Skip to main content

Why Fire Alarm Plenum and Riser Ratings Are So Important

 Fire alarm cable is of the utmost importance to public safety, as it allows the different nodes within a fire alarm system to communicate. If there’s a problem with the wiring and the system can’t communicate, it can’t relay important information about heat, smoke detection, or carbon monoxide to other nodes, smoke detectors, or alarms in the system.

Talk to any civil or electrical engineer about that and they’ll concur. That’s why all of the minute details associated with wiring should be understood - thoroughly understood - before attempting to complete plans or install wiring.

With that in mind, let’s take a closer look at two important fire alarm cable ratings - for riser-rated and plenum-rated cables.

What Is Riser Space?
Riser space, as the name might suggest, allows for utilities to “rise” through a building. That is, it is the vertical space reserved for things like communication lines, water pipes, conduits, and of course, alarm cables, to be vertically distributed throughout a building.

Think of riser space as the “space between the walls” because, in most instances, that’s exactly what it is. It’s also typically sealed off to access from the inside.

As a result, riser-rated cables are typically built to lower or less stringent specifications than plenum-rated cables, but this is not always the case (see below).

What Is Plenum Space?
Plenum space, unlike riser space, is space that is hollowed out between the floor and the ground, or more commonly, between a drop ceiling and the actual ceiling. While plenum space can also be used for water pipes and conduits, it is also the space in a building that is reserved for ductwork and HVAC.

As a result, it is possible for the contents of the plenum space to communicate with the rest of the building. That is to say, if there were, for instance, smoke in the plenum space, it could get into the living quarters of the associated floor.

Consequently, plenum-rated fire alarm cables (and other cables) must be much more resilient to heat and fire than riser-rated cable.

How Does This Affect Fire Alarm Cable?
Since fire alarm cable must be safe for use around people and also resilient to fire in order to work, this has some implications for alarm cable specifications.

Generally speaking, all fire alarm cables should be high heat resistant, self extinguish, and not produce toxic smoke when burned. However, pllenum-rated cable must be more resistant to heat and fire than riser-rated cable because of the nature of plenum space. As a rule, you can use plenum-rated cable in riser space but not a riser-rated cable in plenum space.

Also, one thing to keep in mind is that there are also riser and plenum-rated conduits. If you use a plenum-rated conduit, it may be possible for you to use riser rated cable - but check with an electrical engineer to be sure.

Looking for Fire Alarm Cable?
Looking for a non-power limited or power-limited fire alarm cable that stands up to specific requirements? Visit EWCS Wire at EWCSWire.com or get in touch with them to learn more about their high-quality alarm cables and other products.

Comments

Post a Comment

Popular posts from this blog

Two Important Things You Need to Know About Marine Electrical Wire

Do you own a boat? Are you a member of a ship’s crew? Are you a ship’s mechanic or an electrician by trade? If you answer yes to any of these questions, you will at some point or other come across marine electrical wire in the course of your career. Something important you’ll need to keep in mind is that marine electrical cable and wire is not the same as standard building wire; nor is it the same as automotive battery wire. Here are the two big defining traits. Marine Electrical Wire Is Highly Flexible If there’s one thing you need to know about marine electrical wire (also sometimes called marine battery cable or marine battery wire) it’s that it’s highly flexible. This is accomplished by making these conductors out of very high strand counts of very thin conductors. Typically, marine battery wire conductors are made from pure, 100% copper and each conductor is very thin. Doing so makes the cable very flexible. Why is this necessary? Well, ...
Post a Comment
Read more

Common Questions About Security and Alarm Cables, Answered

Not sure which type of security or alarm cable your facility or system needs? Hopefully, these answers to common questions can help! What cable is used for alarm systems? Security and alarm systems are usually wired with small-gauge wire specifically designed for the purpose. For instance, many security systems are wired with 12 and 18 AWG gauge alarm wire, as these low-voltage applications do not necessarily require larger, heavier wires. However, larger or wire gauges may be required depending on the circumstances. Also, there are some unique requirements for some systems. For instance, fire alarm cables must be made with specific insulation that is heat resistant and which does not produce toxic smoke when burned. What gauge cable do you need for alarm systems? Only your specific system requirements can answer that question, but often large wire gauges (that is, smaller wires) are used as security and alarm cables because of the low-voltage, low-current application. What is ...
Post a Comment
Read more

Factors to Look Out for When Selecting a Boat Battery Cable

Whether you’re an experienced boater or just getting started, it’s important to make sure your boat is properly outfitted with the right battery cables. Boat batteries provide power to the many electrical components of your boat, and the battery cables are responsible for transferring that power safely and efficiently. Selecting the right cables is essential to making sure your boat runs smoothly and that you’re able to enjoy your time on the water. When selecting boat battery cables , there are a few key characteristics to look for. High-Quality and Marine Grade First, you’ll want to look for cables that are made from high-quality materials that can withstand the elements. The cables should be able to handle the rigors of a marine environment, including exposure to saltwater, UV rays, and extreme temperatures. Additionally, you’ll want to make sure the cables are flexible and easy to install, as this will make the job of connecting the cables to your ba...
Post a Comment
Read more