Posted by Admin on September 17, 2018
The word plenum refers to a space below a raised floor or above a ceiling that acts as a receiving chamber for air that has been cooled or heated, ready to be circulated to living spaces. Plenum is also referred to as the space typically used for the heating, ventilation, and air conditioning (HVAC) system in a building. Plenum cable refers to a rating, because plenum rated cables are fire rated.
The National Electric Code mandates that plenum cable must be installed in any air-handling space. The ceilings of most large buildings are used for returning air to the central air-conditioning unit, thus making it a plenum ceiling. In order to meet industry standard requirements, all cables running through the ceiling must be plenum cables.
The National Fire Protection Association Code NFPA 90A is the code and standard for the installation of ventilation and air conditioning systems. This code covers air distribution, the components for HVAC systems, and any other components relevant to building construction.
Plenum spaces are the perfect space within a building for housing both network communication cables and telephone cables. Fire safety is the difference between plenum and other cables, and plenum cable must comply with certain fire safety standards. According to the National Electric Code, plenum cable must comply with specifications for both smoke density and flammability, in addition to NFPA testing methods. In order to achieve a fire-resistant rating, specific jacket plastics are used to cover plenum cable, such as low-smoke and flame-retardant materials.
Cabling is a vitally important tool when it comes to signal boosters, and it plays an important role in the ultimate failure or success of the signal boosting solution being installed. Industrial and commercial cell phone signal boosters require that cables are tough enough to comply with building fire safety codes. To this end, plenum cabling facilitates the installation of cell signal boosters in buildings where standard cable options are not safe or strong enough. Unfortunately, many integrators are still not sure when plenum cabling should be used for an installation, so in this post we’ll take a closer look at how and when this specific type of cabling should be used.
The difference between plenum and riser cable is that the fire requirements are not as strict on riser cable. This means that you cannot replace plenum cable with riser cable in plenum spaces; however, plenum cable can always be used as a replacement for riser cable.
As explained above, an example of a plenum space is the area between a drop ceiling and standard ceiling. It’s in this area that we find the air supply used to support the various HVAC systems of a building. Cabling used in this area must be plenum rated because these spaces are full of fresh oxygen, which means that smoke and fire can travel very rapidly through these spaces. Even a small fire can spread very quickly once it has access to these areas, with the result that smoke will be quickly dispersed via the HVAC system right throughout the entire building.
Because plenum rated cable is treated with a flame-resistant material, like Teflon®, safety is automatically improved in these spaces. In addition, if the cable comes into contact with flames or heat, there is less likelihood of toxicity spreading throughout the building. When burned, other types of cable produce potentially deadly smoke.
Plenum air space standards are set by the National Fire Protection Association Code NFPA 90A, and to ensure that plenum cable meets a strict set of standards it is tested rigorously by one of the United States nationally recognized laboratories. Only after testing is this cable truly classified as plenum rated.
All cell signal booster installation professionals should opt for plenum-rated cabling when running cable through plenum spaces of buildings, and this includes air ducts. While it’s not absolutely necessary to use in some spaces, there are certainly instances whereby plenum cable must be installed. There are many commercial buildings, such as government buildings, secure facilities, hospitals, and so on, where plenum cable must be used in order to meet the fire and building codes.
If standard cabling is to be used in the plenum areas of buildings where less strict regulations apply, then the cabling in these areas must be run within a conduit. However, when it comes to cell signal boosters, standard cabling is not ever recommended because the conduit would need to be punctured and cable run out into the plenum to allow the booster to be connected to the corresponding antennas. This is just one reason why plenum rated cabling should be used at all times when dealing with air ducts and plenum spaces.
Because plenum spaces are typically a factor in the improvement of cell signal, we strongly suggest that all cell signal booster integrators consider plenum cable a vital tool for carrying out installations.
Wilson Pro’s Wilson 400 Plenum Cable is recommended for wireless applications because it’s a low signal-loss coaxial cable. The tight bend radius feature of the Wilson 400 Plenum Cable’s flexible conductor has been designed specifically to simplify any install space situation. In addition, the Wilson 400 Plenum Cable exceeds code requirements for use in plenum air handling areas.
As an installer, and to ensure proper rated cable is being used in every install, it’s very important that you make yourself aware of different cable ratings. Please don’t hesitate to contact us should you wish to purchase plenum rated cabling from WilsonPro, for information on how plenum cable should be used during installations, or perhaps you simply wish to learn more about cable ratings. We’re here to help!