Do you know about COSHH??

[Basrad]

Hi all! (Control of substances hazardous to health (COSHH))

Know it’s a bit off topic, but I am currently doing some research into how COSHH has changed the way we work, or tasks we can complete with regard to electronics.

If you have any experience you might like to share with others it would be fantastic to hear them!

For example: Since COSHH was introduced in 2002, Lead based solder has been banned in most (legally all) work places. What is your experience with lead free solder? Does it do exactly as lead solder does? Does it limit your actions, skills etc.?

This could cover chemicals or processes such as PCB manufacture etc.

Many thanks for your time and input.

 

[westaust55]

I am currently doing some research

Might one ask what is the purpose of your research?
Hobby, Tertiary/Uni project or thesis, etc.

Secondly, it may have been better not to assume that everyone knows what "COSHH" is.
Yes we can Google and ascertain that it is the Control of Substances Hazardous to Health

 

[BeanieBots]

What is your experience with lead free solder? Does it do exactly as lead solder does?.

As with most other things such as petrol, they put the lead in for a reason.
Taking it out, compromises the performance.

Lead free solder has a higher melting point and results in a more brittle joint.
Don't know it compares electrically (ie joint resistance) but on the whole it's a step down mechanically and can cause overheating problems for sensitive components. It's harder to work with because it's wetting properties are not as good and it is a bit more viscous even when higher temperatures are used.

Besides all that, it still does the job but I'm already brain addled after years of working with lead and all my fillings have fallen out due to contamination so whenever possible, I stick with the leaded stuff.

 

[BillyGreen1973]

I'm with you BB,

I don't really like the lead free stuff, but I still have a LARGE stock of good old fashioned lead solder

The lead free stuff is used due to RoHS regulation introduced in UK in July 2006. RoHS prevents new electrical and electronic equipment containing more than agreed levels of hazardous substance from coming onto the market, and of course Lead is one of these substances.

I work with COSHH regulations in my job (school caretaker), but in my job they only relate to chemicals used for things like cleaning and adhesives. I'm not too sure how COSHH relates to electronic equipment, unless you are talking about manufacture.
In manufacturing electronic equipment, COSHH is a MAJOR thing, and has been for many years. All sorts of nasties are used to make components and PCBs (Arsnic, Acids, etc). How the restrictions have effected design and production is a big thing to cover!

I would contact the local health and safety office and ask their advice on where to look for specific regulations etc.

 

[hippy]

In industry the biggest impact of COSHH and related legislation has likely been the need to be aware of substances used, their risks, exposure limits, safe working practices, plus training, monitoring and enforcement of all that.

Other legislation, not directly related to COSHH, ties up with it and the desire to handle things more safely and in a less damaging way; for example WEEE.

 

[Basrad]

it may have been better not to assume that everyone knows what "COSHH" is.

My grandmother always said 'Never make assumptions' .

You'd be surprised the numbers of 'professional' that have no idea what COSHH or RoHS are / means, nor have the initiative to 'Google' it

This research is for a health and safety paper I’m putting together. None will be used for quotation, purely to generate ideas to look into in more depth. Thanks for the input so far. Does anyone have experiences of using etching chemicals?

 

[matherp]

Manufacturers building aircraft avionics have a waiver from ROHS - nuff said

 

[Basrad]

When I was at school, we were allowed to make PCB's using acids and development chemicals. Lead solder was the only solder we knew, and working on 240V was not an issue -Which MUST NEVER be done these days.. Do you think these restrictions have a negative effect on the learning of electronics subjects and the way that practical skills can be learnt? (Students learn about PCB manufacture, but are restricted in many cases of actually conducting the process)

 

[bgrabowski]

I never bought lead-free solder for my pupils to use and do not personally know of any UK school that does. Perhaps a few started to use it but, as leaded solder is still readily obtainable, I suspect that most would by now have gone back to using leaded. The risk is minimal with good ventilation and sensible practices. The hazards of soldering I worry about are skin burns and flux in the eye.

