Molded or extruded rubber products must withstand the effects of ozone cracking and outdoor weathering for satisfactory use. The test provides conditions to find the accelerated aging of the rubber and estimation of the life time for rubber and molded material. This data helps the manufacturer to estimate a reasonable warranty time for the customers.
Sample preparation is very important for these tests. Samples first should be conditioned at room temperature for 2-3 days and then they can be exposed to ozone. During the test, homogeneous ozone concentrations should be created inside the chamber. All part of the samples should be exposed to the ozone. Temperature inside the chamber should be controlled. Humidity of the chamber also should be recorded. The exposure time depends on the agreement between the seller and purchaser but 1-3 days tests are common. The common partial pressure of the ozone during the test are 100mPa and 50 mPa. Ozone test levels can change based on the agreement between the purchaser and the seller.
Crack size is also important. The standard is under 23 magnification there should be a specific crack size. In ASTM D1149 method B, there should not be any crack size.
Please contact us if you need to test your samples based on ASTM standards.
People will often call us asking how to measure ozone levels in their houses. A couple years ago, we wrote an article about using ozone badges to measure ozone levels in houses. While ozone badges are a great option, today we are going to look at using an ozone monitor for the same purpose.
There are many different ozone monitors that would work well to measure ozone in your house. We are going to take a look at the EZ-1X. The EZ-1X is great for homeowners and cleaning companies because it measures up to .14 ppm of ozone and is inexpensive.
Once you have obtained an EZ-1X, you will need to follow these steps to ensure accurate readings:
Plug in the EZ-1X to a wall outlet and let it warm up for 15 minutes. The monitor won’t give accurate readings until it has warmed up for 15 minutes.
While you are waiting 15 minutes, read the manual! These instructions are good, but the manual has many more details. Besides, it’s only 2 pages, you can read that in 10 minutes!
Decide where in your house to measure ozone. The best place to measure is at breathing level; ozone is heavier than air and will sink to the floor. This means that the concentrations of ozone can be much higher near the floor than they are at breathing level. If you are measuring for safety purposes, it is best to take measurements at breathing level.
Place the EZ-1X at the location where you have decided to measure the ozone. Leave the monitor in one location for a couple minutes to ensure accurate readings.
Look at the lights on the monitor and record the reading. Red indicates ozone levels that are too high for humans to remain in the area.
It is a good idea to get a measurements from a couple other locations in the house since concentrations can vary from location to location.
The colored lights make it easy to read the ozone level at a glance.
Here are a couple things to keep in mind:
If the ozone level is at or above .14 ppm, you should leave the area immediately. Since the EZ-1X only reads up to .14 ppm, the ozone level could be much higher and dangerous. See our page on Ozone Safety for more information.
Your nose is not an ozone monitor! Although you can smell ozone, your nose gets less sensitive to ozone over time and is not a good way to check the levels of ozone.
Other gasses can interfere with the EZ-1X. This includes chlorine and vapors from solvents. If you need to measure ozone while these gasses are present, you will need a UV ozone analyzer.
To sum up our ongoing series comparing ozone detection technologies, here is a full list that summarizes the advantages, disadvantages and common applications for various ozone monitor technologies. For further information, visit the Ozone Monitor Technology Comparison page on our website and then browse our product pages for details!
Electrochemical Ozone Sensors
An electrochemical ozone sensor uses a porous membrane that allows ozone gas to diffuse into a cell containing electrolyte and electrodes. When ozone comes into contact with the electrolyte, a change in electrochemical potential occurs between the electrodes causing electrons to flow.
In “zero air”, little or no electron flow occurs. As the presence of ozone increases, the electrical signal increases proportionally. The monitor interprets this signal and displays the ozone concentration in PPM (parts per million).
Good repeatability and accuracy
Very quick response time (1-2 seconds)
Long battery life
Can measure ozone accurately up to 20 ppm
Moderate resistance to interference
Humidity can affect sensor
Sensitive to EMF/RFI
Limited sensor life (12-18months), even if in storage.
Less accuracy at low ozone levels (below 0.1 ppm)
Personnel (portable) safety monitoring (esp. long shifts)
Ozone Leak Detection
Stationary ozone monitoring
Ozone Monitoring & Control
Semiconductor-Based Ozone Sensors
Heated Metal Oxide Sensor Cell (HMOS)
Gas Sensitive Semiconductor (GSS)
A heated metal oxide semiconductor (HMOS) sensor works by heating a small substrate to high temperature (around 300-deg F / 149-deg C). At this temperature, the substrate is very sensitive to ozone and exhibits a change in resistance that is proportional to to the amount of ozone which contacts its surface. The circuitry of the monitor interprets this change in resistance and displays the corresponding ozone level on the display as either PPM or PPB.
