When choosing the right type of cable for your building or project, the terms "plenum rated," "riser rated," and "LSZH" (Low Smoke Zero Halogen) can often be confused. These ratings refer to the cable's ability to perform under different environmental conditions and how it reacts in the event of a fire.
Getting a better idea of these ratings is crucial for both safety and performance. In this article, we will break down these terms and help you decide which cable is best suited for your needs.
Understanding Cable Ratings
Cable ratings primarily refer to the type of insulation used and the conditions under which the cable is designed to operate safely. These ratings are necessary because they help ensure that the cables are safe to use in specific environments, whether for commercial or residential buildings.
The three most commonly mentioned cable ratings are riser-rated cable, plenum-rated cabling, and LSZH. Riser-rated cables are intended for vertical spaces, such as the areas between floors. Plenum-rated cables are used in air-handling spaces, typically above ceilings or below floors, where air circulates.
LSZH cables are specifically designed to emit minimal smoke and no halogens when exposed to fire, making them ideal for sensitive environments. Let’s dive deeper into these cable types and understand their differences and best uses.
Riser Rated Cable
A riser-rated cable is designed for use in vertical spaces, such as communication risers in a building. These areas are typically used to house cables running from floor to floor. The main feature of riser-rated cables is that they can withstand a certain level of fire exposure without spreading flames between floors. Here are some things you need to know about riser-rated cables:
- Insulation - Riser-rated cables use materials that resist flame spread in vertical spaces. They are not as flame-resistant as plenum-rated cables but are safer than non-rated cables.
- Application - Ideal for use in spaces like vertical riser shafts, which are common in multi-story buildings.
- Safety - The riser-rated cable ensures that the fire does not spread from one floor to another through the cable pathway. However, they do not provide the same level of protection as plenum-rated cables.
Common uses include running cables through building risers, elevator shafts, and other vertical conduits. Riser-rated cables are cost-effective and provide the necessary fire resistance for many commercial installations.
Plenum Rated Cable
Plenum-rated cables are engineered to be used in air handling spaces, such as indoor cables, and plenum Cables in ceilings or under floors where air circulates. These spaces are referred to as "plenum spaces," and cables in these areas must meet strict fire safety standards due to the risk of flames spreading quickly in the airflow. Some important characteristics of plenum-rated cables include:
- Insulation - The insulation material used in plenum-rated cables is designed to emit minimal smoke and to resist combustion, ensuring that fire does not spread rapidly. The plenum rating is one of the highest safety standards in the cable industry.
- Application - These cables are best used in areas where air circulation exists, such as HVAC systems and areas designed to facilitate airflow.
- Safety - The main advantage of using plenum-rated cabling is its ability to slow down the spread of fire and reduce smoke production, making it safer in case of a fire.
In high-traffic or sensitive commercial buildings where fire safety is a top priority, plenum-rated cables are often required by building codes.
LSZH Cables
LSZH cables are designed to produce minimal smoke and zero halogen gas when burned, which is important in environments where ventilation is limited, such as tunnels, aircraft, or hospitals. Though LSZH cables are not specifically classified as either riser-rated or plenum-rated, they can meet the standards for use in these spaces. Here is what you need to know about LSZH cables:
- Insulation - LSZH cables use low-smoke, halogen-free materials, ensuring that the cable does not release toxic gases in the event of a fire.
- Application - Best suited for sensitive environments like data centers, hospitals, and underground spaces where air quality is crucial.
- Safety - While LSZH cables are a step up in fire safety due to their non-toxic smoke properties, they do not necessarily have the flame-retardant qualities of plenum-rated cables.
Key Differences Between Riser, Plenum, and LSZH Cables
Choosing the right cable depends on the environment and application. Here’s a quick comparison to help you decide which one suits your needs:
Riser Cable vs. Plenum Cable
Riser cable is for vertical applications, while plenum cable is for air-handling spaces. Plenum cables have a higher fire safety rating than riser cables.
LSZH vs. Plenum
LSZH cables are ideal for environments requiring minimal smoke and no toxic fumes, while plenum cables provide better fire resistance. Both provide safety but in different ways—LSZH focuses on low toxicity, while plenum-rated cables are optimized for air handling and fire safety.
Still not sure when to choose each type of cable? Well, here is a table that can provide you with a better idea about it:
|
Cable Type |
Best Used For |
|
Riser Cable |
Vertical cable runs between floors. |
|
Plenum Cable |
Air-handling spaces (plenums) |
|
LSZH Cable |
Environments where low smoke and halogen gas emissions are critical |
Conclusion
Choosing the right cable is essential for safety, especially in environments with fire risks. Riser-rated cables are perfect for vertical spaces, while plenum-rated cables offer superior fire safety in air-handling spaces. LSZH cables are excellent for environments where minimizing smoke and toxins is a priority.
Selecting the right cable for your needs ensures both safety and compliance with building codes. If you need high-quality cables, contact Delco Cables today for the best in riser-rated, plenum-rated, and LSZH cables.
FAQs
What is a plenum-rated cable?
A plenum-rated cable is designed for use in air-handling spaces and is made to resist combustion and reduce smoke production in case of fire.
What’s the difference between riser and plenum cable?
Riser cables are used for vertical spaces, while plenum cables are for air-handling spaces where airflow exists. Plenum cables offer better fire safety.
Is LSZH better than plenum-rated cable?
LSZH cables minimize toxic smoke and gas but do not have the same level of flame resistance as plenum-rated cables.
Can riser-rated cables be used in plenum spaces?
No, riser-rated cables should not be used in plenum spaces, as they do not meet the necessary fire safety standards for air-handling areas.
Do I need plenum-rated cables for my building?
If your cables are installed in areas where air circulates, such as above ceilings or under floors, you will need plenum-rated cables.