Firestopping Products Williamsport PA

The firestopping industry has certainly seen many changes over its 30-year history. At its inception, it was predominantly used in the nuclear, telecommunications and power plant industries, and has since moved to the industrial arenas, as well as commercial construction.

However, with this acceptance came changes in the fire test standards. In the beginning, firestop designs were tested using ASTM E 119 or UL 263; neither of which addressed the testing procedures or installation methods for firestops in the language of the standard. As the need for proper and more specific testing increased, standards were developed to address through-penetration firestops. These were ASTM E 814 and UL 1479. As further demands were placed on firestops, the standards evolved to evaluate them. For example, the "L" rating has since been added to UL 1479 to gauge the ability of a product to control or restrict air movement at room temperature and at 400 degrees F.

With this increasing demand on firestops came changes in recognition within the building-code community as well. For instance, penetrations in floors were required to be in shafts that greatly limited the ability to run services. Likewise, re-entry of the opening was virtually impossible without creating an opening in the shaft wall. As fire standards became more developed, and the products became available, the building codes were modified for the use of fire-tested firestop products as an alternative to a fire-rated shaft enclosure. And as firestop products became more advanced in their ability, the building codes changed by reflecting the need for "L" ratings (smoke leakage) from UL 1479 in certain types of building construction (Smoke Barriers).

This product evolution is especially evident in the wire and cable industry. The demand from the wire and cable industry has always been ease-of-use and the ability to re-enter a through penetration fire-stop system. With the increasing demand for electricity, additional capacity and speed of new cabling installations, a need arose for firestop products that once were considered permanent, to become far more temporary. End users demanded all of the flexibility of a temporary firestop with all of the performance attributes of a permanent firestop. This caused a major product shift in the industry. Some of the original firestop products were fire-resistant silicone foam and fire-rated mortars.

Product protection

These products were quite effective in stopping fire, but left a lot to be desired for re-entry because they were commonly installed at the full depth of the wall or floor assembly, typically 4.5 to 8 inches. If an additional wire or cable was needed, a new opening was often created due to the difficulty of re-entry into the existing firestopped opening. The next evolution was fire-rated bags for larger openings that required very specific orientation of the bags as the installer filled the opening, in addition to heavy steel cover plates. For smaller openings, intumescent sealant was developed which could be used at much thinner depths than that of foam or mortar. A one to two inch depth served the same purpose as the full depth of the others.

The bags and the intumescent caulk were great steps forward but still did not fully answer the re-entry issue. The bags were cumbersome and typically had to be entirely removed from the opening to add a new cable or wire and the steel cover plates had to be modified. For the smaller openings, the intumescent caulk had to be either chiseled or cut out, which is not preferred due to the potential damage to wire or cable. The next advancement in large opening protecting was intumescent sheets.

These intumescent sheets provided the same level of fire protection as did its predecessors. The sheets were between 1/4- to 1/2-inches thick and were installed on the topside of a floor application, or both sides of a wall application. These products made great strides in making large openings more re-enterable. However, if a cable or wire needed to be added the sheets still needed to be removed from the opening, cut to fit the new cable profile, and then reinstalled. The next step in small opening protection was intumescent moldable putty.

Putting it together

Intumescent moldable putty offers all of the firestopping properties of an intumescent caulk with one major difference: Moldable putty does not dry and harden. It remains flexible and pliable. The cable and wire installer could essentially remove putty from the opening without use of any tools, add a new cable or wire, and then re-install the putty. This was another major step forward in providing a re-enterable product. Over time, and after multiple re-installations, the putty can become contaminated with debris such as gypsum wallboard dust or dirt and lose its adhesive qualities. If this happens, new putty would need to be installed and the old thrown away.

With the continued demands from the cable and wire community for more products that were re-enterable without the limitations of the current products noted above, the firestop industry delivered on that need. Using the ease of installation of the fire-rated bags and the intumescent performance of the boards for large opening applications, the intumescent pillow was developed. This provided all of the fire performance of the previous products with a couple of major benefits. The pillow, from a firestop performance standpoint, did not require steel plates or hexagonal wire mesh as part of the installation. In addition, mechanical anchoring is not required. If a wire or cable needs to be pulled through the opening only one pillow needs to be removed, and then is put back in place with little effort. Using intumescent pillows for large opening applications has made the largest strides in re-enterable firestop solutions.

Next came advancements in small opening protection, which are pass-through devices. These devices have taken the issue of re-enterability further than putty ever could. These devices, in essence, are a metal sleeve with intumescent material inside. The intumescent is typically a pre-formed sheet that is anchored to the inside of the sleeve. This sleeve, with intumescent inside, is then mounted in a floor or wall (Figure 7).

With the intumescent secured to the inside of the device, it allows the wire or cabling to be installed through the middle of the device. Most of these devices have a cable fill approval up to maximum 100 percent visual fill. These pass-through devices take all of the guess work out of firestopping. The pass-through devices have taken small-opening firestopping where the cable and wire industry have wanted to go over the last 25 years.

Are intumescent pillows and the pass-through devices the ideal re-enterable firestop for the cable and wire industry? I will let you be the judge of that!

Brandon L. Cordts is Fire Protection Tech Service & Development Manager for 3M Company — Building Safety Solutions Department. 3M has been creating firestop systems for more than 25 years. For more information, visit www.3m.com.