Overview

Comfort, safety and economical operation of modern buildings is controlled and maintained by environmental control systems. Environmental control systems in buildings are (1) Heating, Ventilating and Air-conditioning systems or HVAC and their supporting systems, and (2) Building Automation and Control Systems or BA(C)S. BAS systems (the most commonly used abbreviation) are the brains of the environmental control systems. They operate and monitor the connected HVAC systems by series of programs and also provide information on the building environmental conditions to the building operation and maintenance personnel, and/or directly to the customers.

It should be noted that environmental systems alone can seldom provide adequate environmental conditions if they are designed as "afterthoughts" to the architectural design. To assure the desired environmental conditions at all load and occupancy conditions (during the four seasons), the building has to be designed from the early program development phase with the end goals in mind - which is occupancy comfort, safe, reliable and economical building operation. Architects, mechanical and control engineers should, as one team, be participating in the entire design, installation and turn over with the building owner to deliver a fully operational building to the building occupants.

One of the ways leading to efficient systems implementation is a method called Total Commissioning and TQM process. (See Viktor Boed: Controls and Automation for Facilities Managers - Efficient DDC Systems Implementation, CRC Press, 1-800-272-7737, Cat. No.: CH 7229). As part of the implementation process, project managers can utilize checklists as a management tool to assure orderly conduct during individual phases of the project. Checklists listed in the above book contain items that require attention at each phase of the project, as well as engineering tips from design development through final walk through. Individual checklists were developed for each phase of the project and can be used throughout the entire system implementation process.

[an error occurred while processing this directive] Checklists are valuable tools and are used in many critical operations. You have probably seen through an open door of a commuter airline pilots doing their pre-flight checks with checklists in their hands - a process they do before every take-off, during every flight. Not that they would not remember which instruments and switches to check, but to assure that all the important items are checked in a proper sequence. They repeat the process throughout the most important phases of the ground and flight operations. Some (prudent) construction managers use checklists for recording and comparing bid items and other activities during bid evaluation of multiple vendors.

For environmental control systems implementation, checklists should be developed for every phase of the project - design, installation and commissioning. This approach also encourages teamwork throughout the entire process, which results in a design that contains inputs from mechanical, controls and facilities engineers. It will optimize the use of architectural, mechanical and controls systems in the building, and minimize the cost for engineering change orders throughout the implementation process. Change orders are the way of life. Checklists and systemized approach will keep the cost for change orders to the minimum, by implementing the changes at the early stages of the project. Focus on quality, systematic approach and the use of checklists will result in delivering a building to the owner, which will maintain designed parameters under all load conditions reliably, and assures optimum first cost as well as operating cost throughout the life cycle of the building.

Fig.1. Cost increase escalation for changes during project phases

Checklists as Quality Assurance (QA) tools.

As said before, checklist should be used as tools to assure quality at every step of systems implementation. Since buildings and systems are "custom made" checklists should be also "custom made" for the given project. However, every checklist contains generic items that along with job specific items can be used for a given job.

Since the article can not list all the checklists, the following is a compilation of selected checklists and items that have the most impact on building design and performance. They are divided into three basic stages - design, installation and commissioning. A full section of activities (and checklists) related to DDC system selection, design, software development, installation, testing and validation is left out from this article. Nevertheless they deserve attention since they are often the least understood by architects, consulting engineers, construction managers and owners.

Checklists for design phases of the project.

A project design phase can have several phases, from program definition phase through design development to construction documentation, depending on the job. Since the design phase shapes the future building and its systems, team work of the participating engineers and agencies as well as clear definition of the goals for building performance is utmost important. Three disciplines that have the most impact on the performance of environmental control systems are: Architectural - HVAC - BAS.

Fig. 2. The three disciplines of a successful design.

Occupancy comfort of buildings is judged by building occupants. Consequently, building owners and managers are interested in having satisfied tenants. In addition, they are also interested in safety, systems reliability, and efficiency of building operation. These should be the design goals set for the design and implementation teams.

