rigid conduits explosion proof?

[Kataeb]

are rigid conduits suitable for isolating electrical cables in an explosive area? it is a new factory with machines making solvent based ink. what do you recommend?

 

[rdrast]

The conduits are, if installed properly, with proper fittings.
Here is a bit from NEC about that, there are other related articles.

 

[Bit_Bucket_07]

are rigid conduits suitable for isolating electrical cables in an explosive area? it is a new factory with machines making solvent based ink. what do you recommend?

Yes, but you'll have to use approved explosion proof condulets, fixtures and sealants.

 

[shooter]

Simple answer is NO.
There is a need for ventilation otherwise the coduit can explode.

 

[kamenges]

I'm not sure what the ATEX ruling on that is. All the ATEX stuff we have done was either IS or was cable entry into and explosion proof housing.

In the US it is permissible to use rigid metal conduit in an explosive area as long as the correct fittings are used and all other applicable requirements of NFPA 70 Section 5 are followed. But that doesn't help you much.

Keith

 

[James Mcquade]

Kataeb,

Before anyone can answer your question correctly, we must know what type of ink and solvents you are referring to.
You must get with the manufacturers of the ink / design engineer / see the reactivity data sheets and see what the reactivity of the ink is with black pipe, galvanized pipe,
stainless steel pipe.

We had to use stainless steel piping when I was at a printing plant in Jackson, TN.

shooter,

I Disagree, Rigid conduit is acceptable.
The conduit fittings must be tight and the approved conductive paste applied. Explosion proof condulets and fittings are required. Seal offs MUST be installed within 18" of the barrier wall on the safe side of the wall and hazardous area to prevent any potential explosive fumes reaching the safe area.
This was required for our Class1 div 1 install.

regards,
james

 

[kamenges]

Guys, look at where the OP SEEMS to indicate he is from. I'm not sure the Class/Div system of NFPA Section 5 apply to him so I don't know that we can make an informed answer.

Keith

 

[James Mcquade]

kamenges,

You are correct in what you are saying, However; some solvent based inks require a good bit of thought in regards to the installation.
That's why i stated he needed to go to the engineers, manuafacturers and reactivity data sheets.

regards,
james

 

[GlenGineer]

As is the case with others I can only comment on the standards of the USA. Yet, unfortunately in this case I can't even comment on that I can only relay what inspectors have required of my company. Years ago, to make room for a new building, we replaced a 20,000 gallon propane tank with a 500. The emergency shut off controls were required to be rigid conduit with fire stop material injected into it. We were required to change it 5 years later. This meant replacing wire and conduit :angr: That was in the nation state of California not the Nation State I currently live in.

 

[kamenges]

James, I should have been clear what I was responding to. It was your reply to shooter. I don't think we have the information to make that determination.

GlenGineer, was is changed because of a change in the explosion proof rulings or because one of the materials in the construction was a newly discovered carcinogen?

Keith

 

[DickDV]

What's approved and what is not approved is entirely a matter of the local regulations. I doubt any of us can help the OP unless we are somehow intimately familiar with those local codes. Quoting North American or European standards doesn't help much, in my opinion

 

[GlenGineer]

"GlenGineer, was is changed because of a change in the explosion proof rulings or because one of the materials in the construction was a newly discovered carcinogen?"


No the inspector was concerned about remote cut off switches. We had a cut off switch at the propane tank but they required us to add....I think it was two remote ones.

 

[Kataeb]

unfortunately, explosion proof is not considered an important issue in our country. so to my knowledge we do not have any standard or real regulations for it. however to keep our system safe we usually follow european and american standards. it is only a matter of saving lifes and equipments. thank you all.

 

[James Mcquade]

kamenges,

you are correct, but when I worked with inks and solvents, we had to be careful.

Kataeb,
I understand your problem. We can only cite the US standards.
My point is that you need to pay attention to the data sheets, reactivity, and engineering specifications.

I worked for a printing press company and an equipment builder. At the printing company, we had highly explosive solvents. At the oem facility, we installed a paint change over system and the paint company rep said we could inject the cleaner while the electrostatic paint system was on. I called the company up and explained what their rep said. The rep was replaced the next day.

Some are tired of my experiences, but they are valuable lessons in safety.

Eventually, your company must decide what to do as we can only make recommendations.

regards,
james

 

[Kataeb]

what solution do you recommend for routing cables at right angle? the cable minimum bending radius is 200mm.
also, one of the machines has moving parts, so the cable should go up and down for one meter. how can we lay the cable in this hazardous location?
thanks