# Powering solenoid valve in hazardous area

1. Aug 5, 2009

### jesse69

Hye everyone~

I am Jesse and i'm new to this forums and i really need your help

so lets get straight to the prob..

can anyone tell me what are the choices i can use if i want to power up a solenoid valve installed in a hazardous area. I've heard about powering it thru system loop, using those MRO and digital output board, but i don't know in details what those MRO and DO board does exactly and how those 2 differs.

So anyone?

thank you :tongue:

2. Aug 5, 2009

### rolerbe

Check out PeterPaul http://www.peterpaul.com/" [Broken]. I've only used their products once, but found them to be very well engineered.

Last edited by a moderator: May 4, 2017
3. Aug 5, 2009

### Staff: Mentor

Welcome to the PF. What kind of hazardous are are you talking about? Do you mean hazardous because of high voltages? Or hazardous because of a risk of explosion?

4. Aug 6, 2009

### Mike_In_Plano

You might try using pneumatics. In the semiconductor industry, the gas cabinets use a great many pneumatic solenoids. You can get gangs of controllers and even get 1/8" color-coded hose. As I recall, Festo sales this type of equipment.

- Mike

5. Aug 11, 2009

### jesse69

hello again everyone~

Thank you so much for all the pointers..really appreciate it

to berkeman: hazardous area i'm referring to is hazardous coz of explosion risk...coz i work at a chemical plant..and the solenoid valves need oni 24VDC of power supply.

6. Aug 11, 2009

### Staff: Mentor

Then you are referring to Intrinsically Safe (IS) design practices:

http://en.wikipedia.org/wiki/Intrinsic_safety

This is not something to be undertaken lightly, or by someone who has no experience with it yet. Obviously the consequences of a design error can be very bad.

Do you have a professional EE there who has IS experience?

7. Aug 11, 2009

### dlgoff

You will probably need to have an explosion proof enclosure something like this for you control electronics: http://www.oempanels.com/alarm.htm?G_NEMA7&gclid=COWdvanVnJwCFSYoawodyVnlOQ" [Broken]
If you need help at your plant, you could always call on these guys to help: http://www.ul.com/global/eng/pages/offerings/services/hazardouslocations/" [Broken]

Last edited by a moderator: May 4, 2017
8. Aug 11, 2009

### vk6kro

Just running 24 volts into a hazardous area isn't a problem.
The risk comes from sparking.
So, as long as the switching takes place outside the area it should be OK.

A solenoid doesn't produce any sparking unless it is part of a relay which has switches on it.
A solenoid that mechanically operates a water valve, for example, would be fine.

We had someone design a "safe" area for storing organic chemicals. It had special $2000 power outlets (but we couldn't afford the$1500 plugs to go with them).
Also in the room was a gas outlet for a bunsen burner!

9. Dec 9, 2009

### db444

Its is a problem! you dont know the ignition temperature of the hazardous area. Sparking alone it not the only case of igntion, also the equipment needs to be certified. Your recommendation is illegal - dont give advice if its not your area!

db44

10. Dec 9, 2009

### vk6kro

As I said,
Just running 24 volts into a hazardous area isn't a problem.

If you generate heat with it, sure you could start an explosion.

How would you suggest you could start an explosion just with 24 volts not connected to anything?

11. Dec 9, 2009

### db444

Well firstly where would you run a cable when the solenoid is in the hazardous area?
And yes the cable itself is a source of ignition becuase if you get a fault it can cause heat, a faulted cable could cause ignition through energy release. There are also rules for cable types for different hazardous areas.

db444

12. Dec 10, 2009

### vk6kro

I don't think anyone even discussed the type of wire to use. You would use wire that was suitable for the job. And you would get it wired so that there was no chance of a fault, obeying local regulations.

We didn't even find out if the solenoid was being used to switch electrical circuits or if it was being used to operate something mechanically.

A solenoid being used to switch something electrically would be called a relay, but this term may not always be used.

By all means contribute to this discussion.
what are the choices i can use if i want to power up a solenoid valve installed in a hazardous area.

13. Dec 10, 2009

### db444

Hi vk, thanks for the reply, My reply was related to the wrong advice being given but I will also contribute to the original question

Yes use wire suitable for the job but that has to be chosen, the type of wire would also depend on the protection method Ex d or IS. This differs from the reply given. Also
wrong! all cables have to be designed for faults and the fault may be equipment connected to the cable and not just cable damage itself. What about the let through fault energy, this is a source of ignition?

Does not matter, you are still wiring and introducing energy into a hazardous area either as a relay, solenoid or cable.

By all means contribute to this discussion.
what are the choices i can use if i want to power up a solenoid valve installed in a hazardous area.

It would be " You could use a HA protection method suitable for the hazardous area such as a Ex me soleniod or a certified solenoid fed via a IS circuit"

Last edited: Dec 10, 2009
14. Dec 10, 2009

### vk6kro

We didn't even find out if the solenoid was being used to switch electrical circuits or if it was being used to operate something mechanically.
Does not matter, you are still wiring and introducing energy into a hazardous area either as a relay, solenoid or cable.

The solenoid is already part of some equipment in the room. So, its suitability is not in question.
The question was how do you get power to it.
The answer is to use wires. What sort of wiring would depend which Country or even which State you are in. And on the hazard.

"Solenoid valve" would normally mean a mechanical actuator which pushed or pulled something to turn a flow of liquid on or off. It would not normally include sparking switches but it could if it turned on a warning light for example.

" You could use a HA protection method suitable for the hazardous area such as a Ex me soleniod or a certified solenoid fed via a IS circuit"
says nothing except that you do not know.

Answers to these questions often vary and you are welcome to add a dissenting view if you like.

15. Dec 10, 2009

I do not think you should be looking on a public discussion forum for advice related to safety, or any practice which is subject to legal requirements.

However strict and authoritative such advice may appear to be, how can you be certain that the provider really has the appropriate experience and qualifications to do so?

There is also a possible issue of different legal requirements in different places - is it even possible to know where your would-be adviser is posting from?

Please refer such important questions to sources whose competency you can be certain of.

16. Dec 10, 2009

### db444

Since I have tried to point out the poor advice given and you are resisting I wont send in any more posts

And to the adjuster, sure regulations vary in different contries but the principles are the same. I have not qouted country specific codes but highlighted the principles and errors

db