Design solutions for aging mid-century laboratories
Aging mid-century laboratories continue to be a pressing challenge for institutions across the country and building owners are at a crossroads with what to do with these buildings.
Aging mid-century laboratories continue to be a pressing challenge for institutions across the country. The post-WWII era brought a surge of increased science research funding that catalyzed a construction boom of science facilities on research and university campuses. Building owners are at a crossroads with what to do with these buildings and the laboratories within them to meet the needs of 21st-century science: is it wiser to renovate these existing structures or completely rebuild?
Often, it is more economical and more sustainable to invest in renovations and system upgrades rather than a brand-new build. To help inform this decision, we have identified the unique challenges that come with laboratory renovations and offer specific solutions to help tackle those challenges.
Mid-century labs are often challenged spatially, with floor-to-floor height as a prime concern. Usually mid-century lab buildings have much less vertical clearance than would be planned for modern labs. Their floor plates are often narrower than current standards, limiting planning options. The structural modules are often incompatible with lab planning modules and are challenged to handle today’s specialized equipment and ADA clearances. We also see a wide range of vertical shaft configurations for building services distribution, including shafts and chases located on the outside of the building. This results in labs with no windows or a large number of small shafts distributed along corridors, which are very difficult to repurpose for modern ventilation systems.
It takes clever planning to work within these constraints and design efficient and flexible labs. Considering alternative ventilation approaches like chilled beams, which allow decoupling of cooling loads and air changes, can often result in smaller duct sizes that fit within constrained vertical clearances. Where possible, open ceilings can also make tight vertical clearances work more effectively.
Through creative analysis of lab planning modules within existing structural grids, we can often find efficient and flexible layouts by offsetting or shifting the planning module from the structural grid. Narrow lab buildings can sometimes be effectively expanded by increasing the width of the footprint, using an offset corridor where greater lab depth can be gained on one side. Sometimes utility shafts can be added to the exterior of a facility and a new, high-performing building envelope can give the building a new look and greatly improve the flexibility and efficiency of the building service systems. This strategy can work to maintain existing systems and occupancy while new infrastructure is added outboard, and outdated internal infrastructure can be sequentially removed afterward to minimize downtime on crucial research.
The lack of documentation is a common issue encountered with older facilities and can become a challenge when faced with a project involving selective demolition. If the project does not require gutting an entire area inclusive of the main utility and central ventilation systems, then one needs to know what is in place and what can be re-used. From an equipment standpoint, it is not only a matter of condition or whether it can be refurbished, but also considering what the performance parameters are and how far the equipment can be pushed. Additionally, if up-to-date construction drawings, the O&M and/or project manuals cannot be found, the team renovating the space will be inclined to replace more than might be needed to be safe.
Investing the time to search for, collect and organize documents is well worth the effort as it will often yield better results. It is amazing what you find tucked away in remote parts of mechanical rooms. Another tool that can help is the use of scanning technologies to document what is installed even if that information would not include performance data. Even if documentation exists, it is still beneficial to have a test and balance contractor—under the direction of the consulting engineer—to take measurements of air and water flows and pressures at critical points in the building services systems. This will establish current system capacities and will provide a path forward for the design. This kind of testing can allow the engineer the ability to keep certain systems in the design, thereby saving project costs. Without this knowledge, the engineer may take a more conservative design path that replaces systems unnecessarily.
Older laboratories often have individual ducts running to each fume hood that lead to separate, small exhaust fans located on the roof. Often, these individual fans are in poor condition, and the stacks do not discharge high enough above the roof level to exhaust the fumes beyond the building wake or that of nearby buildings.
Advances in exhaust fan technology can allow the engineer to design systems that have the ability to achieve very tall, effective stack heights. Manifolded systems became prevalent in recent decades when control systems became advanced enough to support this type of approach. A manifolded exhaust system with a variable air volume control scheme can save operating costs, but the building structure and floor plate need to be able to accommodate the larger, central shafts required.
If research performed in a facility requires many chemical fume hoods using constant volume with bypass technology, then there is great potential to facilitate. In this case, there is a great opportunity to facilitate many types of learning and research while also achieving campus energy conservation goals. The air systems can be right-sized and the laboratories converted to variable air volume where the application permits. It is best to replace the hoods if the budget allows, or sometimes the fume hoods can be modified to permit variable flow operation. If this course is taken, it is recommended to perform an ASHRAE 110 test on a representative hood to see how it performs in capturing fumes after modification. Old fume hoods often need to have a modern airflow monitor installed to ensure the hood is operating safely.
Current code requirements
If the modernization project includes a square footage addition or a change to a building’s occupancy classification, then it is necessary to bring the building up to current code standards. This can be a costly endeavor, with the potential to affect elements or even the entirety of many existing systems, such as emergency power, fire alarm, fire protection, and ventilation and exhaust. Even smaller upgrades will need to be evaluated based on the “repair” and “alteration” categories outlined in the existing building code. While minor patching and replacement of existing materials can be considered a simple repair, the replacement of system elements even in the same place can be considered an alteration, triggering additional code requirements. Additionally, if the project’s area of work exceeds 50 percent of the building area, then the building must be brought up to current code standards, including possibly extensive changes to existing fire protection, accessibility, structure, and egress.
The use and storage of chemicals and other hazardous materials in individual laboratory spaces will also need to be evaluated according to the current code. The types of equipment and chemicals in labs may have changed since the building was initially designed, even if the content of the laboratory work has remained the same. The types and quantities of materials used are governed by the code, and affect fire-rated separations, fire protection systems and occupancy. An evaluation of current usage relative to historic design is necessary, as is thinking of future use and flexibility.
Universal accessibility can also be a challenge, as this vintage of science buildings were built before ADA was the law of the land. Often there is inadequate clearance on pull sides of doors, especially where corridors had shafts or similar elements incorporated. Smaller lab planning modules often result in less than minimum ADA clearances within lab areas between benches. Outdated benching systems and fume hoods are not ADA compliant.
Certain code accommodations, like adding a fire command center that meets modern requirements and installing pressurization systems for existing stairwells, may just be the tip of the iceberg. For example, a required increase in wall fire-ratings necessitated by chemical quantities may affect existing dampers at exhaust duct systems. We often find that many of these labs have been in operation so long that they have accumulated chemicals that exceed the requirements for B occupancies, even following the code requirements at the time they were built. It is often beneficial to consider adding rated chemical-holding areas (either centrally or by floor) so that the labs can be brought into compliance.
In the early 2000s, the International Building Code was changed to require combination fire/smoke dampers instead of simple fire dampers at shaft walls, which were common previously. These new dampers not only needed to be installed, but also required new access doors, power, and fire alarm connections. ADA standards can often be accommodated by converting smaller, closed labs into larger open labs that allows more flexible bench layouts, reducing the number of doors along hallways so that the remaining ones can be made compliant, and new equipment and benching systems can replace non-compliant ones. Using systems thinking, a design team can evaluate such cascading changes holistically and identify them early.
Renovations, when done correctly, can be a cost-saving and effective measure institutions can undertake to not only update facilities but significantly improve their learning and research outcomes.
Original content can be found at www.cannondesign.com.