Joel
For more information, please visit Yourun Synthetic Material.
Why does my new furniture give me headaches? Why does the zero VOC paint I just applied smell so bad and irritate my throat? How can I know for sure if a product will be safe for my newborn child? Why can’t I research the ingredients of building materials like we do with food?
This article goes into great detail about many of the hazardous chemicals used in materials used to remodel or build a home or office. The answers to these questions are critical to your health and are based on my 32 years of researching, troubleshooting, and selling healthier building materials to customers who exhibit a range of environmental issues such as asthma, allergy and chemical sensitivity.
Our goal here is to help you identify and avoid hazardous VOCs so you don’t needlessly expose yourself or your loved ones. Neither the manufacturers nor our government takes responsibility for telling you the whole story about them.
What are VOCs?
Typical Names of VOCs:
Handy Points of Reference:
Where are VOCs Found in your Home?
According to the EPA: concentrations of VOCs are consistently higher indoors (up to ten times higher) than outdoors. Although you can’t see them, there are thousands of VOCs typically found in common household and personal care products such as:
Are VOCs Harmful?
When breathed, VOCs can irritate your eyes, nose and throat. They can also give you headaches, trigger asthma attacks and even cause a host of other respiratory diseases, damage to the liver, kidney, central nervous system, and even cancer. However…
Not All VOCs are Harmful.
Some VOCs are benign. For example, when baking bread at 174° F, ethanol, a VOC, is produced which actually reacts with the atmosphere and causes smog. Yep, baking bread creates VOCs, but the emissions from fresh bread are usually not harmful to humans. Other natural sources of VOC include citrus fruits, like orange and lemon which contain limonene. Pine and eucalyptus and some varieties of oak trees produce terpenoid VOCs. Perfumes and some houseplants also emit VOCs.
Unfortunately, naturally occurring VOCs are subject to the same provisions of the EPA Clean Air Act which regulates synthetically derived VOCs. For example, bakeries have been forced to add catalytic oxidizers to control the VOCs from their ovens.
How Long do VOCs Off-gas?
VOC emissions or off-gassing can occur quickly or over months and even years. How long will the off-gassing continue? It depends on:
For example: Oil-based products which typically have longer curing times often contain solvents that may emit VOCs for months and even years—especially if they are confined in a cabinet or closet with no ventilation. The same VOC can off-gas quickly if used outdoors in dry conditions with plenty of ventilation.
How are VOCs Measured?
VOCs contained in liquids and emitted into the air are measured by their concentration. These are expressed numerically as g/l (grams per liter) or as µg/m3 (micrograms per cubic meter) or as ppm and ppb (parts per million or billion). NOTE: VOCs <10 g/l are considered to be “zero”
This means that if you hire an environmental consultant to measure the VOCs in your home, they may not measure them all. And if you purchase a paint or adhesive product that says it is low or no VOC, the testing protocols used by the organization that certifies the VOCs may not evaluate all of them accurately.
How are VOCs Regulated by the Government?
The EPA does NOT regulate VOC levels inside your home. VOC laws were created only to prevent photochemical smog in the outdoor air only.
Wow! This is very disturbing. If the government is not protecting us from these chemicals, how are average citizens without the knowledge or experience able to avoid them?
Different Standards: Commercial vs. Residential Use
What makes life challenging is that acceptable levels of VOC vary depending on what organization you trust. The following organizations provide different standards and threshold limit values (TLV) for what are acceptable levels of VOCs in occupational/indoor settings
These are very broad standards that are not legally enforceable but are merely recommendations based on examinations of scientific literature. Unfortunately, these standards do not apply to residential living environments. They were designed for commercial and industrial environments!
There are no threshold limits for VOC emissions that were designed for residential use. The closest standards are based on the California Dept of Public Health (CDPH) standard for classrooms. Also, the GreenGuard certification program has developed its own standard for what is safe and what is not. Most of these standards are based on laboratory test results but they only test for 36 VOCs and only after 10-14 days.
5 Things that Impact the Concentration of VOCs in your Home
How to Reduce VOC Off-gassing in your Home
Next Best Options
How to Research a Product’s VOCs BEFORE you Purchase
Unfortunately, researching the ingredients of any building material is not like reading the label of your favorite food. The only information is usually found online in the form of a Material Safety Data Sheet (SDS or MSDS) provided by the manufacturer. These documents are not easy to read unless you have a PhD in chemistry or toxicology.
