Common Data Center Acronyms

Common Data Center Acronyms

A few terms used by I.T. professionals and their definitions:

24-7 or 24-365
This is the common way to describe systems which are always on, e.g. 24 hours a day for seven days a week. 24-365 refers to systems that run all year, meaning no downtime…ever.
25 Pair, 300 Pair, et al
A common copper telephone (and data) cable. The actual cable bundles or wraps together 25 discrete pairs of solid copper wires. (See twisted pair)
The American Society of Heating, Refrigerating and Air-Conditioning Engineers advances the arts and sciences of heating, ventilation, air conditioning and refrigeration. They write a lot of the standards for data center systems designs.
Automatic Transfer Switch; this is a switch which instantly transitions the electrical power for a system from line power (from the utility company) to power from an emergency generator and is considered an integral part of a generator-type UPS system.
A high-speed connection that links many networks, many times this is accomplished utilizing a fiber optic cable.
The range of transmission frequencies that a network can use. The greater the bandwidth, the greater the amount of information than can travel on the network at one time.
Blade Server
black serverThin horizontally (or vertically) mounted computer server that can be stacked in a rack.
British Thermal Units or British Thermal Units per Hour. The measure of heat produced by a HVAC system. To put in perspective 1 “ton of cooling,“ a common unit in refrigeration and air conditioning applications, is 12,000 BTU/h. It is the amount of power needed to melt one ton of ice in 24 hours
Category 3 cable, commonly known as Cat 3, is an unshielded twisted pair (UTP) cable designed to reliably carry data up to 10 Mbit/s, with a possible bandwidth of 16 MHz. It is part of a family of copper cabling standards defined jointly by the Electronic Industries Alliance and the Telecommunications Industry Association. Category 3 was a popular cabling format among computer network administrators in the early 1990s, but fell out of popularity in favor of the very similar, but higher performing, Cat 5 standard. Presently, most new structured cable installations are built with Cat 5e or Cat 6 cable. Cat 3 is currently still in use in two-line telephone systems, although Cat 5 or higher could do the same work while facilitating a transition to VOIP.
Category 5 cable, commonly known as Cat 5, is a twisted pair cable type designed for high signal integrity. Usually it is unshielded but shielded cables can also be purchased. Category 5 has been superseded by the Category 5e or “Enhanced” specification. This type of cable is often used in structured cabling for computer networks such as Ethernet, although it is also used to carry many other signals such as basic voice services, token ring, and ATM (at up to 155 Mbit/s, over short distances).
Cat 6- Category—6, (ANSI/TIA/EIA-568-B.2-1) is a cable standard for Gigabit Ethernet and other network protocols that is backward compatible with the Category 5/5e and Category 3 cable standards. Cat-6 features more stringent specifications for crosstalk and system noise. The cable standard is suitable for 10BASE-T / 100BASE-TX and 1000BASE-T (Gigabit Ethernet) connections. It provides performance of up to 250 MHz.
Telephone (or data) cable made up of solid copper (see Twisted Pair)
Central Processing Unit. The main processing chip in a computer system.
Computer Room Air Conditioner
Cathode Ray Tube. Usually refers to a CRT display or an old style TV-type monitor. These are quickly being replaced with LCD’s.
Dark Fiber
Bulk, raw fiber. Dark fiber is optical fiber that spans some geographic area and is sold to carriers and large businesses without any optical or electronic signaling in its path. The customer is responsible for adding the transmission system at both ends.
(Domain Name Server). A computer on the Internet, which translates between a domain name (e.g., and a numeric Internet address (
Emergency Power Off; usually adjective for switch. This switch is required for all data rooms of a certain size. It allows firefighting personnel to kill all power to the room from one central location.
Ethernet is a large, diverse family of frame-based computer networking technologies that operates at many speeds for local area networks (LANs). Ethernet has been standardized as IEEE 802.3. The combination of the twisted pair versions of ethernet for connecting end systems to the network with the fiber optic versions for site backbones become the most widespread wired LAN technology in use from the 1990s to the present.
A private network that is used to share part of a business’s information or operations with suppliers, vendors, partners, customers, or other businesses. An extranet can be viewed as part of a company’s intranet that is extended to users outside the company.
Fault Tolerant
Fault-tolerant design refers to a method for designing a system so it will continue to operate, possibly at a reduced level (also known as “graceful degradation”), rather than failing completely, when some part of the system fails. The term is most commonly used to describe computer-based systems designed to continue more or less fully operational with, perhaps, a reduction in throughput or an increase in response time in the event of some partial failure. That is, the system as a whole is not stopped due to problems either in the hardware or the software. An example in another field is a motor vehicle designed so it will continue to be drivable if one of the tires is punctured.
A common descriptor for Fiber Optic Cable. This cable is made up of many thin strands of glass fibers where signals are sent via pulses of light instead of electrical current.
Form Factor
The 3d size of a device, or shape. (E.g. different manufacturers who make PC’s to accommodate the same class Motherboard are said to conform to the same form factor.)
The actual floor size of a device or piece of equipment.
File Transfer Protocol. The tool you would use to transfer files through the Internet from one computer to another. For example, you would use an FTP to upload your web page from where you built it (like your computer at home) to a web site so that all of your friends and neighbors can look at it.
A computer that links two networks, routing IP data and often converting protocols or messages from one network to the other. The term can also refer to a system capability that provides direct access to other remote networks or services.
Hyper Text Markup Language. The language/code used to create web pages. HTML is not really a programming language, but a way to format text by placing marks around the text. For example HTML allows you to make a word bold or underline it. HTML is the foundation for most web pages.
(compare Internet and Extranet). Internal systems, based on Internet technology, designed to connect the members of a specific group or single company (a closed-user group). An Intranet is nothing more than a private Internet. In other words, it is a private network, usually a LAN or WAN, that enables the use of Internet-based applications in a secure and private environment. As on the public Internet, Intranets can host Web servers, FTP servers, and any other IP-based services.
ISO 9000

