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Solvent Printers and Air Quality Control
By Larry Miller, Vice President, Island Clean Air
As the printing world has evolved, so too has the advent of the wide-format, solvent-based printing system. Printing operations of all sizes recognize the value of adding these types of printing systems to their production lineups, enabling them to offer new and old customers alike a wider range of printed products.
Vehicle wraps and outdoor signage, just to name two, are rapidly expanding marketplaces, and with that comes the continued reliance on solvent-based printers for providing prints that will stand up to the sometimes extreme conditions that mother nature can throw at us. For all those who have hypothesized the emergence of the UV-flatbed printer would displace the need for the solvent-based printer, you have underestimated the strength of the solvent based printer.
And if sales volumes of current models, as well as the introduction of new brand names are any indication of the strength of the market place, solvent printers are here to stay.
It is no secret that shops running wide-format, solvent-based printers experience a level of fumes and odors that can cause health concerns and discomfort for employees and customers. Many shop owners describe themselves as desensitized to the smells, but often concede that customers entering their store react surprised and respond with, “How can you work all day with that smell?”
As well, new employees will complain of headaches, dry mouth, and sinus trouble until they eventually become desensitized, if not ill to the point of needing medical intervention, or simply quitting because of the hostile working environment.
For years, it has been accepted these operating conditions are par for the course and normal, but we have come to a turning point where these fumes and odors are more than just a nuisance. They pose real health concerns.
Whether you are running an eco-solvent printer, a wide-format printer (up to 3 meters or 9.8 feet wide) or grand-format printer (more than 3 meters or 9.8 feet wide), these concerns are dangerously real and present.
Therefore, shop owners need to be properly educated on the effects of exposure to these fumes and odors, and preventative measures needed to provide employees with a safe and healthy working environment. The shop owner must not only protect his or her employees’ health, but protect the business from liability.
It is important to note that just because there is a really bad fume or smell in a working environment, it doesn’t necessarily mean there are hazardous contaminants present. But just because you can’t smell something bad doesn’t necessarily mean there aren’t hazardous contaminants present.
While often the two go hand-in-hand — and the presence of one can indicate presence of the other — shop owners should not assume they are both present or not. Providing a safe and healthy environment is achievable. But before we can address the solutions for reducing health concerns caused by overexposure to airborne contaminants, we need to have a better understanding about the problem.
The process of solvent-based printing is simple: A solvent component mixes with the ink, carries the ink to the media and is printed on the same media. The solvent then evaporates, leaving the ink behind to produce a print. This is where the problem begins. The evaporated solvent product has been deemed hazardous to people when exposed to high-concentration levels.
The fumes and odors you smell are called “hazardous indoor vapors.” These vapors are regulated in the United States by the Occupational Safety & Health Administration (OSHA). For many of the chemicals used in solvent printers, exposure limits have been set as low as 20 parts per million (ppm). Often information on the permissible exposure limits can be found in the ink’s material safety data sheet, which should be provided by the dealer or manufacturer when you purchase a solvent-based printer.
The permissible exposure limit of any given chemical is important for shop owners to know. If an employee becomes ill or suffers health problems as a consequence of overexposure to hazardous indoor vapor, the shop owner can be held liable for medical expenses, workers’ compensation claims and non-compliance fines from OSHA.
Understanding hazardous indoor vapor, ppm and permissible exposure limits is a complicated process that involves lengthy mathematical equations. It can be too much to expect the average shop owner to know all of the particular elements that can come into play. Furthermore, simply knowing the allowable exposure limit doesn’t tell us if a shop environment is compliant or not. The human senses can detect hazardous indoor vapors, but cannot discern the level at which they are present.
To know the level of hazardous indoor vapor that these machines produce, indoor air quality testing must be done. I have contacted many of the printer manufacturers directly to ask for the level of hazardous indoor vapors produced by their printers.
