Requirements for installing firestopping communications or other low-voltage cabling
The requirements for firestopping communications or other low-voltage type cabling can present a particularly difficult set of complications on a construction project. This is especially true when the lines of responsibility have been blurred — when the electrical contractor provides pathways and a separate contractor provides the cabling. In this situation, it’s difficult to determine who is responsible for the firestopping system. Let’s take a look at how contractors can minimize these complications.
In today’s construction environment, building codes require the compartmentalizing of buildings in order to contain fires and prevent their spread from one area of a structure to another. As part of compartmentalization, fire-rated partitions are installed in the form of walls and floors, which are strategically placed around the building. Oftentimes, these partitions separate two spaces in which the low-voltage cabling must pass. Code requires a listed firestop system be provided, which has been specifically tested to include those cables intended to pass through the partition. These firestop assemblies are tested as a complete system, not as individual parts or components. This means the substitution of different products or pieces is not allowed — and only those items specifically identified in the listing are permitted as part of the system.
Typically, firestop systems include a mechanical device (pathway) used to protect the cables penetrating the partition, a quantity and arrangement of cables allowed to pass through the device, firestop materials to be applied around the pathway, and firestop materials to be installed inside the pathway and around the cabling. These firestop systems can be a combination of individual parts and pieces to be installed in the field, or they may be self-contained units with all internal firestop materials built into the device.
When the scope is separated between multiple contractors, having these different options for firestop systems can introduce an interesting dynamic in how each selects or chooses to bid the firestop systems. In an attempt to keep overall project costs down, the electrical contractor may intend on providing a number of conduit sleeves for the cabling contractor to use. On the other hand, the cabling contractor may base his bid on an expectation that the electrical contractor will provide self-contained units that would require no additional materials as part of the pathway system being provided. Unless the electrical contractor and the cabling contractor are working together, items may be missed if one assumes the other is providing a specific part of the firestop system. Conversely, added costs can find their way into the project if both include the same equipment and work as part of their bids.
Another item that may affect the bid is in cases where pathways and routing planned by the electrical contractor differ from those planned by the cabling contractor. In these instances, the electrical contractor may anticipate providing pathways in locations that minimize any rated penetrations, which, in turn, would reduce their costs. In some cases, this may be acceptable. In others, it wouldn’t.
One example of this would be where the location chosen for the pathway would increase cabling lengths such that they exceed the allowable distances for proper performance. Another would be in a classroom scenario where walls between classrooms are unrated while the corridor wall would be fire rated. The electrical contractor may elect to place pathways between classrooms in lieu of placing a firestop system into the corridor from each classroom. In certain cases, this would be acceptable. In others, however, it might force the cabling contractor to do extra work not anticipated in the original bid. This extra work may stem from having to support the cables between classrooms where they may have planned to use a cable tray or other distribution method that already existed in the corridor. These scenarios often lead to change-order requests or costly rework to one or both of the contractors at the time of installation, all of which could be avoided with proper coordination.
A final consideration that may affect the bidding process is associated with the creation of shop drawings and as-builts. Frequently, contractors are responsible for creating these documents to be delivered to the owner or design firm as part of their contract. If both contractors provide a part of each firestop system, it can become difficult to determine whose responsibility it is for documenting the systems as part of these deliverables. This can lead to contractors incorrectly assuming the other is responsible for the task — or both including the work as part of their bid. If missed, it may result in more work and delays in ordering products as well as additional time in the field to review the locations of firestop systems to include as part of the as-built documentation.
These issues can be compounded even further when the cabling design has not taken place or where firestop systems are to be provided as spares for future cabling. Without a cabling design, the electrical contractor is left to provide pathways for cables that haven’t yet been identified. This can lead to a quantity of empty conduit sleeves being provided for use by the cabling contractor in the future. The issue with this approach is twofold. The conduit sleeves provided may restrict the cabling design due to the limitation of listed firestop assemblies available for the particular cables to be installed. Second, where cables are not installed on day one, the electrical contractor would need to locate and provide a listed firestop system for all empty conduit sleeves penetrating a fire-rated wall. In many cases, this step is missed, and the sleeve is simply filled with firestop putty. While the intent may be genuine, this doesn’t meet the requirements of the Code, unless by accident. While a listed firestop system may exist that includes a conduit sleeve and putty as components, the contractor must first identify the system. Once a system and all its required components have been identified, the contractor can determine what is required to install and label it in accordance with the listing.