ISO 9000 is a family of standards for quality management systems. ISO 9000 is maintained by ISO, the International Organization for Standardization and is administered by accreditation and certification bodies. For a manufacturer, some of the requirements in ISO 9001 (which is one of the standards in the ISO 9000 family) would include:

  • a set of procedures that cover all key processes in the business;
  • monitoring manufacturing processes to ensure they are producing quality product;
  • keeping proper records;
  • checking outgoing product for defects, with appropriate corrective action where necessary; and
  • regularly reviewing individual processes and the quality system itself for effectiveness.
Information Technology. It used to be called (a long time ago…) MIS, Management Information Systems, but management aren’t the only ones who use these systems any more, so it is now just called generically IT.
KA or KW (Power factor)
The power factor of an AC electric power system is defined as the ratio of the real power (KW or Kilowatts) to the apparent power (KA or Kilovolt Amps), and is a number between 0 to 1 inclusive. Real power is the capacity of the circuit for performing work in a particular time. Apparent power is the product of the current and voltage of the circuit. Due to energy stored in the load and returned to the source, or due to a non-linear load that distorts the wave shape of the current drawn from the source, the apparent power will be equal to or greater than the real power. Low power factor loads increase losses in a power distribution system and results in increased cost for electrical energy use.
LANA Common LAN Schematic

Local Area Network. The linkage of computers and/or peripherals in a limited area, usually less than two miles, which allows users to communicate and share information.

Liquid Crystal Display. Refers to a flat screen display. Compared to CRT’s the big advantages include less space (e.g. smaller footprint) less power, lighter weight, greater contrast, wider screen angles. Disadvantages include lower resolution (e.g. jagged edges) higher reject rate during fabrication therefore higher costs, etc.
Voltages typically below 115v AC. Many data systems run on 115v AC, but telecommunications systems historically run DC to the racks at 48 volts.
Mean time between failures. This is the mean (average) time between failures of a system. In other words this is the average life of a system. Hard disks specifications many times include the MTBF ratings.
Megahertz or one million cycles per second. This is applied to alternating currents, clock cycles in CPU’s, or even radio waves.
N+1 or 2N
Level of redundancy in the supporting infrastructure for a network or data center. N = need (e.g. N=2 five ton air conditioners, then N+1 = 3 five ton air conditioners; or 2N = 4 five ton air conditioners).
National Electric Code. (Also referred to as California Electrical Code or NFPA 70.) It is a standard for the safe installation of electrical wiring and equipment. While the NEC is not itself a U.S. law, NEC use is commonly mandated by state (including California) or local law, as well as in jurisdictions outside of the United States. The NEC codifies the requirements for safe electrical installations into a single, standardized source.
National Electrical Manufacturers Association, a U.S. industry group representing those who design and manufacture electrical equipment
National Fire Protection Association, is an independent, voluntary-membership, nonprofit (tax-exempt) organization. NFPA’s mission is to reduce the burden of fire and other hazards on the quality of life by providing and advocating scientifically-based consensus codes and standards, research, training, and education. NAPA publishes many standards used by local fire departments to establish minimums for fire protection systems, including Fire Sprinklers.
Network Operation Center. Similar to a SOC but this will monitor the entire network center on a 24/7 basis, sometimes including several distant data centers.

patch panel

Patch Panel
This is a sophisticated name for a hub with many connections. This is where the network cables connect to the network servers from the clients or desktop computers. It is used to route the many signals into the servers or other switches.
Punch Down Block
This is similar to the patch panels, but it is utilized for analog voice or telecommunications wires.
Power Distribution Unit. Power Distribution Unit (PDU) provides power distribution, and the

pd block

 ability to monitor the aggregate current draw as equipment is connected to the unit. Typically these filter the electrical power to prevent surges, spikes and other anomalies from reaching the data equipment…think industrial
size power strips.
A router is a device (or in some cases software in a computer) that determines t
he next network point to which a data packet should be forwarded toward its destination. There are lots of variations of routers depending on where they occur in a network and how much traffic they are designed to handle.
RF (e.g. screen room)
Radio Frequency. As you know from your physics classes, electrical circuits produce magnetic fields around the circuit and when the frequency is in the radio wavelength spectrum it is called RF. RF interference can impede smooth data flows over data wires and wireless devices hence screening and separation can become critical.
It can either be a program or a computer that is dedicated to a certain purpose. Often it means both at the same time, but sometimes it can be important to know, especially if you’ve just been asked to install it.
Systems Operation Center. Typically a “Mission Control” style room where technicians can monitor the health of a data center on a 24/7 basis.
Soft Crash
When electrical power is unintentionally interrupted to a system and the data systems are served by emergency power (through a UPS) which cannot be reliably provided for an extended outage, the systems operators can execute a systematic shut down to bring down the systems and prevent data loss. When reliable power is reestablished the system can then be brought back up and data services restored. Conversely a Hard Crash is an instantaneous power outage which typically interrupts data flows and results in data loss…not a good thing.
Tier 2, Tier 3, Tier 4
Classification of the level of reliability of a data center or network as established by the Uptime Institute. It classifies systems redundancies, number of alternate data distribution paths, etc. Tier II = roughly 99.75%, Tier III = 99.98%, Tier IV = 99.99% reliability.
Twisted pair
twisted pairA common descriptor of telephone (and data) wire. A pair of solid copper telephone wire can handle a single call discrete call prior to arriving at a switch (which usually includes devices to multi-plex or MUX to combine calls over a single twisted pair or fiber cable. (See 25 pair/300 pair).
Uninterrupted Power Supply; a back-up power supply for computer systems. This can take many forms depending on the scale of the systems. It can be as small as a shoebox-sized box with sealed batteries to support a single computer (CPU) or as large as 10’x14’x14′ high diesel generator, with a Automatic Transfer Switch (ATS), battery banks and/or power conditioning units.
VA or Volt Ampere
A volt-ampere in electrical terms, means the amount of apparent power in an alternating current circuit equal to a current of one ampere at one volt. It is dimensionally equivalent to watts. An example might be an AC transformer rated in electrical terms by volt amperes.
VOIP or Voice over IP
Voice over Internet Protocol, also called VoIP, IP Telephony, Internet telephony, Broadband telephony, Broadband Phone and Voice over Broadband is the routing of voice conversations over the Internet or through any other IP-based network. Essentially your voice (an analog signal) is converted at the instrument (or phone on your desk) into a data signal made up of discreet data packets just like your email message, it is then sent over the internet to an IP address where is reconverted into an analog signal at the receiver’s phone. The instrument is an I.P. type phone and the receiver has to have an I.P. phone or have the signal converted somewhere in between. This is typically handled automatically be the phone switches involved in the transfer of the signal
Watts per square foot. This is sometimes used as a benchmark for how much power can be delivered to a given area. Office spaces typically need about 10~20 WSF. Data centers range for traditionally of up to 85WFS. Newer data centers that cater to Web hosting systems can now exceed 200~400WFS!
Wide Area Network. A computer network in which widely dispersed computers, such as those among several buildings or across a city or state, are interconnected. WANs make use of a variety of transmission media, which can be provided on a leased or dial-up basis.
Web Server
A program (or sometimes referring to the actual machine) that serves up web pages upon request.

