ICT Today

July/August/September 2021 I 53 Firestop system performance Hourly rating Percent fill Firestop product Opening size, distances Annular space Penetrant Base material In summary, firestop solutions can be used globally but would need to have additional testing and approval listings relevant to specific countries and project locations. For specification purposes, multiple country approvals for single data cable penetration solutions do exist today. For more information about international standards, firestopping, testing, and best practices for design and installations, consult BICSI's Telecommunications Distribution Methods Manual (TDMM), 14th edition. FUTURE DATA CABLE CAPACITY Planning for cable capacity is a critical element of a data- com engineer's or consultant's responsibility. Longer term planning for future cable capacity is essential for any data center. As discussed in the firestop testing section, most traditional firestop technologies allow roughly 30 percent maximum fill of the area of an opening. The other approx- imately 70 percent of open area is left to provide sufficient space around the cables to install enough traditional intumescent firestop material, such as putty or caulking. This is of critical importance in a data center environment for both up-front and future installations. FIGURE 4: Components of a through-penetration firestop system. With the extensive number of fiber and/or copper cables throughout a data center, the approximately 30 percent cable fill limitation is a major "pain point" of owners and their network designers because data cables are continually added to existing openings during upgrades. When this occurs, the existing fire-stop materials typically must be removed, thereby poten- tially resulting in a code deficient situation. New firestop materials would have to be reinstalled correctly in accor- dance with a system for each occurrence. This greatly increases the likelihood of code violations due to incorrect installation and potentially the reduction of the original life safety and property risk mitigation efforts. firestop product from any manufacturer that has a fire rating. Only the holistic firestop system can be rated. In addition to the firestop product, there are several components of a firestop system that impact performance (Figure 4). From type and quantity of penetrating items to size of openings, there are multiple variables of a firestop system that must be installed correctly in order to achieve model code compliance and protect lives and property. Regarding data cable penetrations, percent fill is one of the most critical components. Percent fill is the cross-sectional area of an opening that is occupied by the cables. Tested and listed firestop systems with cable penetrations typi- cally list a minimum and maximum allowable percent fill. Why is this critical for data centers? Many traditional fire- stop systems may limit cable fill capacity to a maximum 25 or 30 percent of the opening area. Too many cables can overload the opening with combustible material. Cable jacketing will burn under fire conditions, creating openings for fire, smoke, and toxic gases. If the firestop system is designed only for minimal intumescent expan- sion, all voids that forms when cable jacketing burns away may not stay completely sealed, thereby risking fire and smoke spreading to the next room. Regarding international standards, UL and ASTM standards referenced in U.S. codes are routinely accepted by countries in Asia and the Middle East. However, the final acceptance decision is ultimately up to the authority having jurisdiction (AHJ) in the country and/or city of the project. In Europe, alternate test standards may apply, such as EN 1366-3, DIN 4102, and BS 476. Addi- tional product approvals such as European Technical Assessments (ETAs) may also be required. The ETA docu- ments summarize tested applications for individual products. The materials are tested according to EN standards (e.g.,1366-3 for penetrations) and classified by EN 13501 guidelines.

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