The Ten Most Common Laboratory Design Mistakes

I have designed dozens of laboratories in my 47 year career. I have reviewed the drawings and specifications for many more. Sadly, I all too often uncover easily prevented problems that have cost, schedule, or operational impacts. Paying attention to these common problems can reduce the number of problems in a laboratory design. Here are my top ten common mistakes I see.

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1.??? Not specifying enough exhaust ventilation. Since ventilation is a major component of a laboratory’s construction cost and an even larger component of a laboratory’s operating costs there is always a major incentive to minimize the amount of exhaust and supply in any new laboratory. This problem is aggravated by preliminary designs that fail to identify all the required exhaust. Commonly problems include all of the following.

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Not doing a detailed survey early in the project before any estimate or design is started. Relying on existing drawings or records almost always leads to too low a capacity requirement, as modifications, changes, and additional issues are rarely ever added over time.

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Not including all the many local exhausts, ventilated equipment, and similar “minor” exhausts. Worse is not measuring, or at least confirming,? their actual capacity. I have seen numerous local exhausts marked to indicate a capacity of X CFM that are, in fact, exhausting 2-4 times more than X CFM. Additionally, numerous small exhausts are often scattered about, many in odd corners, that are overlooked, Design firms will argue that they know the capacity of the exhaust fans and so have real “absolute” limits. These are often wrong as many hoods will be found to be exhausting much less than specified due to the numerous extra exhausts that have been slowly added over time. So, using the current fan capacity as a design specification almost guarantees the same problems in the new facility.

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Not reviewing the actual recommended exhaust levels for safety compliance. Many existing exhaust will end up being too low but have been, regretfully, tolerated as viable alternatives simply did not exist. Using the same basis brings the same problems into the new facility.

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Assuming too high a diversity factor based on cursory studies, wishful thinking, or surveys during atypical periods is another major issue. (One design firm sheepishly admitted they did the measurements Christmas week as no one was there to bother their personnel or question what they were doing.) Any diversity factor less than 70% must be viewed with skepticism. It may be right, but it needs to be carefully analyzed and independently verified. Modern laboratories use significant exhaust even when no one is around. (NFPA 45 Fire Protection for Laboratories Using Chemicals recommends a minimum of 4 air changes/hour even when unoccupied.) Most modern laboratory ?equipment runs unattended. Multiple hoods are in operation by the same operator and, despite their best efforts, rarely have their hood doors always closed. Busy laboratories often find it unable to comply with minimum hood usage and still meet operational goals.

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Not including any contingency in the capacity for current needs that have been overlooked or underestimated during the design process. These are bound to arise and require some extra exhaust. Typically, at least 5-10% excess capacity is needed to cover these issues that will invariably arise. When not included, the new laboratory building starts off with insufficient exhaust from the first day.

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Not providing at least 10% excess capacity for future growth. Most laboratories will, in fact, end up requiring 20% more in the first few years of operations. Failure to recognize that future work will probably require more exhaust for safe operation is a common and deadly problem.

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For other issues, please see The Ten Most Common Laboratory Ventilation Mistakes, https://www.dhirubhai.net/pulse/ten-most-common-laboratory-ventilation-mistakes-richard-palluzi/ .

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2.??? Not providing enough supply air. While laboratories, by code, must be negative in pressure with respect to non laboratory areas a significant negative pressure differential always adversely affects proper hood operation. Failure to evaluate the supply air needs and distribution always creates operating problems down the road. Facilities that have some laboratories with small exhaust requirements near other laboratories with major exhaust requirements will often have major long term operating problems that are difficult to solve. The major exhaust users will begin to draw supply air from those laboratories that don't require a lot of supply, making these laboratories positive and not negative as required. Correcting this problem after construction is expensive, difficult, and sometimes impossible. Prevention is the best and easiest solution.

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Another issue is that often the additional exhaust capacity recommended above for both contingency and future needs is frequently not matched by our corresponding increase in supply air capacity. This results in the entire facility always being overly negative over time. The key is all exhaust increases must be matched by corresponding supply increases. See Too Much of a Good Thing: Exhaust Versus Supply in Laboratories, https://www.dhirubhai.net/pulse/too-much-good-thing-exhaust-versus-supply-richard-palluzi for a further discussion.