* Some material excerpted from, the free online encyclopedia that anyone can edit at 


About the Author
J. Edgar “Ned” Fennie Jr. is co founder of FENNIE+MEHL Architects located in San Francisco. FENNIE+MEHL Architects specialize in office development with expertise in space planning, interior architecture and ADA and code compliance consulting.

Ned is also Chair of the Code Advisory Committee to the San Francisco Building Inspection Commission. The Code Advisory Committee (CAC) consists of 17 members who are qualified by training and experience to deliberate and make recommendations on matters pertaining to the development and improvement of the content of the San Francisco Building Code, Mechanical Code, Electrical Code. Plumbing Code, Green Building Code and Housing Code as well as related rules and regulations or proposed ordinances that the Director of the Building Inspection Department determines may have an impact on construction permits. Specific recommendations of this Committee are directed to the Building Inspection Commission for their further action. Additional information.

Ned Fennie, Jr. AIA
Fennie + Mehl
P: 415-278-9596

Is your lease is up within the next three years? We should talk now. We go the extra mile for our clients…big and small.

How Much Will Our Tenant Improvement Project Cost?…It Depends

“How much will our Tenant Improvement project cost?”

“We just want to tear down a few walls and convert the storage room to a small server room, that can’t cost a lot, right?”

“Why is it so hard to determine construction costs up-front?”

During the early phases of an office relocation I often hear questions like these repeated by clients seeking to pin down the cost question, so they can get a handle on the financial commitment they are about to make. Many times the project costs are first brought to their attention when the prospective landlord offers a Tenant Improvement allowance. Invariably I will get a call to confirm that the amount offered is sufficient to cover the actual costs the tenant is likely to incur, so that they will not have to come out of pocket the fund the construction. Although the question is undeniably simple and straight forward, the answer is nonetheless very difficult to answer and at best, if an Architect or Contractor does throw out a number, it is most likely quickly followed by long list of qualifiers which can render the answer meaningless.

Why can’t a tenant get a straightforward answer? It seems simple enough, but it can be frustrating when lease negotiations are proceeding apace and a tenant needs to evaluate carefully the financial ramifications of their lease before they execute the contract. The construction cost is a huge part of that financial commitment and when it can’t be firmly established up-front it adds to the risks of leasing in any given building.

Factory production versus on-site assembly

When you go to buy a car and ask what will it cost, in a few minutes a car dealer will tell you exactly how much your new car will cost. Or how about other large purchases, such as appliances or a boat, the costs are right on the sticker, so why don’t construction prices have a “sticker price”? To answer that question we have to begin by digging further into the processes that lead to the completed item being delivered.

We live in a highly industrialized society, and many items that we consume every day are fabricated or at least processed in a factory setting, from the clothes we wear to the furniture you are sitting on, even the food we eat is processed and shipped to our local retailer, where the price is established. All of the material costs and labor costs (including shipping, marketing costs, and profit) are included in that price. The item has been built up with commodity materials purchased in bulk, and assembled by a skilled, permanent labor force, and shipped in bulk to the store. The item has been designed and redesigned to keep the costs at a minimum, the product quality high, and the assembly time to a minimum. Indeed, the trend over the centuries is to continually reduce the labor time to bring costs down. The labor costs are, for the most part, very predictable and usually highly controlled, either through negotiated contracts established through collective bargaining or through market forces. Costs added by regulation from outside government entities are also fixed and most likely are reflected in the final price, sales tax being the exception. Therefore a producer usually has a very accurate picture of what the costs are (and more importantly how much an item will fetch in a given market) before the item ever leaves the assembly line.

A Question of the Number of Variables

So how is the construction process any different? For the most part the assembly of buildings (or Tenant Improvements) hasn’t fundamentally changed over the centuries. Compared to factory production where most costs are for materials, construction is a labor-intensive process, utilizing generally local materials, assembled by itinerant project teams of a mix of skilled and semi-skilled labor creating a product which is unique in time and space. Picture the Bilbao Museum designed by Frank Gehry or locally the new DeYoung Museum by Herzog and de Meuron and you will understand that it is exactly the uniqueness of a building which belies the desired predictability of the costs for construction. You most likely will hear our politicians exclaim, “They have never built that before.” when describing why a large public works project has gone “over budget”. And they are right. Without the design and redesign processes factories would also struggle with unpredictable costs. Instead of thinking about your project as just like some other project only in this location, consider the construction project as building a full scale mock-up for the first time and you’ll understand what I mean. (The exception to this is what subdivision home developers do; build individual houses using the same design, constructed sequentially in close proximity to the last unit, with fixed teams of skilled workers. This allows them to determine their costs much more accurately.)