 

[BillyGreen1973]

I too developed/etched pcb's at college, used 240v in experiments and used lead solder.
However, I wouldn't say the restrictions have a negative effect on learning electronics. The principles of electrical circuits etc will always be the same, and as for the practical side, todays students are learning todays methods of production. So in some ways they have an advantage of not knowing how it used to be done, so they will be thinking and designing PCB's etc within the new guidlines right from the start.
I'm sure the tighter restrictions mean students today may not get to 'play' with PCB production chemicals etc as we did, but I'm sure thay will still produce their own PCB's and learn the proccess involved as they go along.

Ha, who can forget the first time Ferric chloride burns a hole in your jumper! Those where the days....

 

[Andrew Cowan]

I'm now at University, but at school a few years ago we used lead solder, and made PCBs ourselves using ferric chloride etc.

Exam boards no longer allow any 240v project to be submitted as coursework (due to safety reasons), and exposed 240v is not used in any taught materials any more - that seems to be the only change to education.

A

 

[hippy]

Do you think these restrictions have a negative effect on the learning of electronics subjects and the way that practical skills can be learnt?

Personally, not really. It's a philosophical question; is preventing exposure to risk harmful or beneficial, and practical; what level of exposure to risk is acceptable and appropriate.

 

[Dippy]

I hate lead-free solder wire and paste for all the reasons given above, but there we go.
I have noticed quite a range of performances/behaviours of lead-free solder, but generally a pain compared to leaded.

COSHH , MDHS and RoHS have had a huge impact on production in electronics, much of it for the better I'm sure.
We should all be on a level playing field, but I'm not sure if some of the village factories in China comply or even care ....

"Do you think these restrictions have a negative effect on the learning of electronics subjects and the way that practical skills can be learnt?"
- I really wouldn't know. If you want numbers and facts rather than opinions you may have to ask Educational Authorities or teachers if it has affected the choice of schools whether or not to offer it as a subject.
I'd be surprised if it had affected the desire of a student to apply for the course.

Then again , in my days at school (80s) we actually dissected rats, mice and smelly old fish in A level biology... maybe the kids or parents more mamby-pamby than they used to be? (To all the right-on dudes; I'm just kidding.)

 

[szd51pilot]

Home construction is exempt from the requirements of the RoHS Directive. Medical equipment (Class 8), monitoring and control (Class 9) are also exempt, as is equipment for military purposes.

RoHS2, which is expected to come into force in 2014, will remove the Class 8 and 9 exemptions but I believe that the exemption for military equipment will remain. Hopefully the exemption for home construction will remain.

Below is a quotation from a recent SMART (Surface Mount and Related Technologies) Group e-mail

“After first proposing amending the RoHS Directive in December 2008, the European Commission announced that the Parliament had voted to adopt a final compromise text on November 24th 2010. The most significant impact of the changes will be bringing all ten EEE categories into scope (that is, now including ("Medical Devices" and "Monitoring and Control Instruments") and the creation of an additional "catch-all" category to include all other EEE not mentioned elsewhere. Plenty of manufacturing organisations that have not had to worry too much about RoHS now have to look at the law with renewed interest.”

 

[papaof2]

A catastrophic event that can be traced to lead-free solder - "The auto-pilot caused the 797 aircraft to enter straight-down mode because of an intermittent connection. This bad solder joint problem has been verified on all other AUP100x series devices that have been in service more than 1400 hours." - is probably the only thing that will get reliable solder back in the mainstream. There's enough sue-mania in most of the world for one event to keep the courts full for years and to get members replaced in the various rule-making bodies. *Potentially* harmful substances aren't likely to win out over real litigation.

FYI, they still make lead-acid batteries in the US and that's done with large quantities of pure lead. The workers in the smelting plants wear protective clothing and use respirators, but that gear is similar to what you'd find at a paint shop that uses paint with highly volatile solvents. The lead levels in a smelting plant are many times higher than in even the largest wave soldering operations (the workers there have minimal exposure) and the risk for the users of products assembled with "real" solder is too small to measure. Lead-free solder appears to be another knee-jerk reaction to misinterpreted bits of information.

My inventory of real solder was just updated. I have some prototype boards to assemble which wll see severe service (training device to be mounted in a vest on a dog).

