Tag Archive | "ozone"

Monitoring Ozone (in the air) in Hatchery & Fish Farm Applications

Critical Environment Technologies Canada Inc, (CETCI) offers strategic and reliable gas detection solutions for many applications, including ozone gas detection in the aquaculture industry.

Hatcheries, fish farms and such in the aquaculture industry require clean water to maintain a high survival rate while rearing aquatic animals. Contaminated water increases the risk of infection which in turn can compromise production. A common way to disinfect water is by generating ozone on-site with an ozone generator. Ozone is a powerful bactericide and viricide that decreases the risk of infection from water borne diseases which helps maintain a high survival rate, aerates the water and leaves no undesirable residues. However, ozone is highly toxic to humans and aquatic animals at very low levels. Standards set by OSHA allow a permissible exposure level of less than 0.1 mg/L on a time-weighted average for an 8 hour work period and a maximum single exposure level of 0.3 mg/L for less than a 10 minute duration.

For human safety, the ozone concentrations in the air should be monitored in the locations that could become contaminated with ozone. A typical ozone system for a hatchery operation has an ozone generator and three chambers. The ozone generator creates ozone which is then introduced into the first tank, the counter flow diffusion chamber. Here the oxidization of dissolved matter occurs. The first ozone gas detector should be installed in the ozone generator room to monitor for potential leaks around the ozone generator and piping structures. If the gas detector were to go into alarm, it can be configured to shut off the ozone generator, stopping the production of ozone. In addition, the ventilation and make-up air fans can be triggered to come on and go off at set intervals, including when the gas detector goes into alarm. The second chamber is the reaction or contact tank where the disinfection of the water and slow chemical reactions occur. Depending on the operation setup, the second chamber may be in the ozone generator room or in another room or general area. From the contact tank, the water gets sent to the third chamber which completes the slow reactions and the majority of the residual ozone decomposes. Any undissolved or residual ozone gas is collected and vented by way of the ozone destruction process which will destroy the ozone in the gas before releasing it into the atmosphere. A second ozone gas detector should be installed near the ozone destructor to monitor the exhaust air stream to ensure the ozone destructor is operating effectively.

CETCI’s LPT-A-O3 Ozone Gas Detector offers a fixed, continuous gas monitoring solution for hatcheries, fish farms and other aquaculture operations that use ozone to clean the water. Use as a standalone system, or combine up to four ozone gas detectors with our QCC Quad Channel Controller for larger applications. Each LPT-A-O3 transmitter features an audible alarm, LCD display with real time gas readings and a programmable relay to shut down the ozone generator. When combined with a QCC Controller, three more relays are available for triggering safety events such as switching on/off ventilation fans or make-up air fans and/or activating a remote strobe/horn. More value-added features available are two analog outputs, a data logger, manual equipment ON/OFF switch, top mounted strobe, remote strobe and horn combo and remote display module that offers the ability to view the gas level readings in a separate location from the controller and transmitters.

Ozone is a very reactive gas and can quickly corrode metals and damage plastic materials. There should be regular maintenance checks of pipe fittings, gaskets and seals all along the ozone injection system. In addition to a fixed gas detection system, it is also recommended that portable handheld monitors be used to do spot checks for leaks around piping and in poorly ventilated areas. If there is an equipment malfunction, or if tubing’s and fittings leak, or too much ozone is being produced, a properly installed ozone gas detector system will alarm and shut down the ozone generator before a dangerous environment is created and the health and safety of the workers is jeopardized.


About Critical Environment Technologies Canada Inc.

Critical Environment Technologies designs and manufacturers indoor air quality and fixed gas detection systems including self-contained systems, controllers and transmitters (analog, digital and wireless). Applications include commercial HVAC, institutional, municipal and light industrial markets worldwide. Many of these applications are for vehicle exhaust, but areas of specialization include refrigeration, food processing plants, manufacturing plants, wastewater treatment plants, commercial swimming pools and many more.

For more information about our products, check out our website at www.critical-environment.com or to discuss a tailored gas detection solution for your application, contact us at 1-877-940-8741.



Eugster, Ulrich and Bruce Stanley “The Use of Ozone as a Disinfectant in Fish Hatcheries and Fish Farms.” Web.
   http://www.ozomax.com/pdf/article-seafood-hatchery.pdf [accessed 2 October 2015]
Gearheart, Michael and Steven Summerfelt “Ozone Safety in Aquaculture Systems.” Hatchery International (July/August 2007). Web.
  http://www.ozonesolutions.com/files/research/aquaculture_safety.pdf [accessed 2 October 2015]
Summerfelt, Steven T and John N. Hochheimer “Review of Ozone Processes and Applications As an Oxidizing Agent in Aquaculture.” The
  Progressive Fish-Culturist (1997) 59:94-105. Web. http://www.w-m-t.com/library/pdf/Summerfelt_paper_Review_of_Ozone.pdf [accessed 2
  October 2015]
WorkSafe BC “Ozone Safe Work Practices.” (2006) Web.
  http://www.worksafebc.com/publications/health_and_safety/by_topic/assets/pdf/ozone_bk47.pdf [accessed 2 October 2015]


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Where are the Gas Detectors in Public Swimming Pool Facilities?