Although your Tenant Improvement project may be similar to the last one you did in reality it has never been done before. A team of workers will have to be assembled, many of whom have never worked together before and may not ever again. This means that your contractor will have to collect all workers for your project, orient (train) them about the unique conditions of your particular building space and of this particular design, a design that they have never seen before. Although the contractor will look for people who may know your building or may be familiar with a particular designer’s work, each team and each space is unique. The amount of experience a team has will vary along with the labor costs for individual members. The more experience a worker has the more efficient they are, hence lower cost but possibly higher hourly rate. It is the uniqueness of a team that drives the unpredictability of the labor costs.

Each Project is Unique

Because no two buildings are exactly alike the infrastructure and the existing condition of the space will vary. For example, prior to the tenants arriving some office building developers will have installed the main heating ventilation and air conditioning (HVAC) system (including the chillers and main fans) but not the distribution systems on any given floor. Or they may have installed everything but the VAV boxes for each of the zones on the floor. Another approach is to install the VAV boxes in but no distribution ducts downstream from the boxes. Or even yet, if the space is a second generation space (it was occupied by a previous tenant who made improvements) and offered “As-Is” you may inherit all of the HVAC components, but some pieces may need replacement due to age, and some components likely will have to be relocated and recalibrated depending on your particular room layout. The actual condition and completeness of the HVAC system can have a huge impact on the costs of your tenant improvements. Unless the existing system and your planned redesign of the system are closely evaluated by a knowledgeable engineer or mechanical estimator, HVAC costs cannot accurately be determined.

When your space is built out by the contractor they are charged with buying out all the materials for the project. Some of the materials are purchased regularly, so the prices are predictable, but unstable market forces can and will affect these prices, so they may still be somewhat volatile. Until the actual order is placed the price of any given material is variable, so the longer the time lag between when your estimate is developed and when the orders are actually placed, the higher the risk that the prices could increase.

When you first need to get a handle on costs is usually early in the leasing process and you may feel it is too early for you to sign up a contractor, indeed you are unlikely to even have an approved Space Plan at the point where you begin budgeting your construction costs. But if you have your contractor sign a Lump Sum or Guaranteed Maximum Price (GMP) contract, and the costs go up even though you haven’t changed your design, the contractor will have to absorb the cost increases. If you sign a cost-plus contract you pay for the increases (and benefit from any cost savings as well). But until you sign a contract, you are going to be directly subjected to the market forces.

Alternative Approaches

So back to our initial question, “What’s it going to cost?” The only way to truly answer that question is through the collection of more information. The better your project is defined the more accurate the estimating can be. Traditionally a tenant would hire an architect (who in turn hired design engineers as consultants for the HVAC, Electrical and Life-Safety systems) to complete a Space Plan and the subsequent Construction Documents. The CD’s were then issued to 3-4 contractors for competitive bids. This project delivery approach (sometimes referred to as the Design-Bid-Build approach) was utilized for decades and is still in practice for many projects. However, it has some downsides, one of which is that the Owner goes blindly through the design process without having a good handle on the final price, and typically, if all the bids come in over the budget amount, there is a mad scramble to quickly redesign the project to bring down the cost and try to keep the project on schedule. Cost overruns and schedule delays are common with this approach. So what is the problem with this approach? The person who has the most information about construction costs (both materials and labor), the general contractor, is kept out of the design process. Then they are put into a competitive bid situation which at best keeps him or her at arm’s length from the owner and design team. Animosity is high, changes are not only common, but costly and the contractor’s knowledge and experience is brought in very late in the game. Many design professionals are realizing that this is not the best approach.

A newer approach that is becoming popular is a Design/Build project delivery system or some variation thereof. In this approach the owner, or tenant teams up or partners with a contractor (usually after a selection process which may or may not include a competitive bid process on fees and mark-ups) before any Construction Documents are drawn up. The contractor is brought in early to review the design as it is developed and to produce accurate cost modeling to keep the owner or tenant informed of the likely costs once the project is bought out. If the costs are expected to be above the budget the design can be modified as the drawings area developed. In that way the final Construction Documents will reflect a design the tenant will likely be able to afford, and it eliminates most of the surprises. This in turn helps keeps the project on schedule and without significant delays.

Early on in the preconstruction or design phase, with an approved Space Plan and with the help of an architect and contractor (who are familiar with the particular building and have worked together) your team should be able to give you a reasonable budget estimate, with a +/- 20% range of variability. When the construction documents are 75% complete the contractor should be able to refine the construction cost estimate to within a +/-10% range, and when the project is bid to the subcontractors the prices are locked in and any price variability risk is then transferred from the tenant to the subcontractors.

Some people have questioned the use of the Design/Build process as it gives up some of the hard competitiveness of a normal hard bid process, which is quite possible, although the general contractor should be hard bidding all of his subcontractors, which may amount to 80-90% of the total project costs. So, in reality, you may be giving up hard bid competition of 10-20% of the costs in order to get the contractor onto the design team early in the process; you can proactively control your design and construction costs as the project develops. Many people find themselves in situations where delays can be costly (e.g. lease hold-over clauses with steep penalties, and/or missed business opportunities or milestones) and they find that the risk of project delays outweigh the minimal lost competitiveness in construction costs. And indeed, having the contractor become your partner in the design process usually means the project will be of a higher quality, somewhat lower architectural fees, and be run much more smoothly.

Project Teaming Strategy

So what will it cost? The answer is, “It depends.” It depends on your project delivery approach, your tolerance for risk, your need to deliver the project at the lowest possible price, your schedule, your location and most importantly your team. Critical to assembling your project team is the architect, and they should be hired as soon as you start looking for a space. After discussing your particular situation, your architect should then be able to help you strategize your project delivery approach and budgeting process.