The typical answer was “there are too many variables to determine what concentration level may or may not be present when our printer is running. It is ultimately the responsibility of the shop owner to ensure that he or she provides a safe and compliant working environment for his or her employees.”
As such, the printer manufacturers have been able to pass responsibility regarding hazardous indoor vapor exposure to the end user. And while the manufacturer may be correct in its declaration, this unfortunately doesn’t help the end user establish what may or may not be needed to provide a clean and healthy working environment.
In between the manufacturer and the end user lies the dealer and most quality dealers will take the time to educate the end user about the need for adequate air filtration when employing a solvent-based printer. They’ll also offer proven and accepted solutions so the end user can make the best possible decision on how to provide his or her employees with the cleanest and safest working environment.
These dealers have taken the time and energy to educate themselves on available solutions. As an end user, I recommend that you utilize their knowledge and expertise on this issue. In fact, I believe that a dealer should not sell a solvent-based printer without offering an air-filtration system with it, and taking the time to explain to customers why the system is required.
Having said all of that, it is impractical and costly for end users to hire an indoor air-quality testing company to make sure they remain compliant, or measure if filtration is even necessary. Realizing this hurdle to end users, Island Clean Air Inc. (Vancouver, British Columbia, Canada) contracted an independent California, state-certified air testing company to measure the concentration level for some of the most common printers on the market today. The results were surprising.
Each test was conducted under what was considered an average operating environment of a room that was 100 square feet [3-m-by-3-m (10-foot-by-10-foot)] to 400 square feet [6-m-by-6-m (20-foot-by-20-foot)] in size. The printers were run at average print speeds on full-size media with a full gamut of colors.
Each printer’s production speed was dependent upon the overall capacities of the individual printer. Tested printers included the HP Designjet 9000s, Colorspan Gator 72s, Mimaki JV3-160, and the Mimaki JV5-160. The tests were conducted at various locations on different days to avoid cross-contamination and ensure results were objective.
For initial testing, no air filtration or ventilation was employed. It was simply the printer running in a sealed room. Interestingly, each printer in its tested room size surpassed the exposure limit within 30 minutes of print operation, with a measured range of 20 ppm to 200 ppm, depending on which printer was tested.
As production went past the 30-minute mark, this number continued to increase. Remember, the exposure limit can be as low as 20 ppm.
These tests conclusively show wide-format, solvent-based printers are capable of creating an environment with unacceptable exposure limits. Therefore, shop owners can conclude that if you are running a wide-format, solvent-based printer, you must provide some method of filtration or ventilation to ensure your employees are not working in an unsafe environment.
What shop owners decide to provide for filtration/ventilation is their own prerogative, and debatable among air-filtration system manufacturers. Here are four available methods of hazardous indoor vapor removal, with analysis on their pros and cons.
Exhaust Ventilation: This method usually comes in the form of either running duct work outside of the room (exhausting directly out of the building), or a ceiling-hanging filtration unit (the most widely recognized method, even though it is probably the least effective at removing hazardous vapor from a room).
One drawback of these systems is hazardous indoor vapors are typically heavier than air, and hard to be carried by air movement alone. All air-filtration systems have a capture zone, which is the radius around them that contaminants will be sucked into the system and removed from the environment.
These systems have some effect on the overall air quality. Unfortunately, little of the hazardous indoor vapor will drift into the capture zone and be removed from the environment. This could result in an environment that has a higher than allowable exposure limit.
Exhaust ventilation systems can be costly and bothersome to maintain, and the Environmental Protection Agency (EPA) does not want these harmful contaminants released into the environment. This type of ventilation also often requires special electrical hookups and building permits for installation. Furthermore, fixed systems can limit your ability to rearrange your shop space or add more equipment as your needs change.
Source-Capture System: These systems usually come as a box with hoses that attach directly to the printer and draw in hazardous indoor vapor from the printer, preventing them from escaping into the atmosphere. This proactive method can be more effective than the exhaust ventilation system, but also has several drawbacks.
