Improving lab design

Laboratory facilities have specific environmental integrity and safety requirements. Four experienced engineers share their thoughts on how well-designed systems impact the success of such structures.

04/08/2011


Meet our roundtable participants

  • Danette Hauck, PE, LEED AP, Senior Mechanical Engineer/Project Manager, URS Corp., Cleveland, Ohio
  • Dunstan L. Macauley, PE, Director of Mechanical Engineering, Encon Group Inc., Kensington, Md.
  • Brian A. Rener, PE, LEED AP, Senior Design Manager, M+W U.S. Inc., Chicago
  • Michael H. Schwarz, PE, LEED AP BD+C, Associate/Senior Mechanical Engineer, KlingStubbins, Philadelphia

General

CSE: What engineering challenges does a laboratory facility pose that are different from those of other structures?

Dunstan L. Macauley: Laboratories are designed to promote a safe environment for all personnel. Engineering systems, especially HVAC systems, must integrate with the architectural elements and structural components to provide a safe functional environment. The design of the systems differs from most building types in that the engineer must thoroughly understand all facets of the facility’s operation to provide the optimal design. The engineer must interact with other members of the design team as well as the facility’s operational staff and safety officers to properly design the space. They have intensive ventilation requirements and must meet other health and safety codes, which lead to high supply and exhaust air requirements and energy usage.

Michael H. Schwarz: Ventilation requirements are much more significant in laboratories than other types of structures, and the resulting thermal load is driven by internal load, dilution rate, or exhausted equipment such as fume hoods. Thermal loads in most other commercial building types are driven solely by the plug and/or envelope load. In addition, the processes and agents to be contained within the laboratory need to fully understood; for example, types of chemicals, storage areas, and potential spill locations. Air intake and exhaust design is also critical in terms of occupant safety; the level of dispersion achieved between the laboratory exhaust and air intake points needs to be analyzed.

Brian A. Rener: Challenges include potential use of toxic or hazardous gases, specialized ventilation systems, extensive automation and control systems, high power densities in some areas, and requirements for special classified areas.

CSE: How have the needs and characteristics of laboratories changed in recent years?

Danette Hauck: Owners are more concerned with energy consumption in recent years and therefore are looking for smart and safe ways to reduce energy consumption within the laboratory setting. Labs21 is a very useful design guideline which assists owner, users, and designers in developing a laboratory that preserves occupant safety, optimizes buildings, reduces energy usage, and minimizes the environmental impact.

Macauley: Laboratory systems are designed to be adaptable so that they can be easily modified for other uses. They’re being designed as open labs that can be easily adapted to support multiple processes. Laboratories are also utilizing variable volume hoods and other energy-efficient systems as a method of conserving energy. Systems are also being provided with energy recovery to recover energy from the exhaust airstreams.

Schwarz: In the past few years there have been more renovation projects and greater emphasis on reusing existing infrastructure and building architectural components in an effort to reduce capital cost expenditure or to consolidate operations.

CSE: What recommendations would you offer other engineers in maximizing the effectiveness of their laboratory projects?

Rener: The use of building information management (BIM) software is becoming the new standard for MEP engineers. This software greatly enhances the ability of the architects and engineers to coordinate the extensive utilities and enhance space management.

Hauck: The design team should meet with the owners and the health and safety officer(s) for the facility, and work together to determine the use and function of the lab along with the expected utilization of the lab hoods. Development of precise usage schedules is extremely important, as is a clear understanding of the owner’s intent for future usage. After these items are established, the design team should propose an occupied air change rate and an unoccupied air change rate; this should be presented to the owner’s team and agreed upon prior to progressing with the design. These initial steps will assist the entire team in the future.

Schwarz: Benchmarking of key laboratory criteria, such as program area requirements and watt per square foot metrics, by project and type, can be invaluable in project schematic design. Our firm tracks this information to the extent possible on our projects, as there are few holistic industry resources to rely on for this data. Labs21 is a good resource, but in terms of lab energy consumption benchmarks for example, there currently are no usable benchmarks for laboratory energy use in either the EPA or CBECS databases. In addition, many energy-efficiency measures have trade-offs associated with them that need to be taken into account; for example, heat recovery devices carry an increased air pressure drop, which in turns increases fan energy consumption and can offset heating and cooling energy savings. These devices also bring the exhaust and supply airstreams close together, and this needs to be weighed against the safety requirements and types of chemicals or agents that will be used in the laboratory.

