The Need for Speed
Challenges in cabling and wiring infrastructure are changing almost as fast as the systems they serve
Telecommunications design once existed outside the scope of the architect/engineer. It was the domain of telephone companies or specialized cabling companies who would design-build these networks as part of a project's final finishes. However, user demands have outpaced technology's growth to the point where even recent construction may require system upgrades. Users now expect-and in many cases require-the A/E to address the cabling system, infrastructure and even individual dedicated systems, as part of the whole. Therefore, engineers must identify pitfalls upfront and preplan for key conditions to make wiring and cabling upgrades easier for all parties.
The design process
The first step is to define the user's requirements. A facility's system is not dictated by codes, nor is it based on standard design criteria. Each user has a different set of needs based on the type of data they use.
Some users will have an information technology (IT) department with specific guidelines detailing the quantity of cabling, termination equipment type and topology required. Others will offer little detail and simply want to connect a computer and phone at every workstation.
Second, engineers need to do their homework. Cabling and wiring infrastructure are evolving at a rapid pace. A case in point is the fact that the telecommunications standards themselves are still in the development phase, e.g. the final category-6 cable standards for the new fiber-optic connector for transmission of gigabit Ethernet. Therefore, a designer can only make recommendations as to the current 'best' solution to meet the user's needs today while maintaining future flexibility.
Third, the integration of the telecommunications design with electrical, HVAC, plumbing and lighting systems is not a luxury, but a necessity.
With an ever-increasing number of end users and owners requiring telecommunications design to be part of their projects, coordination has become the most important issue. Design parameters and key system considerations that were once the user's responsibility-the design of wiring closets and equipment rooms, proper cooling for data equipment, adequate electrical service-are now part of the telecommunication design team's scope. Cabling requires adequate distance from lighting and other electrical equipment, minimum bend radii and stringent termination points.
Navigating the pathways
Coordinating the pathways for communications cabling is also critical in today's dynamic work environment. Several options are available such as utilizing a building's steel, installing 'J' hooks or installing cable tray. The latter may be most preferable, as they keep the cable system organized and reserve ceiling space for future cabling. The downside of cable tray is that substantial ceiling real estate can be lost. The decision to use cable tray has as much to do with the construction of the system as it does with the user's desires. Consequently, cable tray has to be closely coordinated with designs for lighting, HVAC ductwork and sprinkler and plumbing systems.
Many existing buildings do not have adequate space for installation of the tray. As a result, cable tray manufacturers have responded with more flexible tray systems made from lighter gauge metal. These systems can both maintain required cable support and bend to accommodate other installations.
Whenever cable pathways are put in place, the designer needs to take future possible needs into account to allow additional cabling systems to be added with minimal disruption.
The need for careful coordination among engineering disciplines and with the architect surfaces again when assigning adequate cable-distribution closets. Many designers and project team members will look at a facility's computer room and, based upon that assessment, assume that there is sufficient space to house cabling for the entire building. But with today's transmission requirements, data equipment is no longer centralized in the computer room. The intermediate distribution frames (IDF), traditionally stuck in closets and above ceiling tiles in any possible space, now need to have clean, sufficient power-possibly an uninterruptible power source-and cooling to meet the needs of the switching equipment.
Building Industry Consultation Services International (BICSI) recommends one closet-a minimum of 6 inches by 8 inches-for every 10,000 square feet of building space. The construction of the IDF closets require that backbone cabling be designed to handle the necessary distribution of data equipment. Typically, backbone cables consist of copper for voice and fiber optic for data.
Coordinating telecom and electrical
Additionally, communication designers may need to work closely with the electrical subcontractor. The coordination of electrical and telecommunications outlets, cabling, raceways and penetrations during the design phase often prevents many of the problems which creep up once a project is completed.
The relationship with the contractor is important because telecom cabling and low-voltage power falls under the Construction Specification Institute's (CSI) electrical division. This has forced the electrical contractor to either start installing telecommunications cabling or to build a strong relationship with a low-voltage subcontractor. This scenario, however, may change, as CSI is considering the addition of a new division for telecommunication specifications (See 'CSI's Division 17: The Great Debate' on page 17 of this issue).
