While low-maintenance interiors satisfy the important goal of maximizing lab uptime and limiting physical intrusions that might interfere with the research mission, their higher first cost can be hard to swallow. At the same time, less expensive finishes and components can prove to be more costly as they generate an increased need for repair or replacement over time.

An exchange among program directors at a recent Tradeline conference detailed several lessons learned regarding construction materials, hardware, and finishes, especially in high-containment labs or those with heavy-duty sanitation requirements.

The participants included L. Eugene Cole II, NCID lead program manager, Centers for Disease Control & Prevention (CDC), Atlanta; Clayton Hayden, director, Research Resources, Merck & Co., Rahway, N.J.; Guy Mulder, director, University Laboratory Animal Resources, University of California, Irvine; and Ned Leverage, president, Life Science Products, Chestertown, Md.

All agree that, along with being easy to disinfect, lab interior surface finishes should have minimal seams or penetrations for an insect- or vermin-free environment; need to endure the rigors of routine wet cleaning; and ought to withstand heavy use or abuse, such as repeated contact with equipment-laden rolling carts.

"Maintenance-free facilities are very pricey buildings," says Eugene Cole, who is currently supporting more than 200,000 sf of lab construction and renovation at the CDC. "If we can spend a little extra money up front to get the finishes that will last, everyone will be much better off."

Durable Floors

Floors constitute a typical lab trouble spot. Of the many different types of flooring available, Cole has found methyl methacrylate, commonly referred to as MMA, to be extremely durable. Not only is MMA long-lasting ("It has held up to just about everything we've thrown at it," he remarks), but installation is a straight-forward process in new construction.

"MMA is pretty simple to put in a new lab," Cole explains. "The primer coat is applied after the concrete surface is roughed up. Then you put down the body coat, in a variety of colors and textures, and then the top coat."

The process is more complex for an existing floor, which must first be strippedback to the concrete and then scarified. A small area should be tested to make sure the MMA bonds to the substrate, Cole advises. The rest of the steps are the same as for a new installation.

Comparing costs, Cole finds that a traditional epoxy floor runs approximately $7.50 per sf installed, while a recent MMA floor in a new facility came in at $11 per sf. For the CDC, the higher price was offset not just by long-term durability but by the almost-immediate availability of the space.

"We did an MMA installation overnight, finishing the job at 2 a.m.," says Cole. "The occupants moved in at 8 that morning, testimony to the material's quick drying time."

The same rapidity applies to repairs, which can be performed by internal personnel after they have been trained by the manufacturer of the MMA product.

"Once your in-house staff have been trained, you don't need a certified installer to make a little patch," says Cole. "In an hour, you are back to work, as opposed to an epoxy that might take three days to cure."

Touted as an improvement over MMA is a brand-new flooring material from Life Science Products. Known as N², the covering is applied in a similar manner, but thanks to a composition of polyester and vinylester resins, it eliminates the volatile organic compounds and hazardous air pollutants associated with many other flooring resins. The LEED-qualified N², which so far has been installed in about 20,000 sf of space in various iterations, is cured almost instantaneously by exposure to ultraviolet light, allowing the space to be occupied (or reoccupied) within minutes of installation.

According to Life Science Products president Ned Leverage, UV curing bolsters the floor's chemical resistance. A new mobile UV light source has also been developed as part of the project.

Floor Decontamination

Guy Mulder had to meet different criteria in selecting the flooring for a BSL-3 section of a new building on the University of California's Irvine (UCI) campus, Hewitt Hall.

UCI's biosafety officer had requested an alternative to the campus' standard floor finish, troweled-on epoxy. When applied correctly, the epoxy stands up well to typical acid and chemical spills, Mulder notes, but clean-up of radioactive material spills may be difficult.

Should even a minute quantity of a radioactive compound contaminate an epoxy floor, the affected area must be removed and replaced. However, the only way to strip off epoxy is by grinding or sandblasting, causing a highly undesirable consequence: the release of radioactive material into the air.

