Safety Lock/out and Low voltage

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smmartin

Member
Can anyone tell me the requirements for Low voltage.
When does OSHA require a lockout of energy source involving low voltage

I am dealing with 28 volt systems

thanks steven Martin
 

muskiedog

Senior Member
Location
Minnesota
Where in 1910.147 does it state 50 volts or less it isn't required? I think you are confusing this with 1910.303 guarding of live parts. Lockout/tagout is required for any enrgy source from my understanding.
 

muskiedog

Senior Member
Location
Minnesota
I do not NFPA 70E handy but is this what it states:

Energized parts that operate at less than 50 volts to ground shall not be required to be de-energized if there will be no increased exposure to electrical burns or to explosions due to electric arcs.?

So it may be required but most likely not?
 

smmartin

Member
I beleive that I will imposing a Lock Out on this due to I have a Liquid Oxygen Vessel with about 145K gallons on Oxygen in it. I believe this constitutes a potential explosion hazards!

Thanks guys you have been very helpful to me.
 

smmartin

Member
Yes it is a non flammable gas.
But I would not like to be the one working around this area if an arc went off in an Oxygen enriched enviroment.

I have seen 3/4 inch steel burn in a Liquid Oxygen enviroment.
 
B

bthielen

Guest
So is LP, Acetylene, propane, etc. These are also non-flammable by themselves. The environment needs a sufficient supply of oxygen for these gases to be flammable.

I'm no chemist, but are there situations where certain elements together are flammable without an oxygen supply?

Bob
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Bob,
So is LP, Acetylene, propane, etc. These are also non-flammable by themselves. The environment needs a sufficient supply of oxygen for these gases to be flammable.
Those are defined as flammable and will have a red placard when shipped. Oxygen is defined as an oxidizer and will have a yellow placard when shipped. An oxygen enriched atmosphere does increase the chances that a fire will start. It does not lower the ignition point for the flammable or combustible product. It does, however, greatly increase the intensity of the fire and the speed of the fire once the product is ignited.
Don
 
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bthielen

Guest
Don,

It is my belief that they are defined as flammable because sufficient oxygen exists naturally in our atmosphere at about 21%. Introduce a spark or some other source of ignition in a 100% methane atmosphere would it burn or would oxygen be required to sustain the reaction?

Bob
 

muskiedog

Senior Member
Location
Minnesota
When oxygen, a fuel source and heat come together they create a chemical reaction that can support a fire. If this reaction happens extremely fast or in an enclosed area, an explosion can occur. This is where oxygen becomes a dangerous safety hazard. As the oxygen level increases, it becomes easier to start a fire. The fire will burn hotter and more fiercely than in air, and will be more difficult to put out. It is even possible to start a fire using pure oxygen where no spark or flame exists, especially if the oxygen comes into contact with oily materials.

Also oxygen can be pulled from the materials that are burning.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
As the oxygen level increases, it becomes easier to start a fire.
Not true. The presence of oxygen in abnormal concentrations does not change the ignition point of the flammable material and has no effect on the ease of starting the fire.
It is even possible to start a fire using pure oxygen where no spark or flame exists, especially if the oxygen comes into contact with oily materials.
You don't need increased oxygen concentrations for spontaneous combustion to occur, however you need non-petroleum oils.
Don
 
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bthielen

Guest
"You don't need increased oxygen concentrations for spontaneous combustion to occur, however you need non-petroleum oils."

That's interesting. Why not petroleum oils?

Bob
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Bob,
That's interesting. Why not petroleum oils?
Spontaneous combustion results from the increased temperature when the product involved oxidizes. The faster the product oxidizes the more heat. Petroleum oils do not oxidize fast enough to reach their ignition temperature, at least not at normal temperatures. Some plant oils do. The most common in linseed oil and other oils used in oil based paints. Also biodiesel is a plant oil based product and can spontaneously combust. Petroleum oils will spontaneously combust in the presence of strong oxidizers such as chlorine. A number of Wal-Mart's burned before they found that they shouldn't be storing motor oil and pool chemicals close to each other.
Don
 
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