Very responsive to low levels of ozone ozone (below 0.1 ppm)
Slower response time to ozone (compared to electrochemical)
Very sensitive to interference
Shorter battery life due to heated sensor element
Not linear at ozone levels above 1 ppm
Ceiling Temperature threshold of 122F or less (depending on model)
The Ozone molecule has an absorption maximum at 254 nm. A UV lamp emmiting 254 nm wavelength of light is used to measure the absoption of ozone within a chamber. This is measured via a photodiode with a built in interference filter centered on 254 nm wavelength
Very accurate (within 1%)
Very linear at any ozone levels
Low ppb detection limits with accuracy
Minimal cross sensitivity to other gasses or interferences
Can read high concentrations (20% or higher)
Durable design with excellent longevity
Bench mount (no handheld)
Ozone badges are one time use cards that use a color change indicator. The indicator used is a small paper strip or circle that is oxidized in the presence of ozone.
There are three primary technologies used to monitor and measure ozone: Electrochemical cells, HMOS / GSS, and UV. Today we will be giving a brief overview of UV ozone analyzers and their use.
UV-based ozone analyzers function on the principle that ozone particles will absorb UV light with a wavelength of 254 nm. When this wavelength of UV light is created and passed through an air chamber, the amount of UV light absorbed is proportional to the amount of ozone present in that airspace. The amount of UV light absorbed in the chamber is interpreted as ozone concentration and displayed or output for our use.
There are many advantages to this technology, but the primary ones are its accuracy and stability over a wide range of ozone concentrations. Depending on the design of the instrument, a UV ozone analyzer may be able to provide reliable, stable readings for single-digit ppb concentrations of ozone. Alternately, another UV analyzer may provide high concentration readings up to 20% by weight (many thousands of ppm).
Another benefit of UV Absorption is its resistance to interference by other gases. Since the principle used is very wavelength-specific, few other gases interfere. This results in much more accurate readings, even in outdoor environments.
The most noticeable downside of UV Absorption technology is price. It is more expensive than HMOS, GSS or electrochemical technologies. For many customers, however, the reliability of UV technology compared to the risk of false readings from other monitors makes UV technology well worth the cost.
Industrial ozone control
Ozone process off-gas measurement
Semiconductor fabrication facilites
Ozone compatibility testing
Here are a few monitors offered by Ozone Solutions that utilize UV Absorption technology:
There are three primary technologies used to monitor and measure ozone: Electrochemical cells, HMOS / GSS, and UV. Today we will be giving a brief overview of Electrochemical sensors and their use.
When ozone contacts an electrochemical cell, it causes electrons to flow. This electric current varies in proportion to the amount of ozone present, so the monitor can interpret this signal as ozone concentration and display or output those values for us.
Due to their construction, electrochemical ozone monitors have several properties that make them unique. One of these is long battery life. Due to the low power consumption of their sensors, they have the longest battery life of any ozone monitoring technology.
Another benefit they share is a resistance to interference from other gases. Electrochemical cells are each built with materials that are designed to be as specific to ozone as possible. While not as good as UV technology in this regard, there are certain situations where they are a necessity.
One downside that these sensors have in common, however, is their limited sensor life. Electrochemical cells will deplete over time even while in storage, so keeping a regular replacement schedule is advised.
Portable ozone safety monitoring
Ozone monitoring & control, especially if interfering gases are a concern
Here are a few monitors offered by Ozone Solutions that utilize Electrochemical Sensor technology:
There are three primary technologies used to monitor and measure ozone: Electrochemical cells, HMOS / GSS, and UV. Today we will be giving a brief overview of HMOS / GSS sensors and their use.
HMOS (Heated Metal-Oxide Semiconductor) and GSS (Gas-Sensitive Semiconductor) based ozone sensors function by heating a small semiconductor substrate to high temperatures, causing it to be extremely sensitive to ozone. This is seen as a change in the resistance of the material, which is measured by the circuitry, interpreted as ozone, and either displayed or output for our use.
One of the key benefits of this sensor technology is that it is very inexpensive, allowing widespread adoption at many facilities. It is commonly used for both portables and wall-mount ozone monitors.
Another advantage to semiconductor-based sensors is their solid ozone response below 0.1 ppm. This allows them to be used in many ambient ozone safety scenarios, with a display resolution as fine-grained as 1 ppb. While not as stable or sensitive as UV-based ozone analyzers in this range, they are worth consideration for ambient safety scenarios where low ozone concentrations are expected.
Disadvantages include a short battery life (due to the continuous heating of the sensor) and the extended warm-up time that the sensor requires.
Ambient ozone safety monitoring
Ozone control scenarios, especially at levels below 0.1 ppm
Here are a few monitors offered by Ozone Solutions that utilize HMOS Sensor technology:
Occasionally our customers will need to measure levels of ozone greater than 3 ppm with their K-7404 Dissolved Ozone Test Kit. To do so, the sample can be diluted, allowing up to 6 ppm of indication.
The video and instructions here, in combination with the standard kit instructions, will allow you to do this in the most effective way possible.
1) Add 5 drops of A-7400 Activator Solution to the sample cup.
2) Add 12.5 mL of distilled water to the sample cup.
3) Add enough sample to the cup to bring the volume to the 25 mL mark
4) Snap the ampoule in the cup, and continue with the standard instructions.
Find the result indicated by your comparator and multiply that value by 2.
The number you get is your dissolved ozone concentration.
For further details about the K-7404 dissolved ozone test kit, or our other dissolved ozone monitors, please visit the links below!
