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Posted By Topic: explosive atmospheres regs

Mar 26 2018 17:58

Saw this in another topic

I\'m after a beginners guide or a place to start reading.

Where does this apply etc

Mar 26 2018 18:51

there is a \'beginner\'s guide\' here:
This is quite a specialised (and well-paid) area to get into.

Mar 26 2018 19:33

In New Zealand there are two regulatory areas requiring zoning. The Electrical Safety Regulations mandate compliance with AS/NZS 60079.14 for any installation using electrical equipment in an explosive atmosphere. For this, any such facilities must be classified in accordance with AS/NZS 60079.10.1 where a flammable gas or vapour is involved, and with AS/NZS 61241.10 where a flammable dust may be present. AS/NZS 61241.10 will be replaced at some stage by AS/ NZS 60079.10.2.

Mar 26 2018 19:42

I can\'t find AS/NZS 61241.10 in standards NZ via EWRB?

Mar 26 2018 21:15

Just for interest, if gear was installed before a certain date it is allowed to remain in service?

Mar 27 2018 08:01

Only if it complied when installed, and isn\'t electrically unsafe [ESR 113]

Mar 27 2018 12:00

That Flashpoint document is really quite old now.

AS/NZS3000-7.7 gives you the standards applicable to start with; amendment A2 replaced the 61241 standards mentioned in the article.

Mar 27 2018 12:02

I would add that for old gear it should also have been maintained in accordance with manufacturers instructions. This should be considered when determining electrically safe or not.

Mar 27 2018 12:52

I\'m going to be pedantic here because this issue trips a few people up...
You\'re not trying to determine \"electrically safe\", you\'re trying to determine \"not electrically unsafe\". Most in-service items are neither \"electrically safe\" nor \"electrically unsafe\", but are somewhere in between.

Mar 27 2018 13:17

And if not maintained you can put it squarely in the not electrically safe cubbie.

Mar 27 2018 13:58

As I said, you\'re not trying to determine whether it\'s electrically safe. Knowing that\'s it\'s not electrically safe doesn\'t tell you whether it\'s electrically unsafe, and that\'s what\'s important here.

Treating electrically unsafe and electrically safe as though they are simple opposites (if it\'s not one then it\'s the other) is like saying if a tool is not as fresh as the moment it came out of the original packaging (equivalent to safe) then it\'s broken (equivalent to unsafe).

Mar 27 2018 14:24

Andrew - I ment to say \"puts it sqwarly in the electrically unsafe cubbie\"

In this case.

Not in all cases.

bu in THIS case:
Old (possibly certified to a regime no longer accepted), and not maintained in a designated hazardous area = unsafe (both electrically and theoretically)

Mar 27 2018 14:38

Sorry, the trouble with being pedantic is it can lead to misunderstandings over typos :)

Mar 27 2018 21:36

In my case i\'m just talking about dust


\"Electrically unsafe means, in relation to works, installations, fittings, appliances, and associated equipment, that there is a significant risk that a person may suffer serious harm, or that property may suffer significant damage, as a result of dangers arising, directly or indirectly, from the use of, or passage of electricity through, the works, installations, fittings, appliances, or associated equipment.\"

I\'m guessing even if equipment was installed maintained and compliant from the 60s or whenever we know its not going to be safe in certain factories.

How do we know if its unsafe?

How do I measure when the dust level gets to an unsafe level?

There is dust everywhere?


Mar 27 2018 21:42

The dust everywhere thing is not so much of a problem unless everywhere includes inside the equipment enclosures that are supposed to be dust resistant.

It depends on what the dust is. Not all dust is flammable / explosive.

Does the site have a compliance dossier? This should also have the original Zone drawings.

Mar 28 2018 07:01

\"Does the site have a compliance dossier? This should also have the original Zone drawings.\"

I have no idea what \"compliance dossier\" is or \"Zone drawings\" is/are?

Mar 28 2018 09:14

Download yourself a copy of ASNZS 60079:14 it should be available through your Standards Link with EWRB. Have a read through it , you can learn a lot from that.
Sounds like you are looking at an old plant somewhere, the first thing I would be doing is establishing if a hazardous area ( explosive atmosphere ) actually exists. Was it ever set up as such originally , or is this something that has developed over time.
As Sarmajor said not all dust is explosive.
You could get an idea from the existing equipment if the area has been set up as a Hazardous area.
Many old buildings such as Grain stores or flour mills etc used the best fittings at the time they were done , these fittings certainly would not comply with the new rules today.
A hazardous zone requires a four yearly inspection so if the site has any paper work at all and the owners are aware that it is a hazardous area then that\'s a great place to start as well , if they don\'t have anything ( and many old places don\'t, then you really have to start at the beginning which is actually establishing what and where the hazardous zones are , if they exist at all.
This is best done by someone who is familiar with the zoning process.

Mar 28 2018 10:15


I now have some knowledge

Before the thread I had no idea, I don\'t recall any information on the topic at our electrical refresher coarse? or my electrical training 25 years ago.


Mar 28 2018 12:24

It\'s a specialist area. Refresher courses are highly unlikely to cover it and even if your training touched on it 25 years ago it would pre-date the NZ use of 60079 standards (although 2381 covered some similar ground).
You can do specific training in explosive atmospheres through polytech or industry courses, but all you really need to know for normal registration is: 1) There are situations when special rules apply. 2) If you are in these situations or you\'re unsure, call in a specialist. 3) If you\'re working on a hazardous zone follow all instructions to the letter - including the requirements to get it verified.


Mar 29 2018 13:10

What kind of Dust in this \"factory\"?


Mar 29 2018 16:04


I also wonder about sawmills, Fertilizer plants.

Mar 29 2018 21:41

Grain - has great potential for explosion. Would highly recommend an expert assessment.

Almost certainly inside process. >5mm on rated equipment is too much and large areas of very thin layers is also to much to maintain a \"safe\" environment for workers.

Sawmills - Can be, wood dust in perfect conditions will explode. Depends on moisture content and particle size of the dust. Generally smoulder capable with enough heat but dry fine particulate has potential.

Fertilizer plants - Not aware of any. Perhaps for some of the batch materials but the bulk products shouldn\'t?

Mar 29 2018 21:42

Grain gone wrong

Mar 29 2018 23:09

Fertilizer Plant Explosion In West, Texas