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ASM CONTROL CENTER BEST PRACTICES

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the control center environment

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Overview:   The Control Room Environment poses a series of dynamic challenges in the design of the physical area surrounding the console and the console operator. As the console operator’s productivity can ultimately effect bottom line profits, the ability of the surrounding area to support this task is of paramount importance. The design must be developed expressly for this purpose, and venture beyond standard architectural practices to address the issues inherent in this unique building type.

Two major issues serve to direct the overall design philosophy. The planning and programming of this environment will serve to incorporate Best Practices if decisions are being formulated in response to the issues.

Design:   How can the design of the Control Center support the operator’s critical role and assist them in focusing on their tasks?

Though a formula for assuring the success of the design is challenging and unique for each Control Environment, pragmatic planning in concert with user input or buy‑in will help to assure the design’s success. An outline of issues critical to this process follows below.

Culture:   How can the culture respond favorably to changes brought about by technology, and support the process?

Cultural changes pose challenges which are difficult to measure in physical terms. The design of the environment may be well planned and intended to focus on the issues, and in theory may appear to succeed. It should be noted however, that in some cases the architecture can not change the culture. It is important in the development of this area to be sensitive to the capacity of the culture to support the cause.

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focus on operator productivity

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Focus on operator productivity: Systematically the Control Center Environment can be classified into three layers, all of which Focus on Operator Productivity ‑ each layer building upon the other, beginning at the center , or the console operator. For each Layer a list of areas has been enumerated, however, individual programs may require some modifications.

Layer I:  The Control Room Environment and critical support functions. This area is defined by the physical space as it directly effects and supports the Console Operator, and includes the Control Room and critical support functions. Critical Support Function areas which are qualified by their need to be directly adjacency to the Control Room

Layer II:  Secondary Building/Suite Functions are areas programmed to be situated within the Control Building but not necessarily contiguous to the operator. The Control Room Environment could function with or without these spaces. Their inclusion in the building is due largely to individual programmatic requirements.

Layer III:  Building/Suite Systems consist of the engineering disciplines required to enable the space/building to function properly.

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LAYER I: THE CONTROL ROOM ENVIRONMENT

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ISSUE:  How can the design of the operator’s environment serve to support the operator’s critical role, promote proper interaction, minimize disruptions, and enable them to focus on their tasks?

Shape and Size

Determining console size, configuration, and layout is a major issue in formulating a Control Room plan. Typically, building architecture and console instrumentation will develop concurrently. It is necessary to determine initial spatial requirements for the Control Room by formulating assumptions, which qualify overall console requirements. The specific console layout can evolve with this approach as the design process continues.

As the console layout is being developed, additional issues will surface. Also of importance are the vertical requirements for the console, qualifying single and multi tier configurations. Support for the console in the form of alarm panels and large screens directly effect the control room layout. Where multi bay configurations exist (more than one console or individual workstation), careful attention to console location and their relationship to one another is crucial to promote proper operator interface. Input from a systems expert, and/or human factors engineer is quite helpful in understanding the ramifications of the layout. Future expansion should be addressed in the initial planning stages of a control room to account for growth. Once a diagram has been determined, the control room, and key adjacent areas can take shape.

While configuring a plan for the Control Room, it is not necessary to restrict the shape of the room to a rectilinear resolve. Exploring other options such as curves or angled walls can enhance and follow the console layout. An area free of obstructions (columns) and one that allows for ample vertical space is preferable to insure proper operator interface, and leaves more options to integrate proper lighting to support the console as well as provide space for HVAC systems.

Access and Egress

As the design for the console layout evolves, other key elements, which directly effect the console operator, can be determined. With the development of the console layout it is important to consider traffic flow entering and exiting the space. Entries need to be strategically located to properly control traffic within the control room and more importantly within the console area. Minimizing unnecessary disruption to the operator is of paramount importance. The design must also take into account individual(s) programmatic requirements regarding shift turnovers, and upset conditions, allowing for additional personnel in the Control Room when circumstances exist. When possible, entries should be limited in number to further restrict traffic flow. Locations of entries also need to be considerate of the path of travel and the operator’s orientation to this path. In many cases, operators prefer visual connection with entries into the space, as this also reduces the element of surprise by approaching from the back. For equipment access and console installation the width of the entries should not be overlooked. The design must provide the quickest path and clearest sight line between the Control Room and its Key Adjacencies.

