Do i need a plenum?

Last Update: May 27, 2022

This is a question our experts keep getting from time to time. Now, we have got the complete detailed explanation and answer for everyone, who is interested!

Asked by: Krystal Weissnat
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If there is no sheet metal duct; just the open ceiling or wall space, then you are required by law to use Plenum Rated cable. ... The lack of wall or ceiling return air grates is usually a sure sign that you require Plenum Rated Cable. Computer Rooms typically use a raised flooring system for the server racks.

Where is plenum required?

Most building codes mandate that only plenum-rated (CMP) cable be used in “plenum spaces” and air ducts. For large public spaces like hospitals, schools, and airports, building codes in some cities and towns mandate plenum cable even for non-plenum spaces.

When should I use plenum cable?

Plenum cable is mandated to be installed in any "air handling" space. For example, most large office buildings use the ceiling to return air to the AC unit. This qualifies this ceiling as a plenum ceiling, and all the cables that go through that ceiling must be plenum rated.

What's the purpose of a plenum?

In building construction Plenum is a separate space provided for air circulation for heating, ventilation, and air-conditioning. It is commonly found in the space between the structural ceiling and a drop-down ceiling or under a raised floor.

Is plenum better than riser?

Because plenum cables are built to a higher fire resistance standard than riser cables, plenum cabling is more expensive than riser cabling. While you can substitute plenum cabling for riser cabling in a “riser” space, you cannot substitute riser rated cables for plenum rated cables in a plenum space.

What is PLENUM SPACE? What does PLENUM SPACE mean? PLENUM SPACE meaning & explanation

19 related questions found

Do I need Riser or Plenum cable?

Plenum rated cables have a higher fire rating for both commercial and residential use. When cables are needed in the air ducts, plenum cables are the primary choice. Riser cables, namely CMR cables, are widely used for regular networking from floor to floor in non-plenum areas.

What is plenum vs non-plenum?

Plenum-rated cable has been manufactured to withstand higher temperatures in the event of a fire and does not cause the same level of smoke or toxicity when burning. Non-plenum does not have these characteristics, and as a result costs much less (usually half as much).

How much does a plenum cost?

Generally, a return air plenum will cost approximately $50 to $60 per unit. The other costs to consider are those for the labor and materials needed to install the return air plenum. The installation takes an average of about five hours with the sum of labor costs between $290 and $370.

How does plenum ventilation work?

a system of mechanical ventilation in which fresh air is forced into the spaces to be ventilated from a chamber (plenum chamber ) at a pressure slightly higher than atmospheric pressure, so as to expel foul air.

What size plenum do I need?

One is that the supply plenum should be no larger than the blower opening off the top of the air handler, which seems small, at only 16x11". But most opinion, particularly from the HVAC supplier, is that the plenum should be the same size as the overall A.H. cabinet size, which is 17.5 x 21".

Is CAT6A faster than CAT6?

As well as being able to easily support 1 Gbps network speeds, CAT6 can also support higher data rates of 10Gbps. However, 10Gbps is only supported over shorter distances of 37-55 metres. CAT6A is capable of supporting data transfer rates of up to 10Gbps at a maximum bandwidth of 500MHz.

Is an attic a plenum space?

Plenum-rated cables got their name from an old HVAC term referring to “Plenum Spaces”. Plenum is a type of jacket in Ethernet cables. Plenum spaces in any building are those spaces that have regular air circulation. ... Generally, spaces between the structural floor or a dropped ceiling are plenum spaces.

What's the difference between riser and plenum cable?

Many customers ask, "What is the difference between plenum rated cable & riser rated cables." Plenum rated cables are used in plenum areas meant for use in commercial and residential spaces. ... Riser rated cables run between floors through cable risers or in elevator shafts in non-plenum areas.

What is the difference between a plenum and a duct?

As nouns the difference between duct and plenum

is that duct is a pipe, tube or canal which carries air or liquid from one place to another while plenum is (physics) a space that is completely filled with matter.

Is plenum cable required in house?

If there is no sheet metal duct; just the open ceiling or wall space, then you are required by law to use Plenum Rated cable. ... The lack of wall or ceiling return air grates is usually a sure sign that you require Plenum Rated Cable. Computer Rooms typically use a raised flooring system for the server racks.

Is drop ceiling plenum?

Space between the structural ceiling and the dropped ceiling or under a raised floor is typically considered plenum; however, some drop-ceiling designs create a tight seal that does not allow for airflow and therefore may not be considered a plenum air-handling space.

Should the plenum be insulated?

Supply and return air ducts and plenums shall be insulated with a minimum of R-6 insulation where located in unconditioned spaces and where located outside the building with a minimum of R-8 insulation in Climate Zones 1 through 4 and a minimum of R-12 insulation in Climate Zones 5 through 8.

What are the effects of poor ventilation?

Polluted air in combination with poor ventilation causes dry throat and eyes, concentration disorders, fatigue, headaches, shortness of breath, poor sleep, drowsiness, dizziness. In addition, complaints may develop such as chronic colds or respiratory infections, development of asthma or other lung diseases.

What is a supply and return plenum?

A supply plenum works by taking in the new cool or warm air from the heater or air conditioning system and, in turn, distribute it throughout the building using the HVAC's ductwork. A return plenum takes in that used air and, using the ductwork, sends it back to the core HVAC system.

What happens if there is not enough return air?

If there is not enough return air available, your HVAC system will not heat or cool properly. ... If not enough air is brought back, your HVAC system will not be able to keep up with temperature demands. In some cases, two returns may be necessary to provide enough return air.

Do bedrooms need return air?

Each bedroom needs either: A return air grille ducted back to the furnace; A through-the-wall transfer grille connecting the bedroom and the adjacent hallway; or. A crossover duct (a jumper duct) connecting a ceiling grille in the bedroom with a ceiling grille in the hallway.

Is UTP cable plenum?

Solid Plenum Cat6 is designed to meet the strictest of electrical codes; our plenum cable meets or exceeds many common cable standards. The slow burn, low smoke jacket is comprised from CMP rated PVC.

What is considered a plenum space?

Simply stated, the NEC defines a plenum area as, “a compartment or chamber to which one or more air ducts are connected and that forms part of the air distribution system.” It also references, “the space over a hung ceiling used for environmental air-handling purposes,” and, “areas beneath raised floors for information ...

Is an open ceiling a plenum?

The retail store's open ceiling is not a plenum area. All the merchandise would have to be rated to be installed in the air ducts.