The quantity and type of VOC emissions have become one of the primary metrics used to rate the safety of building materials. However, researching a building material only by the quantity of VOC emissions can be very misleading. Why? Because VOCs are only one class of hazardous indoor air pollutants. Many others may be even more dangerous such as: biocides, fungicides, lead, asbestos, radon, PFAS, BPA, crystalline silicates, sawdust, etc. These can leach out and be absorbed through the skin, ingested, or breathed in.
A MSDS may be useful as a starting point, but it won’t tell you the whole story. That’s because the requirements for posting were designed for employers to give to their employees and were never intended for consumer use. MSDS are voluntarily created by the manufacturers and are not checked for accuracy by any government agency. The information included is not guaranteed to be accurate, complete, or up to date. Proprietary ingredients are not listed here either.
As a consequence, there may be dangerous chemicals that are unknown or not tested by the manufacturer. Also, the threshold limits of exposure are typically for individual chemicals created in a laboratory, nor are they tested on animals. They are not based on the synergy of all the chemicals used nor tested on humans. At best, what you learn from an MSDS is only about a few known hazards that the manufacturer agrees to reveal. Learn how to read a Material Safety Data Sheet here.
Advice for Product Choices
Where and When to Purchase?
We also recommend that you educate your contractor and his/her subcontractors about your special needs and post a list in a visible space of products that are acceptable and products that are not acceptable.
Where Can You Learn More on These Subjects?
Contact us to discuss your requirements of Low VOC Catalyst. Our experienced sales team can help you identify the options that best suit your needs.
Want more info? Read here: IAQ and your health; A deeper look at formaldehyde and VOCs.
Here’s the list of hazardous air pollutants from the EPA. Bear in mind that just because a chemical shows up on this list does not always mean it is harmful to you. It depends on the concentration and your personal sensitivity to it. Always test first before using.
Here is another much larger list from the International Living Institute. It’s called the RED LIST which contains the worst in class chemicals in the building industry. The chemicals contained are not all VOCs, but are capable of polluting the environment, bio-accumulating up the food chain until they reach toxic concentrations, and are harmful to factory workers and humans in construction.
Here is a list used in California’s Proposition 65. The list contains a wide range of naturally occurring and synthetic chemicals that are known to cause cancer or birth defects or other reproductive harm. Not all are VOCs. These chemicals include additives or ingredients in pesticides, common household products, food, drugs, dyes, or solvents.
In sum: building or remodeling with VOCs is like trying to avoid sugar or salt in your diet. It’s almost impossible to completely eliminate them so you have to make intelligent choices and reduce where you can. We know how challenging this research can be which is why we created Green Building Supply to make your job much easier. We may not have all the answers, but after 32 years of experience, we certainly can help point you in the right direction and make your experience of purchasing easier and healthier.
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Related Articles
by Green Building Supply's
Joel Hirshberg
Copyright © May 21,
Mohit Uberoi
MEGTEC Systems
99-896
Mohit Uberoi
Vice President, Industrial & Environmental Products
MEGTEC Systems
Steven E. Rach
Regional Sales Manager, Industrial & Environmental Products
MEGTEC Systems
ABSTRACT
Catalytic oxidizers have been used to reduce VOC emissions from various industries including printing, chemical, paint, coatings, etc. A catalytic oxidizer uses a catalyst to reduce the operating temperature for combustion to approximately 600º F, which is substantially lower than thermal oxidation unit. Title V requirements have renewed the debate on the best methods to assure compliance of catalytic oxidizers, with some suggesting the need for continuous emission monitoring equipment. This paper will discuss the various aspects of catalytic oxidation and consider options such as monitoring inlet/outlet temperatures, delta T across the catalyst, periodic laboratory testing of catalyst samples, and preventive maintenance procedures as means of assuring continuous compliance.
INTRODUCTION
Federal and state environmental regulations are requiring higher destruction and improved capture of Volatile Organic Compounds (VOC). Title V requirements may also increase the need for end users of emission control equipment to demonstrate continuous compliance. With many state and local permitting authorities having begun issuing title V permits, the subject of periodic monitoring has proven to be one of the most challenging aspects of the rule. This portion of the rule, codified at title 40 of the Code of Federal Regulations (40 CFR), part 70, has been one where there have been many interpretations of this requirement. Catalytic oxidizers have long been used as reliable, cost effective solutions for VOC destruction. However, since catalytic oxidation is not an area of expertise of the majority of emission control equipment users, there have been various questions and concerns voiced about the longevity of the catalyst. In order to best address this subject, we shall review how this technology works and then how periodic monitoring under the requirements of Title V can be effectively achieved.
