10 Critical Vivarium Design Considerations

Solutions Require Collaboration among Facility Operators, Users, Vivarium Experts, Architects, and Engineers
Published 2-12-2020
  • Cage rack spacing

    Sufficient space between cage racks allows for easy removal of cages for cleaning and the safe operation of squeeze back cages.

    Courtesy of FLAD

  • Crowded cage racks

    These cage racks are placed far enough apart to allow the change hoods to move between them for cage changes, but space for clean and soiled cage carts is limited.

    Courtesy of FLAD

The growing complexity of research has heightened vivarium design requirements, making it imperative that facility operators and users work closely with the architect and engineers in the early planning stages of construction and renovation projects. Resolving these 10 recurring issues up front can help avoid problems down the road:

  1. Which rooms should be ABSL-2?
  2. Required ABSL-2 details
  3. Amount of working space between animal racks
  4. Plans A and B for preferred wall surface
  5. Necessary doors and hardware
  6. Necessary air changes per hour (ACH) in animal housing rooms
  7. Desired temperature/humidity ranges
  8. Lighting requirements
  9. Location of animal room receptacles
  10. Operational considerations

“Facility managers must pay attention to their own operations when planning,” says Dr. Clifford Roberts, a veterinarian and former director of the Laboratory Animal Resource Center at the University of California in San Francisco. “They need to explain how they use their equipment in their space, and specify the sizes and utility requirements of that equipment. Architects are often pushed by their clients to rush into design development without proper or sufficient consideration of the operations of their particular client. I encourage architects to stand firm and not proceed until biosecurity; adjacencies; and movement of animals, people, materials, and waste are clearly understood.”

Roberts, who has consulted on numerous animal facility renovation and construction projects over the past 50 years, says creating the most efficient space does not mean building the largest one that fits into the budget. Travel times and movements used in each operation may mandate a smaller space to optimize the activity of individual workers.

Avoiding Common Client Collaboration Issues

Direct communication between stakeholders and architects—throughout the planning, design, and construction or renovation process—is essential to address the design requirements, the National Institutes of Health (NIH) guidelines, and research needs. Common operational issues that must be considered during planning include housing a variety of species, addressing an increased emphasis on the microbiome and gnotobiotics, providing easy and unlimited access for investigators, ensuring the facility is low maintenance, and accounting for constrained first-cost funding.

“We need to insist on having the competent folks at each meeting at every step of the way,” says Roberts. “That way, the veterinarians and facility managers aren’t asked to operate a facility that wasn’t designed the way they need it.”

Veterinarians and facility operators want to discuss room layouts and details about items they can see and touch, such as epoxy floors and a certain type of ventilation, while architects are looking at the bigger picture of the functional space relationships by creating diagrams and drawings. The process requires patience, since many animal care specialists are not experts at reading architectural drawings.

Roberts suggests that architects and engineers explain their process to the users and ask that the veterinarians and facility operators take notes so they can provide their input at the appropriate time in the process. The users also must decide what equipment and how much space they need at the beginning of the planning, so the information can be integrated into the design.

It is equally critical to know precisely who is responsible for reviewing and approving submittals. The architect and project manager will look at specifications in terms of how they can best complete the work and possibly do so in a less expensive way, rather than looking at what it takes to operate the facility from the users’ perspective.

“Facility operators and veterinarians need to look at those specifications,” says Roberts. “This is time-consuming, but it is key to having a successful construction project.”

Key Questions to Ask

Designing a facility that offers the safest and most productive work environment, facilitates complex and evolving research, and accommodates multiple species of animals begins with knowing what questions to ask and understanding the answers. The goal is to design a vivarium that both excludes and contains infectious microorganisms, which must be taken into account when considering all room finishing details.

Roberts suggests following the NIH Design Requirements Manual when answering the questions, while noting any client exceptions for issues such as sound levels and transmission, cage change intervals, sterility requirements, and animal room ACH. All questions should be answered, and the information should be provided to architects at the beginning of each project.

Which Rooms Should be ABSL-2?

All animal housing and procedure spaces should be capable of ABSL-2 containment, in case there is a need to assign rooms for quarantine, contain spontaneous disease outbreaks, or to address other infectious incidents, says Roberts. The rooms should have sealed penetrations, finishes that are impervious to disinfectants and other chemicals, readily accessible hand wash sinks, casework with no vermin-accessible voids, and reversible room-to-corridor pressurization.

“Current building practices call for all of the penetrations into the animal or procedure rooms to be sealed with a sealant or gasket, so the room itself can be periodically decontaminated,” he says. “In my experience, the significant difference between an ABSL-1 animal room and an ABSL-2 in relatively new facilities is that additional personal protective equipment is required if the room is operated at ABSL-2.”

How Much Working Space Should Be Included Between Animal Racks?

Rodent racks mounted perpendicular to the wall should have at least 3 feet between them, and there should be at least 5 feet between rows of racks that are parallel to the wall. A special case is the squeeze back nonhuman primate cages, where the back of the cage has a grate that can be moved forward to restrain an animal in the front of the cage. Squeeze back cages require enough space between facing cages for the squeeze mechanism, for the length of the operator’s arm, and the length of the arm of the nonhuman primate in the cage behind the operator. The additional space prevents the operator from coming within reach of any nonhuman primates.

The space between racks also must facilitate the removal of a rack for washing without moving other racks, provide enough area for change hoods and biosafety cabinets, and accommodate clean cages and soiled cages during cage changing. Workers must be able to move racks and carts around the room, including turning corners, without disturbing other cages.

