“Know your protocol before you go to design,” advises Ned Leverage, president of Life Science Products Inc. and Seamless Technologies Inc., both based in Chestertown, Md. “Select finishes when you design the purpose of the rooms. A lot of times, finishes are selected by the general contractor at the end of the value-engineering process with very little thought about what happens to the program itself.”

More upfront discussion is necessary to ensure the floors will not buckle under the strain of cage racks and the finishes will not fail in the future. The biomedical research industry is constantly evolving and these changes must be figured into the equation when selecting finishes. Unfortunately, finishes continue to fail because they are not being selected based on the essential needs of the industry.

Just as the research industry continues to change, environmental regulations are becoming more stringent in dictating what type of coatings can be used. New technologies are being developed to meet the changing industry needs and environmental concerns. As a result, the same solvents that used to help with inner coat adhesion, curing times, and density years ago may no longer be safe. Knowing which finishes to choose requires attention to the vivarium program, the industry needs, and the environmental regulations.

Advice from the Guide

The Guide for the Care and Use of Laboratory Animals, simply referred to as “the Guide,” does not specify what materials to use or how to construct a vivarium. However, it does serve as a starting point for establishing industry recommendations about quality animal housing. In general, the Guide states that building materials should facilitate efficient and hygienic operations, and finishes should be durable, moisture-proof, and fire-resistant with seamless applications.

According to the Guide, finishes should be highly resistant to the effects of cleaning agents, scrubbing, high-pressure sprays, and impact. The facility should be well-planned, well-designed, well-constructed, and properly maintained in order to facilitate efficient, economical, and safe operation.

The Guide includes specific recommendations for floors, walls, and ceilings.

Floors:

The floors should be moisture-resistant and non-absorbent to ensure enhanced durability. The useable life cycle of the floor is decreased if the durability of the finish is compromised by moisture.

In addition, floors should be resistant to impact, biological materials, and hot water. They should also be capable of withstanding cleaning agents and disinfectants, and be able to support racks, equipment, and stored items. Floors in a vivarium should be relatively smooth with minimal joints.

Sloping the floors toward drains is a good idea, especially since flooring resins function better over time if they are not constantly immersed in water. Sloping can also eliminate water puddles that create safety hazards for employees. If the floors are not sloped, cleaning chemicals that are allowed to dry as the water evaporates can expose the floor to chemical damage. The recommendation to assure water flow to the drain is to slope at a minimum rate of one-eighth inch fall per foot of linear run to the drain.

Walls:

The guidelines for walls are similar to those for flooring. For example, walls should be moisture-resistant, non-absorbent, impact-resistant, and smooth. They should be free of cracks, unsealed penetrations, and imperfect junctions. The walls must also be able to withstand high-pressure washing and cleaning with detergents and disinfectants that are used to reduce contamination.

“We want impervious surfaces because we don’t want the walls to absorb any of the chemicals that may be used,” says Leverage. “The Guide also says that curbs, guardrails, and corner guards should be used to protect the walls to reduce both the cost and interruption to programs associated with maintenance.”

Ceilings:

Suspended ceilings are undesirable unless they are made of impervious materials. The recommendations for ceilings are nearly identical to those outlined for the walls and floors. The ceilings should be moisture-resistant and smooth with no imperfect junctions. They must be washable and capable of withstanding detergents and disinfecting products. They should be sealed or painted.

“We could take the information from the Guide and we would still be a little lost if we were developing new technology because it really doesn’t tell us where to go specifically with programs that are being developed for a certain vivarium. When the industry approaches new technology today, we are listening to customers because they are responsible for what we determine as the drivers,” says Leverage. “The customer ultimately pulls new technology from the development phase to the practical application in facilities. If it doesn’t have applicability, it is not going to be used.”

Shift Toward New Technology

The primary drivers of new technology are needs that evolve as the industry continues to develop. The needs drive solutions that ultimately become an integral part of the daily operation of a facility.

“What we are finding today is that customers have a new and different set of expectations than they did 10 or 15 years ago,” notes Leverage. “We are doing things a lot differently now than we did before. The new coating technologies are trying to keep up with the changes in the industry.”

Today’s customers have a new set of demands for flooring and coatings. In particular, they want a quick cure so operations are not interrupted for days after the installation of a wall coating or floor finish. Customers are also requesting that coatings be installed quickly with a clean resin. A concern for the health of employees and the animals is fueling a demand for cleaner, greener technology.

High-performance coatings are in demand because they are stronger, more resistant to chemicals, and provide better wear. The new generation of products features high-performance coatings that are critical to sustainability. In turn, sustainability is critical to the continuation of facility programs without interruption, lost productivity, and additional maintenance costs.

Customer demands also require an improved physical performance to enable flooring to better accommodate heavier cage racks. The industry now includes larger rack systems, such as the micro-isolator racks. The newer, heavier equipment results in much higher rolling loads with point loading approaching 17,000 pounds per square inch (psi), which can place a tremendous strain on a conventionally designed floor.