Mulder circumvented the epoxy removal issue by installing industrial or high-grade sheet vinyl flooring instead. Commonly used in a broad range of applications, from commercial garages to factory floors, rolled vinyl is very impact- and chemical-resistant, Mulder says, and he expects it to have a long life in the lab.

Best of all, the remedy for a radioactive spill is simply to cut out the affected section of the floor and replace it with a new piece of vinyl. Welding the repair with heat eliminates all seams, ensuring there will be no vermin infiltration.

Seamless Walls

Walls in the BSL-3 environment should possess the same characteristics as the flooring.

Among the numerous possibilities for interior finishes, Mulder has found that the rudimentary gypsum board covered with epoxy paint, typically installed in older labs on the UCI campus, is neither impact- nor moisture-resistant, creating the need for frequent maintenance and upkeep. A step up is CMU, or cinder block wall. Either hollow or concrete-filled, CMU presents an impervious surface that can be painted and easily cleaned. However, it is not very adaptable to change, making remodeling a very expensive proposition.

In Hewitt Hall, Mulder opted to install GridLock™ fiber-reinforced panels, or FRP, also from Life Science Products. Often used in the food industry, another moist environment with stringent sanitation requirements, FRP offers the advantages of minimal seams and ease of disinfection.

"We've used these panels in another campus facility for about six years, with few if any maintenance issues—they require no painting and are difficult to damage," says Mulder, who also concedes one drawback: the panels, approximately 9 feet tall by 30 to 40 feet long, can be challenging to work with, especially for contractors who haven't used them before.

FRP installation takes a fair amount of coordination, imagination, and planning, he warns, particularly in smaller rooms and around corners. The material is, however, ideal for building a containment facility with a very tight outer envelope.

"Instead of the traditional four-foot by eight-foot wallboard, FRP creates floor to ceiling walls that can run for 40 feet with no seams corner to corner," he says. "The only penetrations are for electrical connections or other services. This is very good for containment and cell culture labs, as well as cage wash areas, where there is high-pressure water and a lot of steam. It also helps to maintain appropriate air balances."

Hardware Makes a Difference

Once the lab walls have been installed and finished, some form of protection is necessary to shield them from impact with hard objects to ensure their long life. CDC's Cole is a staunch advocate of the SANI-rail system.

"I haven't seen any other system that matches it in design or durability," he maintains.

The bumper guards serve the purpose of keeping carts or cages from direct contact with the walls, without creating places for roaches or bugs to hide. Available in either stainless steel or aluminum, the rails also have a good chemical resistance.

However, Cole does proffer a caveat, the result of direct experience, about the importance of their anchoring method. Plastic sleeves are simply not strong enough to secure the rails in a concrete block wall. Loose rails can be wrenched free.

"The best way to attach bumper guards to CMU is by using a stainless steel sleeve expansion anchor from McMaster Carr," says Cole. "Once inserted, it will never come out."

Door Hang-ups

Doors and their hardware present a multitude of maintenance challenges, including damage from collisions with carts and the need for frequent repainting and re-hanging. After experience with a variety of materials, from hollow metal to stainless steel, Cole recommends FRP doors as a more durable alternative.

"FRP doors have the virtue of being extremely impact resistant," he says, citing an installation where they have held up for about 10 years with no replacement necessary. He compares this to a pair of stainless steel doors that lasted less than two years in one CDC facility. "They actually warped from the impact of rolling cages," he notes.

Keeping doors aligned properly on their frames is critical for a tight seal, necessary for proper pressure relationships, and as a barrier to vermin.

"If a door is off even by one-eighth of an inch, it will not sit flush against the frame," remarks Cole.

He and Merck's Clayton Hayden both observe that the standard three or four hinges commonly used to hang doors are not adequate to support complete closure over a long period of time in these environments. As a solution, they propose using a continuous hinge, such as the full-length stainless steel piano hinge installed on the doorframes in a recent Merck facility.

"This type of hardware is very heavy-duty, and it can take a lot of abuse," Hayden says.

It also retrofits easily onto an existing doorframe during remodeling, adds Cole. "Because the hinge is one continuous piece, the door operates smoothly, with no binding due to bad alignment," he explains.

