Waveguide in other spaces used for environmental air (plenum)

Status
Not open for further replies.
It a good question but I've never had any restraints running wave guide. I don't see anything in the NEC the says wave guide has to be plenum rated to run in environmental air spaces...

I don't ever consider wave guide to be a conductor....
 
Twoskinsoneman said:
It a good question but I've never had any restraints running wave guide. I don't see anything in the NEC the says wave guide has to be plenum rated to run in environmental air spaces...

I don't ever consider wave guide to be a conductor....
Click to expand...

Interesting. If this is RF waveguide, why wouldn't if be?
 
I don't have the code in front of me right now but I think you can find what you are looking for in article 770.
What you will be looking for is OFNP or OFCP rated cable.

OFNP stands for Optical Fiber Nonconductive Plenum Cable and OFCP stands for Optical Fiber Conductive Plenum Cable. OFNP and OFCP cables must have resistance to flame spread and reduced smoke generating properties. These cables are approved for placement in air handling ducts and chambers without the use of fireproof conduit.

Hope this helps you.
 
Torxtimer said:
I don't have the code in front of me right now but I think you can find what you are looking for in article 770.
What you will be looking for is OFNP or OFCP rated cable.

OFNP stands for Optical Fiber Nonconductive Plenum Cable and OFCP stands for Optical Fiber Conductive Plenum Cable. OFNP and OFCP cables must have resistance to flame spread and reduced smoke generating properties. These cables are approved for placement in air handling ducts and chambers without the use of fireproof conduit.

Hope this helps you.
Click to expand...

unless I didn't understand what the op was talking about fiber optics has nothing to do with his question. I don't see where the NEC talks about wave guide and I wouldn't trying to apply the closest thing I could to it.

JMO but I don't see WG as a conductor because the power isn't transmitted through or in the wave guide material. The electromagnetic energy is just guided by it as it bounces through it. Unless there is a building code (of which I admit I don't if there is) that says something to the effect that ANYTHING put in enviromental air space has to be plenum rated, regardless if it has anything to do with anything I wouldn't worry about it. IMO the NEC is silent on it.

Is there such a building code? Like any material period in environmental air space must be plenum rated?

gndrod said:
Interesting. If this is RF waveguide, why wouldn't if be?
Click to expand...
 
gndrod said:
Interesting. If this is RF waveguide, why wouldn't if be?
Click to expand...

Waveguide is not a conductor.

Now, the boundary conditions are these:

1). Electromagnetic waves do not pass through conductors, but rather, they are reflected.
2). Any electric field that touches a conductor must be perpendicular to it.
3). Any magnetic field close to a conductor must be parallel to it.

These boundary conditions eliminate an infinite number of solutions to the wave equation, and the ones that remain are the possible solutions to the wave equation inside the waveguide. The rest of the analysis of the solutions of the electromagnetic waves inside a waveguide gets very mathematical.
Click to expand...

http://en.wikipedia.org/wiki/Waveguide
 
Twoskinsoneman said:
unless I didn't understand what the op was talking about fiber optics has nothing to do with his question. I don't see where the NEC talks about wave guide and I wouldn't trying to apply the closest thing I could to it.

JMO but I don't see WG as a conductor because the power isn't transmitted through or in the wave guide material. The electromagnetic energy is just guided by it as it bounces through it. Unless there is a building code (of which I admit I don't if there is) that says something to the effect that ANYTHING put in enviromental air space has to be plenum rated, regardless if it has anything to do with anything I wouldn't worry about it. IMO the NEC is silent on it.

Is there such a building code? Like any material period in environmental air space must be plenum rated?
Click to expand...

It is in the Mechanical code and the building code.
 
Twoskinsoneman said:
Can you post the quote from the applicable code?
Click to expand...

It is in 602.2 of the 2006 uniform mechanical code.
"Combustibles within ducts or plenums.
Materials exposed within ducts or plenums shall be noncombustible or shall have a flame spred index not greater than twenty-five (25) and a smoke developed index not greater than fifty (50),,,,,,,,,,,,,,,,ETC."
 
Symmantecs= equipment grounding conductor bonding metal parts that can be energized.

Symmantecs= equipment grounding conductor bonding metal parts that can be energized.

K8MHZ said:
Waveguide is not a conductor.



http://en.wikipedia.org/wiki/Waveguide
Click to expand...

Waveguide is an extruded metal channel. In X and K band, the metal must be bonded to a chassis ground plane to drain off static energy. The NEC does not cover all areas of surrounding equipment interfaces. Microwave as an appliance is indirectly referred to in the NEC but is not correlated to communication systems.
 
Last edited:
acrwc10 said:
It is in 602.2 of the 2006 uniform mechanical code.
"Combustibles within ducts or plenums.
Materials exposed within ducts or plenums shall be noncombustible or shall have a flame spred index not greater than twenty-five (25) and a smoke developed index not greater than fifty (50),,,,,,,,,,,,,,,,ETC."
Click to expand...

Thanks for posting that.
Anything about Other Space Used for Environmental Air (non duct or plenum)?
 
My reply was based on reading wavegudie and plenum together meaning "Light Waveguide" in a plenum area, I did nor realize it was an RF Wavegude.
Sorry about that.
 
Electrical equipment with a metal enclosure can be ran above a suspended ceiling that is used as a plenum return. Is that what we are talking about?

If the waveguide is metal, I don't see a problem, unless the supports are plastic or non-metallic, or unless there is a enclosure around the waveguide that isn't metal.

Steve
 
Waveguide in other spaces used for environmental air (plenum)

This is what the waveguide looks like:
http://awapps.commscope.com/catalog...467&productID=1375&categoryID=69&imgTableID=6

Copper covered with polyethylene. I asked if we could remove the cover, the manufacturer says no.

My main question is, can you use this product,
http://www.thermalceramics.com/pdfs-...Protection.pdf

PlenumWrap, to cover non plenum rated cable in an environment airspace and be in compliance with code? Should I be looking at a mechanical code and not the NEC?
 
Status
Not open for further replies.
Top