Selecting an ESD flooring solution for your cleanroom or lab is about more than reducing static electricity. There are several variables at play — specifically, operational and installation challenges as well as ESD electrical properties. This article will address all three by asking the questions you should be asking when selecting your ESD flooring.
ESD electrical properties
What is the most critical chip sensitivity?
You want to control the static buildup in the environment based on the most sensitive chip in the electronic devices of your cleanroom or lab equipment. Some chips can be damaged at 200 volts, others at 100 volts. Some of the newer, smaller chips can be damaged with as little as30 volts. Your ESD management program would start with your most sensitive chip, which would drive the level at which you want to maintain the static in the environment. Different flooring options will reduce the charges on a person to different levels. Preferably, you want to select tiles that keep static electricity generation on a person below 30 volts.
What standards are you trying to adhere to?
There are industry-accepted standards that are built around sensitivity. The generally accepted standard is S20.20, which is designed around 100 volts. You can use that as your standard, as it’s typical for most electronics manufacturers. Many cleanrooms use the S20.20 standard.
Based on the above, do you need conductive or dissipative ratings?
If your work involves an ultra-sensitive chip, in general, you should go with conductive. If not, dissipative will suffice. This is something we help customers determine as part of our survey/screening. Some customers will demand a specific rating. Some companies have an internal ESD protocol they must follow and want conductive, even though the actual use may not require it.
Is humidity controlled in the area? If not, what range will it vary within? (This affects the ESD properties of some materials.)
Some flooring products are affected by humidity and some are not. If you have a very sensitive chip and don’t control humidity, things could get very dry and the flooring may lose its ability to conduct static charges to the ground. That’s why there are certain products you should not use in those types of situations. We’ve seen companies use products that are sensitive to humidity and then start pointing fingers when the product doesn’t work.
Do you require the floor to be portable for reconfigurations or future moves?
Some types of facilities require flooring to be portable. Expansions, downsizing, or relocation to a new facility are just some of the reasons why companies want a flooring they can move. When you choose a glue-down option for flooring, you sacrifice portability. Glued down tiles can’t and shouldn’t be removed and used again. There are ESD flooring products out there that utilize an interlocking system so flooring can be moved, should your lab or cleanroom need to be moved to another location.
What are the VOC and particulate requirements of the room?
Some floors are better for cleanrooms than others. Epoxies and vinyls work well in cleanrooms. Cleanrooms will have standards to which they have to adhere — that’s something the flooring dealer should review with customers. For example, some products generate particulates when scrubbed. This requires a sealant to be applied to prevent that from happening. Again, this should be part of a review you conduct with the flooring company to ensure the flooring meets the requirements of the cleanroom properties.
Do you require any type of chemical resistance?
As a lab or cleanroom, it’s possible your facility might employ chemicals that may impact the material used on the flooring you select. Having a detailed conversation about your operation is critical to making a wise selection. If there are chemicals in your work environment, there are some possible solutions. For example, resistance to certain chemicals such as solvents or acids. Vinyl is resistant to many chemicals and is generally a good choice. Rubber is good for other chemicals like chlorinated solvents.
If possible, get a sample of the flooring that you are considering and be sure to test it against the chemicals that you have in your area.
Do you require special slip resistance?
Obviously, you want to select a tile with ESD qualities and slip resistance. Some environments may need greater slip resistance. If your facility requires a greater level of slip resistance, then you will want to steer clear of slick materials like epoxies. Seek out products that provide more secure footing. Tiles that utilize a coin-top texture offer better slip resistance.
Do you require comfort, ergonomic, or anti-fatigue properties in cleanroom/lab flooring?
Quite simply, some floorings are better than others for humans to stand on for long periods of time. For example, epoxies are hard. The same holds true with glued-down vinyl flooring. Unfortunately, the more ergonomic and comfortable the floor, the higher the cost. Going the extra mile can provide a return on investment in that lab or cleanroom workers who are more comfortable will be more productive and miss less time due to standing-related injuries, like plantar fasciitis. Fewer injuries and more comfortable work conditions will also improve staff retention.
Does the underlying concrete pass moisture tests?
If there is concrete beneath your existing flooring, moisture could be an issue and will need to be checked first — particularly, if the flooring you’re considering is a product that needs to be glued. In that scenario, it’s also not advisable to glue the new floor onto the old floor. It should be installed onto the underlying concrete. If you are planning on using interlock flooring, first you need to test the old flooring for asbestos. Removing flooring with asbestos is a very detailed process. Areas of the floor need to be sectioned off with plastic as air pressure is used to contain any dust.
If using new concrete, can you wait for the 90-day cure period?
If you can’t glue on concrete with moisture issues, it stands to reason that newly installed concrete floors must cure before you can glue down new flooring. Ninety days is the recommended amount of time.
If there is an existing floor, does it have asbestos either in the tile or adhesive?
Both the flooring and the adhesive of your old flooring should be tested for asbestos prior to gluing down new flooring or, honestly, before installing interlocking flooring. Dealing with asbestos is costly and will delay installation. Interlocking tiles can be installed on top of old asbestos-containing floor without having to remove it.
If there is an existing floor, do you want to install without removing it?
One of the beauties of interlock flooring is that it can be installed over existing flooring. Some facilities managers prefer flooring that requires an adhesive. In that scenario, removing the old flooring first is recommended. You can choose not to take on the expense of floor removal. It’s just not preferable.
Can your facility tolerate the dust generated from a sub-floor preparation?
When you rip out the old flooring, it will generate some level of dust. Will that have an impact on the equipment and electronics at your facility? That must be considered and assessed. It could have an impact on your decision to go with a glue-down flooring or interlock. There are other considerations and questions to ask before making your final selection. Things like operational considerations, maintenance requirements, aesthetics, and of course cost. If you start with these three major areas, the choice of an ESD flooring that meets EPA standards becomes clearer.
Thomas Ricciardelli is the president of SelecTech Inc., a manufacturer of flooring products from recycled materials. www.selectech.com