CSE: What are some common missteps that engineers might make on a laboratory project?

Schwarz: If energy-efficiency or LEED certification is part of the project’s goals, whole-building energy modeling typically needs to be employed early in the schematic design process. Low-energy laboratory design concepts, such as low pressure drop air handling equipment and ductwork systems, not only require increased capital expenditure but increased space requirements. If the building design progresses without taking those requirements into account, they may be difficult and costly to incorporate in the design-development, or worse yet, construction documentation design phases. This problem may be compounded further in a design-build delivery method where there is already a contract and price set. Also, criteria development such as identifying lab equipment heat loads requires some analysis on any laboratory project, as key criteria will have a profound effect on HVAC equipment capacities and performance; this typically involves discussions with the lab users and facility personnel early in the design process.

CSE: How does a “dry” facility (i.e., one that tests semiconductors and other equipment) differ in its considerations from a “wet” facility (i.e., one that tests biological materials)?

Rener: Any time you have the presence of hazardous or toxic materials in wet labs, you’re going to have specialized exhaust and waster systems. This adds extra complexity in coordinating utilities among the trades, space management issues, and controls and life safety concerns.

Automation and controls

CSE: What factors do you need to take into account when designing building automation and controls for a laboratory?

Hauck: The HVAC and fume hood controls for a laboratory setting are more sophisticated and specialized than in a standard office building. The team needs to determine what level of control the space will have. The design team must work with the owner and end user to determine required control for each laboratory. In addition, the owner must determine if the fume hood will have occupancy sensors, sash position indicators, and alarms, and whether all of these will be interfaced with the controls for the variable volume hood exhaust, general exhaust, and supply. The team should determine if there are specific chemicals or compounds in the lab they want to test for in the space via air sampling.

Schwarz: Besides advanced system-level submetering, advanced lighting controls are becoming more common. These types of controls may include dual switching, occupancy sensors, daylight sensing controls, and digital addressable lighting interfaces (DALI). Advanced lighting control systems are promising energy-efficiency measures, but in order to work properly they require more advanced coordination between all the building design disciplines and must be compatible with the intended function of the laboratory spaces.

Macauley: It is critical to understand the functionality of safety devices that provide protection to personnel working in the laboratories, such as ensuring that the laboratories are provided with the proper supply and exhaust airflows as well as the ensuring that proper alarms are provided within the system.

CSE: How does implementing automated building controls in an existing structure differ from designing controls for a new one?

Rener: There may already be a BMS in place. How to integrate any new laboratory control systems in a way that will both be compatible and allow for competitive bidding.

Macauley: The biggest challenge with implementing new building controls in an existing facility is installing the infrastructure. Unless the new system is being installed during a major retrofit project, most of the installation will be installed in finished spaces. The installer has to carefully plan to minimize the disruption of the facility’s operation.

CSE: What are some common problems you encounter when working on such systems?

Rener: Commissioning is crucial to ensure proper performance. Automation and controls systems are among the biggest sources of startup issues, and proper commissioning can alleviate this.

Codes and standards

CSE: How have changing HVAC and/or electrical codes and standards affected your work on laboratory facilities?

Schwarz: Many of our lab projects are tracking for LEED certification; in practice this is requiring whole-building energy modeling from schematics to completion of the design. Besides complying with the minimum requirements of ASHRAE 90.1-2007, the project models are being compared to the performance of a baseline building as defined in Appendix G of the standard (Performance Rating Method). We also use the models to track compliance with the DOE’s Federal Energy Management program and potential for federal tax incentives related to energy-efficient buildings.

Electrical/power

CSE: What’s the one factor most commonly overlooked in electrical systems in laboratories?

Rener: Flexibility. Laboratory use, equipment, and functionality can change. So the question is, how easily can the electrical systems adapt to provide flexibility?

CSE: What types of products do you most commonly specify in a laboratory, and why? Describe the UPS system, generators, etc.

Rener: Segmented modular raceways for data and power outlets are common in many laboratories. Higher power demands often require the specification of specialized busway systems. Where the labs make use of toxic or hazardous materials, we see the use of generators and UPS systems.