Example of Damage

Leverage cites one example where the floors of a relatively new facility were damaged as the result of the wear and tear from the casters on cage racks. The rolling loads exerted by the casters due to the heavy rack weights left behind white tracks that look like scratches on the floor. A closer examination of the floor under a magnifying glass reveals that the clear seal coat underneath the track of the caster has numerous cracks and fissures. The fractures are dense enough that the light refraction looks like a scratch on the floor, but the irregularities are actually within the seal coat.

Tracking is a recent phenomenon that is neither predictable nor of epidemic proportions. It is difficult to predict under what conditions or on what kind of floor it is likely to occur. However, there is a tendency for tracking to occur when a facility uses racks that weigh in excess of 1,200 pounds with phenolic, autoclavable casters. When the weight is applied through the casters, the load is unforgiving on the floors. The casters are typically two inches wide, but only about a half of an inch in the middle makes contact with the floor.

“When the point loading of the rack exceeds the compressive strength of the floor, the flooring begins to show minute fractures in the resin composite which leaves white tracks where the caster travels,” explains Leverage. “This problem can only be eliminated when the physical properties of flooring are improved.”

The casters can also cause collateral damage such as marred floor surfaces. Likewise, the weight of the racks can damage the casters, creating a jagged point of contact with the floor. To combat this problem at one facility, aluminum oxide was used to create an aggressive non-skid surface that casters would not destroy. However, the aluminum oxide eroded the casters, making them more abrasive and causing subsequent marring of the floor.

The tracking problem can be addressed by using lighter rack systems and avoiding the use of unforgiving phenolic casters. Improved technology is geared toward creating less abrasive casters and flooring that is more durable. Flooring systems are typically divided into three categories: mortar, broadcast, and composite. Mortar, also referred to as a troweled epoxy floor, is inherently porous and has a tendency to absorb water, chemicals, and other liquids. The mortar systems have the lowest compressive strength and, therefore, are not capable of enduring heavy loads. The average compressive strength of a mortar floor is about 8,000 psi.

The broadcast systems are virtually non-porous, meaning any damage from impact is isolated to a localized area. Since the damaged area in the resin-rich broadcast floors is smaller, this type of floor is easier to repair. The average compressive strength of broadcast flooring is 10,000 psi.

Composite flooring, which is stronger and more durable, is comprised of several materials working together. The new composites have a compressive strength of approximately 18,000 psi and are more sustainable.

Customer Demands

Customers want floors and coatings that are resistant to the newer, harsher chemicals that are being used in the research environment, including chlorine dioxides, ammonium chloride, potassium chloride, phosphoric acid, hydrochloric acid, and liquid nitrogen. New cleaners and disinfectants should be spot tested on the floor prior to use. Likewise, potential flooring can be tested prior to purchase to determine how resistant it is to chemicals that will be used in the vivarium. Published tables that outline the level of resistance exhibited by a certain flooring to various chemicals should be used only as a guideline.

Quality control testing should be included as a specification guideline at the time of bid with the right to refuse a bid if the flooring or wall and ceiling coatings are not resistant to chemicals. Record the lot numbers of all the materials that are used and retest them again. The lot numbers can be used later to verify the proper material with the right amount of resistance has been installed.

Customers are also demanding reduced life cycle costing with a higher value product, less down time for repair, and enhanced durability. Leverage points to a case study where two prices were received to install flooring in a 9,350-sf facility. The facility planners thought they were saving $17,000 by opting for the $69,000 floor instead of the one priced at $86,000. None of the proper testing was done to determine if the floor would be resistant and durable. After one year, the floor had to be totally replaced, meaning the facility actually lost money instead of saving $17,000.

Today’s educated customers want quick installations and repairs because they realize time is money. Epoxies and urethanes require a 24-hour cure time before you can walk on the floor, 48 hours before you can work on it, and 72 hours before you can get it wet. If a facility with 500 cages is down eight days, the total per diem loss is $4,000, which can be slashed by $1,500 by reducing the downtime to five days. Downtime is minimal if the flooring is made of composite products (N²) or methyl methacrylates (MMA).

Customers also want more green technology to ensure a cleaner environment.

“Today’s new products must perform like a Ferrari, have the utility and function of a Hummer, and be as environmentally clean as a Honda hybrid,” says Leverage.

New Trends

Resins that cure quickly after being exposed to ultraviolet light are becoming popular. UV-cured resins result in a faster installation time, lower shutdown costs, and a tighter cross-link for better wear and improved chemical resistance. More controllable, predictable results occur in the final curing process, resulting in better looking, cleaner products. This clean technology is LEED-compliant because it does not use dangerous hazardous air pollutants or volatile organic compounds.

The trend toward cleaner and safer products includes UV-cured resins and composite technology, which are available in vinylesters, epoxies, polyester, Novalacs, and urethanes.

“It is a whole new breed of chemistry that is going to be utilized in animal research facilities, so this is a good time to be working in this field,” says Leverage.

By Tracy Carbasho

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ISSN: 1096-4894