Items having the most impact on achieving the above goals, divided into the three disciplines are:

• Architectural design has the greatest effect on the overall building design, energy usage and building maintenance. The essential design features having profound impact on the environmental control systems design and performance are listed below. They should be itemized on the checklists along with job specific items.
• Building envelope and location of the building determines energy losses, amount of natural lighting, space allocation/zoning, and natural ventilation. Buildings should be designed to take advantage of the ambient environmental conditions, such as free cooling, natural lighting, etc. (green building).
• Windows provide natural lighting and prevent heat gain and losses. The type of windows used in the building influences the selection of HVAC systems and their controls. For example, variable air volume (VAV) HVAC system is a poor choice for buildings with operable windows.
• Doors, Loading docks and other large openings should be designed with airlocks to prevent loss of building pressure and penetration of outside air. Adjacent areas should be designed with additional heating/cooling to compensate for losses.
• Air exhausts and intakes should be located so as to prevent short cycling of exhaust/intake air, discharging pollutants to the surrounding environment (including noise) and supplying contaminated air to the building.
• Space allocation and zoning is important especially in buildings with mixed use. Space allocation and zoning has also an impact on systems operation and energy conservation, especially for zones with different requirements for environmental conditions and operating schedule (i.e. labs, versus offices).
• Design of mechanical rooms and spaces for HVAC and BAS equipment on individual floors, horizontal and vertical chases, service access and lighting are often omitted. However they are important for building operation and maintenance.
• Design for local conditions and building occupants. For example occupants in office buildings like their VAV controlled rooms and fix windows. On the other hand, students like to open their windows during nice sunny days. Their behavior suggests the use of operable windows in dorms, which provide natural daylight, as well as ventilation.
• Setting realistic values during design. For example, temperature and humidity requirements for book-stacks (vaults) with minimum human presence can be more stringent then of book stacks in reading rooms with public access. While the vault's temperature and humidity can be controlled at very close tolerances (for a cost), it would be very expensive and technically challenging to meet the same design parameters in public access places of the library.

Table 1. Checklist for architectural design

HVAC design has to compliment the architectural design and provide the desired heating, cooling, ventilation and safety. It also have to assure economical and reliable operation to keep the operating cost at the minimum level. HVAC design features having the most impact on the environmental control systems design and performance are:

• The HVAC system has to be designed and sized to compensate for envelop losses, provide adequate ventilation, heating and cooling for year round operation. It has to match the zoning of the building for good controllability and to prevent migration of air from one to another zone. The design has to assure safe and economical systems operation, minimum downtime, energy use and maintenance cost.
• The design has to provide interconnections to other (existing) HVAC systems, fire suppression systems, fume hoods, etc., and to provide coordination with other building systems.
• The design has to define utility connections and required electrical, chill water, steam or hot water loads for the project. It also has to define other design variables, such as : Voltages and kW for normal and emergency power systems, building transformers, main switch gear, for electrical system. Pressure and temperature parameters of the heating and cooling systems. Condensate return, if the building is supplied by central steam distribution systems. Define and size all intake points and risers.
• Energy conservation measures, such as energy efficient lighting, emergency lighting, their zoning, energy efficiency motors, energy programs such as free cooling, equipment scheduling, etc., should be defined and coordinated with the architectural and BAS design.
• Ventilation and Indoor Air Quality (IAQ) requirements should be designed and air intake sizing and location coordinated with the architect; ventilation and IAQ design coordinated with the BAS design.
• The design has to comply with site standardization. The design should include equipment and material, which meet site-specific requirements. Facilities standardize on equipment, material and maintenance practices to contain their maintenance and operating cost.
• Special operating and maintenance requirements should be included in the design. Such as requirements for specially trained maintenance personnel, training, etc., to assure trouble-free operation of the building systems.
•     

Table 2. Checklist for HVAC design

BAS design has to provide the operating logic, alarming and reporting requirements and to meet the level of desired automation expected by the owner. Today's Direct Digital Control (DDC) systems are more then just a bunch of single loop controllers in one box. The owner pays for a "full" DDC system and expects to get one with all available controls and automation capabilities. BAS application engineers should be part of the design team. Their contribution could reduce the HVAC system cost and result in better overall design. The BAS system design should include:

• DDC systems architecture. Since the BAS architecture differs from vendor to vendor, timely pre-selection of DDC system(s) is very important.
• Point list should be developed jointly with the HVAC engineer and facilities engineer to optimize the number of DDC points for the application.
• Sequence of operation should be discussed among the DDC applications engineer, HVAC design engineer and facilities engineer to provide the level of desired automation, alarm and management reporting.
• Meeting job specific requirements for hardware, installation, sequence of operation, and maintenance practices.
• Person Machine Interface (PMI) and requirements for the Operating Work Station (OWS) should be defined to meet job specific requirements and operating practices.
• Interfaces to third party controllers, other BAS systems, and other facilities networks. Interfaces became a way of life. At this phase of the project the design team must decide on all integration related issues and coordinate it with engineers responsible for networking. Systems integration as an after thought can be very difficult, expensive with poor results.