Indoor swimming pools provide exercise and recreational fun for all ages. To ensure swimmers are submerged in crystal clear, sanitary water, a disinfectant maintenance program using Chlorine, or Chlorine & Ozone are commonly followed to treat the pool water. Chlorine is a powerful, corrosive disinfectant and in both gas and liquid forms it is toxic and hazardous to living beings at concentrations as low as 1 ppm. Ozone is created by exposing oxygen to a high voltage or ultraviolet radiation. It is more powerful than Chlorine and when used in conjunction with Chlorine it helps provide an odourless, clear water environment. Less Chlorine is required when Ozone is used as part of a swimming pool sanitization program.

The areas for potential gas leaks of Chlorine and Ozone are found around the equipment in the Chlorine Feed Room and the Ozone Generator Room. In a typical swimming pool application where only Chlorine is being used to disinfect the pool water, we suggest a controller or transmitter with  a display, audible alarm and relay outputs, be mounted outside the Chlorine Feed Room beside the inspection window so it can provide a visual confirmation of the gas level readings prior to entry. If there is a Chlorine leak, the controller or transmitter will alarm and trigger the relays to shut down the ventilation system until it is safe to exhaust the gas from the contaminated area, or activate the ventilation system depending on the local regulation codes. Inside the Chlorine feed room should be mounted a remote transmitter with a Chlorine sensor that provides continues monitoring for leaks and communicates with the controller outside the room. Chlorine is heavier than air and tends to collect in low-lying areas, so the gas detector inside the room should be mounted 6 inches above the floor, close to the area of a potential leak, but away from the ventilation fans and any pockets of air currents.

Similarly, in a typical swimming pool application that uses Chlorine & Ozone to disinfect the pool water, in addition to the aforementioned gas detection system for Chlorine, we suggest a similar set-up for the Ozone Generator Room. A controller with a display, audible alarm and relay outputs should be mounted outside the room to provide confirmation of the gas levels inside the room prior to entry. A remote transmitter with an Ozone sensor should be mounted inside the generator room, near the equipment and between the generator and the destructor. Pure Ozone is slightly heavier than air but does not necessarily settle to the floor. If additional reaction tanks or destructors are more than 16 ft (5 m) away from the existing sensor, an additional sensor may be required. If there is an Ozone leak, the controller will alarm and trigger relays to activate the emergency air exhaust system.

For both applications a remote visual alarm device such as a strobe should be mounted on the ceiling or wall inside the pool area to provide an additional visual alert in the event of a leak inside either room.


View Diagram


There are outside influences that affect the operation of gas detectors and the equipment with which they interface. In addition, sensors change characteristics as they age; they have a set lifespan and deteriorate over time. Regular maintenance of the gas detection system by a qualified technician is as important as a proper installation. For a newly installed system or as part of a very thorough maintenance schedule it is recommended that a bump test be done every 30 days. A bump test basically follows the same procedure as a calibration, but it normally uses less gas and requires less understanding of the intricate workings of the gas detector. A bump test tells you if the detector is malfunctioning or operating normally, if the sensors are responding to the gas as they should and if the low, mid and high alarms are being triggered. This level of upkeep allows you to determine that the daily readings are accurate and the devices are working correctly. If the system malfunctions or goes into fault, patrons and workers would be unprotected if a leak was to occur during that time.

If a bump test fails, a full calibration is required. Calibration is more time consuming than a bump test and should be done by a qualified technician. It is recommend that a full calibration be done every 6 months, regardless of the performance or type of gas detection device. Calibration is like resetting the parameters of the device, in terms of telling what it should be doing at what level. It could be compared to a reset button. As the sensors age, their sensitivity to the gas decreases. Calibration allows you to compensate for that deterioration and keep the sensor detecting the gas at the appropriate levels so that the low, mid and high alarms go off as they should.

It is important to keep a maintenance log with dates and services performed. After a full calibration, a service sticker should be place on the device indicating when the next calibration should be done.