John

 

[fernando_g]

I used to work in a large manufacturing facility of a large corporation when the RoHS directive became effective...... It was an unmitigated nightmare converting all the BOMs to RoHS equivalents just by the sheer number of components involved; and by the fact that some component vendors decided to obsolete dozens and dozens of low volume components and suddenly one was faced with a bunch of obsoletes where substantial circuit modifications were required.

The problem was compounded by that two-letter, ink-and-paper company, of former High Performance fame; which insisted that any RoHs replacement to be fully re-qualified even if the change was a straight resistor swap.

It is over now, but it was a difficult, and very expensive excersise.

 

[hippy]

A catastrophic event that can be traced to lead-free solder - "The auto-pilot caused the 797 aircraft to enter straight-down mode because of an intermittent connection. This bad solder joint problem has been verified on all other AUP100x series devices that have been in service more than 1400 hours." - is probably the only thing that will get reliable solder back in the mainstream.

Though acknowledging a bad solder joint that statement by itself does not state that the bad joint was caused through using lead-free solder. You may be right but we'd need an authoritative source.

Bad solder joints existed with lead-based solders and were involved in plane crashes going back to 1983, the "Gimli Glider", and probably earlier

 

[Dippy]

Yes, it's a bit tricky to condemn a bad joint to the solder material without an expert opinion.
It could have been down to incorrect/unsuitable soldering techniques or training.

Nasty old lead fumes.
I haven't time to Google but , as we all know, there is considerable evidence about health and lead fumes with leaded petrol. How do atmospheric concentration figures compare with soldering assembly lines etc.?

My favourite knee-jerk (emphasis on 'jerk') nannysyndrome is the amusing sight of seeing Civil engineers and chums wandering around the middle of a field with hard-hats and toe-tectors on.

 

[BeanieBots]

Manufacturers building aircraft avionics have a waiver from ROHS - nuff said

Same is true for medical equipment. (but comming soon).
Interesting that in areas that are 'critical' these legislations don't apply!

 

[hippy]

Same is true for medical equipment. (but comming soon).
Interesting that in areas that are 'critical' these legislations don't apply!

Not really, and as you say it is coming soon.

It's wrong to take 'allowed in some circumstances' to lead to suggestions it is inferior or not suitable in others. There can be many reasons why legislation did/does not apply to various sectors, from caution ( warranted or not ) to simple lobbying or public opinion.

Just because military and medical equipment is exempt does not mean those entire industries have steadfastly avoided lead-free solder, ardently allowed only leaded to be used as 'the only safe thing to do'.

Those industries have had a period of time to try and test lead-free solders, while allowed to use lead-based, and if it were entirely unacceptable there would be a far greater outcry about changing.

 

[BeanieBots]

It's because the change over is very expensive, requires extensive testing and in many cases IS inferior. That doesn't mean it shouldn't (or can't) happen but that the authorities accept it is not as simple as just changing over. The rest of industry simply has to "get on with it" because they've been told to.

 

[matherp]

Companies in avionics did change over and then had to change back following repeated failures in the field. Now this may be that they didn't have enough knowledge of using non-lead products, although these were not beginners in electronics, but it is clearly the case that non-lead is harder to use reliably and therefore more prone to unacceptable results.

 

[geoff07]

One of the problems with lead-free solder is the high tin content and the crystalline 'tin whiskers' that grow and short things out. NASA lost at least one satellite due to this and have a web site that explains it all. This is why, for example, you won't find many new old stock transistors in the TO-7 encapsulation e.g. OC171 that still work. If you want your stuff to last 30 years (not much chance of that I grant you) don't use it.

Take a look here http://nepp.nasa.gov/whisker/background/ if interested

 

[Dippy]

Well I never... I'd never heard of this before.
So it is my turn to Google.
I see it's not just confined to tin solder but tin plating too.
Inadvertently , and I usually spec (made in UK) production boards with silver plate, I wonder if that helps?

I can't find much real scientific info. , so where does this tin migrate from to form the whisker?
Is it affected by certain temperatures or atmospheres?
Is it slowed or halted by non-tin plating or conformal coating or hermetic sealing?
I can't find any mention of time scales either - i.e. rate of growth.
I'd love a link rather than a guess...


