Continues to be a good interesting thread…
CE compliance is still seeming to cause a bit of confusion in this discussion. The simple fact is, that anyone that is using a laser projector in a workplace. i.e. at an event etc, whether it is homebuilt or not, still needs to make sure it complies with CE marking requirements; Which in turn means making sure it has all the relevant engineering features as set out by the harmonised standard BS/EN 60825-1. The legal requirement is set out in PUWER(1998), one of sets of H&S regulations that are law in the UK. A laser projector being used in a workplace falls under scope of these regulations, (a point mentioned on our courseJ). When using a laser projector outside of a workplace environment, (i.e. as a hobbyist would) this legal obligation does not exist.
I would tend to disagree that HSG95 is useless. It’s actually deliberately been written to be non prescriptive on purpose, so that there is still some flexibility among its users. This is the preferred approach by HSE, rather than trying to write down strict ways in which something must be carried out. This is one of the main reasons that you would not have seen HSE publishing lots of ACoPs in recent times, as was once the favoured route a while back. What does need improving is Local Authority enforcement.
In any event, HSE and H&S must not be too overbearing. Which leads onto the subject of risk assessments, where there have been publicised cases of 12 page risk assessments being generated by organisations in relation to making a cup of tea. The main thing with a good risk assessment it that it identifies the main hazards, what the risks are, and who is affected by them, so that necessary control measures can be decided to reduce any unacceptable risks.
John O’Hagan’s example, (which actually as a couple of glaring errors in it if is just copied verbatim – Knowing John, probably deliberate, to see how people use it J!), is a good starting point, and covers many of the things that should be considered in a risk assessment. But bear in mind that there many different ways to do a risk assessment, and how to document the important findings, so don’t feel that you need to stick to how the example tackles things.
Thanks Paul for the comments about the course we run. I understand what you are saying, and would love to, but given the amount of material we have to cover during just one day, the example measurement with the Digital Storage Scope, Photodiode and Power Meter on the Laser Crab (deliberately chosen for the classroom environment), is about as much as we can physically fit into the day, after all the theory has been discussed. Before measurements can be confidently taken, the user needs to have a good grounding in where the various MPEs are derived from. Simply showing how to do a measurement or two without knowing the science behind what is being measured is fraught with pitfalls too. But with the theory presented, and the examples spoken about and shown, a definite grounding is in place for people to take it further, which I know happens.
The thing to remember about all of this, is that just going on a course, (however long it is), or just fitting a scan fail card, or using safety calculation software, or just buying a power or energy meter, etc, in isolation are not going to be the magic bullets to being able to instantly perform lasershows below the MPE. They are all tools that will help you to achieve that. Some people decide it’s simply too much work, and don’t bother with audience scanning. Others think the same, and just audience scan in any event, whilst some see that there are fairly straightforward ways to make audience friendly laser effects. …Everyone is different.
Kevin’s comment about me not attending the five day HPA course is a bit puzzling, and I’m not quite sure where it was supposed to be taking the discussion. But he should know that I’ve been on a number of laser safety courses, since the early nineties, including sitting the exam taught over a similar length of time by David Sliney in the US. The course also requires that every three years that attendees have to prove themselves by submitting details of safety work, education and training etc, in order to maintain the qualification. In addition to this, my experience is bolstered by a further good mix of ongoing projects, participation in various safety events, and formal qualifications in the wider H&S field. Our one day course has a strong emphasis on dealing with hazard that could result in ocular problems, reflecting the fact that 90% of HSG95 takes this approach, and attendees expect this.
I think the idea of the open source laser safety project is a great idea, and it pleases me to see such a good range of enthusiasm for this important topic. It’s probably worth working out some basic rules at the start though, to protect everyone and the technology against things going wrong. Things to think about would be; who owns the technology, both now and in the future? e.g. what happens if a someone uses the idea to make a commercial product? Will there be an open licence for people to do this? Will there be any comeback on those that contributed? What about any ownership rights of any of the ideas presented? Could you end up using IP that belongs to someone else? Pangolin’s PASS is fairly straightforward to exclude from this as the two detailed patent docs are freely available on the net, (I think Kevin has already mentioned about infringing Bill’s patents a bit earlier in the thread), but what about any other ideas? Will someone come crawling out the woodwork if they think their circuit has been used? None of these things are showstoppers, but probably quite important to have worked out.
Best regards
James Stewart