While it does keep a large percentage of hazardous indoor vapors from getting into the air, it cannot capture 100 percent of the vapors produced by the printer. This is because off-gassing occurs from many points on the printer.
Likewise, as prints roll off of a printer, they off-gas, and will continue to off-gas when placed on drying racks for a long period of time. Once the hazardous indoor vapors are out in the air, these systems are not able to remove them.
Furthermore, once the printer is shut off, so is the source-capture system. Any hazardous indoor vapors not already processed through the system would escape into the air. The debate with these systems is if the percentage of removed hazardous indoor vapors is enough to keep the accumulating level in a production room below the OSHA exposure limits.
In a test that utilized a leading brand source-capture system on a popular solvent based printer, the exposure limit was exceeded as quickly as 30 minutes of printer operation. While it did keep the vapor level in the room considerably lower than with no filtration, the source-capture system did not seem to be able to remove enough hazards to remain below the exposure limits.
Often, shops are required to provide additional air filtration when using a source-capture system. Other issues include expensive consumables, a unit size that takes up production floor space and special electrical requirements.
Ambient Air Filtration: These systems are usually free-standing units that draw air in through a filtration system, and return the clean air into the room through its exhaust outlet. The key to these units working effectively is that they have enough air movement to circulate all of the air in the room, ensuring that all of the hazardous indoor vapors are given a chance to pass through the unit’s filters.
A small device may not move enough air to get all of the vapors into its filtration system. Another drawback is that the system takes up considerable floor space, similar to the source-capture system. But ambient air filtration units can be more easily moved around in the production room.
This method also is a reactive approach to removing hazardous indoor vapor, since 100 percent of the vapors end up escaping into the air before the device can remove them. However, if an adequate ambient air-filtration device is employed properly, it can keep the exposure limits in a printer room below the acceptable limits.
The key here is making sure you use an adequately sized unit for your environment. Furthermore, this type of unit can be left running 24 hours a day and will continue to remove hazardous indoor vapors created during drying times.
On the ambient air-filtration unit tested, the consumable levels were considerably lower than those of the source-capture system (standard 110v electrical power was required). This method has proven to be more effective than exhaust ventilation systems or source-capture systems alone.
Source Capture & Ambient Air Filtration: This type of system acts as a dual-purpose unit, and is the most effective of all the options available. It will hook directly to the printer to remove hazardous indoor vapors directly as a source-capture system, and also circulate and clean hazardous indoor vapor from the air.
This device appears to be the most viable solution for keeping hazardous indoor vapor levels to a minimum, and well below the exposure limits. By acting in a proactive manner to remove vapors directly from the printer, the hazard concentration allowed to escape into the air is considerably lower than if you just used an ambient air-filtration system.
Also, by circulating and cleaning the atmosphere in the room, any hazardous indoor vapor not removed by the source-capture action — or caused during off-gassing and drying — is removed in a short time frame, ensuring your shop remains OSHA compliant. Testing concluded that with this dual-purpose, air-filtration system in place, the hazardous indoor vapor levels in a facility area measured well below the exposure limits.
It is important to recognize that not all printers have the ability to hook up a source-capture system. While most manufacturers recognize the need to provide exhaust ports on their printers, many printers are still free-standing units with no hook-up options available.
For those systems that do not have any pre-existing exhaust ports, an adequately sized ambient air-filtration system would be the most effective method for ensuring OSHA compliance.
There are many factors that will determine if, and at what level, filtration is required:
Utilization of a solvent-based printer can be a very effective tool for any printing operation to expand the products and services they offer, contributing to the operation’s overall long-term success. But this effective tool comes with risks that should not to be feared. They should be recognized and neutralized so that the printer operator can function in a healthy and safe environment.
This article appeared in the SGIA Journal, 4th Quarter 2007 Issue and is reprinted with permission. Copyright 2007 Specialty Graphic Imaging Association (www.sgia.org). All Rights Reserved.
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