Table 3. Checklists for BAS design.

Checklists for installation phase of the project.

The approach to Total Quality Management, and the use of checklists is an excellent management tool in this phase of the project. The installation (construction) phase of larger projects are usually managed by professional construction management firms. They have their ways of coordinating job activities and job schedules. Scheduling of individual trades and their coordination is probably the greatest challenge during the installation phase. Larger and smaller jobs alike can benefit from systemized approach to management.

During the installation phase the focus should be on:

• Conformance with site standards, specifications, codes and job documentation (checklists can be used with specific items related to the job and customer requirements);
• Transfer of information from one trade to another (checklists for items requiring multi-trade involvement should be developed as a management tool);
• Quality assurance by inspecting the job site by trade supervisors and construction managers (checklists can be developed for each visit);
• Progressive inspection and review of the installed systems by the owners O&M personnel (checklists can be developed for each visit and trade).

The above items are often omitted from the process unless there is an owner's appointed commissioning agent or inspector for the job. Nevertheless, they are important for quality of installation and for operation of the installed systems. Many "shortcomings" (and we know there are some on every job in effort to meet deadlines) become invisible since the components are hidden behind walls, ceilings and in other building cavities closed in as the job nearing completion. They, usually, show up later as maintenance items (nightmares) after the job is turned-over to the owner. The cost for "fixing" these problems is then much higher then it would have been if discovered during installation. Also, the cost associated with these problems burden the O&M department, which usually does not have construction (nor start-up) related costs in their budget. Most importantly, the building occupants, who expected to move into a new comfortable and trouble-free building are inconvenienced by problems originating from systems installation (or design).

Progressive inspection of the construction site by the O&M personnel, is important for several reasons: First, the owners O&M personnel familiarize themselves with the location of individual components - very important for time optimization when responding to emergency or routine maintenance calls. Second, the O&M personnel develop feeling of "ownership" to the building even before completion of the job. Over the years we have experienced high level of acceptance of jobs by the O&M personnel when they had a chance to participate in field inspections and/or in custom development of graphical DDC screens, alarm definitions and other job related activities.

Due to the limitations of this article only one checklist, for DDC installation, is presented as an example. However, construction, project and facilities managers should develop other checklists for mechanical, HVAC, electrical and other installations.

Table 4. DDC installation checklist

Checklists for commissioning phase of the project.

Environmental system commissioning is a complex task. Systems commissioning should confirm:

1. the installed systems meet design parameters,
2. they are properly installed and set up,
3. they operate properly under various operating conditions,
4. they interact and are interoperable with other systems,
5. provide the owner with a set of start-up operating values - a very valuable information for future system maintenance
6. provide instructions to O&M personnel on how to operate the building.

There are a number of contractors (disciplines) involved in commissioning under the three basic groups:

• HVAC contractor
• Testing, adjusting and balancing contractor
• DDC contractor

The owners O&M personnel should be fully involved in this stage of the project. They should be part of setting up a commissioning plan, witness functional and performance testing, validation and verification of systems operating parameters. They should verify operation of the installed systems under normal and emergency conditions, during shut-downs, start-ups, etc. They should receive operator training and as build documentation prior to final acceptance. They should be involved in post-acceptance systems performance verification for a one-year (four-season) systems performance warranty.

The commissioning documentation should be part of the acceptance documentation package and should aid the owners O&M personnel in future maintenance and systems calibration.

The following example is a short version of a checklist for hot water exchanger commissioning.

Table 5. Nameplate Data

Table 6. DDC Data Checklist

Table 7. Demonstration of control loop sequence of operation for normal and emergency conditions

Conclusion.

Checklists from design/ implementation phase of the project serve the project management during the implementation phases of the project. They provide important information to the owners O&M personnel long after completion of the job. As part of the turn-over documentation they become a resource for building maintenance for re-testing and re-calibrating the building operating parameters. They are a good source of information for years after a job completion for design engineers involved with building, systems or space renovation of the building.

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