Electrical Business

Features
Network infrastructure planning for intelligent buildings requires cooperative design


February 26, 2021
By Carol Everett Oliver

Topics


February 26, 2021 – The key to planning and installing an efficient intelligent building infrastructure is cooperative design between the end user, contractor, system designer and facilities personnel. This means detailed meetings and careful project management between all parties.

Planning for a smart building involves more than just connecting the various facilities, systems and building functions. It involves connecting the systems that need to be integrated, usually done through a unified management system to gather, monitor and aggregate data from multiple subsystems.

The list of IP-enabled building applications is growing, and wile many continue to operate over different open communication protocols, they can be integrated via IP protocols (TCP/IP). Examples of these systems include:

• Building automation systems (BAS and HVAC)
• Energy, lighting and electrical power management
• Audio and video systems
• Electronic safety and security (ESS) systems

Advertisment

Resources for the network designer and installer

Several key organizations offer definitions and guidelines for planning and installing an intelligent building infrastructure. They all possess some key similarities, such as defining interoperable systems, providing installation guidelines and, ultimately, improve building management and create cost efficiencies.

Although they complement one another, each document serves a unique purpose:

• ANSI/TIA-862-B (2016) “Structured cabling infrastructure standard for intelligent building systems”.

• TIA-TSB 184-A “Guidelines for supporting power delivery over balanced twisted-pair cabling”.

• ANSI/TIA-569-D (2018) “Telecommunications pathways and spaces” and Addendum 2 “Additional pathway and space considerations for supporting remote powering over balanced twisted-pair cabling”.

• ANSI/BICSI-007 (2020) “Information communication technology design and implementation practices for intelligent buildings and premises”.

• ANSI/BICSI N2-17 “Practices for the installation of telecommunications and ICT cabling intended to support remote power applications”.

• ISO/IEC TS 29125 (2017) “Information technology – telecommunications cabling requirements for remote powering of terminal equipment”.

• ISO/IEC 14763-2 (2012) “Information technology – Implementation of operation of customer premises cabling (Part 2: Planning and Installation)”.

Also be sure to reference the relevant installation sections in the CE Code for additional guidance on communications circuits, allowable ampacities, etc.

Centralized, decentralized or hybrid architecture

When designing the network infrastructure, it is important to look beyond just Day One and plan for the future. The first critical decision is locating the computing power and storage, which will usually be in the data centre or cloud, or the enterprise telecom room(s), or at the edge devices themselves.

The three topology choices are: 1) centralized, 2) decentralized, 3) hybrid.

Centralized architecture

A centralized approach utilizes a central location where analysis, storage and computing occurs. Building applications and devices are connected back to this central location, typically the telecom room or data centre. A single location allows for easier management of active equipment from Day One, but may make it difficult to integrate further applications in the future.

Decentralized architecture a.k.a. zone cabling

In a decentralized architecture, the computing power is located nearer the devices, which usually run on embedded microprocessors. Information is processed locally rather than communicating all the way back to a central location, thereby avoiding potential latency that could inhibit application performance and reliability.

Each zone has one or more enclosures that house the networking and processing equipment, as well as the cross-connections. When new devices are added, the horizontal cable is run from the zone enclosure (versus pulling a new cable from the telecom room).

Hybrid architecture

Depending on the processing, networking, power and storage requirements of the individual applications, a hybrid approach—which employs characteristics from both centralized and decentralized layouts—may be necessary.

Now that the overarching architecture has been decided, let’s get into the design steps for a common infrastructure for data and PoE, the telecom room, cabling and work area outlets.

Designing telecom rooms

ANSI/BICSI-007 provides different layouts and size options for telecom rooms, guided by the space allocated within the building. While it is best practice to plan for the future and allow at least a 50% growth in equipment, it is sometimes not feasible in an existing facility.

The two telecom room options include: 1) a single TR to house the telecom equipment and specialty systems or 2) dual TRs, one for the core network and one for the other systems.

[For graphics, check out the article as published in the February 2021 edition of Electrical Business Magazine.]

In the single TR scenario, the core network is usually located in racks in the middle of the room to allow front and rear access to the equipment and patching fields. The ancillary systems would be terminated either in a separate rack or in wall cabinets. The downside to this layout is that the core network is accessible to other services, which compromises security.

A dual (two-room) TR separates the core network from the additional systems, limiting the accessibility to outside services and providing maximum security for the core. Many new facilities, such as hospitals and financial institutions, are adopting the dual layout for this reason.