3.??? Overspending on high end casework. Specifying high end casework looks impressive and is often perceived as providing significant long term flexibility. This high end casework, however, comes with a correspondingly high cost which is usually taken from other, even more critical needs. High end casework often fails to deliver the flexibility desired and creates problems often overlooked during the design phase. Design firms, lacking real operational experience, often fail to highlight these issues to the owners to help them make a more informed decision. Common problems include lack of stability, which can create weighing or reading issues, limited electrical outlets, leading to overuse of extension cords and modular outlets, much more limited flexibility and adjustability in real world situations then envisioned, leaky utility connections, limited storage, and many other issues rarely discussed or evaluated. Rarely can mobile casework be moved around anywhere people want in an instant. There are no utility taps, there are minimum aisles always required, there are other things in the way, and few laboratories can really be changed around instantaneously as researchers envision based on designer promises. Providing the utilities via connects and flexible hoses is also difficult as these are expensive to provide everywhere and so are generally limited. Worse, they are prone to leakage yet difficult to leak test. That means that substantial amounts of gas will, over time, end up being wasted. Hazardous gases and liquids also cannot safely be provided except on the surface of casework, which effectively locks the casework in place, or on nearby pillars or frames which again limits the ability of the casework to be moved around.

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Sadly, in my experience, all too often flexible casework requires significant time and effort to change heights to add or remove storage and a host of other problems which makes it much less flexible for long term effectiveness in a research environment.

4.??? Failing to integrate safety requirements and equipment such as showers, eye washes, fire extinguishers, and emergency egress requirements into the proposed laboratory layout. Too many laboratories are laid out with only one exit creating a needless hazard. Others, with multiple exits, are nevertheless laid out such that corners and annexes are a considerable distance from any exit, needlessly increasing the risk.

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Safety showers and eyewashes are dropped in the most convenient location, from a design perspective, that create needless long term operational issues. Sink mounted eyewashes are specified to save plumbing costs with little thought to how the space to reach them will be maintained clear of the normal paraphernalia blocking sinks. Safety showers and fire extinguishers are placed at the maximum recommended distances to save installation costs requiring each laboratory occupant to memorize where their specific units are located. This is asking for problems during an emergency.

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The cost savings of these type of? minimum cost (and minimum thought) placements are small; the long term operability issues are large and the potential safety concerns significant. See Get The Fire Extinguisher! Thoughts on Where to Locate Them for Maximum Safety, https://www.dhirubhai.net/pulse/get-fire-extinguisher-thoughts-where-locate-them-maximum-palluzi , “We Didn’t Think That Through”: Emergency Response in Research Applications, https://www.dhirubhai.net/pulse/we-didnt-think-through-emergency-response-research-richard-palluzi , Safety Showers: Often Specified But Less Often Thought Through, https://www.dhirubhai.net/pulse/safety-showers-often-specified-less-thought-through-richard-palluzi/ , and

“Don’t let the door hit you on the way out”: Door Swings in Laboratories, https://www.dhirubhai.net/pulse/dont-let-door-hit-you-way-out-swings-laboratories-richard-palluzi/ for more information.

5.??? Failure to understand and, more importantly, explain to the eventual users, the maximum allowable quantity (MAQ) of hazardous materials that fire and building codes will allow in a laboratory. This is a complicated issue with which many design firms have limited experience. This often leads them to an incomplete or incorrect evaluation or interpretation. They often fail to explain the issues and requirements, in sufficient detail, to all the affected users to allow them to determine if there are any issues with compliance. While 90% of the research areas may not have trouble complying, the other 10% can find they cannot do their intended research or need to later provide expensive remote storage to continue.? See Making Sense of Laboratory Fire Codes, R P Palluzi, Chemical Engineering Progress, July 2017 and? What is the Maximum Allowable Quantity (MAQ) of Hazardous Materials Allowed by Code in a Laboratory or Pilot Plant Area?, https://www.dhirubhai.net/pulse/what-maximum-allowable-quantity-maq-hazardous-allowed-richard-palluzi for a more detailed discussion of these requirements.

6.??? Incorporating larger pilot plants in normal laboratory spaces. While there is nothing wrong with having pilot plants in a laboratory, their presence requires careful additional hazard analysis and risk assessment. Their total inventories must be included in the maximum allowable quantity (MAQ) assessments. The MAQ must include staging and temporary storage of feeds awaiting loading, waste awaiting removal, cleaning and flushing solvents and similar transient needs.

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Higher pressure hazardous gases also create significant additional hazards. A higher area electrical classification may be necessary. Secondary containment may be required which can create tripping and access hazards in a standard laboratory. Weight may become an issue. Placing these type units in separate rooms or process areas, is usually more prudent. See? What is a Laboratory Versus a Process Space?, https://www.dhirubhai.net/pulse/what-laboratory-versus-process-space-richard-palluzi , Design Mismatch: The Need for Assessing the Safety and Operational Issues With New or Modified Research Facilities, https://www.dhirubhai.net/pulse/design-mismatch-need-assessing-safety-operational-issues-palluzi/ ,? and Can I Put a Pilot Plant in a Laboratory?, https://www.dhirubhai.net/pulse/can-i-put-pilot-plant-laboratory-richard-palluzi/ for an additional discussion.

