quote from: NiHaoMike on April 11, 2015, 01:23:32 amI have no idea, i will actually have to find out, im pretty sure the building was made with the idea in midn to make it eco friendly so i suspect it does not have HVAC system, i will find out tho...Quote from: IanB on April 11, 2015, 02:01:50 amits a public library in Mexico City, it was made in 2008, look for biblioteca jose vas concelos in google images if you want to see more, when you are there its actually a breathtaking libraryI have reading most of the posts and reading more about the theory that has been posted, it all makes sense now, from what all i have been reading If static electricity only becomes an issue after the building is completed, the approach becomes one of ‘damage limitation’ rather than a full solutionLeaving me with very few options that might include humidity control, antistatic sprays or coatings, floor coverings, antistatic mats, air-ionisers, carpet treatments and replacement or modification of fixtures and fittings.the easy way would be to paint the entire floor with conductive something to keep you from building up a charge on your body or place some antistatic mats all over the place, but this would rape the visual aspect of the librarythey need to keep the humidity really low so the books don't mold. so the air is really dry causing static charges to build upThe most reasonable (and profitable) thing would be to get a little 'we're sorry our architect was a ponce' basket and sell static dissipators at the front desk out of it for a small donation.any other ideas or techniques would be nice to have, at leas now i know how not to build my house

author: bitwelder
author_rank: Super Contributor
timestamp: April 11, 2015, 07:02:55 am
content: I wonder if it would be possible to have conductive mats placed only at section 'ends': arches, room entrances, end of book isles, stairs, etc. so that they won't impact too much visually, and they might help also in stopping dirt to spread around.Not sure how that library is used on average, but perhaps a proposal at the entrance for the visitors like "leave your boots here and borrow a pair of relaxing clogs/sandals(*)" might work(*) conductive, of course

author: Mechatrommer
author_rank: Super Contributor
timestamp: April 11, 2015, 07:11:12 am
content: that is a good news, you can tap free energy from there.

author: ataradov
author_rank: Super Contributor
timestamp: April 11, 2015, 07:34:12 am
content: What library is this? Are there more picture of it? This looks amazing.

author: mikerj
author_rank: Super Contributor
timestamp: April 11, 2015, 09:33:03 am
content: Quote from: bitwelder on April 11, 2015, 07:02:55 amConductive ESD shoes only work properly when combined with a conductive floor, otherwise where can the accumulated charge go?As someone previous mentioned, this is a triboeletric problem. Glass gives up electrons very easily when rubbed with most materials, accumulating a positive charge. To minimise this you'd need your shoes to be made from a material very close to glass in the triboelectric series e.g. leather,rabbit fur, asbestos (probably not the best choice!).

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 11, 2015, 09:48:36 am
content: That looks awful! -- I should say, the visual is stunning, dizzying even; but I have to wonder how practical such designs are. A classic case study was, a new German school building I think, which had this type of open design -- the classrooms opened right into the common space, and absolutely, positively no one could hear a thing over the noise coming from everywhere else!But perhaps it's not as bad. The carpet flooring will help dampen some sound... but not static shock, as you have noted.The best solution would seem to be, get them to install humidifiers. Which may also be healthier for the books (dry paper cracks more easily). I suppose in the heart of Mexico, in a huge building, this may not be the easiest or most economical solution, though!Discharging yourself is the only other solution, yes. Carry around a metal implement so that, when you do zap the railing, the current is distributed over your hand, rather than in your fingertip. You will still get a spark, but you won't feel it (as much). Or use a high value resistor, so it is discharged more slowly (a 1M+ resistor may still spark, but it won't be noticeable, and will discharge you quickly). Or try to walk around while holding onto the shelves or railings (may not help if the paint is a good insulator).Tim

author: Marco
author_rank: Super Contributor
timestamp: April 11, 2015, 11:45:24 am
content: Nylon is a very common material and close on the triboelectric series ... get some nylon tape and cut some hexagons out of it and stick em under a set of cheap shoes?

author: Kalvin
author_rank: Super Contributor
timestamp: April 11, 2015, 11:52:51 am
content: - Excuse me, I am looking for a self-help book about vertigo ...- Ah, you may find it in the top floor, top shelf, near the railing.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: April 11, 2015, 11:55:14 am
content: ITO coating on the glass floor? Could be a bit expensive though...

