Selecting the right ingredients for Augmented Cat 6 firestopping
At the BICSI conference in Nashville last August, CI&M chief editor Patrick McLaughlin asked me what I thought was the hottest topic concerning the new Augmented Category 6…to which I smiled and replied, “firestopping.
At the BICSI conference in Nashville last August, CI&M chief editor Patrick McLaughlin asked me what I thought was the hottest topic concerning the new Augmented Category 6…to which I smiled and replied, “firestopping.”
He looked a little puzzled, until I explained.
We had just discussed the same issue in the BICSI Standards Committee meeting hours earlier, where it was agreed that a “cautionary statement” would be issued to BICSI members. It is now late January 2006, and the statement is almost ready for release. So, consider this as an “early” heads-up that a more detailed statement should be released by BICSI soon.
Without going into the specifics of the various burn tests, engineered firestops are tested and then listed to allow a finite number of particular cables to pass through the firestop without burn-through over a specific amount of time. How many will ultimately depend on the size and materials used in the cables.
Imagine for a moment your catalog of engineered firestop assemblies as a “cookbook.”
You choose one of the “recipes,” and when you assemble the ingredients according to the directions, you will have a “cake”.
Some of this, some of that?
When baking a traditional pound cake, for example, the recipe calls for a pound of butter, a pound of sugar, a pound of flour and six eggs.
But if you change the measure of any of the ingredients, while you may still have a cake, it won’t the one you’d get by following the original recipe.
Given that a pound is always a pound, then the “eggs” are the only variable. So, in our “pound cake recipe” analogy, let’s assume that the cables are the eggs.
Now let’s “bake” some firestops. We have our “cookbook,” or, in this case, catalog of listed firestopping assemblies, and we choose our “recipe” based on the number of four-pair cables that we have to accommodate within the firestop.
But on this project, our four-pair cables are not the same as the ones that we have used in the past. They are Augmented Category 6 cable. The copper conductors are larger, so the amount of conductor insulation material is increased to cover these fatter conductors. To improve the cables’ transmission performance, there may also be a non-conductive separator inside the jacket. And then there is the jacketing material itself.
Just as we cannot substitute ostrich eggs for the chicken eggs (which is what everyone assumes that our pound cake recipe is calling for) and expect the same results, neither can we substitute the new larger Augmented Category 6 cables for the Category 3, 5 or 5e cables assumed in the firestop catalog and wind up with the same “cake.”
Because of the increased material in the cable, when the firestop is activated during a fire event, it could fail-and fire could breach the containment barrier and travel to other parts of the structure. But this may not be apparent unless there is a fire event, because unlike our pound cake, when we assemble our firestop, we hope that it never gets baked.
If it looks like a duck, and quacks like a duck, we at least have to consider the possibility that we’re looking at a small aquatic bird. But remember, looks can be and often are deceiving.
Bag of tricks
Let’s do an experiment to illustrate. We will take two plastic trash bags: one cheap store brand and one 3-mil heavy-duty contractor bag. Open and place each of them on the floor. Now load about 50 pounds of books into each bag. (This is a great time to use those encyclopedias that have been collecting dust for years.) Close each bag with the bag ties provided, stand back, and take a look. Other than color, they should look pretty much the same.
Of course, trash bags are not designed, manufactured and sold based on how good they look sitting in the middle of the floor, half full of books. Their purpose is to get trash to the curb. So, pick up each bag by the top. The heavy-duty contractor’s bag will meet the challenge, but when you attempt to lift the store-brand bag of books, you will very likely have only the top of the bag in your hand.
But before you “activated” these bags, you really could not detect with your eyes much of a difference. And neither can the AHJ when they are doing building inspections. If the cables are not the same size and materials as the ones used to get the listing during the original burn test, then counting the number of cables passing through the firestop can be deceiving.
This is sort of the dirty little secret that no one really wants to address, but these firestop assemblies will need to be retested using the new ostrich egg-sized cables to determine how many of the cables the firestop can accommodate.
Retesting costs money-about $1,000 each-and the products are already listed. So, if you as the designer or installer choose to misuse the listed product by overloading the firestop, then any failure during a fire event is not the fault of the firestop manufacturer or the listing agency-but you.
So, what can you do?
As a longtime government employee, I became very familiar with the “monkey on your back” game. Did you ever play? No, this is not a children’s board game but a sort of “cover your assets” thing.
If there is a possibility of a problem arising in the future, then move that “monkey” off your back. (Could this be the reason for all those huge file rooms? Hmmm…)
I see at least three choices:
• Look for firestop assemblies that have been listed for use with cables that have up to 22 AWG conductors, with overall sheath diameters up to 0.354 inches.
• If you are required by contract to use a particular manufacturer’s product, and they do not have a product that has been retested and listed for the larger diameter cables, then contact the firestop manufacturer and ask for a letter for your project file stating the number of these larger cables that can be accommodated by their firestop assembly. If they refuse, take the issue back to the contract manager.
• Do what you are doing today and hope that you never have a problem-not recommended.
DONNA BALLAST is BICSI’s standards representative, and a BICSI registered communications distribution designer (RCDD). Send your questions to Donna via e-mail: firstname.lastname@example.org