Surrounding Planes and Finishes

With the development of Control Room plan, attention must be given to the selection of materials and substrates on the surrounding planes and consider how these surfaces can best be treated to support the console operator. Issues of function, durability, acoustical qualities, efficiency (especially with regards to lighting), economy, and aesthetics place additional emphasis on the envelope, which surrounds the console.

Floors:

Cable connections to the console from the Rack Room or IO require access, which can be accomplished most often by a raised computer floor (RCF). However, when RCF is not viable, a platform can be constructed, provided it allows proper access. Trenches can accommodate needs when cable connections are isolated, (this is often limited to situations where existing conditions prohibit an elevated area.) Careful attention to the RCF cavity is important to assure a dry space (no water seepage), and one that minimizes dust. The Raised Computer Flooring itself should be specified to sustain the load of the console, address anti‑static issues, and acoustical concerns. Regardless of the substrate, finish options should be selected to enhance the space acoustically, for which carpet tile is optimum. When the program requirements restrict the use of soft surface flooring, appropriate hard surfaces should be chosen to address durability issues and be compatible with the substrate. Vinyl composition tiles (including static dissapative) and laminates (as provided by RCF manufacturers), integral to their products, are alternative solutions. Careful attention should be paid to color selection to minimize reflectivity (glare on the screen) and hide dirt.

Walls:

Wall surfaces require careful attention, as sound reverberation from the walls surrounding the console must be controlled. These surfaces should be treated with acoustical materials over the entire space encompassing the console. The number and frequency of panel alarms, shift changes, upsets and additional personnel will heighten the noise level within the space. This can be effectively reduced with the inclusion of acoustical treatments on a greater portion of the wall plane. Color and texture added to these surfaces, carefully chosen for proper LRV (Light Reflectance Values) is also important to provide a proper backdrop, which complements but does not compete with the operator’s ability to focus on the screen.

Glass:

Interior glass is often included with the Control Room to provide a visual link to adjacent areas. This surface and its location need to be placed with discretion. Too much glass can leave the operator with the feeling of working in a fish bowl. As well, the reflective nature of the material can promote glare on the screen. Methods of reducing glare risks include anti‑reflective treatments for glass and installing it at an angle appropriate to deflect reflections away from the console.

Ceilings:

Ceiling treatments must include acoustical materials, and consider access as required for electrical and HVAC systems. Ceiling plans and elevations may vary and can effectively conform to support console layout below. This further serves to capture sound over a given area, as well as minimizing cross‑console disruptions. Location of access panels should be considerate of console layout, to eliminate the need for someone to be performing maintenance directly above an operator. All efforts to maximize the acoustical capabilities of the ceiling plane should be addressed to ensure effective control of noise within the Control Room.

Lighting:

A properly lit control room is critical to the operator’s ability to perform their task. The introduction of computers into the Control Environment presents a particular challenge as the VDT screens inherently reflect light, and complicate the operator’s task due to glare on the screen. All precautions must be taken in designing lighting in the Control Room to minimize glare. Indirect or ambient light fixtures are optimum when properly installed. Lighting should be designed to offer an even wash of illumination on the ceiling plane, with careful attention to fixture location. Placement and distribution of lights when possible should minimize “hot spots”, or the reflection of fixtures in the console screens.

Lighting controls are another issue in the Control Environment. Individual operators should maintain some flexibility for lighting within their domain to accommodate individual user preference. Controls are best when located at or close to the console for efficiency and flexibility. Although individual controls must accommodate personal preference, the overall effect is also important. Therefore, varying levels of illumination (one operator area at maximum illumination with an adjacent operator particularly dim) need to be monitored, with options set within acceptable ranges. This will limit one area’s ability to adversely effect another.

Furnishings:

Minimal furnishings are required for the Control Environment. A most important element, however is the operator’s seat. A carefully selected, ergonomically correct chair will provide comfort, support, and flexibility. The furnishings will be used by more than one individual, requiring adjustability in height, back, and lumbar region when possible. Typically, a medium to large‑scale chair is selected for optimum flexibility. The selection should consider tradeoffs as the larger chairs can make certain individuals feel lost, however.

Additional functions within the space:

The Control Room Environment may require additional functions. These elements should be accounted for within the design of the space, and pragmatically designed into the layout. Some examples of this may include but are not limited to:

Reference Material/Reference Area,

Copier, printers, fax, collating area,

Meeting area,

Audio Visual capabilities

For each environment, providing a design solution which anticipates all functions associated with the console operators’ task will offer the operator the required support in a well designed setting.