What is the Preferred Wall Surface and PlanB?

The gold standard for walls is fiberglass reinforced plastic (FRP) designed specifically for research facilities (not the kind available in retail stores for application on drywall). The FRP panels provide a monolithic wall that resists impact, water, and chemicals. It offers a low lifecycle cost with an excellent appearance that withstands wear and does not need to be refinished for at least 20 years.

Impact and moisture-resistant gypsum board mounted on metal studs is an alternative to the FRP panels. This type of wall can be disinfected by all conventional methods, and is considerably less expensive where hosedown cleaning is not required.

What Doors and Hardware Are Needed?

According to Roberts, doors and the accompanying hardware are often not installed correctly due to complex specifications and submittals. The basic standard calls for a single leaf door that is flush on six sides with stainless steel hardware and measures 42 by 90-96 inches. The doors and door frames should be made of a non-corrosive material like fiberglass or stainless steel. The specifications for hardware are more difficult, because there is typically more than one subcontractor involved for the door closers, latches, armor plating, and bottom seals.

“This is a critical element of an animal room, and the client must pay close attention to what is specified and how it is to be installed,” says Roberts. “In particular, door closers come in many varieties, but must be installed so they are not in the doorway when the doors open, and that they preferably have a built-in hold-open and stop function in the closer. I still see door openings restricted in height because of the closer.”

The automatic bottom sweeps should be surface or rabbet-mounted and not recessed into the door bottom. Butt hinges, instead of piano hinges, should be used. Windows in the door should be covered with magnetic frames or red film, since rodents have dichromatic vision and do not easily see red.

How Many Air Changes Per Hour Are Needed in Animal Housing Rooms?

The client must first know what kind of individually ventilated cage (IVC) racks will be used and how they handle air. It is important to know the vendor and model of the racks to answer the questions pertaining to how much, what quality, and where the air is supplied and exhausted from the room. IVC racks vary greatly in ventilation requirements, and the flexibility to meet any rack model requirements is costly.

“Knowing your equipment is critical, before the engineers start designing your system,” says Roberts.

The NIH generally specifies a minimum of 15 ACH, but that number was set when animals lived in open-top or filter-top static cages. Now that animals live in IVC, the ventilation rate in the room is less important, especially if the racks are ventilated from the building itself rather than from blowers on the rack that take their air supply from the room.

Roberts has found it acceptable to have about 6 ACH in the room, while maintaining 30 to 50 ACH in the cage. This provides a thermoneutral temperature for the rodents and keeps the room comfortable for workers.

The ventilation question also must consider low noise standards set by the NIH for sound ratings for HVAC-generated noise. Higher velocity air moving through the ductwork requires a client to spend more money to install silencers.

What Are the Desired Temperature/Humidity Ranges?

These particular controls differ by species, but the current practice is for rodent rooms to be closer to the rodents’ thermoneutral zones of about 75 degrees. It is helpful to house species together if they have similar temperature requirements.

Thermostats and hygrometers should not be installed on walls subject to liquid disinfectants. Thermostats should be installed in the supply or exhaust ducts to measure the temperature the animals are exposed to rather than the temperature in the room.

What are the Lighting Requirements?

Many institutions are using LED lights because they are less expensive, and the client can control the amount and color of lighting. However, the specifications for LED lights are relatively new, so architects are often not able to provide sound guidance. Roberts recommends using the standard guidelines from the NIH that specify approximately 700 lux when workers are in the room, and 300 lux when only the animals are present. A 100-lux timed red room override is suggested for night work, with a 50-100-lux range for the hallway at night. A Color Rendering Index (CRI) of at least 90 should be specified.

Shielded or remote controllers should be used to reduce ultrasound harmonics, and light timers should be placed on the biosafety cabinets and change hoods.

Where Should Animal Room Receptacles be Located?

Twist-lock receptacles should be used, and should be located in the ceiling for three principal reasons:

  • Much of the equipment that is plugged in is tall, and the ceiling is the closest location to the power.
  • The walls are clean and free of obstructions that might make cleaning and disinfection more difficult.
  • There is less electrical conduit and wiring required, so ceiling receptacles are less expensive.

Installing an additional receptacle near the door at about 48 inches off the floor is a good idea for investigators who bring in computers or other equipment.

“The most important issue related to lighting and electrical receptacles in the animal room is not the quality or quantity of the light itself, but rather the reliability of the control systems in the case of lighting, and the proper number of receptacles on emergency power for electrical systems,” says Roberts. “It’s too common to find light control systems that fail in many different ways, so that the lights are either on or off constantly. Each facility needs an operational method to determine whether the light cycles are functioning properly, and a system to determine whether receptacles that are supposed to be on emergency or standby power are actually connected that way.”

Operational Considerations

Other issues that are important for users to convey to architects include having timed shutoff valves for carbon dioxide, proper waste container space, security cameras in the vivarium, vermin-proof casework, and employee break room design that coincides with the organizational culture.

Vivarium operators may need guidance to analyze and understand issues such as cage wash throughput, autoclave throughput, the number of lockers needed for staff, and how much storage space is needed for supplies.

“It is important for every animal facility manager to know the metrics of those elements that contribute to cost or efficiency of their operation,” says Roberts. “It’s critical to be able to measure and report on changes in operational efficiency using real numbers based on the operations of the specific facility.

By Tracy Carbasho