When selecting your architect make sure that the party whom you chose is adept at providing functional, unique designs in a team environment, and is open to working with the contractor to deliver the best possible project, on time and at your expected cost. Egos need to be checked at the door and all members of the design team will need to work together to develop a functional and affordable design. Excluding the contractor from the design team keeps an important member of the team from bringing important cost and schedule information to bear on the project, and ultimately delays the answer to the cost question, until you have traveled quite far down the design road. Bring them in early, make them a part of your design team and start getting your cost questions answered early on. It is obvious why this approach is quickly becoming popular for tenants looking to relocate their facilities. If you want a smooth, predicable project with few surprises, build up your team early in the process with a seasoned architect and a contractor experienced in preconstruction services, and you won’t regret it.

About the Author
J. Edgar “Ned” Fennie Jr. is co founder of FENNIE+MEHL Architects located in San Francisco. FENNIE+MEHL Architects specialize in office development with expertise in space planning, interior architecture and ADA and code compliance consulting.

Ned is also Chair of the Code Advisory Committee to the San Francisco Building Inspection Commission. The Code Advisory Committee (CAC) consists of 17 members who are qualified by training and experience to deliberate and make recommendations on matters pertaining to the development and improvement of the content of the San Francisco Building Code, Mechanical Code, Electrical Code. Plumbing Code, Green Building Code and Housing Code as well as related rules and regulations or proposed ordinances that the Director of the Building Inspection Department determines may have an impact on construction permits. Specific recommendations of this Committee are directed to the Building Inspection Commission for their further action. Additional information.

Ned Fennie, Jr. AIA
Fennie + Mehl
P: 415-278-9596


Is your lease is up within the next three years? We should talk now.

We go the extra mile for our clients…big and small.

Seismic Retrofit Requirements and Their Triggers

When a tenant or building owner contemplates making changes or renovations to an existing building, invariably the topic of code-required seismic upgrades comes up (or more specifically, alterations to strengthen the lateral resistance capacity of the building). Most people want to know in advance of doing any design work, what the seismic requirements will be and what parts of the renovation project will trigger any seismic work. Be aware that the type of project you may be considering and the scope of the anticipated alterations can trigger upgrades to the structural system, and your building permit application will need to include the seismic work as part of the scope of work covered by the permit.

The cost of this type of work can be significant, depending on a number of factors such as the age of the building and how inherently strong it is resisting earthquake forces. The costs can be a “dealbreaker” in many leasing situations.

So how can a tenant get a clear answer on whether his or her Tenant Improvement project will trigger an upgrade? Unfortunately the simple answer is, “It depends.” The real answer needs more thorough analysis and you are advised to seek the help of a registered architect and/or structural engineer to ascertain the code requirements for your project. However, a discussion of the general concepts for the triggers and the requirements can be useful in reviewing potential lease spaces and their renovation requirements prior to selecting a potential building.

Building Code Requirements

The building code (which covers all new building construction, additions and renovations) is where the applicable seismic provisions are typically enforced. In addition to structural design requirements, the building code also covers fire resistance, disabled access and other life safety requirements.

Identify the jurisdiction

So to begin to answer the million-dollar seismic upgrade question, first we start with the project location and whether the building is under the jurisdiction of the local municipality. Certain building types are exempt from local building department review (and subsequently local amendments). For instance, federally owned buildings are exempt from local review and the California Building Code (CBC). Hospitals and other types of medical facilities are generally not under the jurisdiction of the city or county where they are located, but rather they are reviewed by the Office of Statewide Health Planning and Development (OSHPD). Schools and other types of K-12 facilities are generally not under the jurisdiction of the local municipality, but rather they are reviewed by State Fire Marshall’s Office (SFM). State Office buildings are reviewed by the Office of the State Architect (OSA). Prisons and other correctional facilities area reviewed by the California Board of Corrections, and so on.

So you must first identify who actually owns the building and if the local building department has jurisdiction. If the building is located in San Francisco and is subject to the jurisdiction of San Francisco Department of Building Inspection, the local building code amendments do include a more detailed set of seismic upgrade requirements and specific triggers depending on the scope of work and occupancy of the building. [See San Francisco Requirements below]

Occupancy and Buildings covered by the CBC

The occupancy group classification of the building (or more simply, how it is used) determines which provisions of the building code apply. It is therefore important that the existing and intended uses are clearly ascertained. The CBC divides the regulations into two broad categories: (1) occupancy or use of the building, and (2) construction type or what the building is made of. [This makes good sense; the life-safety qualities of any building are a function of how intensely the building is used (e.g., a warehouse with few people and no combustible items have fewer limitations than say a movie theater with lots of people and some highly combustible materials) along with how strong and fire resistant the main building materials are. For example, a highly combustible wood framed building has more restrictions than a virtually non-combustible concrete framed building.]

The seismic upgrade triggers included in the CBC are all tied to changes in occupancy or use [Title 24, Section 3408.4]. Therefore, if your building is covered by the CBC without local amendments you will need to determine the approved use of the building (e.g., how it was classified when it was permitted) and confirm that the intended use after the renovation are in the same group. [See sidebar at right]

The CBC states that an existing building will have to “conform to the seismic requirements for a new structure” when a change of use is contemplated that intensifies the use (e.g., increase the number of occupants and/or the amount of combustible materials stored in the building). This means that the building, as renovated, will have to meet all current strength requirements, and depending on the age of the existing building, this can be costly. This is due in part to the code-required strength levels that have systematically increased over several decades as engineers have concluded that the expected demands on buildings from earthquakes in our area are greater than previously anticipated.

Therefore, assuming your building was classified as Group B and the intended use falls clearly into one of the listed Group B uses, and the building is subject to the CBC without local amendments, no seismic strengthening will likely be triggered by the renovation work.

San Francisco Seismic Triggers

In San Francisco, the building code has been amended to require building owners to upgrade their building(s) as they are renovated. The type and scope of the renovation will determine the amount of structural work required. However, when seismic work is triggered, it typically does not have to meet the full strength levels as defined by the CBC, which can significantly reduce the cost of the seismic work. [See San Francisco Structural Design Requirements vs. CBC Requirements below.]