Key Adjacencies:

The Control Room Environment is not limited to the Console Operator and the space immediately surrounding the console. In order to determine which areas require immediate adjacencies to the Control Room Environment, a programmatic approach to the support areas should be developed early on in the design process. The required adjacencies/will impact the Control Room Environment and ultimately may effect the console layout.

Key adjacencies are areas that directly support the console operator. Access to them its critical. A list of areas requiring critical adjacencies to the Control Room is enumerated below:

Key Adjacencies

Break Area/Kitchen                                                                    Meeting Space

Bathrooms                                                                                Rack Room or 1.0.

Exercise Room/Equipment                                                         Outside operators area (or similar function)

Alertness Recovery (*)                                                               Training/Hot Spare

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layer ii: secondary building functions

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ISSUE:  How are secondary spaces effectively integrated into the Control Building/Suite? How do these functions support each other as well as the console operator?

Secondary Spaces:

Secondary spaces are qualified as areas whose functions within the Control Building are desirable based on a particular program. Their relationship to the console operator is relevant, but not considered a critical concern. That is to say if these functions were to be eliminated, the operator and key adjacencies as qualified in Layer I could still effectively perform their task. A typical example of secondary spaces as listed below.

Typically the program will determine the areas included in this list. Aside from the Control Room Environment and Key Adjacencies as qualified in Layer I, the areas in Layer II include all other spaces within the building with the exception of Building Support Systems (re: Layer III which follows). As the building layout is being formulated careful consideration should be given to these secondary spaces. Although these areas are not considered critical to the Control Room Environment, the inclusion of additional functions brings disciplines and personnel in to the Control Building and can impact the console operator. This issue can be controlled somewhat by the layout, and careful planning and placement of these areas. The building architecture has limitations however, regardless of the care with which it has been planned. And placing more people within the building can serve to support or impair the console operator’s effectiveness. These areas can also greatly impact the overall building size. The addition of offices, meeting rooms, and even laboratories to a Control Building adds to the occupancy/capacity of the building. This can affect costs, incrementally add to size requirements as life safety issues are addressed, and greatly impact the overall project.

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LAYER III: BUILDING SUPPORT SYSTEMS

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ISSUE:  How do building systems support control operations and the overall corporate philosophy and culture for plant processes?

Site Selection

This issue should not be underestimated. Typically, the Real Estate value of land owned or leased by the plant is of concern. Current and future needs must be evaluated. Real Estate dedicated for buildings is a 20‑30 year commitment. This land is sacrificed for plant process needs. Obviously plant buildings including Control Buildings do not directly produce revenue. Therefore, return on investment is not as tangible as plant equipment and process facilities. Nevertheless the location of a control building is at least as important as any other capital investment and in many cases it may be the most meaningful decision that plant management weighs for a generation.

Issues with respect to comprehensive centralization of controls vs. a more distributed strategy are the topic of another paper, beyond the scope of this discussion. Site selection is an issue for any control building that controls all or part of a plant. First, is the building sited within the heart of the process area? This can offer convenience for field personnel because information can flow rather expeditiously because distance is not an issue. Historically, this has been the case because pneumatic controls were of course limited in distance from the process area. The physical limitations of older technology established a culture or a mindset that a control station belongs within the process area. Today the physical limitations that once framed our thinking, is no longer present. The control console can be within a plant, on the periphery of the process, or miles away. For that matter, a console could theoretically be set at company headquarters, within a large metropolitan area. Technology has freed us from the issue of distance in a sense. Yet distance is now an operational issue. How far away from the plant should the board operator be from the process? How does site selection affect field operators and maintenance personnel?

Some companies have utilized technology to remove control systems from the potential hazards of the process. Recently, in two ambitious re‑instrumentation projects Phillips Petroleum Company located centralized control facilities on the periphery of the plant [re: Borger, Texas; 1994 and Sweeney, Texas; 1996]. This opportunity was afforded because land was available in each case. Further, it located controls near to engineering and administrative buildings offering multiple benefits, locating personnel outside an area of risk and grouping multidisciplinary people into adjacent buildings. The only people that were in the plant were those that absolutely had to be there and their time was minimized. This concept reinforced the corporate philosophy that multidisciplinary interaction should be encouraged and people should be located away from potentially hazardous areas.

Of course people and control systems can be protected without removing them completely from a process area. Structures can be designed to withstand a vapor cloud release, or blast, or significant lateral load. This design is commonly referred to as “blast resistant” construction. Along with other provisions outlined herein, a safe operational philosophy can be maintained while control systems are located within the process area. The primary mission of safety should also include reference to the functionality of running the plant. For this and undoubtedly other reasons companies have elected for closer proximity of controls and process. A very important factor in this or any site selection is a comprehensive risk analysis by a specialty consultant.