When bump testing or calibrating a Chlorine or Ozone sensor, there are a few things to keep in mind. Both Chlorine and Ozone are considered to be one of the “sticky gases”, meaning they adhere to surfaces and as a result, decrease in concentration. During the flowing of the gas over the sensor, the gas will adhere to the inside of standard tubing and the lengthier the tubing the less gas is left to hit the sensor. Using Teflon lined tubing is recommended, as is a length of tubing no longer than 2 to 3 feet so the gas flow concentration doesn’t lessen over the distance from the gas cylinder to the sensor.

Last but not least, when calibrating a Chlorine sensor, to ensure you get true readings, it is recommended that you use a Chlorine gas generator rather than a cylinder of Chlorine gas. The stability and quality of the chlorine gas is much higher from a generator, making calibration easier and accurate.

For suggestions on gas detection systems, indoor air quality monitors and calibration, please visit www.critical-environment.com


Written by Rebecca Erickson

Ozone Safe Work Practices, 2006 ed. WorkSafe BC 
Chlorine Safe Work Practices, 2002 ed. WorkSafe BC

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Importance of Air & Water Testing in Indoor Pools

Have you ever wondered why your eyes hurt or why you have a cough after swimming at an indoor pool? We all assume that it’s from too much chlorine in the pool but that is false!

If the pool staff doesn’t regularly test and monitor both the air and water indoors, the environment becomes very toxic and unsafe to everyone in the building. Water is an essential ingredient for all life as we know it, and unfortunately that means that many different organisms thrive in untreated pool water.

Untreated pool water rapidly deteriorates and cause many irritants to all users and employees; such as stinging eyes, nasal irritation, coughing, wheezing, e-coli, guardia, and asthma. These toxins (by products) are created when chlorine binds with sweat, urine and other wastes from swimmers. As the concentration increases in the water, these toxins then move into the surrounding air. Without enough fresh air flow over the water, the pool & air will become saturated with these toxins.

If you or your child plans on using an indoor pool, it’s a very good idea to shower with soap before you enter the water and after. With children you should check often if they need to use the bathroom and never change your child’s diaper on the pool side.

The most common disinfectant used in pools is Chlorine and is available as a pure gas, mixed in a granular powder or liquid form. Chlorine is an odorless gas but the chloramines’ compounds resulting from its interaction with ammonia or organic contaminants have the strong odor typically associated with chlorinated pools.

This is why it’s so important to test the air & water at indoor pools. Some indoor pools will use special UV ultra violet light or ozone for treatments in addition to chlorine disinfection to improve air & water quality. Most pools will monitor all levels for any chemical used to treat & maintain toxins to ensure the health and safety for all users and employees. Most indoor pools will have a ventilation system in place; the key is to make sure there is lots of fresh air flow into the pool areas. In order to monitor the ventilation, pools will install fixed gas detectors to monitor ammonia, chlorine and / or ozone depending what is used as a treatment.

For suggestions on fixed gas detectors, please visit www.critical-environment.com.

Written by: Ambur Vilac & Teresa Kouch



Barlowe, Barrett. “What Are the Dangers of Indoor Swimming Pools?” Livestrong.com. 14 June 2011. Web. 06 March 2012. <http://www.livestrong.com/article/258007-what-are-the-dangers-of-indoor-swimming-pools/#ixzz1ekIDtD2Z>.

Barlowe, Barrett. “Swimming Pool Chemical Treatment.” Livestrong.com. 14 June 2011. Web. 06 March 2012. <http://www.livestrong.com/article/231589-swimming-pool-chemical-treatment/#ixzz1ekJgTyY6>.

“Irritants (Chloramines) & Indoor Pool Air Quality.” Centers for Disease Control and Prevention. 12 April 2010. Web. 06 March 2012. <http://www.cdc.gov/healthywater/swimming/pools/irritants-indoor-pool-air-quality.html>.

“Leak Detection on Indoor Swimming Pool in Essex.” Professional Swimming Pools. 20 January 2012. Web. 06 March 2012. <http://www.professionalswimmingpools.com/2012/01/leak-detection-on-indoor-swimming-pool-in-essex>.

“The Hazards of Swimming Pool Chemicals.” Professional Swimming Pools. 2010. Web. 06 March 2012. <http://www.professionalswimmingpools.com/psp-services/members-area/pool-chemicals/the-hazards-of-swimming-pool-chemicals>.

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Gas Detectors

CETCI gas detectors are used to detect many different gases. Some of the most common are Carbon Monoxide, Carbon Dioxide, Nitrogen Dioxide, Nitric Oxide, Ammonia, Chlorine, Ozone, Combustible Gases like Methane and Propane, Oxygen, Refrigerants and more.

IAQ Monitors

The YES Series of IAQ Monitors are essential for those responsible for conducting Indoor Air Quality (IAQ) Investigations. These instruments are specifically designed to measure and record the quality of indoor air in offices, buildings, homes, schools, parking garages, ice rinks, etc.