7.??? Failing to show everything, particularly the unglamorous minutia, a laboratory requires.? This includes solvent cabinets, garbage cans, stools, shelves, glassware racks, broken glass cans, and dozens of other small items that take up space. When not shown on a layout, a spacious laboratory can often change into a cramped and crowded space.

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Equipment is often quickly measured as rectangular blocks, leading to numerous places where smaller parts stick out and create pinch points or narrower aisles. Ancillary equipment like power conditioners and supplies, autosamplers, etc. are not included but – in the end – must fit somewhere. Operations in other areas to be relocated to the laboratory in question for efficiency are not understood nor included. Neither their space, power, exhaust, nor furnishings are often placed. Work up space, the inevitable areas needed to do some operations, is ignored.

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Walking through the proposed layout before it is finalized with the actual end users is rarely done. Even less performed is questioning the users to ensure they evaluate some options. Asking “are you sure you don’t need work up space near that?” or “what access do you need for routine maintenance” can often open a new line of concern they had not thought about before.? As a result, their requirements are rarely fully addressed. See How Big Is That Doggie In The Window: Problems With Measuring Research Equipment, https://www.dhirubhai.net/pulse/how-big-doggie-window-problems-measuring-research-richard-palluzi , Where is the Best Place to Put a Flammable Storage Cabinet?, https://www.dhirubhai.net/pulse/where-best-place-put-flammable-storage-cabinet-richard-palluzi , and Safe Where It Is; Safe Where It Is Going: The Often Unrecognized Hazards of Moving Research Equipment, https://www.dhirubhai.net/pulse/safe-where-going-often-unrecognized-hazards-moving-research-palluzi/ .

8.??? Overly complicated laboratory pressurization schemes. NFPA 45 Fire Protection for Laboratories Using Chemicals and ASSP Z9.5-2022 Laboratory Ventilation both require laboratories to be at negative pressure with respect to non-laboratory areas. The easiest and most reliable way to ensure this is to control based on a fixed offset between the supply and exhaust. (I.e., control the differential between them to ensure the exhaust is always more than the supply so the laboratory must remain negative.) Controlling differential pressure is also possible but is usually more complex and less reliable. Except for some specialty usually high risk laboratories (radioactive, biologics, etc.) there is no need to meet CDC requirements for high face velocities. Many design firms do not really understand these requirements and often implement them poorly. This creates needless long term operating and maintenance issues as well as being energy inefficient.

9.??? Door swings specified the wrong way and without panic hardware. NFPA 45 Fire Protection for Laboratories Using Chemicals requires laboratory doors must swing in the direction of exit travel (i.e. ,out of the laboratory) for Class A and B laboratories. Doors may slide or swing against the direction of exit travel in Class C or D laboratories. (The classification of the laboratory depends upon the construction. Class A laboratories require a 2 hour fire rating, Class D require no fire rating. Each class allows different amounts of flammable inventories, Class A being the highest and Class D the lowest.) It is a best practice to always have all laboratory doors swing out from the laboratory.

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Just as importantly, while most laboratories do not have the personnel density that require panic hardware, best practice and common sense suggest that it always be provided to allow for rapid egress in an emergency. See “Don’t let the door hit you on the way out”: Door Swings in Laboratories, https://www.dhirubhai.net/pulse/dont-let-door-hit-you-way-out-swings-laboratories-richard-palluzi/ for a further discussion.

10. Poorly distributed exhaust airflow that does not fully sweep the laboratory. Often hoods, ventilated enclosures, and local exhaust are clustered together to reduce the cost of running ductwork. While some clustering may be acceptable, it is important the entire laboratory space be properly swept. Supply should pass over all the laboratory on its way to its exhaust ?location. Often, I find numerous side areas, corners, or even significantly larger portions of a laboratory that is not really swept at all. This almost invariably leads to odors and operating problems. See also Where is the Best Place to Locate a Hood in a Laboratory?, https://www.dhirubhai.net/pulse/where-best-place-locate-hood-laboratory-richard-palluzi .

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These are far from all the problems I have seen in my design drawing reviews and safety audits, but they are the most common. Paying attention to them during the design phase can save money and time trying to correct them later and make your laboratory a safer space long term.

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For additional information on successful laboratory design, you may want to consider Engineering Career Solutions course Successful Laboratory Design: Grass Roots, Renovation or Relocation (https://ecstechtraining.com/lab-design-1) or Pilot Plant and Laboratory Safety: Basic Principles and Code Compliance (https://ecstechtraining.com/pilot-plant-lab-safety ).

#safety #laboratorydesign #researchanddevelopment