This analysis will incorporate the potential load that could result from a vapor cloud release, its distance from potential sources and a statistical measure of occupancy by personnel over a period of time.

Another site criteria worth noting is that of electrical classification. There is certainly an economic benefit to selecting a site that is not in a classified area. For instance, the safety of a Class I Division II area is based upon eliminating equipment from an area that can induce a spark, or placing it a special housing that isolates this potential. Equipment must be specifically designed and rated for use in classified areas. It is not unusual but absolutely necessary for site lighting to be designed and readily available for use in classified areas. Although these fixtures are at a premium over standard industrial fixtures, they are not cost prohibitive. However other equipment used for buildings may not be so available or adaptable. For instance, air handling units and condensing units are not readily available off the shelf to be used in classified areas. Adapting these units for on site, exterior use can increase the cost for this equipment tenfold. Further, maintenance and replacement costs for this specialized equipment will be at a premium.

Blast Resistant Construction

Two important criteria are revealed from a risk analysis with respect to blast resistant design. For each given site and/or exposure, a load {usually in pounds per square inch (psi)) and duration of load {generally measured in milliseconds}. These two interrelated criteria set standard that is deduced from the loading scenario. This is the starting point for engineering the structure of the building. Engineering prior to the completion of a risk analysis will be based on assumption and will require confirmation at a later date. Concurrent with a risk analysis is the preparation of a geo‑technical report. Soils findings will determine the type of foundation that can be used for example spread footings or piers. Floor construction can also be determined and concrete slab on grade is an economical system. However if soils are determined to be highly expansive, an elevated floor (with a void space under the slab) is used to isolate the floor from potentially moving soils. Further, understanding the expected behavior of soils during the induced force of a blast load is of interest. The force that is transferred from walls to foundation to the supporting earth can in an instant “liquify” the soil. In this case, the foundation must be designed to anchor the structure in place.

All of these issues affect the performance of a structure along with its cost. Perhaps the most important structural issue is the selection of the wall and roof system that will satisfy the loading criteria. It is worth noting that there is other criteria that is part of the structural design of any building. Local and national building codes establish minimum standards for live and dead loading for structures. These include wind, snow, occupancy and seismic loads to name a few. Blast loading criteria is such a specialized science that it is not included in building codes. In most cases, blast criteria far exceed any other load {including seismic } . The only issue is explaining to the local authorities enough about blast resistant design to satisfy their interest and curiosity.

Note that there are two types of analysis for blast resistant design. The most sophisticated type is a dynamic analysis. The least complicated is a static analysis and quite often this type will satisfy most of the local authorities. The difference between static and dynamic analysis is the interpretation of how a structure will behave under load. However, many companies are requiring engineering to model the structures under a dynamic mode. The extra attention to this matter has been considered worthwhile.

The selection of wall and roof systems will be limited by the blast loading criteria. For instance concrete and steel systems will satisfy the mid to high range of blast loads. Metal buildings can be designed to satisfy lower range loads. Within these systems there is also a range of structural “strategies” to consider. The family of concrete structures includes: poured in place, offsite plant cast panels, and on site tilt‑up. Each of these has benefits and limitations and should be evaluated for the specific requirements.

Plant cast concrete may be considered because of the availability, quality, and cost competitive market of local suppliers. It can also be erected very quickly with minimal site disruption. On the other hand, the lack of reputable precast plants, or the availability of low labor costs may favor a poured in place strategy. Another consideration for roofs and walls is the level of redundancy of the structure. The roof may bear on the walls at the perimeter of the building. Theoretically if the walls fail under load, the roof collapses. Lives are at risk from the building itself along with the ability for an orderly plant shutdown. Extra protection can be provided, rather economically by supporting the roof at the perimeter with a redundant line of structure { i.e. another row of columns). It is analogous to a “belt and suspenders” strategy.