author: Psi
author_rank: Super Contributor
timestamp: April 11, 2015, 11:56:51 am
content: Quote from: Smokey on April 11, 2015, 01:54:19 amIt looks like that scene at the end of the movie Interstellar.

author: amyk
author_rank: Super Contributor
timestamp: April 11, 2015, 01:29:42 pm
content: Wear anti-static strap around your ankle(s), connect the discharge wire to a 10M resistor and leave the other bare end dangling on the ground, maybe with the strands spread out to increase the surface area. It might get you some odd looks though...

author: TimFox
author_rank: Super Contributor
timestamp: April 11, 2015, 02:00:04 pm
content: Back in my college days in a dorm, with carpeted floors and very dry winter air from central heat, I always carried a 10k/0.5W carbon resistor with me to touch the metal doorknobs as I walked down the hall. Otherwise, I built up a huge charge before I hit the doorknob at the exit.

author: ajb
author_rank: Super Contributor
timestamp: April 11, 2015, 03:16:49 pm
content: Carry around a 1M resistor, hold one lead and touch the other to any metal object before touching it with your bare hand. With a little bit of metal tubing, you could even make yourself a nice little 1M keychain to keep with you at all times.

author: Zero999
author_rank: Super Contributor
timestamp: April 11, 2015, 04:02:35 pm
content: The climate is probably also a factor. The OP said there's probably no HVAC, probably because (according to Wikipedia) Mexico city's climate is warm and dry most of the time but not extremely hot.https://en.wikipedia.org/wiki/Mexico_City#ClimateNow is probably the worst time of year as the relative humidity is lowest. Spraying the floor with a dissipative coating an installing a humidifier may help.

author: SeanB
author_rank: Super Contributor
timestamp: April 12, 2015, 08:23:29 am
content: Wash the floors with a static dissipative cleaner, you can use simple liquid fabric softener in water to do this, it works well to leak the accumulated charge away, and also as the floors likely will be regularly mopped it will be replaced as needed. You do not need much to get the thin film needed to keep the floor static down.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: April 12, 2015, 09:29:13 pm
content: If the static is bothering the staff and other patrons of the library as much as it bothers you there may be enough demand to purchase and use anti-static coatings such as Staticide.http://www.aclstaticide.com/antistatic_coatings.htmlThis is just one example, there are others on the market.I don't know the aesthetics of this or similar materials applied to a glass floor, but do know that it will require repeated application to remain effective. In shops where I have worked the interval was quarterly, but that was on different materials and different use patterns.By the way, very nice library to look at. Hope it is as good to use as it is to look at.

author: max666
author_rank: Frequent Contributor
timestamp: April 12, 2015, 10:39:56 pm
content: Quote from: SeanB on April 12, 2015, 08:23:29 amI was going to suggest the same thing, because getting a fixed anti-static coating on already installed glass is probably next to impossible, expensive and most like won't last very long, but using a detergent with anti-static additives or adding such additives to your regular detergent seems simple to me.Or you could carry around an air ionisers, which I thought would make a nice joke to unload a charged situationuntil I found out ASUS made a laptop with integrated air ioniserhttp://www.asus.com/Notebooks_Ultrabooks/N51Vf/

author: aveekbh
author_rank: Regular Contributor
timestamp: April 13, 2015, 04:38:25 pm
content: A technique I use is to firmly grab my keys on one end and let the spark jump from the tip to any metal surface. That way, I dissipate my charge without feeling the zap.Another idea I could think of is to wear conductive gloves - not too conductive though, like an ESD mat.

author: SeanB
author_rank: Super Contributor
timestamp: April 13, 2015, 07:20:11 pm
content: When I go to Makro in winter, I always look for a trolley with a grounding chain on it, as the others have a bad tendency to build up a massive charge as you push them, and this belts you when you touch other than the insulated PVC handlebar. Otherwise I just drive it bumper car style, and aim to hit every shelf I go near to discharge to the metalwork. You get a spark every time then. I do use the keychain method as well to discharge if I am going to touch the trolley, hooking my finger through the ring and using the dangling keys.