If these whiskers are so common how come electronic failure isn't really so common.
The rumours are of growths of a mm and greater. Well that means that just about every modern-ish chip is vulnerable.
Very interesting and worrying.

This was interesting re: reflow (haha)
http://www.ems007.com/pages/zone.cgi?a=60261&artpg=1

 

[hippy]

One of the problems with lead-free solder is the high tin content and the crystalline 'tin whiskers' that grow and short things out. NASA lost at least one satellite due to this

Lost a satellite due to 'tin whiskers', or lost a satellite due to tin whiskers as a result of using lead-free solder ? With a quick skim of the web page it wasn't clear.

I'm always a bit caution with 'NASA says this' or when other experts are being cited, especially when that isn't exactly what they are saying; as notably happened with battery Memory Effect. It's not a matter of fact or fiction - Memory Effect is real as NASA noted - but more a case that fact got translated into what became more fiction than fact.

 

[Dippy]

I never heard of a Shuttle load of astronauts with magnifying glasses going around inspecting PCBs , so I was wondering about how the conclusion was arrived at. Maybe they did?


Then when I clicked the link from the NASA link I got confused:-
http://nepp.nasa.gov/whisker/failures/index.htm#satellite

"The following commercial (non-NASA) satellites have reportedly suffered on-orbit failures of their satellite control processors (SCP) due to tin whisker induced short circuits where the whiskers grew on pure tin plated... "
- so, that's 100% blame the whiskers. And a number of sites blame the plating as much as the solder.

Then, just 2 lines below, with not quite so much confidence :-
"Suspected Root Cause = Tin Whisker Induced Short Circuit "
- mmm , starting to hedge our bets a bit....

Will the next table have the title:
"A bloke down the pub said it was Tin Whiskers but he'd had a few pints"

Bless 'em

Also, with the fettish towards acronyms, will we be calling this a "TWISC" event soon?
And maybe some of these alledged faults are due to Tin Whisker Attribution Tendency ?


That NASA website says that little is known about the mechanism of growth.
If this is really such a problem involving failures in the £$billion ranges , then surely NASA or Murdoch would be happy to pay a coupla million for a few PhD Chemists to do a 2 year research programme?

I genuinely would like to know.

 

[slimplynth]

Like Chromic acid, used in aircraft manufacture.. to anodise parts.. this is not on the naughty boy list for REACH as yet.

I guess that has to be in part due to the sensible actions of the likes of Airbus etc... to change and re-qualify a process on that scale - eek! They are looking at Tartaric/Sulphuric options but info is only slowly coming out.

 

[geoff07]

I grant you it is a bit hard to do a post failure analysis when the failure is whizzing past your head at 17,000 mph. And it is true they don't know the mechanisms. But it does seem the case that high tin content materials have the problem. Unfortunately it isn't just tin apparently. I would imagine it is quite easy to get a research grant on this one right now, so maybe we will learn more in due course.

I'm not sure NASA are accusing lead-free solder. Just high tin-content alloys. Of which LFS is one. QED.

More than half of the batch of NOS OC171s that I bought to restore old Eddystone radios were dud; I am convinced by NASA photomicrographs I have seen that this was a reason. And may well be why the radios needed fixing in the first place. Sadly the circuits were designed for germanium trannies so it is surgery to convert to silicon, best avoided.

 

[Dippy]

It appears to be quite a serious potential issue.

I do feel uncomfortable when certain bodies assume a failure is due to a certain thing without actual evidence.
It kind of reminds me of the Millenium Bug panic , but I'm not knocking the reality.

Nonetheless, with the evidence to date, wouldn't it be better if any manufacturer of safety critical electronic equipment was exempted from Tin solder and tin plating discouraged?

With a little nerding I have just seen several things about research grants and also blaming some of Toyota's woes on TWs.
http://www.thetruthaboutcars.com/2010/02/tin-whiskers-implicated-in-unintended-acceleration-problems/

You'd have thought that at the ripoff prices of car electronics that the extra 10p for silver plating could be afforded.

An interesting subject and it goes to show that (with 20:20 hindsight) pennypinching on plating doesn't count.
Anyway, I'll leave it there.

Apart from: blimey, everything seems to whisker. I guess we'll just have to choose the slowest/smallest