There are many different triggers in San Francisco. Mainly they break down into three categories:

  • Increase in building size or occupant load
  • Structural modifications or repairs
  • Extent of renovation

Increase in building size or occupant load:
Assuming there is no change of use or occupant load and the building size is increased through a vertical addition (e.g. added story), the new addition will likely have to meet the CBC requirements and the vertical load path from the addition to the foundation will have to be adequate to carry the new loads. Projects that include vertical additions should be reviewed early on in the design process by a structural engineer to confirm the existing structural elements are adequate to handle the loads and will meet current demand/capacity regulations as defined in Sections 1609 and 1613 of the CBC.

Assuming there is no change of use or occupant load, and the building size is increased through a horizontal addition, and the area of the horizontal addition is less than 30% or the original building area (as defined by SFBC 3403.4.1.1), only the new addition will likely have to meet the SFBC upgrade requirements with no upgrades required for the remainder of the building. Larger horizontal additions that are not isolated structurally from the original building structure will likely have to be built to CBC standards and the original building will likely have to meet SFBC upgrade requirements. If the structure of the new horizontal addition can be isolated, then only the new structure will likely have to meet CBC standards with no upgrade required for the original building.

If the anticipated project changes the use, which in turn increases the occupant load by 10% and the occupant load for the building is more than 100, the entire building will likely have to meet the SFBC upgrade requirements.

Structural Repairs and Modifications:
Structural modifications are those which typically change columns, beams and shear walls or braces. If the structural work you would like to do is repair or replace more than 30% of the floor or roof areas and/or their structural supports (cumulative, beginning on May 21, 1973), – the entire building will likely have to meet the SFBC upgrade requirements.

It should be noted that seismic upgrades to the structural system, which are not triggered by a renovation or addition, can be done on a voluntary basis and typically will not trigger other seismic requirements. The upgrades may trigger accessibility upgrades (or other life-safety requirements) and you should consult with a registered architect prior to proceeding on the design work.

Extent of Renovation:
Depending on how much of the building is to be remodeled by non-structural Tenant Improvements (TI), the TI work may also trigger seismic upgrades. What is somewhat unique in this requirement is that the renovation work over the last two years is taken into account along with the renovation project in question. Be aware that it is possible that a small Tenant Improvement project on one floor of a multistory building could, where other projects have been completed over the last two years, trigger a full upgrade to the building. The trigger is defined as where two-thirds or more of the floors (excluding basements) in the building are “Substantially Altered” (e.g., partitions or ceilings are renovated or have been changed in the last two years, per SFBC 3404.7). In this event, the entire building will likely have to meet the SFBC upgrade requirements.

So assuming there is no change of use or occupancy, and the project is limited to one floor or less in a multistory building that has not seen any renovation activity for at least two years it is unlikely that it will trigger any seismic upgrading.

San Francisco Structural Design Requirements vs. CBC Requirements

In the event your project must meet SFBC seismic requirements when triggered by a renovation or addition, the force levels and other detailed standards contained in the current CBC have been relaxed somewhat. The main item is that the seismic force level is only 75% of the requirement in the CBC. Also, what is referred to as the near-field effect factor as required in the CBC to account for the proximity of active faults and the subsequent increase in force levels is held a 1.0 ( or no required increase for nearby faults.) However, for most buildings (less than five or six stories) in most parts of San Francisco (closer to downtown), there are no near field effects, due to the distance to the nearest active fault. There are a number of other exceptions to the CBC that your engineer can take advantage of when designing seismic upgrade projects in San Francisco.

There are also a number of other minor exceptions and you may find that even your structural engineer may not have a clear picture on how the specific regulations apply to a particular project. In this event, building permit applicants are encouraged to request that their architects or engineers apply for a Pre-Plan Review meeting to discuss the project in detail with the building department officials. That way, the seismic triggering issues and the subsequent design requirements can be clarified and documented in writing before proceeding with the construction documents and permit application. This will speed up the department plan review and avoid costly surprises and delays in the permit application process.

Also, it should be pointed out that the building code is a minimum standard, and therefore not only can you exceed the requirements contained therein, but you are encouraged to do so whenever feasible.

With the help of your architect or structural engineer the seismic upgrade issues can be identified and quantified early on in the design process, so that all the parties to a lease will know their respective responsibilities and minimize their exposure to surprises in the tenant improvement process. And the earlier the question of whether a seismic upgrade will be triggered can be determined, the more time will be available to design cost-effective solutions to meet the requirements.

About the Author
J. Edgar “Ned” Fennie Jr. is co founder of FENNIE+MEHL Architects located in San Francisco. FENNIE+MEHL Architects specialize in office development with expertise in space planning, interior architecture and ADA and code compliance consulting.
Ned is also Chair of the Code Advisory Committee to the San Francisco Building Inspection Commission. The Code Advisory Committee (CAC) consists of 17 members who are qualified by training and experience to deliberate and make recommendations on matters pertaining to the development and improvement of the content of the San Francisco Building Code, Mechanical Code, Electrical Code. Plumbing Code, Green Building Code and Housing Code as well as related rules and regulations or proposed ordinances that the Director of the Building Inspection Department determines may have an impact on construction permits. Specific recommendations of this Committee are directed to the Building Inspection Commission for their further action. Additional information.

Ned Fennie, Jr. AIA
Fennie + Mehl
P: 415-278-9596

Is your lease is up within the next three years? We should talk now.

We go the extra mile for our clients…big and small.