CSE: How have sustainability requirements affected how you approach electrical systems?

Rener: The primary sustainability issue for electrical is lighting and lighting controls. Sustainable lighting types have expanded with the expanded availability of LED-based lighting. Lighting controls may include automatic controls such as occupancy sensors or microprocessor-based time controls. Dimming is also encountered in some labs due to the need for adjustable illumination. Labs may also have exterior windows and can make use of daylight harvesting.

CSE: What common mistakes do you see in laboratory electrical systems designed by other engineers?

Rener: Miscoordination with laboratory furniture systems and with mechanical and process piping systems are frequent areas of error.

CSE: Due to the nature of material being tested, reliable power is a large concern. What special considerations does a laboratory facility pose?

Rener: Reliable power can include anything from power quality to backup power. Transients and noise are issues in labs that can be addressed by TVSS’s, filters, isolation transformers, and proper grounding. Large disturbances usually require some sort of backup power. It is important to differentiate between code-required emergency power and standby power. Emergency power for labs would include things like life safety alarms and hazardous exhaust systems.

Sustainable buildings/energy efficiency

CSE: What sustainability issues concern your laboratory clients?

Schwarz: Energy and water efficiency are probably the foremost concerns of our clients—not so much for the cost savings, but because there may be corporate initiatives in place to reduce energy consumption by certain thresholds over time. They also recognize it’s the admirable thing to do in the public’s eye and that there may be more stringent regulatory energy initiatives coming down the road. Also, some clients are looking to the future and focusing on avoidance of carbon emissions, which really takes energy-efficiency beyond the building level and to where and how the energy itself is generated. Some clients also have rigorous standards in place that permit using only refrigerants with low or zero global warming potential, not specifically because of the LEED credits, but that would be an advantage if a building project was going to pursue certification.

Macauley: Typically HVAC systems supporting labs tend to be 100% outside air systems. When coupled with the temperature and humidity requirements for the critical spaces, laboratory HVAC systems consume a lot of energy to maintain their critical operation. Due to escalating energy costs and a need to be better stewards of the environment, clients are looking for more energy-efficient systems for the facilities.

Hauck: Clients are concerned with the large amount of energy required to run a laboratory and the costs associated with the energy. They are looking for the design team to develop a building that serves the laboratory functions, reduces energy usage, and reduces the impact to the environment.

Rener: The desire to achieve LEED or Energy Star certification has been increasing among our laboratory clients. Increasingly, many state and local codes are adopting and mandating portions of these sustainability goals, primarily energy efficiency.

CSE: With changing awareness of sustainability issues and an increased number of products, has working on green structures become easier, or more challenging?

Hauck: The increased number of green products available for laboratory environments has made it easier to find sustainable products and energy-efficient equipment. The challenge with sustainable buildings is finding the appropriate balance of energy efficiency, sustainability, function, and the budget for each client and end user.

Schwarz: It has become challenging because stakeholders often come to the table with many ideas that they heard or read about, but are not fully vetted for the application or may not add much to the overall sustainability of the building. This can sometimes add complexity to the analysis effort that’s truly required for optimization of building energy-efficiency. Many of the best design ideas often involve off-the-shelf technologies that have been around for a while, but can be implemented in a different manner or combination that is more cost-effective than the latest “better mousetrap” idea.

Rener: It has become easier. More products are now provided to assist in achieving suitability goals like LEED or Energy Star. The variety of certified products makes specifying them easier and also has reduced construction costs.

Macauley: Implementing sustainable/energy-efficient measures in facilities requires careful planning and design strategies. Generally, laboratories were designed as 100% outside air spaces with high air changes. The cost related to cooling and dehumidifying, and heating and humidifying the high volume of outside air has led to more energy-efficient strategies like variable air volume fume hoods, recovering energy from the exhaust airstreams to precondition the incoming outside air, etc. Unlike labs designed in the past, where the systems operated at their maximum flow rates to ensure safety, the design engineer must verify that the safety requirements are met at all operating conditions.

CSE: What issues affect your ability to retrofit or retrocommission laboratory facilities?

