Possibly the most important concept to understand in upgrading or installing a fire alarm system is the separate ratings that exist for different space types within a building. Whether residential, commercial, or industrial, all buildings have two types of space, each of which has a different standard for cable insulation type based on its respective risk of fire. Ensuring your fire alarm system follows fire codes involves choosing the correct fire alarm cables for the space you are installing them in. Even more vitally, following cable rating guidelines ensures your system is the safest it can be for those who are living in, working in, or passing through your building.

This article is devoted to exploring each type of space and helping you come to an understanding of each space type’s parameters. By the end of the article, you should have a basic idea of what you need to look for before you buy your fire alarm cables.

1. Riser Space
Riser cable is largely PVC-coated cable that is designed for places that are at low-risk of high-heat fire in the case of an emergency. Riser cable is less heat resistant, more flexible, and generally cheaper than plenum-rated cable, which will be explored below. Generally, riser cable will be used in environments that are well-sealed or otherwise do not have access to direct air circulation. However, it is not always appropriate to use riser-rated fire alarm cables even in places that are sealed.

Riser space must be carefully considered and inspected. The need for inspection comes from the fact that riser space can very easily become plenum space if fresh, circulated air is introduced to the system. For an example of how this might come to be, consider a sealed space that an enclosed air duct passes through. While the space around the sealed duct may itself be sealed, a breach of the duct before the point or within the point could easily fill the riser space with fresh air, making it just as dangerous to your fire alarm cables as plenum space.

As a result of the unfortunate ease at which riser space can be converted to plenum space, it is sometimes advisable to lay plenum-rated cable in riser space, but it is not appropriate to ever substitute plenum cable for riser cable in plenum space.

2. Plenum Space
Plenum space, as touched on above, refers to space with an active circulation of fresh air. As a result, plenum cable is cable that is insulated with much more heat resistant insulation types. The downsides of plenum cable are that the increased insulation reduces flexibility and increases costs.

Plenum space is what most between-floor space in a building will be categorized as since most places are not sealed-off enough to be considered riser space. Any location with vents that open into floor space, unsealed panels, or other ceiling types that do not create a seal are considered plenum space and will require plenum-rated cable.

The reason that plenum-rated cable is so important to utilize in spaces with air circulation is that, in the case of a fire, air circulation encourages increased heat and spread of fire. Between-floor space that is categorized as plenum space and is exposed to fire could generate incredible temperatures which could damage alarm cables and cause the system to malfunction, putting lives and property at great risk.

Choosing your cable types carefully is a matter of safety, and if you are unsure of what a space should be considered, always assume that it is plenum space. As mentioned above, riser space can quickly become plenum space, so it is both wise and advisable to consider unknown space as active or potential plenum space.

When working with plenum-rated cable, it is also important to consider length needs with extra care. Because plenum cable is considerably less flexible, there may be places in which you will need to run the cable wide in order to avoid over-flexing the cable and damaging it. Measure your distance carefully and be sure to measure under the assumption that you will have less flexibility to work with.

3. Conclusion
Keeping plenum and riser ratings in mind is incredibly important to the integrity of your fire alarm system, the safety of your building, and the well-being of its inhabitants. If you have any doubts about your setup, don’t be afraid to consult an expert. Fire code compliance is important, and doing the job right the first time will save you money, time, and effort.

When you’re ready to buy, make sure you buy from a team of professionals. Here at www.ewcswire.com, we stock only the best cables for the best prices. Our team can help guide you to the cables that are right for the job, and buying from us will leave you with peace of mind in knowing you don’t have to worry about your supplies. Come visit us today!