Space Planning: How Much Space Do You Really Need?

by: Ned Fennie

Try Ned’s 3-question Space Calculation


At the onset of a search for office space a real estate broker will invariably want to know right away how much space will be needed by the prospective tenant. If you have been through this estimating the right amount of space required for a new facility can be tricky. Leasing too much space and cash flow can be hobbled by an excessive rent payment and under-utilized space, too little space and staffing growth will be limited. This may result in the need to relocate, prior to your lease expiration—potentially a very expensive exercise. Adding the architect to your leasing team early in the process to develop reliable space requirements (before you begin looking at potential lease spaces) can make all the difference in leasing the right size and type facility for your company.

If you are the owner of the company, an experienced architect will arm you up front with all the crucial information, so you can confidently make the correct strategic real estate decisions for your firm. This will save you precious time and effort. Having this information in hand when you begin looking for space will allow you to pre-screen potential lease spaces and quickly zero in on only those spaces that really meet your long term business plans. The overriding goal is to make sure that when the dust settles your new space not only meets your functional requirements, but reflects positively on you and your company throughout the duration of the lease term.

If, on the other hand, you are the person responsible for finding facilities for a larger organization, you know that relocating your corporate offices, or opening a new branch office can be a very challenging experience, one that will demand the most from you and your team.

What’s most important is that the transition be as painless as possible for all involved, users and management alike. Your team should help you get moved in on time while avoiding any bumps along the way. This is best accomplished by having a clear program of the space and functional requirements early on, and this is best collected by a professional architect. This program information will assure you there are no surprises for upper management and provide them with a clear picture of the size of the office being considered, as well as the projected head count for this particular site.


The first step an architect will usually do is derive a baseline of your existing facilities. This is accomplished by surveys, discussions with user groups, and interviews with principals or group leaders to ascertain the company goals (both in the near and far term). The architect will then collect all this information and carefully analyze trends in your space allocations and your cultural and functional organization.

This information should be formally presented back to you in a report format which can be quickly reviewed and endorsed by management, and then passed along to the leasing agent. The program report should document both the quantifiable aspects of the new office as well as the more subjective or qualitative goals for the architectural design. Once this report is accepted and based on that information your broker can then quickly develop a short list of the building spaces which potentially meet your needs for review by you and your architect.

Important Factors to Consider

There is a series of metrics which is invaluable for analyzing the efficiency of any office space, both existing and planned spaces. These metrics form the yardstick which you will need to measure the potential candidate spaces and layouts. Your architect will assist you in the analysis of your current space and the plan(s) for your new space. These numbers usually take the form of a series of ratios and the most common ratios are listed here. There are others which would apply to your specific work-flow and functional organization; and where applicable, these will be identified and tabulated by the architect.

Gross Density Ratio

One ratio which can be helpful is to determine your current Usable Square Feet per person ratio. While this will give you a general idea of the density of your existing space, if you are considering a significantly larger or smaller office, extrapolations using this ratio can be misleading, as not all rooms or spaces grow or shrink proportionally. For example, the amount of space dedicated to support areas and rooms, such as server rooms or copy/mail areas is not usually directly proportional to the number of private offices or open cubicles. Additionally if you plan to adjust the office-to-open cubicle ratio in the new office, this will change your gross density ratio. Typically this ratio ranges from 175 USF/person (and lower) for densely planned, larger, all cubicle offices and up to 325 USF/person for smaller, private office intensive service firms with frequent in-office client/visitor meetings.

Enclosed to Open Ratio

This is the number of staff in private or enclosed offices compared to those in systems furniture or open cubicles. Generally enclosed offices take up more space on a per person basis, so this ratio can have a direct impact on total space required. It also will have a big impact

on the corporate culture and it can affect how your firm is perceived in the marketplace by both clients and potential candidates for hire. Law firms, large accounting firms and some software firms generally have a higher private office ratio

than average, whereas computer hardware, telecom companies and other horizontally managed firms tend to favor a more open office environment with a lower than average private office ratio. Both approaches are valid for the respective organizations and depend on many factors within the company. Security, communication between staff, levels of hierarchy in management and other cultural factors all play a role in the definition of this ratio. This should be considered carefully before locking in the desired size of a lease space for consideration.

Conference Room Ratio

The ratio between number of staff served by each conference room is another metric for programming a space requirement. Firms operating in predominantly open office environments tend to need more rooms for private meetings between staff, both for small personnel meetings as well as large team or group meetings. This ratio can range from one conference room to 10 employees in an all open office environment to one conference room per 20 employees in a private office-rich environment. This ratio should be carefully considered and your architect can guide you to an appropriate ratio based on discussions with management. Once the private/open ratio is established, the architect will then be able to recommend an appropriate amount of conferencing rooms or other spaces and the resultant space requirements.

Circulation Factors

At first glance it may appear simple to just list all the spaces needed, along with their respective sizes and arrive at a total square footage requirement; however, additional space should be allocated to account for hallways and circulation paths within your space. This can vary dramatically depending on how efficient a layout that can be accomplished within a given building footprint.

For example, the dimension between the outside wall of the building and the interior building core rooms (toilet rooms, elevator shafts, etc.) should allow for hallway to give access to one or more rooms on each side of the hallway. A low dimension here will likely mean only one side of the hallway (referred to as “single loaded”) will serve the rooms and the circulation factor in this type of area will be higher. Where this dimension is adequate to serve rooms on either side of the hallway (or “double loaded”) this area is more efficient and will have a lower circulation factor. Usually for early planning purposes this factor is established at 25-35 % of the room/cubicle area. Once again, the enclosed office/cubicle ratio will affect this number, but your architect should be able to help you determine the appropriate ratio for your organization.

Sizing the Rooms

Here’s where most people start listing the numbers of staff and their respective spaces. How big to make the spaces naturally will affect the overall square footage so care must be taken to size the rooms appropriately for the given activity. Listed below are some of the more common rooms in an office environment. The actual room size is a function of many factors, and they should be reviewed with your architect to determine the appropriateness for your operations.

Private Offices

An office of 20’x15′ can easily accommodate a senior executive desk, credenza, a conference table for 4 people and lounge seating for 2-3. This size is not uncommon for the CEO’s office in small to mid-sized companies.