Cabling selection for data and power

Cable selection is dictated by the requirements (bandwidth [data] and power [PoE]) of the applications. Since the ratification of IEEE 802.3bt, PoE now enables up to 90 watts to be transmitted over all four pairs of a twisted-pair cable from the power source equipment to the powered device.

One of the main concerns, especially with running remote powering above 60W, is heat build-up within cable bundles, as well as the potential for electrical arcing damage to the connector contacts supporting remote powering applications.

System designers should refer to CE Code-Part I, TIA-TSB-184-A and ANSI/TIA-569-D-2 for safety and design practices for best cable performance and sizing of pathways. These documents all focus on defining acceptable temperature rise as it relates the bundle size, conductor size (AWG), ambient temperature and insulation temperature ratings.

When planned properly, heat build-up and signal loss can be minimized or mitigated. TIA recommends:

• De-rating the cable by reducing the horizontal channel length to make sure the specified cable does not exceed the channel length that matches the cable type and operating temperature.

• For higher power, select a larger-gauge cable (e.g. 22 AWG) to improve heat dissipation, which also allows for further distancing and lower voltage drop.

• Unbundle the cable in cable tray to allow for improved air circulation, as well limiting the maximum bundle size to 24 cables.

• In a pathway, mix cables carrying PoE with those only carrying data.

For new installations, both TIA and BICSI provide a summary of minimum and recognized cabling performance for balanced twisted-pair and optical fiber media. The recommended minimum 4-pair copper cable is Cat 6A/Class EA.

However, BICSI also indicates there are times where the use of other horizontal cabling shall be allowed, so long as the cable does not violate code or authority having jurisdiction requirements, or when the existing installed cable is in use and meets or exceeds Cat 5e/Class D (especially when the installed cable is a result from expansion or other alterations to the system).

Pathway distances for cable runs from the termination equipment in the telecom room require careful planning, and must adhere to industry standards or the cable’s specs. TIA limits twisted-pair cabling to 100 metres for both delivery of data and power. However, the placement of devices (e.g. wireless access points) may well extend beyond that limitation. In such cases, alternative cable or optical fiber should be specified.

Optical fiber cable offers many advantages over twisted-pair for IP-based transmission, as it is able to transmit higher bandwidth over greater distances. Supported optical fiber cabling media per the standards includes OM3, OM4 and OM5 multimode fiber, and all forms of single-mode.

Hybrid fiber cables (where fiber is jacketed with copper strands for power delivery) are available, but this this solution requires additional media converters and active components.

Telecom outlets versus service outlets

There are two categories of work area outlets in enterprise buildings: telecom outlets and service outlets. From a technical and performance standpoint, the two are basically the same, but differ in their application and location, and the person(s) who regularly access them.

• Telecom outlets (TO) are primarily used in locations where the end device is administered by the user (e.g. computer, phone).

• Service outlets (SO) connect to a “non-telecommunications” device (e.g. door controller, security camera).

[For graphics, check out the article as published in the February 2021 edition of Electrical Business Magazine.]

A service outlet is part of the building system; it is relatively permanent and devoted to a specific application. Because of their location, both BICSI and TIA allow service outlets to connect directly to the end of the horizontal cable run, versus having to terminate at a workstation outlet then running a patch cord to the device.

Key to overall reliability

A connected infrastructure for an intelligent building must be planned with five main considerations: performance, space, budget (OPEX and CAPEX), growth and sustainability. Key considerations for network infrastructure planning is the careful selection of the infrastructure components, pathways, spaces and cable management systems that suit the applications.

Pre-planning involves collaborative design, including staying on top of the many resources available (e.g. white papers, updated technical bulletins), and by partnering with industry associations and manufacturers.

A high-performance cabling system creates an efficient, connected, intelligent building that is able to handle the growing demand for power and data while reducing bandwidth bottlenecks and latency issues, and supports the migration toward future IoT demands.


Carol Everett Oliver, RCDD, DCDC, ESS, is the principal of CEO Communications, an ICT consulting firm focused on marketing, industry training and presentations. She is the first female president-elect for BICSI (2020-2022), and will serve as president in 2022. She possesses over 25 years of experience in the industry, and has worked for various cable and connectivity manufacturers. She also chairs the BICSI Intelligent Building standards subcommittee. She can be reached at ceo@ceocomm.com or coliver@bicsi.org.

This feature—along with other great content—appears in the February 2021 edition of Electrical Business Magazine. Even more back issues are located in our Digital Archive.



learning curve Sponsored Content
Post your tech sheets, white papers, new technology etc. Contact Anthony Capkun