Catalytic oxidizers can convert VOCs to carbon dioxide and water at much lower temperatures than thermal oxidizers by using a catalyst inside the combustion chamber. This significantly reduces the need for auxiliary fuel, resulting in lower operating costs. The basic elements are a pre-heating section that is used to heat the process gas, followed by the catalyst bed and heat recovery equipment. Catalyst systems operate between 400 and 700° F. Various types of catalyst are available in the marketplace.
A typical catalyst is composed of:
Catalysts are used in two common configurations:
The basic catalytic system includes a fan to pull the air from the processes and push it through the oxidizer, a heat exchanger to preheat the exhaust stream to the oxidizer, a burner to heat the air stream up to catalyst activation temperature, and a catalyst bed to hold the catalyst in place. A typical system is schematically presented below.
With the technology having been defined, we can now address the subject of EPA requirements for periodic monitoring in a manner that is scientifically and practically sound.
US EPA provide a number of a guidance documents for periodic monitoring. For example US EPA provide the following inputs;
Section 504 of the Clean Air Act (Act) makes it clear that each title V permit must include "conditions as are necessary to assure compliance with applicable requirements of [the Act], including the requirements of the applicable implementation plan" and "inspection, entry, monitoring, compliance certification, and reporting requirements to assure compliance with the permit terms and conditions."
As US EPA further address the subject of periodic monitoring they note that this must provide a reasonable assurance of compliance with requirements applicable to the source; "The periodic monitoring process should begin by evaluating whether monitoring, including record keeping, reporting, or periodic testing, applies to the emissions unit in question under existing applicable requirements for that unit. If the already-required monitoring is sufficient to yield reliable data from the relevant time period and is representative of the source's compliance with a particular applicable requirement, then no further monitoring for that applicable requirement at that emission unit is required in the permit."
This leads us to determining what data can provide proper assurance of compliance during operation. The basis for such data as specified by EPA as including the following;
"Operational data collected during performance testing is a key element in establishing indicator ranges; however, other relevant information in establishing indicator ranges would be engineering assessments, historical data, and vendor data. The permit should also include some means of periodically verifying the continuing validity of the parameter ranges."
Here we find the guidance that allows us to determine that data to show assurance of compliance during operation. In many cases, it has been assumed that an ideal indicator of compliance for a catalytic oxidizer is the temperature increase across the catalyst bed (DT) which does provide an indication of the heat release from the VOCs being converted in the process. Unfortunately, this is an ideal indicator only for those applications where the VOC concentration is consistent. Many applications have varying VOC loading as process operational parameters vary (example is a printing press where each job has a different amount of ink applied to the web and therefore, VOC evaporation rates change). This situation becomes further complex when more than one process is being controlled by a single emission control system. Here the potential for variation in DT is even greater and using such an indicator would prove to be misleading for anyone using DT for compliance purposes.
This situation has been again addressed by US EPA in their Compliance Assurance Monitoring rule where they state that "other information such as historical monitoring data, and engineering assessments can be used in combination with parameter data collected during performance testing to establish indicator ranges that are representative of normal operating conditions. As long as changes are not made to the control device settings used during normal operation (e.g., changes to oxidizer temperature set points), the results of performance tests can be used in combination with historical monitored data collected during periods of normal operation and engineering assessments to establish indicator ranges indicative of normal operation."
A catalyst can lose its activity by loss in surface area due to sintering (exposure to a very high temperatures), or poisoning/masking by compounds such as silicone and phosphorous. To ensure that a catalytic oxidizer is meeting VOC conversion requirements, it is important that catalyst deactivation is measured, and procedures put in place to continually monitor the performance of the catalyst. There have been some issues and concerns about the best possible method of field catalyst sampling so that a representative sample could be obtained.
The single most important factor in any analysis technique is the collection of an accurate sample. If a non-representative sample is taken, the results may be skewed, and any recommendation based on these results would be biased. In most catalytic systems, air flow moves vertically from top to the bottom or horizontally from one side to another side of the bed. As the leading edge of the bed is exposed first to the process gas, any poisons in the process gas will initially deposit there. Therefore a sample taken from this part of the bed would be expected to exhibit "worst case" performance. Conversely, a sample taken from the trailing edge of the bed would be expected to exhibit "best case" performance.