Ozone Solutions has created a new video that illustrates proper use of our K-7404 Dissolved Ozone Test Kit. If you are curious about how these vacu-vial test kits work, this video will walk you through the process and show you the simple steps involved.
For more information about the K-7404 or any of our other dissolved ozone test kits, visit the product pages here!
One question we commonly receive is “Do your ozone monitor calibrations come with NIST traceable calibration certificates?” The answer is simply yes, our ozone monitor calibrations (and our ozone analyzer calibrations) do indeed come with NIST traceable calibration certificates.
Another question we receive somewhat less often is, “What IS a NIST traceable calibration?” We will discuss that topic briefly here.
To start out, NIST is the National Institute of Standards and Technology, which was founded in 1901 and is responsible for governing national standards of measure here in the United States (among other things). From the NIST website:
NIST is responsible for developing, maintaining and disseminating national standards – realizations of the SI – for the basic measurement quantities, and for many derived measurement quantities. NIST is also responsible for assessing the measurement uncertainties associated with the values assigned to these measurement standards. As such, the concept of measurement traceability is central to NIST’s mission.
Traceability, then, refers to your ability to follow documented calibration paperwork in an unbroken chain all the way back to the official NIST standard itself. The calibration certificate for any ozone monitor should list the source that it was calibrated against. If you obtain the calibration sheet for that source, you will again find the source that it was calibrated against and so on and so on. If you follow the chain, you will eventually find a calibration source that was calibrated at NIST itself.
Note that with each “hop” of the traceability chain there is some amount of uncertainty that is added to the resulting calibration. The more “hops” from NIST, the larger the uncertainty. The length of the traceability chain will give you an indication of how much uncertainty you may encounter as compared to the NIST standard.
What is the benefit of all this paperwork? One standard. The NIST ozone standard is deemed to provide the one, true standard for an ozone measurement. As consumers, if you purchase an ozone monitor that has a NIST traceable calibration certificate, you can rest assured that the measurements indicated by your ozone monitor should be comparable to a true ozone measurement.
When you purchase a piece of ozone detection equipment from Ozone Solutions, or when you have ozone monitors calibrated at Ozone Solutions, you will receive a NIST traceable calibration certificate which indicates our dedication to quality ozone detection products and quality service. Ozone Solutions prides itself in having a short NIST traceability chain, minimizing uncertainty to provide the most accurate ozone readings possible.
For further information on our calibration process, please refer to the following links:
Ozone’s affect on Microarray systems has been documented by both researchers and equipment manufacturers during the past decade. The consensus is that ozone in concentrations as low as 5-10 ppb can degrade cy5 sufficiently within a few minutes to adversely affect a sample. This means that the level of ozone commonly encountered in outdoor environments, especially in urban areas, is far beyond the level necessary to affect microarray samples. Likewise, indoor ozone is often too high since those ozone levels will regularly track the fluctuations in outdoor ozone, though to a somewhat lesser degree. The result is that 2 steps are required for any lab to avoid ozone degradation of cy5:
Filtration of lab air through carbon filters (or other ozone destruct media) to reduce ozone levels
Monitoring of ozone to ensure the levels stay within the recommended range of 2 ppb or less.
Ozone Solutions recently put up a new application page which focuses on the intricacies and caveats of Step #2 – Ozone Monitoring for Microarray Applications. To summarize that page briefly, it is tempting for labs to purchase sensor-based ozone monitors (monitors utilizing HMOS, GSS or electrochemical based sensors) due to their low price points and readings that cover the 0 – 0.1 ppm range. There are dangers to using these technologies for microarray applications, however. Customers should consider the following points with regards to sensor-based ozone monitors:
Their Design Intent
The possibility of Interference with ozone readings
Decreasing Ozone Response over time
Once these factors have been considered, the evidence strongly points to UV-based Ozone Analyzers as the best method of monitoring ozone levels for microarray use. Their reliability, accuracy at low-ppb ozone levels, and stable readings over time all lend themselves quite well toward this purpose – and can prevent a lot of trouble (spoiled samples) during the life of the equipment. Prior research into the effects of ozone on microarrays seems to agree with this conclusion, with UV analyzers being the equipment cited in these studies. Click through to our article to find out further details about the use of UV-based ozone analyzers for microarray applications.
This Ozone Journal is a blog managed by the employees of Ozone Solutions. The purpose of this blog is to inform and educate the readers about the world of Ozone, provide news about the ozone industry, and have an easy opportunity to inform about new ozone products.
Check back often, ask questions, and let us know if there is anything you would like to hear about.
What is ozone?
Ozone is an oxidant. Ozone (O3), sometimes called “activated oxygen", or "triatomic oxygen", contains three atoms of oxygen rather than the two atoms we normally breathe. Ozone is the second most powerful oxidant in the world and can be used to destroy bacteria, viruses, and odors.
Ozone is a gas at ambient temperatures and pressures with a strong odor. Ozone can be produced as a gas from oxygen in air, or concentrated oxygen. This ozone gas can be dissolved into water, or used in the gas phase for a variety of applications discussed in this Journal.