Schwarz: Sometimes when retrofitting a laboratory—or any building for that matter—that needs to remain partially occupied during construction, the HVAC system type cannot be completely changed since portions of the system need to be on-line for the entire duration of construction. This could limit the potential energy efficiency of the completed facility, but of course if the existing systems were old and very inefficient, then substantial improvements may still be made and the construction and carbon emissions associated with building a completely new site and/or building core and shell can be avoided.

Rener: Lack of accurate as-built drawings and operational manuals/records hampers both design retrofits and retrocommissioning. Extensive use of surveying, inspection, and testing is often necessary to establish baselines for retrofit design and retrocommissioning.

Macauley: One critical factor in retrofitting an existing facility is how economically the systems can be upgraded with more energy-efficient systems. The design engineer has to investigate if most of the existing infrastructure (ductwork, structural supports, etc.) can remain in place and maintain the minimum safety requirements while the facility is upgraded.

CSE: Systems associated with laboratory facilities, such as advanced ventilation, can challenge the energy efficiency of such structures. How do you maintain a balance?

Macauley: The design team should investigate the life-cycle cost to determine the benefits of the more efficient systems. As long as the engineer can justify the cost for the improvements, and the systems do not impact safety, the engineer can make a case for the improved efficiency.

Rener: Variable air volume systems, extensive automation and controls, and heat recovery systems can help balance the needs for extensive ventilation and air changes.

Schwarz: One item that has come up recently in terms of lab fan system power is Addendum P for Standard 90.1-2007, which makes it somewhat easier for certain laboratory fan systems to comply with the fan power limitations outlined in the standard. It also provides credit in the baseline energy model for some of the devices that are typically required in laboratory HVAC systems such as ducted return/exhaust, filtration, heat recovery devices, and lab equipment such as fume hoods. These credits reward energy-efficiency measures such as heat recovery and low-pressure drop air distribution design in the performance rating method calculation required by LEED. We also have been looking at demand-control ventilation systems on laboratory projects which automatically vary the ventilation airflow by measuring total volatile organic compounds and particulates in the exhaust airstream as a measure of room-level cleanliness—this type of automation has the potential to drastically reduce the energy consumption of a ventilation airflow-driven facility, such as a vivarium for example, over its entire life cycle.

HVAC

CSE: What unique requirements do laboratory HVAC systems have that you wouldn’t encounter on other structures?

Schwarz: The one predominant feature that differentiates lab HVAC systems is ventilation. Most structures are designed with minimum code ventilation rates, but in labs it may be driven by owner criteria and equipment requirements, which can vary by project and application.

CSE: Test facilities often dictate that a laboratory’s ventilation system contain advanced capabilities, to preserve integrity of samples and keep a stable environment. How do you maintain this delicate balance?

Schwarz: Typically the room-to-room air and pressurization balance for a lab building needs to be mapped-out in detail when performing the HVAC system sizing calculations and room ventilation schedule. The pressurization and transfer air requirements need to be clearly documented so that the system can be balanced to provide the required integrity. The room-to-room pressurization also needs to be coordinated with the architectural design, doors, partition details, etc.

CSE: How can automated features and remote HVAC system control benefit laboratory clients?

Macauley: With the advancement in building control systems, clients can now operate and monitor their critical spaces remotely. This gives the clients “real-time” information on their laboratory spaces. Clients now have the ability to remotely monitor the spaces to verify they are maintaining the required temperature, humidity, and airflow requirements.

Schwarz: Operation, alarm, and diagnosis of problems within systems can be performed in a much more effective manner, but energy metering is really the key to being able to perform investigation into system problems. A facilities operator can watch a building or system-level energy dashboard and really become aware of how the system operates under different conditions and be alerted when equipment may need maintenance to perform at the expected level of efficiency. This helps to provide a form of ongoing retrocommissioning.

Hauck: Utilizing a variable volume system supply and exhaust for the fume hoods with occupancy sensors and sash control can greatly reduce the energy utilized in the building. Ensuring that the occupancy schedules are correct for the lab users will protect occupant safety and prevent wasted energy.

CSE: What are the most important factors to consider when working on such a system?

Schwarz: When designing a green building, we recommend implementing system energy meters at a minimum according to ASHRAE Standard 189 (Standard for the Design of High-Performance Green Buildings), which is something that we may hear much more about in the future as it is a “codified” green building standard.