Another contribution to tight closure is a drop seal on the bottom of the door. The seal mechanism, a neoprene gasket, drops down and sweeps against the floor when the door is closed. On opening, the spring-loaded strike plate raises the seal to produce a slight gap (roughly one half-inch) allowing smooth travel across the floor.

"The door fits flush and plumb, and closes completely," says Cole.

Door handles can also be problematic.

Having gone through the disruption and expense of replacing worn-out door handles within a year of occupying a new facility, Merck built a mock-up of several different handle types to assess their ease of use and ability to withstand collisions with rolling racks.

While paddle-type handles were judged easy to activate, especially for lab workers who have their hands full transporting equipment, they have a distinct downside: the internal workings of the latch mechanism are not meant to take heavy abuse.

For its latest lab, Merck traded convenience for practicality, selecting the traditional lever-type handle.

"Although they don't offer hands-free operation, the levers are a lot more durable," says Hayden. "We've discovered that if you don't get the hardware right the first time, it will give you nightmares for years."

Keeping It Simple, Sometimes

Also tested in Merck's mock-up was a device that permits telecommunications cabling to pass from one lab to another through the wall. The apparatus eliminates the possibility of air flowing through the opening between rooms by compressing itself over the wire it encloses, making an air-tight seal.

"This product is a fantastic application of technology," says Hayden, "but it is also fairly expensive and complex to deploy."

Facing a cost of approximately $100 per box, Merck decided to back off on the innovative solution, instead adopting a markedly low-tech approach.

"We wound up running the cables in a PVC tube inserted through the concrete wall with an air-tight cap on either end. There is some air movement through the tube," Hayden allows, "but we can manage the air flow differential by controlling pressurization in the room."

The tubing alternative proved not only easy to install but also much less expensive, costing less than $10 per box.

The simplicity principle should not always rule out technology, however, especially where repetitive manual activity presents high ergonomic risk and exposure to potential allergens can cause problems for human workers. In its latest lab building, Merck decided to invest in robotic systems to handle the sanitation processes associated with rodent housing.

The facility features two automated cage wash systems on two separate floors, with centralized clean bedding delivery and waste bedding management. Manufactured by Steris, the system was purchased as a package, including all integration.

Starting on the dirty side, a robotic arm grabs the soiled cage and inverts it over a vacuum dump station, which sucks the contents (used bedding and animal waste) away to a central collection point near the loading dock. Here it is automatically packaged in a cardboard box designed specifically to fit on the infeed conveyor of the on-site incinerator.

In the meantime, the robotic arm deposits the plastic cage in an automated tunnel washer, which Hayden describes as a 40-foot-long version of a cage washer with a conveyor belt. The system transports the sanitized cage to a clean bedding fill station, which also uses a vacuum to transfer granular corncob bedding material from a storage area on the first floor. Another robot arm then stacks the filled boxes and places them on pallets on a conveyor system, to be used by animal care staff.

Because the cages come in different sizes, the robotic devices are equipped with sensors to distinguish boxes with different dimensions and orient them appropriately on the conveyor. The tunnel washer is indexed to stop and start according to the load arriving at the infeed.

Merck also installed an automated system to empty, clean, and refill water bottles, a chore that is repeated thousands of times a day.

Dirty bottles are fed into the Tecniplast KRONOS system in crates of 25. The system removes each bottle's integral cap and sipper tube, then flips it over to make sure it is empty. The empty bottles are transferred into the washer, along with the caps and tubes. Once they are clean, the bottles are righted and filled, and the integral cap and supper tube is replaced. The fresh bottles are then stored on pallets, ready for use by animal care staff.

The sheer quantity of items processed justifies both systems financially, with the added benefits of protecting workers and boosting their productivity elsewhere.

"Emptying soiled caging is a heavily repetitive, painfully boring task for humans," states Hayden. "In addition, from one to three percent of the people working in animal facilities develop some allergy symptoms during their career, and being able to keep humans out of this kind of environment is a great motivator," he concludes.

By Nicole Zaro Stahl