After the installation of the new cabling system, one of the major decisions is the removal of the old cabling. If the project is part of a major renovation where the user vacates the space, it is always best to remove the old cabling.
But in a construction or renovation project where the client needs to remain operational and will transition to the new system upon completion, the decision is more difficult and possible reuses for the cable should be identified. For example, the old cable might be used for voice applications or as an additional lower-speed data connection. If so, this must be identified early in the project.
In the long run it is always best to remove abandoned cable. This keeps the system organized, leaves more space for additional cabling and eliminates mistakes when installing additional cables. Some local inspectors may require the removal of abandoned cable, so the designer needs to check the local codes.
A final element that is often overlooked is documentation. At a minimum, the client should expect an AutoCAD drawing of the cable system as it was built, along with test results for every cable installed and a spreadsheet with the patch panels and cross connects referenced. This gives the user the information needed to add or change the system without spending significant time and money evaluating actual conditions.
Meeting the needs
As buildings become more complex and facility uses change, the engineer is becoming more involved in meeting the end user's requirements for voice and data infrastructure and systems. With technology driving an increased need for speed, cabling and wiring infrastructure are changing almost as fast as the systems they serve.
Early planning will meld telecommunications requirements with the rest of a project's systems and will go a long way in delivering a successful project.
Cabling Historic Buildings
More often than not, when cabling is installed in any of the 73,000 historic structures listed in the National Historic Register, it is done with very little, if any, prior planning.
Most of these historic structures were built more than 50 years ago, when voice was the equivalent of Ma Bell and no one knew what data was. Today, when cable is added to these buildings, it is not uncommon for the cables to be stapled around baseboards and doors, or to see surface raceway and conduit. In addition, equipment rooms often double as a coat room.
However, this doesn't have to be the case. It is possible to preserve elements like the original trimwork, gilt decorations and even plaster, while equipping a facility with the telecommunications systems needed to operate in today's business world.
The first step is to have a telecommunications designer join the process early on. Make sure the designer has experience with both the building's existing and planned technology.
Second, select a good contractor. The key to getting the project done right is to have a contractor who will spend the time to get the cabling in place while taking care to preserve the building's historic elements. Carefully evaluate the potential contractor's experience with historic buildings and don't overlook a reference check from a contractor's current customer list. Taking a few extra steps in the beginning of a project will only help the project succeed later.
If it is a public project where the low bid wins, it is important to work with the client to review bidding statutes. There are ways to keep the cabling out of the low bid process. Most of the bidding laws have provisions for specialized services, and telecommunications can be considered a specialized service.
Lastly, check whether the telecommunications designer spent the time to survey and detail every element of the project. It is not enough to lay out a cable route, locate telecommunications closets and outlet locations, and then let the contractor go from there. The telecommunications designer must provide enough detail so that the selected contractor has a blueprint for a complete installation and does not need to improvise.
Open Office Design
Open office design has presented numerous challenges to today's telecommunications designer, namely coordinating adequate systems distribution while maintaining design flexibility. In a typical open office environment, 30% of all workstations are moved or changed at least once during the course of a year.
Classic distribution methods involve floor penetrations, power poles or walls and columns to feed the telecommunications cables. Because new cabling needs to run to each workstation every time the workspace is reconfigured, an appealing alternative is zone cabling.
This alternative involves running voice and data cabling to a termination point outside of the actual workstations. A separate cable is then run to each workstation jack location. These zone cabling termination points can be located in the ceiling above the workstation's feed points or at a column base where cabling feeds into individual workstations.
Zone cabling also allows the last 20 to 50 feet to be disconnected during an open office reconfiguration. When the workstations are set up, the cabling contractor has to run cabling only from the termination point to the individual workstation, resulting in substantial time and money savings for the owner.
Even though these systems cost more upfront due to the additional termination points, there can be substantial savings over the life span of a dynamic work environment.