In order to make a good recommendation about the status of the catalyst bed, it is important to determine the condition of the catalyst at the top, middle and bottom of the bed. Depending on the amount of catalyst in the unit, only a portion of the catalyst bed needs to be in good condition in order to meet expected clean-up levels.
A variety of sampling techniques can be used to obtain a meaningful catalyst sample. Many oxidizers contain sample cores that can simply be extracted from the catalyst bed and labeled "TOP" and "BOTTOM". The core is split into various parts in the lab to test catalyst performance at various levels. Monolith cores can be tested as is or by extracting smaller samples from the larger cores.
Typically, bead samples that arrive in sample cores are tested in two segments. The top part of the core is tested first. If it appears to be in good condition, no further testing is required. As was explained earlier, these are "worst case" beads, and if they are in good condition, the rest of the bed can be assumed to be in better condition. If however the beads do not appear to be in good condition, a second test is done on the beads in the middle of the core. A recommendation is then made based on those results. Samples can also be tested as a composite of the whole bed.
If an oxidizer does not contain sample cores, a different approach is recommended. Most bead-based oxidizers contain their catalyst in trays. Several trays are used to minimize total pressure drop. Since each tray is exposed to the same air stream, it is necessary to take samples from only one tray or bed. Three samples are taken from this one bed and put into three separate clean containers. The first sample would be catalyst from the top 1" of the bed, this sample is labeled "TOP". Without disturbing any more of the bed than is necessary, the top catalyst is moved away so that a sample of the middle can be taken. This sample is labeled "MIDDLE". Continue to carefully move catalyst away from the sample area until the bottom inch of catalyst is exposed. This third sample is taken from the last inch of the catalyst bed. It is labeled "BOTTOM". The three portions are sent in for testing in their separate containers. This approach is less rigorous than the sample core approach.
Catalyst samples brought to the laboratory are tested for VOC destruction efficiency, contamination (Si, P, Cl, etc.), and BET surface area. Conversion efficiencies obtained at various temperatures in the laboratory accurately reflect the relative activities of the samples tested compared to fresh catalyst, and compared to other catalyst in varying levels of degradation. But it doesn't equal the conversion efficiency to be expected from a unit containing this catalyst. This is due to different process conditions in the laboratory versus the field, wall effects in lab units, etc. Laboratory testing provides activity levels under standard conditions, which allows the sample to be compared to a large data base of samples tested under those same conditions. These standard conditions may not be the same as field conditions. Since process conditions in the field can vary considerably, this type of standardized testing ensures "apples to apples" comparison, and allows a better judgment call when deciding whether catalyst replacement should be considered.
BET surface area is also a measure of the performance of the catalyst. As the catalyst is exposed to high temperatures, it can sinter and lose its surface area which results in loss of catalyst activity. A loss in catalyst surface area of more than 30% could result in substantial loss in the activity of catalyst in the field.
Another indicator of catalyst life is the amount of poison or masking agents on the catalyst. Typically, in a bead catalyst, if there is more than 1.5% of the combination of silicon and phosphorous, the catalyst activity may be very low and not sufficient to meet field requirements. A catalyst supplier usually makes a recommendation as to whether the catalyst is in good condition, poor condition, borderline condition, etc. If the catalyst is in borderline, or poor condition, it is generally recommended that a stack test be performed.
It is difficult to predict the life of a catalyst. It varies depending on the operational history of the field unit, the catalyst composition, the susceptibility to poisons, etc. However, most catalyst manufacturers can compare a sample's laboratory performance with tests that have been performed in the past and determine whether there is likely to be a problem or not. While the actual field clean-up of the unit cannot be predicted, a catalyst that performs well by lab standards will perform well in a unit, provided the unit is mechanically sound. Therefore it is highly recommended that regular preventive maintenance checks be conducted to ensure the sound mechanical operation of the unit. Along with regular catalyst testing, this is an excellent and cost effective way to be sure that oxidizer performance expectations are being met.
In summation, the best method of assuring compliance of a catalytic oxidizer is to use the combination of factors noted below:
Catalytic oxidizers have been proven to meet requirement for BACT and even LAER in many industries. The lower energy usage provides an added advantage as precious energy resources are not consumed in the process of achieving air quality goals. With the development of new, improved catalyst and properly designed systems, the ability to prove compliance via periodic monitoring can be achieved in the steps noted above.
For more information, please visit bismuth catalysts.