The installation of a firestop system that has been listed specifically for an empty conduit sleeve could also become confusing to the cabling contractor (or owner) who wishes to use the sleeve for cabling in the future. It wouldn’t be uncommon for the cabling contractor to simply remove whatever firestopping material is in the conduit, install the new cables, and then reapply the firestopping material around the cables. While again the intent may be genuine, the cabling contractor (or owner) should ensure he has first identified the correct listed system and installed it in accordance with the listing information. For this reason, the electrical contractor should label all firestops on both sides of the partition upon installation with the listing and system number. This labeling will allow anyone using the firestop in the future the ability to look up the system listing information to determine its permissible uses.
One preferred way to help these situations is to choose re-enterable firestop systems that require no additional fill materials and accommodate a wide range of cables and configurations. These systems often include the ability to be left unfilled or will accommodate cable capacities of up to 100% visual fill. Although they may be more expensive up front, they will not only reduce ongoing costs, but also will help ensure a Code-compliant installation is maintained through the life of the building and any changes to the cabling.
One final point that needs to be addressed is where a penetration does not extend through both sides of a fire-rated partition. These types of openings are considered membrane penetrations, and, in most cases, are required to be protected with firestop materials. Some exceptions do exist that allow these openings to go unprotected, as long as the opening does not exceed certain sizes. However, more often than not, they do require fire-rated materials. This is of concern where the method of installation for low-voltage cables is what many in the industry commonly refer to as “ring-and-string.” This method of low-voltage cabling distribution does not rely on conduits and back boxes at the device locations but merely depends on openings in the gypsum wall, using the stud cavity for the routing of cables. This practice can reduce costs but also presents some unique issues when installed in a wall that is also a part of a fire-rated assembly. In these instances, the necessary back boxes, conduit, and firestop materials should be provided in order to deliver a Code-compliant installation. Contractors must coordinate these locations to ensure the proper pathways and firestop materials are provided.
A few techniques can help minimize these breakdowns in coordination. First is to have one contractor responsible for all firestops for low-voltage cabling. By going this route, the determination of an appropriate system for the cabling is dramatically simplified and will ensure their placement is appropriate for the systems to be installed. In certain cases, such as where union contracts prohibit certain contractors from doing this work or where due to scope assignment it isn’t possible, there are some additional techniques contractors can use. First, they should identify where all fire-rated partitions are on the project. From there, a coordination session must be setup to identify the desired cable routing and where these routes will cross any fire-rated partitions. As part of these coordination meetings, the cabling contractor should provide a list of cables expected to penetrate each location and a firestop system that will be appropriate at each location. Where possible, these cable routings should include any cables that are expected to be installed day one as well as any future cables that can be anticipated or are known to be required in the future.
Once the firestop systems have been determined, the contractors should identify which portion of the system they are responsible for and who will be responsible for documenting as part of any submittals and as-builts, as well as the necessary labeling. After construction begins, the contractors must work together to ensure their portion of the installation is done at the appropriate time and the components for which they are responsible for have been done properly and in accordance with the system listing. At the completion of the project, each contractor should be able to walk away knowing that they provided Code-compliant firestops and left the occupants in a safe environment.
Maintaining the compartmentalization of buildings and fire zones is an important aspect to any project as it helps to keep the building occupants safer. As part of this, the penetration of fire-rated assemblies through the use of appropriately installed firestop systems should be a priority for any contractor. If coordinated properly, it should not be difficult to achieve this goal. Where problems arise is when there is breakdown of coordination or an assumption of someone else’s scope.
Hancock is a senior technology specialist with Henderson Engineers, Inc., Lenexa, Kan. He can be reached at brian.hancock@hei-eng.com.