The Building Envelope

The building envelope includes exterior walls, the roof system, and any penetrations through them. The envelope should have the integrity to protect its occupants and control systems from the exterior environment. It should be an assembly of components that is designed and constructed with a consistent level of protection in mind. In addition to the blast resistant considerations above, there are other issues worth noting. First, exterior doors should offer a level of protection consistent with perimeter walls. It is important to note that the provision of blast resistant construction is not a building code requirement: There are no statutes that delineate minimum blast resistant requirements. The responsibility rests with the company and supporting specialists to measure the level of risk and respond with appropriate design and construction. This is the essence of “Best Practices”. The best blast resistant doors are those that are designed and tested for this use. Several manufacturers provide doors that are standardized for various levels of blast resistant construction. Although the doors are rated for a specific assembly, they do not necessarily match the level of protection of the adjacent perimeter wall. For instance, a door rated for a 3psi 20‑millisecond assembly is not as substantial as the wall that it is anchored into. It is analogous to the integrity of a fire rated door and wall assembly. The exterior walls and roof are the primary protectors. However, for a building to function there must be penetrations. People must enter and exit, air has to be brought in and relieved, utilities and data cables have to penetrate exterior walls. These requirements do not necessarily violate the integrity of the envelope, depending on how they are specified, detailed, and installed. As a rule, penetrations should be minimized and assembled with a consistent level of protection in mind. Ultimately, this comes down to a cost vs. benefit issue. While blast resistant doors may be considered a worthy investment and consistent with prudent risk management, blast valves at the air intake may be leaning toward over design. Again, a building must have penetrations and they will no doubt be less protective than the exterior walls.

One of the objectives of a well designed Control Building is to provide a facility that can shut a plant down in an orderly manner in the event of an incident. In other words, people and control systems must be protected in order to effect a safe shutdown and minimize the risk of further loss. The scenario may be a damaged but repairable building, while protecting lives and control equipment.

With this in mind, the envelope should be designed to not only contemplate a tremendous force, but also the subsequent implications of it. A fundamental requirement of any building is to protect the inhabitants from the weather. It must protect against rain, wind, snow and properly moderate temperature and humidity. However, the design of a control building should consider the provision of another layer of protection in the aftermath of a plant incident and/or a catastrophic weather condition. For instance, facilities located in hurricane or typhoon regions might have extra attention to their roof design, beyond that of typical building practices. The uplift force of a hurricane can potentially tear roofing material from its deck even a roof that is designed to satisfy the building codes of that region. For this reason, a redundant roof assembly may be worthy of consideration. If one roof blows off, a substrate or sub roof remains to keep water from entering the building, preventing a potentially catastrophic scenario for control system equipment; as a result of this consideration, the building envelope has done its job!

Single Story vs. Multi Storv

This issue inevitably surfaces in most early design considerations. The issue is loaded with complexity and a little bit of myth. The resolution will certainly affect the functionality of the building, its cost and the planning of future site development at the plant. There are three fundamental alternatives. For the purpose of this discussion, single story means one finished floor level at or near grade, multi story suggests two alternatives, a grade level with a second story above or a grade level with a basement.

Multi story structures can be designed to be as blast resistant as one that is single story. In other words, a two level structure with one floor at grade is not necessarily excluded from the principles of blast resistant design. Even though two levels result in a greater exposure of wall area, connections at the foundation, second floor and roof can efficiently provide proper support. A level below grade intrinsically offers protection due to its low profile of exposure. In fact, at first glance a subterranean facility, or one that is at least partially below grade seems to make sense. However, experience has proven time and time again that there are many interrelated issues that need to be understood and resolved before jumping to this conclusion.

Thoughtful programming of a building’s needs will reveal some clues. That is, what rooms, if any can be on floor that is not at grade? What is the strategy to protect the board operator from undesirable foot traffic through the building? Perhaps the operators should be located on the second floor to isolate them. How do outside operators and maintenance people deal with multiple levels? How are data cables brought into and distributed within the building? The answer to these and many other relevant questions reflect the values and operational philosophy of each plant. However, while each plant may have a history of what works and what is preferred for single vs. multi story, the trade off of benefits and risks should be recognized. For instance, locating i/o and electronic equipment in a basement may suggest economic savings over construction at or above grade. After all, basements are almost like “free space”. In truth, basements are not free and locating equipment in a space that is exposed to ground water and surface drainage, is a risk that should not be overlooked. Similarly, placing HVAC (heating, venting and air conditioning equipment) below grade is an option. However, the servicing and replacement of this equipment should be considered. Certainly the sophistication of state of the art air supply and filtration systems necessitates rather large equipment. Below grade installation of HVAC units may lead to future problems.