An office of 15’x15′ can include an executive desk and credenza, a conference table for 3-4 people and either a bookshelf or a small sofa for 2-3. This size is what we normally find for vice-presidents of mid-sized firms.

The 10’x15′ office is very prevalent these days and can fit a mid-manager desk and return, two guest chairs and a bookshelf.

Some offices at the smaller end of the spectrum are 10’x12′ or an even smaller 10’x10′. At this size a regular size desk and return are possible along with two guest chairs.

Cubicle Sizes

These vary greatly depending on the systems furniture manufacturer’s panel and work surface modules, panel thicknesses and clustering capabilities. Popular sizes are roughly 9’x12′ for middle managers or engineers with multiple computer systems; 8’x10′ for engineers or senior staff; 8’x8′ for general staff; and 8’x6′ or 6’x6′ for administrative or telephone support personnel. Your firm will likely vary somewhat from these sizes, but the module areas in square feet will most probably be similar. Once again your architect is the best person to guide you to a reasonable module standard.

Conference Rooms

The appropriate size for a conference room depends on a multitude of factors (i.e., Audio Visual needs, maximum group size vs. typical group size, frequency of use, video and teleconference requirements); however if you allocate 20-25 USF per seat in the early planning stages you will be allowing sufficient space which can then be fined-tuned in the Space Planning or design phase later on.

On-site Training

Firms dedicated to keeping their company current with the advances in technology are usually committed to the ongoing training of their staff (and many times these firms will do on-site training of their clients’ staff as well), therefore the space program will include a need for special in-house training rooms. If you plan on having tablet arm type seating allow 20 USF per person. If your training involves people seated at tables with computer monitors allow 50-60 USF per person. (Depending on the frequency of use, you might consider renting off-site facilities which can then be paid for on a per use basis, in lieu of burdening your real estate overhead. This should be discussed with your architect and broker prior to committing to a lease.)

Avoiding Common Pitfalls

Your architect and broker form an important team in the leasing process. Optimally they should have a track record of working together to get you the best space possible for the least rent commitment. They will provide all the assistance you will need to find an appropriate space to lease on your terms. But there are some things which you should consider so that you are not caught off-guard as you are reviewing potential lease spaces.

Usable Square Feet versus Rentable Square Feet

Your architect will normally calculate your need based on Usable Square Feet (USF) as define

d by standards established by the Building Owners and Managers Association (BOMA). Depending on the building and the nature of your occupancy (retail, full-floor or multi-tenant floor) a load factor multiplier will be applied by the landlord to the square footage you actually occupy in your space or USF. The result is a Rentable Square Footage (RSF). This load factor accounts for your pro-rated share of the Common Area in the building that you share with other tenants (i.e. building lobbies, corridors, toilet rooms etc.)

The RSF is typically what rent rates are quoted on, so when communicating your space needs to your broker be clear that your needs are calculated using USF. The broker will then adjust for the correct RSF amount depending on the building and the respective load factor. This load factor is important when comparing buildings as it can vary significantly and it goes directly to the bottom line.

Allow For Enough Growth

It usually is hard to plan accurately for growth, but sometimes good indications can be derived from department budget projections, headcount projections, hiring histories and other market indicators. Usually some additional space needs to be included for growth. Optimally the new space should be sized to accommodate all the staff projected through the midterm in the lease, e.g. 30 people are expected on move-in and your firm should grow to 50 by the end of the lease, then ideally you should plan a space for about 40 people. Also, if you reconfigure teams often you should allow for additional space that will be needed for staging the moves.

Steps in Space Programming

Hire the architect early on in the process

This will ensure you have an accurate heads-up picture of your space requirements.

Collect Relevant Data

Assemble any Organizational Charts, Headcount Projections, Furniture and Equipment Inventories, As-built Floor Plans of Existing Space, CADD Files, Etc.

This can greatly assist your broker-architect team in determining a meaningful estimate of the required area.

Adjust for Changes in the Culture—Allow for Flexibility

Now is the time to make sure you plan for the necessary space to foster productivity in the new office.

Make sure your firm has sufficient space to adjust easily to market forces.

Calculate Growth Space

Include room for a reasonable growth in your staff. Usually you can’t grow revenues without some increase in staff.

Do Test Fit Plan(s) for Targeted Building(s)

Have your architect do check layouts of typical floors or areas to confirm density ratios, furniture and office module compatibility.

This will allow you to uniformly compare the various potential spaces from both a design as well as an efficiency standpoint.

Start Early!

Don’t get caught rushing. A mistake in this early preplanning stage will most likely mean you’ll soon be going through the process all over again.

A little up front analysis and planning, through the help of a professional architect with experience in office planning, can go a long way in laying the necessary groundwork for a smooth transition to your new office. Assuming your architect has performed the proper analyses and documented accurately your needs for the new office, you can be assured that ultimately your new company home will be a good fit for your organization. And just as importantly the subsequent phases of design and construction will go more quickly and without surprises.

About the Author
J. Edgar “Ned” Fennie Jr. is co founder of FENNIE+MEHL Architects located in San Francisco. FENNIE+MEHL Architects specialize in office development with expertise in space planning, interior architecture and ADA and code compliance consulting.
Ned is also Chair of the Code Advisory Committee to the San Francisco Building Inspection Commission. The Code Advisory Committee (CAC) consists of 17 members who are qualified by training and experience to deliberate and make recommendations on matters pertaining to the development and improvement of the content of the San Francisco Building Code, Mechanical Code, Electrical Code. Plumbing Code, Green Building Code and Housing Code as well as related rules and regulations or proposed ordinances that the Director of the Building Inspection Department determines may have an impact on construction permits. Specific recommendations of this Committee are directed to the Building Inspection Commission for their further action. Additional information.

Ned Fennie, Jr. AIA
Fennie + Mehl
P: 415-278-9596

Is your lease is up within the next three years? We should talk now.

We go the extra mile for our clients…big and small.