Another consideration is the duplication of space allocation that is inherent in multi story buildings. For instance, restroom facilities may be required on each floor. This is not for ease of use but a matter of building code requirements. Space must be dedicated for stairs, usually two sets, which is necessary for safety and or code requirements. Corridor space must be defined to control and direct foot traffic through the building. This space will be duplicated on each floor, if nothing else to connect the two stairs that must be remotely located from each other {again, a fundamental code requirement}. Janitor rooms may be on each floor, for ease of use, but nevertheless worth noting. Finally, there is the potential requirement for an elevator. Depending upon the distribution and classification of space on each level, an elevator may be required by standard building codes to move people, and it will also need to by sized appropriately to accommodate the any equipment, if any, located in the basement.

Perhaps the overriding variable with this issue is the availability of land. If a facility is programmed for 10,000 sf and only 5,000 sf is available, multi story it will be. Then the pros and cons of below grade space must be evaluated. In general, the disadvantages of subterranean space have outweighed the benefits. The potential cost savings of basement space is inconsequential. In fact, a recent study indicated that a multi level facility with a basement scheme may cost more than the single story alternative. (Experience indicates that each cost comparison may yield varying results.) With respect to efficiency, or the ratio of useable space to total gross area, a single story facility wins hands down. Because of this efficiency, it can also be the most economical of the three alternatives. Further, it offers the greatest convenience of use, with all spaces accessible at grade. It is worth a hard look at land availability and tradeoffs therein to get to a single story solution. In conclusion, the ranking of options is, first, single story at grade, second, multi story above grade, and then multi story with a basement.

Windows and Skylights

It is easy to forget that artificial lighting has only been around for about a generation. Thomas Edison changed our world forever. We were liberated from nature’s cycle of night and day. Couple that with the Industrial Revolution, life on earth would never be the same. Today’s industry is 24 hour day, seven days a week, fifty‑two weeks a year. Of course this resulted in shift work, humans are not machines and can only work productively for 8 to 10 hours a day. However, one generation does not modify centuries of human evolution. We are physiologically and psychologically connected to the diurnal cycle. In addition to the 24‑ hour workday, control buildings are like bunkers. In order to satisfy blast resistant requirements, windows are limited if not totally absent.

Further, windows introduce an uncontrolled source of light that can result in reflected screen glare, an intolerable condition in a modern control room. Operators need daylight, but can’t get it at an appropriate time for their shift, and if it is available it is problematic.

Much like blast resistant doors, blast resistant windows are available. They are thick, heavily reinforced sections of glass or special plastic. From a performance perspective, they are slender, vertically oriented rectangles. This optimizes the length to width aspect ratio, resulting in a strong window profile. Further, it is a good shape and size { 1 x 4 feet} to block a projectile from entering occupied interiors. They are also rather expensive. The disadvantages do not end there. Because of the optimal slot shaped configuration, they let light in but it is limited. Viewed from within the building, they can be a point source of glare, particularly on east and west exposures where the sun angle is low. This can be disturbing in an office environment, even more so in a control room. Run in a series along the facade of the building they can have a ” prison” like appearance. These units can

be constructed in a larger profile, even similar to a bay window or picture window. Of course that is a premium. Further, the issues of uncontrolled light and glare are still there to deal with. More than one contemporary control facility has large blast resistant windows only to be covered most of time with shades. Then there is the issue of what do with the window view? There may be benefits to viewing the plant from the control room. Does this mean that the location and orientation of the control room should be dictated by a line of sight to the plant? Could this need be satisfied by a video monitor? Perhaps the ideal control room is four walls of glass that somehow provides a blast protected, glare free environment. If so, and there certainly could be argument against, construction technology hasn’t gotten there in a cost effective manner.

This is not an endorsement against the use of exterior windows in the control room environment. It simply points to the multiplicity of issues related to glass openings in the building envelope. It also suggests that illumination with the benefits of natural daylight, supplemented with full control { i.e. an artificial source} would be of value. This technology certainly does exist and has been utilized in operating control centers and projects that are currently in design. Specifically, daylight simulating skylights and projected sky domes are being used to supplement ambient and task lighting. The opportunities and potential benefits are tremendous. This is the type of provision, along with others outlined in this paper that contribute to the management of abnormal situations.

Mechanical and Electrical Systems

Mechanical and electrical systems can represent up to a third of the cost of a control facility. Further these systems account for long term costs with respect to energy consumption and maintenance. Temperature, humidity, air quality, pressurization, reliability and controls are important factors to name a few. Most complaints about buildings, controls centers or otherwise, are related to HVAC and electrical systems. Similar to a well‑defined strategy of blast resistant design, these systems should show integrity in design and execution. Although these are applied sciences [engineering] there is almost a quality of art to these disciplines. The only rule is to get it right, provide dependable results based upon a well‑defined set of design criteria.

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